Expertddx: Brain and spine

ii

Anne G. Osborn, MD, FACR

Kevin R. Moore, MD

Distinguished Professor of Radiology William H. and Patricia W. Child Presidential Endowed Chair in Radiology University of Utah School of Medicine Salt Lake City, Utah

Pediatric Radiologist and euroradiologist Primary Children's Medical Center Department of Medical Imaging Salt Lake City, Utah

Jeffrey S. Ross, MD Neuroradiology Barrow eurologicallnstitute St. Joseph's Hospital Phoenix, Arizona

Lubdha M. Shah, MD Assistant Professor of Radiology University of Utah School of Medicine Salt Lake City, Utah

Miral D. Jhaveri, MD Karen L. Salzman, MD Associate Professor of Radiology Division of Neuroradiology University of Utah School of Medicine Salt Lake City, Utah

Assistant Professor Department of Diagnostic Radiology & Nuclear Medicine Rush University Medical Center Chicago, Illinois

Bronwyn E. Hamilton, MD Julia Crim, MD Chief of Musculoskeletal Radiology Professor of Radiology University of Utah School of Medicine Salt Lake City, Utah

Bryson Borg, MD Chief of Neuroradiology, MagnetIC Resonance Imaging Keesler Medical Center Keesler Air Force Base,Mississippi

Assistant Professor of Radiology Oregon Health & Science University Portland, Oregon

Susan I. Blaser, MD, FRCPC Staff euroradiologist The Hospital for Sick Children Associate Professor, Neuroradiology University of Toronto Ontario, Canada

Gregory L. Katzman, MD, MBA Professor and Chairman, Radiology University of Texas Medical Branch lohn Sealy Distinguished Endowed Chair of Radiology Galveston, Texas

AMIRSYS Names you know. Content you trust.

iii

.-

m ••

parietal o Fat density, signal • Epidermal Inclusion Cyst o Location similar to dermoid cyst o Fluid density, signal • Venolymphatic Malformations o Multiseptate cystic masses ± intracystic hemorrhage/fluid levels o ± Phleboliths (signal voids) • Neurofibromatosis Type 1 o Plexiform neurofibroma unencapsulated, infiltrating • Langerhans Cell Histiocytosis o "Punched-out" skull lesion without reactive sclerosis o ± Enhancing soft tissue mass

Lipoma

I 1 4

Axial NECT shows a posl-lraumauc acute hyperdense subgaleal hematoma not confined by sutures ~ as well as an epidural hematoma

=.

Axial NECT shows a homogeneous fat density lipoma (;8 in the frontal scalp.

,.-

SCALP MASS

(Jl

c: Cl

::l

Co

..,

OJ

Sebaceous Cyst

Metastases, Skull

Cl

(Left) Axial NECT shows a well-defined fluid density sebaceous cyst [;g in the subcutaneous fat of the occipital scalp. (Right) Axial T1 C+ MR shows a destructive metastasis &:I centered in diploic space that destroys both inner & oUler tables and extends both medially into epidural space & laterally into subgaleal space.

Dermoid

Cyst

::l (Jl ()

0> "0 (Jl

""c:

Basal Cell Carcinoma (Left) Axial NECT shows a

=

well-circumscribed,

oval

lesion within the subcutaneous tissues near the right orbit with density similar to that of the

subcutaneous rat, typical or a dermoid cyst. (Right) Coronal CECT shows an enhancing soft tissue mass ~

with superficial

ulceration

P.:;. On

excisional biopsy, this proved to be a basal cell

Neurofibromatosis

Type 1

carcinoma.

The underlying

calvarium

was not involved.

Langerhans Cell Histiocytosis (Left) Axial T2WI FS MR in patient with neurofibromatosis type 7 and a scalp mass shows the infiltrating "whorlsl! of tumor that are typical of

=

plexiform

neurofibroma.

(RighI) Axial CECT shows a lytic skulliesioll ~ in a child with an associated large enhancing scalp mass typical of Langerhans cell

a

histiocytosis.

I 1 5

"HAIR ON END"

OJ

-'"

(f)

0-

ro ()

DIFFERENTIAL DIAGNOSIS

c: nl

•... llJ "0

c: nl

• Expanded diploic space Thalassemia • Most severe in thalassemia major o Sickle Cell Disease • 5% of radiographs show "hair on end" • Hemangioma, Skull o Sharply marginated expansile skull lesion o Spiculated "hair on end" (sunburst) or "honeycomb" pattern • Metastases, Skull o Localized or diffuse o Dural/scalp involvement common o Often known primary malignancy o

(f)

Common • Anemias o Thalassemia o Sickle Cell Disease o Hereditary Spherocytosis • Hemangioma, Skull • Metastases, Skull Less Common • Neuroblastoma, Metastatic • Iron Deficiency Anemia • Cyanotic Congenital Heart Disease Rare but Important • Leukemia • Osteopetrosis • Granulocyte Colony-Stimulating (G-CSF) Treatment

Factor

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • "Hair" o Expanded diploe + spiculated periostitis o Accentuated trabeculae between inner/outer tables • "On end" o Trabeculae oriented perpendicular to inner, outer tables Helpful Clues for Common Diagnoses • Anemias o General etiology • Red marrow hyperplasia

Helpful Clues for Less Common Diagnoses • Neuroblastomar Metastatic o Skull/orbit ± sutural widening • Iron Deficiency Anemia o Severe, chronic o Mostly nutritionally deprived children • Cyanotic Congenital Heart Disease o Marrow expansion in uncorrected complex CHD can mimic thalassemia Helpful Clues for Rare Diagnoses • Leukemia o Almost always with sub- or epidural tumor • Osteopetrosis o Expanded marrow space ~ spiculated periosteal reaction o Pattern similar to severe anemias • Granulocyte Colony-Stimulating Factor (G-CSF) Treatment o Long-term treatment in severe congenital neutropenia

Thalassemia

Thalassemia

I 1 6

Lateral radiograph shows typical appearance of thalassemia with dense striations in a widened diploic space, giving the "hair on end" appearanceEB

Axial bone CT shows lypical "hair on endM appearance of the skull secondary to marked thickening of the diploic

marrow

most common

space

EB

Thalassemia

major

cause of this imaging finding.

is the

"HAIR ON END"

(J)

" c: III

::::l

Co

..•

OJ

Sickle Cell Disease

Sickle Cell Disease

III

(Left) Lateral scout radiograph from CT shows marked diploic thickening

=

with "hair on end"

appearance

in

a

patient

with

sickle cell disease. (Right) 5agiltal T1 WI MR shows marked diploic thickening ~ with "hair on end" appearance in severe sickle cell anemia.

::::l (j) Cl

OJ "0

(j) A

c:

=

Hemangioma,

Skull

Neuroblastoma,

Metastatic (Left) Anteroposterior radiograph demonstrates a well-demarcated lesion within the left frontal bone &J with spiculated or honeycomb appearance from intra diploic trabecular thickening. (Right) Coronal T1 C+ MR shows classic "hair on end" pa£lern, typical for metastalic neuroblastoma =:I.

Neuroblastoma,

Metastatic

leukemia (Left) Anteroposterior radiograph shows periosteal new bone projecting

from

both inner &J and outer =:I table of the skull with bidirectional spiculation in metastatic neuroblastoma. (Right) Axial CCCT shows a spiculated appearance of the outer and inner calvarium

~

due to extensive

involvement

in

marrow

leukemia.

Note large enhancing masses along the dura =:I and in the scalp~".

I 1 7

THICK SKULL, GENERALIZED

-'(fJ'" 0-

ro

u

• Phenytoin (Dilantin) Use, Chronic o Look for combination of thick skull + cerebellar atrophy = probable chronic Dilantin therapy o Up to 34% among patients with seizure disorder + anticonvulsant therapy • Shunted Hydrocephalus o Chronic shunted hydrocephalus often associated with diffuse calvarial thickening o Look for thick skull + shunt + chronic collapsed ventricles • Metastases (Diffuse Sclerotic) o Fat-suppressed Tl C+ scans helpful in detecting calvarial, subtle dural metastases o Common with prostate & breast metastasis o Look for associated focal/diffuse dura-arachnoid involvement • Paget Disease o Initial osteolytic change of skull in osteoporosis circumscripta o Late osteosclerotic phase • Osteoblastic areas crossing sutures • Marked thickening of the diploic space • "Tam-o'-shanter" skull • Focal areas of sclerosis in expanded diploic space: "Cotton wool" appearance (of skull) o Platybasia with basilar invagination

DIFFERENTIAL DIAGNOSIS

(fJ

c: co

"-

III "0

c: co

Common • Skull Normal Variants o Diffusely Thick Skull, ormal o Hyperostosis Frontalis Interna • Phenytoin (Dilantin) Use, Chronic • Shunted Hydrocephalus • Metastases (Diffuse Sclerotic) • Paget Disease Less Common • Microcephaly • Fibrous Dysplasia • Hyperparathyroidism • Acromegaly • Subdural Hematoma, Chronic (Calcified) • Anemias o Iron Deficiency Anemia o Sickle Cell Disease o Thalassemia • Extramedullary Hematopoiesis Rare but Important • Sclerosing Bone Dysplasias o Osteopetrosis o Pycnodysostosis o Melorheostosis • Fluorosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Diffuse diploic space expansion with/without adjacent cortical thickening • Most common cause by far of "thick skull" normal variant!

I 1 8

=

Helpful Clues for Common Diagnoses • Skull Normal Variants o Most common cause o Females normally have significantly thicker parietal/occipital bones than males o Hyperostosis frontalis interna • Usually bilateral, symmetrical • Spares areas occupied by superior sagittal sinus, cortical venous channels • Often ends at coronal sutures • May extend to parietal bones, orbital roofs • Females> 3S years old • 0 clinical significance • Etiology unknown

Helpful Clues for Less Common Diagnoses • Microcephaly o Skull overgrowth occurs secondary to small brain o Small brain causes = developmental anomalies or a result of very early insult • Fibrous Dysplasia o Can involve any aspect of skull o Can be focal or extensive o Medullary expansion with ground-glass appearance is classic o Four disease patterns • Monostotic (70-80%) • Polyostotic (20-30%) • Craniofacial (can be isolated; up to 50% of polyostotic) • Cherubism (mandible, maxilla) • Hyperparathyroidism o Granular appearance of skull with multiple areas of normal bone interspaced between • "Salt & pepper" or "pepper pot skull" appearance o Loss of distinction of inner & outer table

,.-c:

THICK SKUll, GENERALIZED Loss of lamina dura o Brown tumors o Chronic renal disease: Secondary hyperparathyroidism o t Serum calcium, t parathyroid hormone, ~ serum phosphorus Acromegaly o Calvarial hyperostosis (esp. inner table) o Prognathism (elongation of mandible) o Sellar enlargement, erosion o Enlarged paranasal sinuses (mainly frontal): 75% o t Growth hormone & IGF-l Subdural Hematoma, Chronic (Calcified) o Chronic calcified subdural hematoma along inner table simulates thick skull o Look for subtle cleavage between calcified membranes and the inner table Anemias o Chronic anemias: Hemolytic or iron deficiency o "Hair on end" skull with beta thalassemia o Thick skull due to diploic space enlargement o Parietal bones most commonly affected, relative sparing of the occipital squamae Extramedullary Hematopoiesis o ECT: Smooth homogeneous hyperdense masses mimicking subdural hematoma o Osseous findings of underlying disease • Thalassemia: "Hair on end" skull • Osteopetrosis: Dense bone obliterating medullary space o

•

•

•

•

Diffusely Thick Skull, Normal

CJl

Helpful Clues for Rare Diagnoses • Sclerosing Bone Dysplasias o Osteopetrosis • Marked sclerosis and deposition of osteopetrotic bone • Neurologic deficits: Blindness, conductive hearing loss, facial nerve palsy due to foraminal encroachment o Skeletal series diagnostic for diffusely dense bones • Fluorosis o Skull shows minimal changes in fluorosis o Bones at the base show marked thickening o Occipital protuberance very prominent, falx calcification o Skeletal survey helpful Other Essential Information • Appearance of thick skull caused by o Thick cortex (e.g., hyperostosis frontalis) o Expanded diploic space (e.g., metastases, anemia) o Adjacent tissue (e.g., old calcified subdural hematoma)

SELECTED REFERENCES 1. 2. 3. 4.

Chow KM et al: Cerebral alrophy and skull thickening due to chronic phenytoin lherapy. CMAJ. 176(3):321·3.2007 She R et al: Hyperostosis frontalis interna: case report and review of literature. Ann Clin Lab Sci. 34(2):206-8, 2004 Hollar MA: The hair-on-end sign. Radiology. 221(2):347-8, 2001 Ita K et al: Accentualed temporal line on the frontal skull radiograph: a sign of hyperparathyroidism. Radiology. 192(2):497-S02, 1994

Hyperostosis

Frontalis Interna

I Axial bone CT demonSlrales a diffusely lhick skull. which is commonly seen as a normal variation.

=.

Axial bone CT shows diffuse skulllhickening with classic changes of benign hyperoslosis inlerna predominantly bifronlal in this pauent.

1 9

THICK SKUll,

GENERALIZED

Shunted Hydrocephalus (Left) Sagillal TI WI MR demonslrales dirruse skull lhickening ~ secondary 10 chronic

Oilanlin

therapy.

NOlice also cerebellar alrophy (Right) Laleral radiograph shows diffuse skulllhickening in a patient wilh chronically shunted hydrocephalus. The shunt lube ~ is also seen.

Metastases (Diffuse Sclerotic) (Leh) Axial bone CT shows a diffuse thick skull wilh focal sclerotic

regions

in

a

patient with prostate melaSlasis. (Right) Axial T I WI MR shows lhe lypical MR appearance of diffuse, extensive skull Paget disease wilh diffuse calvarial diploic thickening and heterogeneous marrow ~.

(Left) Axial bone CT in an extremely retarded 5 , year old shows diffuse skull thickening

secondary

to

small brain. (Right) Axial bone CT shows a Ihick skull due 10POlyoslOtiC (ibrous dysplasia. NOle lhe characteristic ground·glass appearance or the diploic space l:ll.

I 1 10

Paget Disease

en

THICK SKULL, GENERALIZED

~ c:

III

:J

C-

..,

O:! Hyperparathyroidism

Subdural Hematoma,

III

Chronic (Calcified) (Left) Axial bone CT shows thick skull with mild sclerosis and a granular appearance of the diploe, as well as loss of distinction of inner & Duler table, in a patient with chronic renal failure and secondary hyperparathyroidism. (Right) Axial T2WI MR demonstrates chronic, calcified, bifrontal subdural hematomas EE resulting in skull thickening.

Sickle Cell Disease

:J Ul () Q)

-0

Ul

'"c:

Thalassemia fLeft) Coronal T2WI MR shows diffuse bone thickening with marked diploic widening E±l of both calvarium & skull base. (Right) Coronal bone CT shows diffuse diploic thickening

=

with

"hair on

end" appearance caused by blood-forming bone marrow hyperplasia. The underlying brain is normal.

Osteopetrosis (Left) Coronal T1 WI MR shows diffuse skull thickening and a dural-based mass in extramedullary hematopoiesis. (Right) Axial bone CT shows dirruse sclerosis and thickening involving the skull base and facial bones in a patient with

=

osteopetrosis.

I 1 11

THICK SKULL, LOCALIZED n. ('(l ()

DIFFERENTIAL DIAGNOSIS

(j)

c: III

•...

a:l 1J

c: III

=

Common • Hyperostosis Frontalis lnterna • Meningioma • Metastasis (Osteoblastic) Less Common • Fibrous Dysplasia • Paget Disease • Dyke-Davidoff-Masson • Cephalhematoma (Calcified) • Chronic Subdural Hematoma • Osteomyelitis (Chronic)

( alcified)

Rare but Important • Osteosarcoma • Osteochondroma • Frontometaphyseal Dysplasia • Osteopetrosis • Osteopathia Striata

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Focal cortex t ± diploic expansion • Look for associated dural lesion Helpful Clues for Common Diagnoses • Hyperostosis Frontalis Intema o Middle-aged, older women o Bilateral, symmetrical (bifrontal) o Overgrowth mostly inner table o Ends at coronal suture • Meningioma o Three patterns

Hyperostosis

I 1

Sagittal T 1 WI MR shows a typical example 01 local skull thickening lrom benign hyperostosis Note that the thickening

12

Frontalis Interna

stops at coronal

suture

=. =.

• Sclerotic: Dural-based mass, adjacent calvarium thickened, ± dural tail • lntradiploic: lntradiploic mass thickens, expands calvaria ± cortical d estru ction/thicken ing • "En plaque": Nodular dural thickening + associated extensive hyperostosis (juxta-orbital most common site) • Metastasis (Osteoblastic) o Common with prostate, breast metastasis o Look for associated focal/diffuse dura-arachnoid involvement Helpful Clues for Less Common Diagnoses • Fibrous Dysplasia o Young patient o Medullary expansion ("ground-glass") • Paget Disease o Late osteosclerotic phase o Focal areas of sclerosis in expanded diploic space ("cotton wool" appearance) • Dyke-Davidoff-Masson o Cerebral atrophy + ipsilateral compensatory osseous hypertrophy & hyperpneumatization of paranasal sinuses • Cephalhematoma (Calcified) o Birth trauma, subperiosteal hemorrhage o Early: Thin calcified shell, late sequelae: Incorporation of the calcified rim into the outer table of the skull • Chronic Subdural Hematoma (Calcified) o Chronic calcified SDH along inner table simulates thick skull o Looks like "double" skull on MR

Meningioma

Sagittal T1WI MR shows an intradiploie meningioma 81 with a massively thickened calvarium ~

THICK SKULL, LOCALIZED III

::l

C-

...

D) III

Fibrous Dysplasia (Left) Axial CECT shows localized hypemslOsis B>' with associated enhancing dural-based soft tissue ~ in pmstate metastasis. (Right) Axial bone CT shows well-de(ined focal calvarial thickening with gmund-g/ass appearance characteristic

:::l

(JJ

'"c

=-

for fibrous

dysplasia.

Paget Disease

Dyke-Davidoff-Masson (Left) Axial bone CT shows both lytic and blastic Paget disease as evidenced by focal lysis with sclemtic diploic expansion and thickened cortices EB. (Right) Axial bone CT shows left fmntal calvarial thickening with over

=

=

pneumatization

of the frontal

sinus E1 in Dyke-Davidoff-Masson.

Cephalhematoma

(Calcified)

Chronic Subdural Hematoma (Calcified) (Left) Axial CECT shows localized skull thickening due to a calcified cephalhemalOma SlI. (Right) Axial T2WI MR shows an

unusual appearance resembling a "double skull". Outer dark lines Ei:I are outer table, while the middle dark line ~ represents inner table; the intervening area is marrow.

Note additional

crescentic area deep

£0

table demarcated by an unusual third black line This represents an old calcified

chronic

hematoma.

inner

=.

subdural

I 1

THIN SKUll, GENERALIZED

;;:J .::£ (f)

a. ro u

DIFFERENTIAL DIAGNOSIS

(f)

c: ro •...

CD

"0

c:

'"

;;:J .::£ (f)

Common • Normal Infant Skull • Obstructive Hydrocephalus • Aqueductal Stenosis Less Common • Lacunar Skull • Hyperparathyroidism • Hypophosphatasia Rare but Important • Rickets • Osteogenesis Imperfecta • Cleidocranial Dysplasia • Primordial Dwarfism

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Gradual calvarial thinning: Chronic t ICP (e.g., aqueductal stenosis) • Demineralization: Hyperparathyroidism • Poor ossification o Hypophosphatasia, rickets o Osteogenesis imperfecta Helpful Clues for Common Diagnoses • Normal Infant Skull o Newborn: Vault thin, comprised of membranous bone o Parietal bones thin, often barely visible o Frontal, occipital bones more ossified o Severe underossification common in premature infants

• Obstructive Hydrocephalus o Etiology can be intra- or extraventricular o Unless shunted -+ skull gradually thinned • Aqueductal Stenosis o Lateral, 3rd ventricles t, 4th normal Helpful Clues for Less Common Diagnoses • Lacunar Skull o Membranous bone dysplasia -+ thin bone • Thinned calvarium is developmental, NOT caused by hydrocephalus • Resolves spontaneously by age 6 months although minor residua may persist into adulthood o Associations • Chiari 2, myelomeningocele ± encephalocele • Hyperparathyroidism o Osteopenia + cortical thinning o "Salt and pepper" calvarium o t Parathyroid hormone • Hypophosphatasia o Serum alkaline phosphatase ~ o Decreased ossification of skull, vertebrae • Skull may be "boneless" • Short tubular bones poorly/irregularly ossified with "frayed" metaphyses (similar to rickets) Helpful Clues for Rare Diagnoses • Osteogenesis Imperfecta o Osteoporosis + osseous fragility o Multiple fractures o Thin cortex, ~ ossification BOS o Multiple wormian bones

Normal Infant Skull

I 1 14

Axial bone CT shows normal generalized thin calvarial bones in a newborn E!:I with mildly overfapping sutures.

Axial NECT shows massively dilated ventricles in chronically obstructed hydrocephalus associated with diffuse thinning of calvarium E:I.

THIN SKULL, GENERALIZED III

::l

Co

OJ ..,

Lacunar Skull

III

Lacunar Skull (Left) Late,al ,adiograph in a patient with Chiari 2 malformation

shows the

typical appearance of "lacunar" skullEz, also known as Luckenshadel. (Right) Axial bone CT in the

::l

en n III -0

en

'"

c

same patient shows a characteristic in Chiari

Hyperparathyroidism

2

"lacunar" skull

malformation.

Hypophosphatasia (Left) Anteroposterior radiograph in a 13 year old with parathyroid adenoma shows demineralization and generalized thinning of the skull Note the subtle "saIL and pepper"

=.

appearance

of the calvarium

~ (Right) Lateral radiograph shows the hypomineralized, markedly thin skull of a newborn

=

with infantile

hypophosphatasia.

Cleidocranial

Dysplasia (Left) Anteroposterior radiograph of a skull shows a classic "boneless" skull in osteogenesis imperfecta. Ossification of only the facial bones and two small regions of the cranium

It] is present.

(Right) Bone CT with 30 shaded surface display shows generalized

calvarial

thinning with multiple wormian

bones in and

around lambdoid

suture.

I 1 15

THIN SKULL, LOCALIZED

:J

-'(j)"

a. ro cortex, nonenhancing • Paget Disease o "Osteoporosis/osteolysis circumscripta" o Early destructive phase • Well-defined lysis; frontal> occipital • Both inner, outer tables involved (inner usually more) • Scalp Lesions o Pressure erosion of outer table o Dermoid, epidermoid cysts; neurofibroma Helpful Clues for Rare Diagnoses • Meningioma o Can erode, invade, destroy calvarium

Arachnoid

Cyst

Axial NECT shows a typical arachnoid cyst with localized thinning of the adjacent calvarium =:iI.

,..

CJl

THIN SKULL, LOCALIZED

c:

III

::l

a. III .., III

::l

(Left) Sagittal T I WI MR

(Jl

shows a mega cisterna magna associated

()

with mild

thinning

of the adjacent

occipital

bone lID. Vermis

and fourth ventricle

Q)

"0

,.. c (Jl

are

normal. (Right) Axial T/ C+ MR shows a nonenhancing low signal intensity oligodendroglioma in the left frontal region

=

associated

with subtle thinning 01 the left frontal bone 81 as compared to the right.

(Left) Axial T2WI MR shows

a very classical appearance of a well-delineated cortically based "bubbly" mass, a ONET8I. Note focal cortical thinning ~. (Righi) Axial T2WI MR shows a lobulated cortically based ganglioglioma -7 causing localized

thinning

of

the skull 81.

(Left) Lateral radiograph

shows osteoporosis a specific appearance in early Pagel disease of the skull 81. (Right) Coronal J 1 C+ MR shows an atypical circumscripta,

meningioma

with solid and

cystic components

invading

the SSS81 with associated focal thinning of the calvarium c::£

I 1 17

LYTIC SKULL LESION, SOLITARY c. C1l U

DIFFERENTIAL DIAGNOSIS

CfJ

t:

•... '"

III "lJ

t:

'"

Common • Skull Normal Variants • Surgical Defects, Calvarial o Burr Holes o CSF Shunts and Complications • Metastasis Less Common • Epidermoid Cyst • Langerhans Cell Histiocytosis • Plasmacytoma • Paget Disease • Hemangioma • Dermoid Cyst • Fibrous Dysplasia • Leptomeningeal Cyst • Osteomyelitis Rare but Important • Cephalocele • Tuberculosis • Neurosarcoidosis • Sinus Pericranii • Aneurysmal Bone Cyst • Aggressive Fibromatosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Margins of lytic lesion helpful o Surgical defects: Well-marginated o Metastasis, osteomyelitis: Permeative o Epidermoid: Dense sclerotic o Histiocytosis: "Beveled" edge

I 1 18

Helpful Clues for Common Diagnoses • Skull Normal Variants o Vascular grooves • Inner table: Meningeal arteries, veins • Outer table: Superficial temporal artery o Venous channels • Thin-walled veins, venous "lakes" • Connect meningeal veins/dural venous sinuses with pericranial veins • Diploic venous channel can usually be traced into venous lakes o Pacchionian (arachnoid) granulations • Within/adjacent to dural venous sinus • Round/oval filling defect in venous sinus • Large lesions remodel inner table • CSF density/signal intensity

• Surgical Defects, Calvarial o Check history! o Burr holes, surgical defects well-marginated • Metastasis o Destructive, permeative o Enhancing mass centered in diploe o ± Associated dural/scalp soft tissue o Often known primary malignancy • Breast, lung, prostate most common Helpful Clues for Less Common Diagnoses • Epidermoid Cyst o Involves both inner, outer tables o Well-defined o Lacks central trabeculae o Dense sclerotic margins o Typically round or lobulated o Restricts (hyperintense) on DWI • Langerhans Cell Histiocytosis o "Eosinophilic granuloma" o Well-defined lytic lesion o "Beveled" edge (inner table involved> outer) o No marginal sclerosis o ± Adjacent soft tissue mass 0 occipital o Inner & outer tables both involved; inner usually more o Cortical thickening, coarse trabeculation hypointense Tl/T2WI • Hemangioma o Lytic diploic space lesion o Well-circumscribed o "Spoke wheel" or "reticulated" pattern o Strong enhancement • Dermoid Cyst o Well-circumscribed unilocular cyst containing fat o Expands diploe

(J)

LYTIC SKULL LESION, SOLITARY

Commonly near the anterior fontanelle, glabella, nasion, vertex, subocciput • Leptomeningeal Cyst o "Growing fracture" on radiography/NECT o Late complication of skull fracture with dural laceration o Smoothly marginated skull defect o Hyperintense on T2WI • Osteomyelitis o Usually complication of trauma, sinusitis, mastoiditis o Frontal> temporal bone o Mixed lytic/proliferative lesion o Moth-eaten/permeative medullary & cortical destruction o "Pott puffy tumor" = frontal soft tissue swelling o Often associated: Epidural abscess! o

Helpful Clues for Rare Diagnoses • Cephalocele o Herniation of brain, meninges, CSF,or a combination of all three o Dural laceration + dehiscent skull defect o Can be congenital or acquired (surgery, trauma) • Congenital: Parietal, occipital; young patient • Acquired: Basifrontal, history of trauma/su rgery • "Atretic cephalocele" should be in differential diagnosis of any midline subscalp mass in child, especially parietal region

Skull Normal Variants

c: "

• Neurosarcoidosis o Isolated area of bone translucency • Well-demarcated margins o Uncommon presentation o Look for associated • Pituitary/infundibulum, dural-based masses • Hilar adenopathy (CXR) • Sinus Pericranii o Vascular scalp mass communicates with dural venous sinus via transcalvarial vein o Transcalvarial vein courses through well-defined bone defect o Common frontal (40%) o Midline or paramedian o Superior sagittal sinus most commonly involved • Aggressive Fibromatosis o Benign fibrous tumor of infancy o Solitary/multiple benign myofibroblastic tumors • Subcutaneous tissue, muscle, bone, occasionally viscera • Neck lesions may extend intracranially o Well-defined lytic lesion with/without sclerotic rim o Can mimic any malignant or aggressive infection! o May need biopsy

Coronal 3D NEG shows a burr hole .-7, shunt tubing Ell in this patient with history of myelomeningocele and

& veins

Chiari 2 malformation. Premature closure of the right corona/suture is a/50 present

arachnoid granulations

a norma/thinning

" c

Burr Holes

Sagittal NECT - 3D VRT display of normal inner calvarial vault shows vascular groove for middle meningeal artery of squamous temporal bone!CB

(f)

I 1 19

=~

LYTIC SKULL LESIONr SOLITARY

OJ

(/)

0-

ro ()

(/)

Metastasis

C III •...

llJ 1J C III

Epidermoid Cyst

(Lefl) Axial bone CT shows a Iylic skull lesion with irregular margins in a lung carcinoma metastasis t:2S. (Right) Laleral radiograph of skull shows an epidermoid cyst presenting as a well-defined lytic lesion with

dense sclerotic margins 81.

Langerhans Cell Histiocytosis (Left) Axial NECT shows an epidermoid cyst presenting as a well-defined lytic lesion with dense sclerotic margins SI. (RighI) Axial NECT shows a large destructive lesion with associated soft tissue mass in a patient with Langerhans cell histiocytosis

SI.

Plasmacytoma (Left) Axial bone CT shows a typical appearance of plasmacytoma involving the petrous apex, inner ear, and

clivus =:I. (RighI) Axial bone CT shows bOlh lytic and blastic Paget disease as evidenced by focal lysis =:I within a background of diffuse sclerotic diploic expansion and thickened

cortices

I 1 20

Paget Disease

,.., (Right) Axial NECT shows scferosis and fusion of metopic suture thaI caused a "keel-shaped" forehead (trigonocephaly) in this 7 month old infant.

=

I 1 29

SCLEROTIC

SKUll

nl

"-

lD "0

c: nl

Common • Metastases, Skull less Common • Fibrous Dysplasia • Paget Disease Rare but Important • Hyperparathyroidism • Osteoma • Osteopoikilosis • MeJorheostosis • Osteopathia Striata

("Brown Tumor")

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Osteoblastic metastasis, especially from prostate, by far the most common cause Helpful Clues for Common Diagnoses • Metastases, Skull o Osteoblastic or treated • Most common = prostate carcinoma • Any lytic metastasis following favorable response to treatment o Other malignancies with sclerotic metastases include breast, colon, melanoma, bladder, soft tissue sarcoma Helpful Clues for less Common • Fibrous Dysplasia o 20-30% polyostotic

Diagnoses

30

Axial bone CT shows multiple sclerotic metastases from prostate carcinoma.

Frontal, sphenoid, maxillary, ethmoid bones more commonly involved o Widened diploic spaces with outer table> inner table involvement o Ground-glass or sclerotic appearance • Paget Disease o Late osteosclerotic phase o Blastic lesions, often crossing sutures o "Tam-o'-shanter" skull: t t Diploic space, particularly inner table o "Cotton wool" skull: Focal areas of sclerosis within previous areas of osteoporosis circumscripta Helpful Clues for Rare Diagnoses • Hyperparathyroidism ("Brown Tumor") o Trabecular bone resorption in cranial vault o Alternating areas of lucency and sclerosis: "Salt and pepper" appearance o Brown tumors: Can become ossified during reparative process • Osteoma o In Gardner syndrome, multiple osteomas • Round dense lesions of outer table (less common in inner table) o Colonic polyposis + soft tissue tumors (especially desmoid) • Osteopoikilosis o Sclerosing bone dysplasia • Multiple radiopaque round, oval, or lanceolate spots of t radiodensity o Predilection for epiphysis/metaphysis in long and short tubular bones o Skull involvement rare

Metastases, Skull

Metastases, Skull

I 1

MULTIPLE

o

DIFFERENTIAL DIAGNOSIS c:

lESIONS,

=

=

Axial bone CT in a patient with lung carcinoma shows mixed lytic, sclerotic calvarial metastases with adjacent ossific foc; E!2 from destroyed bone ;n

adjacent dural soft tissue masses.

SCLEROTIC SKULL LESIONS, MULTIPLE III

:J

Co

..,

OJ

Fibrous Dysplasia

III

(Left) Axial bone CT shows mulliple lesions of classic polyostolic fibrous dysplasia H2 with expansion and ground-glass matrix. (Right) Axial bone CT shows mixed

:J (j) ()

OJ -0

sclerotic, lucent process af(ecting sphenoid bone, leFt

maxilla. Maxillary sinus lumen is obliterated PlIiJ; leFt pterygomaxillary Fissure~ is

narrowed.

Paget Disease

Paget Disease (Left) Lateral radiograph shows a classic appearance

of

Pagel disease,

with

changes consistent with osteoporosis circumscripla H2 and a "COllon wool" appearance due to multiple sclerotic lesions (Right) Axial bone CT shows diFFuse calvaria/thickening

with

multiple sclerotic areas 11:.'I in a background of osteolysis in a palient with Paget disease.

Osteoma (LeFt) Coronal bone CT shows generalized skull thickening secondary to chronic renal insufficiency and secondary hyperparathyroidism. Note the Focal areas of osteosclerosis 8:1. (Right) Anteroposterior radiograph shows large osteomas =::l. I-Iere, they are part of Gardner syndrome. This patient a/so has a long history of polyposis of the colon.

I 1 31

MACROCEPHALY n.

ro

u

DIFFERENTIAL DIAGNOSIS

CI)

c: III

•...

a:l "'0

c: III

::::J

-" en

Common • Benign Familial Macrocrania • Hydrocephalus and Obstructed CSF Spaces o Intraventricular Hemorrhage o Aqueductal Stenosis o Arachnoid Cyst o Enlarged Subarachnoid Spaces o Villous Hypertrophy of the Choroid Plexus o Subdural Hematoma, Chronic Less Common • Dandy-Walker Continuum • Neoplasm o Glioblastoma Multiforme o Teratoma • Neurocutaneous Disorders o Neurofibromatosis Type 1 o Tuberous Sclerosis Complex • Hemimegalencephaly • Megalencephaly Syndromes Rare but Important • Hydranencephaly • Inborn Errors of Metabolism o Glutaric Aciduria Type 1 o MLCI o Mucopolysaccharidosis o Alexander Disease o Canavan Disease • Achondroplasia • Fibrous Dysplasia

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Macrocephaly = head circumference> 2 standard deviations above mean for age-matched controls • Macrocephaly = macrocrania • Megalencephaly = subtype of macrocrania • Imaging infants/children with macrocephaly o Hydrocephalus or white matter abnormality found? Use contrast! • Glutaric aciduria type 1 = child abuse mimic

I 1 32

Helpful Clues for Common Diagnoses • Benign Familial Macrocrania o Family history important • Intraventricular Hemorrhage o Hemosiderin not always apparent on follow-up images

• Aqueductal Stenosis o Look for associated hemosiderin, vascular anomalies • Arachnoid Cyst o Steady-state acquisition sequence to identify cyst wall • Enlarged Subarachnoid Spaces o Look for traversing veins o Natural history: Resolution by 12-18 months • Villous Hypertrophy of the Choroid Plexus o Likely on a spectrum, including choroid plexus papilloma o Bilateral choroid plexus lesions typical • Subdural Hematoma, Chronic o MR identifies hemorrhagic components Helpful Clues for Less Common Diagnoses • Dandy-Walker Continuum o Classic Dandy-Walker & Blake pouch cyst: Vermian angulation, large bony posterior fossa o Classic Dandy-Walker • Incompletely lobulated vermis, deficient fastigial recess/primary fissure o Blake pouch cyst • Intact vermis, fastigial recess, and primary fissure • Neoplasm o Large, bulky neonatal tumors o Glioblastoma Multiforme • Enhancement, necrosis, hemorrhage o Teratoma • Fat, calcium, enhancing soft tissue • Neurofibromatosis Type 1 o Look for foci of abnormal signal intensity (FASI), optic nerve gliomas, cafe-au-lait spots o Macrocrania predominantly derived from bulky white matter • Tuberous Sclerosis Complex o Cutaneous markers (ash-leaf spots) may be occult in 1st year of life o Look for Ca++ subependymal nodules, radial Iines • Hemimegalencephaly o Look for cutaneous markers & stigmata of overgrowth syndromes • Hypomelanosis of Ito • Proteus syndrome • Linear sebaceous nevus syndrome

en ;J;

MACROCEPHALY

c:

• Megalencephaly Syndromes o Clues in name • Megalencephaly, polymicrogyria syndrome • Megalencephaly with dilated Virchow-Robin spaces • Cerebral gigantism (Soto syndrome) • Macrocrania-cutis marmorata telangiectatica congenita Helpful Clues for Rare Diagnoses • Hydranencephaly o Distinguish from maximal hydrocephalus o MR shows cortex, falx • Glutaric Aciduria Type 1 o Bilateral temporal lobe hypoplasia & large sylvian fissures o Resembles bilateral middle cranial fossa arachnoid cysts o Crisis: Caudate, putamen, globus paIlidus swelling, & t signal • MLCI o Diffusely t white matter signal o Temporal pole & frontoparietal cysts o Macrocrania differentiates from CMV (common microcephaly) • Mucopolysaccharidosis o Dilated perivascular spaces • Alexander Disease o Enhancement is the key to diagnosis! o Infant: Frontal swelling & t signal & enhancement o Juvenile: Brainstem foci of t signal & enhancement

• Canavan Disease o MRS key: t t NAA • Achondroplasia o Small skull base • Jugular foramina coarctation: CSF drainage impaired • Foramen magnum coarctation: CervicomedulJary compression • Fibrous Dysplasia o Focal or diffuse (leontiasis ossea) may head circumference o Classic radiograph/CT: Ground-glass o MR (T2): Black velvet appearance

::l C. OJ

..• III

::l (J)

n

D> "0

(J)

A

c:

t

SELECTED REFERENCES 1.

2.

3.

4.

5.

Colombani M et al: A new case of megalencephaly and perisylvian polymicrogyria with post-axial polydactyly and hydrocephalus: MPPH syndrome. fur J Med Genet. 49(6):466-71,2006 Groeschel Set al: Magnetic resonance imaging and proton magnetic resonance spectroscopy of megalencephaly and dilated Virchow-Robin spaces. Pediatr Neurol. 34(1):35-40, 2006 D'Ambrosio AL et al: Villous hypertrophy versus c1,oroid plexus papilloma: a case report demonstrating a diagnostic role for the proliferation index. Pediatr Neurosurg. 39(2):91-6,2003 Medina LS et al: Children with macrocrania: clinical and imaging predictors of disorders requiring surgery. AJNR Am J Neuroradiol. 22(3):564-70, 2001 Wilms G et al: CT and MR in infants with pericerebral collections and macrocephaly: benign enlargement of the subarachnoid spaces versus subdural collections. AJNR Am J Neuroradiol. 14(4):855-60, 1993

Hydrocephalus Benign Familial Macrocrania

III

and Obstructed Spaces

CSF

I Sagittal T1WI MR shows a normal-appearing corpus callosum and callosal isthmus E'l gyral pattern, myelin

maturation, and midline

slfuclures

benign familial macrocrania.

Anteroposterior radiograph shows massive macrocrania in a child with untreated hydrocephalus.

1

in this child with

33

MACROCEPHALY

:::>

->
and a primitive fused hippocampus ~

=

(Left) Sagittal T I WI MR shows mildly hypoplastic vermis with prominent surrounding CSF. The fasligial recess, primary fissure, and vermian lobu/aUon are present (RighI) Sagittal T2WI MR shows upward rotation of severely hypoplastic vermis in an infant with callosal agenesis, microcephaly, and only primitive sulcalion Fastigiaf crease and primary fissure are seen. Vermian lobulation is simplified. The mesencephalon is "angled" but not "Z4shaped".

=.

(Left) Sagittal T1WI MR shows a very thin corpus callosum SlI in this microcephalic infant (RighI) Axial T2WI MR shows corresponding severe hypomyelination.

I 1 42

Midline Anomaly

MICROCEPHALY OJ

::::l

C.

OJ ....• Microlissencephaly

OJ

(Left) Sagittal T2WI MR shows a "Z-shaped"

brainslem and severe cerebellar hypoplasia. There is open inferior 4th ventricle microcephaly, callosal agenesis, and a smooth cortical surface. (Right) Axial T2WI MR shows a complete lack of cerebral gyral formation

Aicardi-Goutieres

::::l Ul



OJ -0

Ul

c '"

in the same child.

Aicardi-Goutieres (Left) Axial N[CT in this infant shows TORClI-like calcifications

within the basal

ganglia. (Right) Axial T2WI MR shows hypomyelination and severe atrophy in the same patient.

Calcifications

SI are

relatively occult on MR in this child.

(Left) Axial T1WI MR shows volume loss, hypomyelination, and hazy increased signal intensity of the basal ganglia 8l representing

calcification.

(Right) Coronal T2WI MR

shows volume loss and hypomyelination in the same child. These findings became more apparent with serial imaging.

I 1 43

SECTION 2

Meninges Anatomically Based Differentials Dural Calcification(s) Dural-based Mass, Solitary Dural-based Masses, Multiple Falx Lesions

1-2-2 1-2-4 1-2-8

1-2-12

Generic Imaging Patterns Thick Dural Arachnoid, Pial Enhancement Dural Tail Sign

Generalized

1-2-14 1-2-16 1-2-20

DURAL CALCIFICATlON(S)

CIl

OJ Ol C C

OJ

::2 c C1l

•....

aJ "0

c C1l

DIFFERENTIAL DIAGNOSIS Common • Physiologic Calcification, Dura • Osseous Metaplasia (Falx Contains Fatty Marrow) • Meningioma • Subdural Hematoma, Chronic Less Common • Basal Cell Nevus Syndrome • Benign Nonmeningothelial • Hyperparathyroidism • Hemodialysis • Meningitis

Tumors

Rare but Important • Pseudohypoparathyroidism • Familial Tumoral Calcinosis (Hypo- or Hyperphosphatemic)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Physiologic calcification of the dura common incidental finding on NECT Helpful Clues for Common Diagnoses • Physiologic Calcification, Dura a Common in the middle-age and elderly, falx or tentorium • Osseous Metaplasia (Falx Contains Fatty Marrow) a Incorrectly labeled "dense calcification" on NECT

ot be confused with true falx lipoma on TlWI • Meningioma a Calcified (20-25%): Diffuse, focal, sand-like, sunburst, globular, rim • Subdural Hematoma, Chronic a Inner membrane calcification (in 0.3-2.7%) termed "Matrioska head" or "armored brain" a

Helpful Clues for Less Common Diagnoses • Basal Cell Nevus Syndrome a Multiple jaw cysts (odontogenic keratocysts in 80-90%), mandible> maxilla, rib anomalies a Calcification of falx (eventually 100%), tentorium, peri-clinoid ligaments, dural, choroid plexus & basal ganglia • Benign Nonmeningothelial Tumors a NECT best diagnostic tool a Osteoma most common: Round dense lesion of the inner or outer table (outer table more common), no enhancement, no diploic involvement a Chondroma, osteochondroma less common • Hyperparathyroidism a Dural calcification, osteopenia and osteosclerosis of skull giving "salt and pepper" appearance • Hemodialysis a Long term hemodialysis, associated secondary/tertiary hyperparathyroidism a Calcifications falx, tentorium common Osseous

Physiologic

Calcification,

Dura

Metaplasia (Falx Contains Marrow)

Fatty

I 2 2

Axial bone CT shows physiologic calcification of the falx.

Axial NEeT shows thick calvarium and very prominent, thick ossification along the falx

=.

en

DURAL CALCIFICATlON(S)

c: "" ll.l

~

Osseous Metaplasia (Falx Contains Fatty Marrow)

a. OJ ....

Meningioma

III

(LeFt) Sagiltal T1 WI MR shows high signal Irom fat-containing osseous metaplasia along the lalx cerebri Cl:I. (Right) Axial bone CT shows marked hyperostosis and calcification in this plaque-like meningioma Cl:I along the lelt inner table 01 the skull.

Subdural Hematoma, Chronic

~

Basal Cell Nevus Syndrome (Left) Axial bone CT demonstrates bilateral chronic subdural collections with dense calcification along the inner membranes. Shunt tubes are noted in the lateral ventricles. (Right) Axial NECT demonstrates extensive dural calcification primarily involving the (alx cerebri and tentorium cere belli 9- in a patient with basal cell nevus syndrome and multiple jaw cysts.

(Left) Axial NECT demonstrates a rare, lobulated, calcified, chondroma

arising from the

lelt Iron tal dura Cl:I. (Rigl1t) Axial NECT shows densely calcilied dura, especially prominent along the tentorium

=.

Faint

calcification in the basal ganglia SI is seen.

I 2 3

en

Q)

DURAL-BASED MASS, SOLITARY

Ol C

·c Q)

:2 c

...

a:l"' "0

c

"'

Common • Epidural Hematoma • Meningioma • Metastases, Meningeal • Neurosarcoid • Lymphoma, Metastatic, Intracranial • Empyema less Common • Tuberculosis • Meningioma, Atypical and Malignant • Benign Nonmeningothelial Tumors • Malignant Nonmeningothelial Tumors • Langerhans Cell Histiocytosis • Plasmacytoma • Neuroblastoma, Metastatic • Leukemia Rare but Important • Pseudotumor, Intracranial • Hypertrophic Pachymeningitis • Extramedullary Hematopoiesis • Rosai-Dorfman Disease • Neurocutaneous Melanosis (Melanocytoma/Mela noma) • Fibro-Osseous Lesion (Calcifying Pseudo neoplasm)

•

•

•

•

ESSENTIAL INFORMATION

•

I 2 4

Does not cross sutures unless sutural diastasis/fracture present, can cross falx & tentorium o Trauma history, calvarial fracture in 85-95% Meningioma o Hyperostosis, cortical irregularity, calcification, peritumoral edema, trapped CSF clefts common o Best imaging tool: MR + contrast 095% enhance homogeneously & intensely, dural tail often present o MRS: Elevated alanine Metastases, Meningeal o Multiple> solitary lesions o Skull often but not always infiltrated o Often known extracranial primary neoplasm Neurosarcoid o 5% present as solitary dural-based extra-axial mass o Presence of associated leptomeningeal enhancement additional clue o Abnormal CXR, labs (increase ESR, ACE levels) Lymphoma, Metastatic, Intracranial o Localized dural mass mimicking meningioma o 10-30% of patients with systemic lymphoma may develop secondary CNS involvement o Leptomeningeal, parenchymal involvement more common Empyema o Extra-axial fluid collection with rim-enhancement & restricted diffusion o Look for paranasal sinus or mastoid disease o

DIFFERENTIAL DIAGNOSIS

Helpful Clues for less Common Diagnoses • Tuberculosis o Giant tuberculoma may mimic meningioma o Abnormal CXR, lab values o Travel history to endemic areas, immunocompromised o MRS: Elevated lipid/lactate • Meningioma, Atypical and Malignant o Dural-based lesion locally invasive with areas of necrosis & marked brain edema o Indistinct tumor margins, may extend into brain, skull, scalp o Biopsy is essential

DURAL-BASED • Benign Nonmeningothelial Tumors (}Lesions of dura, skull, skull base, NECT best diagnostic tool (}Chondroma: Expansile, lobulated, curvilinear matrix calcification, mild enhancement (}Osteochondroma: Stalk is contiguous with the parent bone intramedullary marrow, may see calcified matrix in cap atop cortical bone (}Osteoma: Round dense lesion of the inner or outer table (outer table more common), no enhancement, no diploic involvement • Malignant Nonmeningothelial Tumors (}Highly aggressive dural, skull, scalp lesions invading locally (}Biopsy is essential • Langerhans Cell Histiocytosis (}Well-defined lytic skull lesion, beveled edge, associated dural & scalp soft tissue (}Younger age group • Plasmacytoma (}Solitary dural mass in patient with multiple myeloma, mimics meningioma (}Skeletal survey may help • Neuroblastoma, Metastatic (}Age < 5, known extracranial disease, calvarial-based mass, often around orbit/sphenoid wings (}NECT: "Hair-on-end" spiculated periostitis • Leukemia (}May present with or mimic hematoma

MASS, SOLITARY (}Homogeneously enhancing extra-axial tumor(s) in patient with known or suspected myeloproliferative disorder Helpful Clues for Rare Diagnoses

• Pseudotumor, Intracranial (}Enhancing, infiltrating meningeal mass (}Predilection for meninges of cavernous sinus area or basal meninges (}Intracranial involvement in absence of orbital disease is rule (> 90%) • Extramedullary Hematopoiesis (}Patients with chronic anemia or marrow depletion (}Multiple> solitary (}Lobulated, homogeneous (}Mimics subdural hematoma on NECT (}Strong homogeneous enhancement • Rosai-Dorfman Disease (}Sinus histiocytosis with massive lymphadenopathy (}Multiple> solitary (}Mimics meningiomatosis, sarcoid, extramedullary hematopoiesis

SELECTED 1.

2.

3.

REFERENCES

Sahin F et al: Dural plasmacytoma mimicking meningioma in a patient with multiple myeloma. J Clin Neurosci. 13(2):259-61, 2006 Richiello A et al: Dural metastasis mimicking falx meningioma. Case report.J eurosurg Sci. 47(3):167-71; discussion 171, 2003 Goldsher 0 et al: Dural "tail" associated with meningiomas on Gd-DTPA-enhanced MR images: characteristics, differential diagnostic value, and possible implications for treatment. Radiology. 176(2):447-50, 1990

Epidural Hematoma

=

Axial NEeT shows a classic biconvex hyperdense mass in the left middle cranial fossa typical for epidural hematoma Left (rontal contusions are a/so present

Coronal T1 C+ M R shows a densely, homogeneously enhancing dural-based mass with faim "sunburst" pattern ~ Note the U,ill dural tail associated with the

8'1.

massl!:lD.

=.

I 2 5

DURAL-BASED

(f)

Ql

Ol

c C Ql

:2 c C1l

•...

al

(Left) Axial T I WI MR shows

"0

a renal cell carcinoma

c C1l

=

metastasis involving the calvarium with associated scalp and dural-based mass. (Right) Axial T7 C+ MR shows a neurosarcoid with linear and nodular coating of the medulla, pons, and midbrain and focal dural-based mass along the tentorium B.

=

(Left) Coronal T7 C+ MR shows a dural-based enhancing mass in the region of the cisterna magna in a patient with systemic lymphoma. Note prominent "dural tails" PJ:!:l. (Right) Coronal TIWI MR show "en plaque" focal dural thickening SiI that can mimic meningioma. Notice the faint ependymal

=

enhancement around the temporal horn ~ ependymitis.

indicating

(Leh) Coronal T7 C+ MR shows enhancing mass mushrooming inwards (deforming underlying brain) as well as outwards into the scalp PJ:!:l with displacement/invasion of superior sagillal sinus ~. (Right) Axial bone CT demonstrates a large expansile hyperde/lSe lesion with a chondroid matrix arising from the left occipital bone. Ilistologically proven chondrobfastoma.

.=

/I

/I

=

I 2 6

MASS, SOLITARY

DURAL-BASED

MASS, SOLITARY

(f)

" C

Neuroblastoma,

Metastatic (Left) Axial CECT shows

heterogeneous

enhancement

of a primary meningeal sarcoma with a dura/-based mass skull destruction, and scalp infi/tralion 8:11. (Rigl1t) Coronal T7 C+ MR

s: CI>

:J :J co CI> CJ>

demonstrates an intensely enhancing diploic space/scalp metaSlasis with displacement of the superior sagillal sinus by the epidural tumor EillI.

=

leukemia (Left) Axial CECT

demonstrates homogeneously enhancing extra·axial dura/-based masses in patient with systemic leukemia. Note poorly defined margins, brain infiltration

[;>J

with

edema. (Rigl1t) Coronal Tl C+ FS MR shows mass in lefl cavernous sinus in a patient with infiltrating intracranial pseudolumor.

=

Dural "taW' P.:tJ along middle fossa (foor a/50 represents pseudOlumor.

(Left) Coronal T7 C+ MR shows a solitary dural-based mass in a patient with

=

striking spinal extramedullary hematopoiesis. This was the only intracranial lesion. (Right) Axial Tl C+ MR shows dural-based, strongly

enhancing masses in this patient with known sinus histiocytosis with massive lymphadenopathy.

I 2 7

DURAL-BASED MASSES, MULTIPLE

(/)

Q) Ol

c::: c::: Q)

DIFFERENTIAL DIAGNOSIS

~ c::: solitary lesions o NECT, bone algorithm, for osseous evaluation o MR C+ if dural, scalp involved o Often known extracranial primary neoplasm • Prostate, breast, neuroblastoma • Subdural Hematomas, Chronic o Remote trauma history o NECT • Varying density • Fluid-fluid levels • Less common: Calcification of inner membranes o

I 2 8

MR

• T1 C+ thick, enhancing, membranes

dural

• ± Foci of old hemorrhage

Helpful Clues for Less Common Diagnoses • Neurosarcoid o Multifocal, dural-based foci o Presence of associated leptomeningeal enhancement additional clue o Other findings • Abnormal CXR • Increased erythrocyte sedimentation rate (ESR) & serum angiotensin converting enzyme (ACE) • Neurofibromatosis Type 2 o Multiple inherited schwannomas, meningiomas, & ependymomas o Best diagnostic clue: Bilateral vestibular schwannomas o Schwannomas on cranial nerves and spinal nerve roots o Only 10% of patients with multiple meningiomas have F2 • Lymphoma, Metastatic, Intracranial o Multiple or solitary dural mass mimicking meningioma o 10-30% of patients with systemic lymphoma may develop secondary CNS involvement • Parenchymal> dural involvement Helpful Clues for Rare Diagnoses • Extramedullary Hematopoiesis o Found in patients with chronic anemias or marrow depletion o Smooth homogeneous dural-based masses o Mimics subdural hematoma on NECT o Isointense with brain on T1 WI, hypointense on T2WI o Enhances strongly, homogeneously o May show osseous findings of underlying disease o Confirm with Tc-99m-sulfur colloid scan • Langerhans Cell Histiocytosis o Well-defined lytic skull lesion with "beveled edges" o Associated dural & scalp soft tissue masses common o Patients often present with diabetes insipidus • Thick, enhancing infundibulum • Absent posterior pituitary bright spot • Erdheim-Chester Disease o Non-Langerhans type histiocytosis

DURAL-BASED

MASSES, MULTIPLE

(/)

" c:

Affects multiple organs (including long bones, skin, lung, soft tissue) o Histiocytic infiltration of long bone metaphyses • Manifests as sclerotic appearance on conventional radiographs o Dural mass lesions most common • Falx cerebri, tentorium, sella/parasellar regions • Biopsy essential for diagnosis o May involve brain parenchyma • Rosai-Dorfman Disease o Sinus histiocytosis with massive lymphadenopathy o Propensity to arise from the base of the skull, para sellar region, orbit o May resemble multiple meningiomatosis, sarcoid o CNS Rosai-Dorfman disease has definite male predominance o Dural-based, extra-axial enhancing masses most common finding o May infiltrate brain with striking perilesional cerebral edema o Biopsy essential for diagnosis • Epidural Hematoma o Trauma history o < 5% multiple/bilateral o NECT (acute phase) • Hyperdense biconvex extra-axial mass • 90-95% associated skull fracture o Does not cross sutures • May if sutural diastasis/fracture present o Can cross falx & tentorium

o

o

Meningioma (Multiple Meningiomatosis)

± Underlying contusions

of brain

parenchyma • Myeloma o Dural-based masses with lytic skull lesions o Skeletal survey may be helpful • Leukemia o May present with or mimic hematoma o Homogeneously enhancing extra-axial tumor(s) in patient with known or suspected myeloproliferative disorder • Tuberculosis o Marked meningeal enhancement, with basilar predominance, parenchymal tuberculomas, pachymeningeal involvement with dural thickening, enhancement (may mimic meningioma) o Abnormal CXR & lab values o Travel history to endemic areas, immunocompromised

III

:l

Co

OJ ., III

:l

$:

CD :l :l

'C QJ

0..

en QJ

U 'C

C QJ

>

:J

DIFFERENTIAL DIAGNOSIS Common • Asymmetric Lateral Ventricles (ALV) • Intraventricular CSF Pulsation Artifact (Flow-Related) • Cavum Septi Pellucidi (CSP) ± Cavum Vergae • Coarctation of Anterior Horns Less Common • Connatal Cysts • Germinolytic Cysts Rare but Important • Open Inferior 4th Ventricle (Blake Pouch Remnant)

-"en

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • ormal variants are asymptomatic • Frequency varies with site o Lateral ventricle variants common o Fourth ventricle less common o Third ventricle variants (such as thick floor) uncommon (rare at imaging) but important for endoscopic third ventriculostomy • Clinical history key! o Headaches o Papilledema o History of prior trauma, infection

I 3 2

Helpful Clues for Common Diagnoses • Asymmetric Lateral Ventricles (ALV) o Leaflet of septum pellucidum ± "pushed" to smaller ventricle side o ALV + normal hemisphere • Usually normal variant • Exclude obstruction at foramen of Monro • Cyst or web • Tumor (e.g., choroid plexus neoplasm) o ALV+ abnormal hemisphere • Larger hemisphere: Hemimegalencephaly (ipsilateral ventricle large, often deformed) • Smaller hemisphere: Unilateral atrophy or porencephaly o ALV = sign of functioning shunt if shunt in smaller ventricle o Helpful techniques in evaluating ventricles, possible obstruction

• • • •

Sagittal, coronal thin-section T2WI High resolution FIESTA CSF flow study Intraventricular contrast outlines obstruction • Intravenous contrast (helpful in detecting small lesions) • Intraventricular CSF Pulsation Artifact (Flow-Related) o Most common on high field MR • FLAIRsequence most commonly affected • Look at another sequence or another plane (artifact disappears) • Typically occur in phase-encoding axis • Look for phase artifact propagating across image • When in doubt, change phase-encoding direction and repeat sequence • Cavum Septi Pellucidi (CSP) ± Cavum Vergae o Developing ventricle closes from posterior - anterior • Therefore cavum vergae (CV) does not occur in isolation • CSP can exist ± CV but not reverse o CSP lacks ependymal lining (term "5th ventricle" inaccurate) o CSP leaflets should be parallel • If septal leaflets are not parallel, consider encysted cavum • Look for signs of obstructive hydrocephalus • Look for evidence of prior trauma with epi-GRE or SWI to detect hemorrhagic residua • Coarctation of Anterior Horns o Normal variant o Exclude subependymal pseudocysts seen with inborn errors of metabolism, TORCH, ischemia o Findings helpful in distinguishing coarcted anterior horns from pathologic subependymal pseudocysts • Peroxisomal biogenesis disorder (Zellweger): Cortical dysplasia, hypo myelination, stippled epiphyses, hypotonia • Mitochondrial disorders: MRS lactate doublet

VENTRiClES, NORMAL VARIANTS • TORCH (cytomegalovirus): Look for microcephaly, periventricular calcifications • Hypoxic ischemic insult of newborn: History of perinatal distress! Helpful Clues for less Common Diagnoses • Connatal Cysts o Considered normal variant o May be anterior choroid plexus cysts • Controversial entity • Transient finding • Present at birth • Spherical form • Can be multiple • Lined with epithelium • Partial "double wall" due to ependymal folding • No hemosiderin • No septations • Germinolytic Cysts o Juxtaventricular subependymal pseudocysts • Result from germinolysis • Lined with germinal/glial cells (not ependymal cells) • May have hemosiderin • May have septations o Probably NOT normal variant • Rarely isolated, look for other signs of CNS pathology • Distinguish from connatal cysts

Asymmetric

lateral

Ventricles

(AlV)

=-

Axial TlAIR MR s!lows mild asymmetry ventricles. Right lateral ventricle is larger

of laleral bUl both

are normal in size. There is neither obstruction nor perivenuicular edema.

III

Helpful Clues for Rare Diagnoses • Open Inferior 4th Ventricle (Blake Pouch Remnant) o Presence of complete vermis, fastigial recess • Differentiates Blake pouch remnant from Dandy-Walker cyst o Usually non-obstructive o FIESTA, CSF flow sequences helpful

::J

Co CIJ ....• III

::J

SELECTED REFERENCES I.

2.

3.

4.

5.

6.

7.

8.

Kiroglu Y el al: Cerebral lateral ventricular asymmetry on CT: how much asymmetry is representing pathology? Surg Radiol Anal. 30(3):249-55, 2008 van Baalen A et al: Anterior choroid plexus cysts: distinction from germinolysis by high-resolution sonography. Pediatr Int. 50(1):57-61, 2008 Munoz A et al: Cisternography and ventriculography gadopentate dimeglumine-enhanced MR imaging in pediatric patients: preliminary report. AJNR Am J euroradiol: 28(5):889-94, 2007 Robinson AJ et al: The cisterna magna septa: vestigial remnants of Blake's pOlich and a potentia) new marker for normal development of the rhombencephalon. J Ultrasound Med. 26(1):83-95, 2007 Robinson AJ et al: The fetal cerebellar vermis: assessment for abnormal development by ultrasonography and magnetic resonance imaging. Ultrasound Q. 23(3):2) 1-23, 2007 Born CM et al: The septum pellucidum and its variants. An MRI study. Eur Arch Psychiatry Clin Neurosci. 254(5):295-302, 2004 Rohde V et al: Virtual MRI endoscopy: detection of anomalies of the ventricular anatomy and its possible role as a presurgical planning tool for endoscopic third ventriculostomy. Acta Neurochir (Wien). 143(11):1085-91, 2001 Bakshi R et al: Intraventricular CSF pulsation artifact on fast fluid-attenuated inversion-recovery MR images: analysis of 100 consecutive normal studies. AJNR Am J Neuroradiol: 2] (3):503-8,2000

Asymmetric

lateral

Ventricles

o' ::J (J)

(AlV)

Coronal T2WI MR s!lows mild bowing of seplalleaflets across midline without any evidence of interstitial edema. Upper third ventricle, Fornices are also sligl1tly displaced across midline.

p:m

;;0 CD co

=

I 3 3

VENTRiClES,

l/)

c

NORMAL VARIANTS

a

Ol Q)

a:::

~ ~ :J

U

E c Q)

>

'C Q)

0.. l/)

Q)

u 'C C Q)

>

Intraventricular CSF Pulsation (Flow-Related)

Artifact

Intraventricular CSF Pulsation (Flow-Related)

Intraventricular CSF Pulsation (Flow-Related)

Artifact

Intraventricular CSF Pulsation Artifact (Flow-Related)

(Left) Coronal FL4IR MR shows typical bilateral anterior horn CSF Ilow related pulsation artilact I:'JI. (Right) Coronal T1WI MR in the same case during the same examination shows absence of any mass or bleed within the normal-appearing anterior horns.

(Left) Axial rL4IR MR shows prominent, inhomogeneous signal within third ventricle ~ loramen 01 Monro I:'JI. (Right) Coronal T1 C+ MR shows prominent {Jow artifact in anleroinferior third ventricle. Artifact can mimic colloid cyst but fornices ~ are normal (colloid cysts typically in upper third ventricle, wedged between pillars 01 lornix).

=

Cavum Septi Pellucidi (CSP) ± Cavum Vergae (Left) Axial FL4IR MR shows cavum septi pellucidi PJ::l. The fornices are represented by tear drop-shaped thickenings allhe posterior aspect of the septalleallets I:'JI. Walls of CSP are parallel. (Right) Axial rL4/R MR in the same case as previous image, shows cavum septi pellucid; is continuous with patent cavum vergae. The septal leaflets are parallel and unbowed.

I 3 4

Artifact

VENTRICLES, NORMAL

VI

VARIANTS

" c:

Coarctation

of Anterior

Horns

Coarctation

of Anterior

Horns (Left) Axial TI WI MR shows right caudate head "stuck" to anterior wall of anterior horn of lateral ventricle. Coaptated (coarcted) frontal, occipital

horns are not uncommon

< CD ~ :::!. n

CO

'"

variants. (RighI) Axial T2WI MR shows similar ependymal attachment leading 10 coarctation of right anterior horn.

=

;0

CD



'C

OJ

D...

CI)

OJ

U 'C

C OJ

> C III

~ CO "tl

c III

Subependymal

Giant Cell Astrocytoma

Focal Cortical

Dysplasia

(left) Axial CECT shows ventriculomegaly & a mixed calcified, cystic & solid subependymal giant cell astrocytoma E2 at the foramen of Monro. SCCAs are identified in 10-15% of patients with TSC. (Right) Coronal FU\IR MR shows a characteristic band of high signal =::I extending to the ependymal surface in conjunction with focafly thickened abnormal appearing cortex ~ in this patient

with focal cortical

dysplasia.

Heterotopic

Gray Matter

Developmental

Venous Anomaly

(left) Axial T2WI MR shows subependymalnodules of gray maller

=

lining inner

margin of lateral ventricles. Islands of left frontal dysplastic gray matter are also seen extending to the ventricle !:ll. (Right) Axial T1 C+ FS MR shows classic "Medusa head" of a

developmental venous anomaly. Dilated hair-like medullary veins converge on a single "collector vein II E2 that drains into subependymal venous system.

=

Multiple (left) Axial FU\IR MR shows a hyperintense mass-like lesion in a patient not previously diagnosed with MS. Note involvement of the corpus callosum !:ll & extension to the ventricular ependyma E2. (Right) Coronal T1 C+ MR shows a mass in the right temporal lobe biopsy proven GBM. A 4th ventricular mass ~ with subependymal

enhancement

= represents

CSF tumor spread.

I 3 10

Sclerosis

Glioblastoma

Multiforme

EPENDYMAlISUBEPENDYMAL

en ,.-

LESIONS

c: ell

::::l Co

...

to Choroid

Plexus Carcinoma

ell

::::l

(Lefl) Axial CECT shows perivenlricular

enhancement

!:::l representing subependymal spread of primary CNS lymphoma. Secondary lymphoma often causes dural disease. (RighI) Axial T7 C+ MR shows massive left lateral ventricle choroid plexus carcinoma ~ with multiple nodules of metastatic CSF spread

;:0 Cll C III

•... CO "tl

c III

Choroid

Plexus Papilloma

(Left) Axial FLAIR MR shows the colloidal vesicular stage of neurocysticercosis with intraventricular lesions ~. Often the eccentric scolex may be seen in the vesicular stage on T2/rLAIR & post-contrast images. (Right) Axial CECT shows lobulated, enhancing, trigonal mass with hydrocephalus. Margins of this choroid plexus papilloma show characteristic frond-like irregularities. Etiology of the hydrocephalus may be mass effect or CSF overproduction.

Metastasis,

Intraventricular

(Left) Axial T1 C+ FS MR shows large meningioma in the atrium of left lateral ventricle. Tumor has "trapped" occipita/8ll and temporal horns. IRight) Axial T1 C+ FS MR shows an enhancing mass in the frontal horn of the lateral ventricle in this patient with metastatic melanoma. Following resection of this mass, the patient developed additional brain parenchymal

=

metastatic

foci.

Subependymal (Left) Axial FLAIR MR shows a classic SCCA I:] in the foramen of Monro in this tuberous sclerosis patient. Moderate hydrocephalus & corticallUbers ~ are seen. (Right) Axial T1 C+ MR shows a bubbly mass in the body of the right lateral ventricle with heterogeneous enhancement & enlargement of the right frontal horn. The mass is attached to the septum pellucidum, typical of central neurocytoma.

I 3 14

Giant Cell Astrocytoma (SGCA)

Central Neurocytoma

LATERAL VENTRiClE

MASS

Ul

" c:

Neurosarcoid (Left) Axial FLAIR MR shows

a small mass in the left lateral ventricle near the septum pellucidum. There is no evidence of obstructive hydrocephalus. The mass is hyperintense to gray matter & did not enhance following contrast, typical of subependymoma. (Right) Axial T1 C+ MR shows intensely enhancing masses in the choroid plexi of both lateral ventricles & thickening of infundibulum ~. eNS involvement is seen in approximately 5% of sarcoid patients.

=

< C1> :::l

~

Q: C1> en

;0 C1> c: parenchyma> ventricles o Intraventricular cysts are often isolated, 4th ventricle most common o Imaging varies with stage, host response • Epidermoid Cyst o Congenital epithelial inclusion cyst o 90% intradural, primarily in basal cisterns • CPA: 40-50%; 4th ventricle 15-20% o Nonenhancing, lobular, extra-axial mass o Follows CSF on all sequences except FLAIR &DWI

• Hemangioblastoma o Intra-axial posterior fossa mass with cyst & enhancing mural nodule abutting pia o Associated with von Hippel-Lindau disease o 90-95% posterior fossa: 80% cerebellar hemispheres; 15% vermis, 5% other (medulla, 4th ventricle) o 7-10% of posterior fossa tumors 060% cyst & "mural" nodule; 40% solid • Metastasis, Intraventricular o Intraventricular metastases often involve choroid plexus

FOURTH VENTRiClE MASS

CIl

" c:

Gray-white junction lesions most common Primary tumor often known • Atypical Teratoid-Rhabdoid Tumor (ATRT) o 50% infratentorial, most off-midline; CPA, cerebellum &/or brainstem o Large mass with cysts &/or hemorrhage o Variable enhancement o Very young patients, usually < 3 years o May mimic medulloblastoma o o

Helpful Clues for Rare Diagnoses • "Trapped" 4th Ventricle o Related to extraventricular obstructive hydrocephalus (EVOH) or "communicating" hydrocephalus o EVOH: Obstruction distal to 4th ventricle outlet foramina o Etiologies include thickened meninges (often related to SAH, meningitis, CSF tumor seeding, venous obstruction, NPH) • Ependymal Cyst o Typically lateral ventricle: Body or atrium o 4th ventricle location rare o Follows CSF on all sequences • Dermoid Cyst o Commonly sellar/parasellar/frontonasal o May occur as primary 4th ventricle mass o Fat appearance with droplets in cisterns, sulci, ventricles if ruptured • Lipoma o Well-delineated lobulated extra-axial mass with fat intensity o 40-50% interhemispheric fissure

Sagittal T1 C+ MR shaws heterogeneous enhancement of this 4th ventIicufar medulloblastoma. Hydrocephalus & CSF seeding are characteristic of these WHO grade 4 tumors.

o Rarely involves 4th ventricle • Encephalocraniocutaneous Lipomatosis o Rare congenital neurocutaneous syndrome characterized by ipsilateral cranial, facial, ocular, & CNS anomalies o Unilateral hemispheric cerebral atrophy & ventriculomegaly in a child with ipsilateral alopecia overlying a scalp lipoma o CNS lipomas occur inconsistently • Rosette-Forming Glioneuronal Tumor o Newly described rare tumor of 4th ventricle, WHO grade 1 o Midline mass of 4th ventricle; may involve brainstem, vermis • Central Neurocytoma o "Bubbly" mass in frontal horn or body of lateral ventricle o 4th ventricle, extremely rare, < 1%

;:0 ct>



Alternative Differential Approaches • 4th ventricle mass in a child o Medulloblastoma, ependymoma, pilocytic astrocytoma, brainstem glioma, ATRT • 4th ventricle mass in an adult o Metastasis, choroid plexus papilloma, subependymoma, hemangioblastoma • 4th ventricle mass, all ages: Neurocysticercosis, epidermoid, dermoid, "trapped" 4th ventricle

Sagittal T1 c+ MR shows an enhancing 4th ventIicular mass with extension through the foramen of Magendie. Note ventIicufar obstIuction with an enlarged cerebral aqueduct =::I & a dilated 3rd ventIide EI.

I 3 33

FOURTH VENTRiClE

(f)

c

MASS

.Q Ol Q)

0:::

~ Cll

:::J

U 'C

C Q) >

'C Q)

a.. (f)

Q)

~ C Q)

> C III

~

ell

"0 C III

Pilocytic Astrocytoma

Brainstem Glioma,

essential for characterization of a pediatric

posterior

fossa

mass. Detecting the relationship of the mass to the 41h ventricle is key. (Right) Sagitlal T2WI MR shows a focal glioma, localed in the dorsal pOnlomedullary junction wilh mild mass effect on the anterior 4th ventricle.

Choroid (Left) Sagittal T2WI MR shows a typical T2 hyperintense,

inferior

4th

ventricfe subependymoma E!lI. Lack of hydrocephalus is typical of subependymoma. These intraventricular masses are often asymptomatic. (Right) Sagittal T1 C+ MR shows a lobular, midline 4th ventricular mass with robust enhancement & hydrocephalus. Other 4th ventricular tumors would not demonstrate such strong enhancement. These tumors may be in the 4th ventricle or at the lateral recess.

Neurocysticercosis (Left) Sagi!!al T1 WI MR shows a cyst with a nodule within

the inFerior 4th

ventricle~.

The lesion

showed no enhancement, in

I 3 34

Pediatric

(Left) Sagitlal T I C+ MR shows a mixed cystic & solid posterior fossa mass with patchy enhancement of the tumor nodule. Note the 3rd ventricular obstruction. Multiplanar MR imaging is

keeping wilh the vesicular stage. The protoscolex is the viable larva within the thin-walled cyst visible on MR. (RighI) Axial FLAIR MR shows the 4th ventricular lesion & mild edema in the adjacent brain E!lI. As Ihis was a solitary lesion~ it was resected for diagnosis. Intraventricular NCC lesions are best seen on T7 & FLAIR MR.

Plexus Papilloma

FOURTH

,.-c:

VENTRICLE MASS

CJl

Ql

::l Co tll ...•

Hemangioblastoma

III

(Left) Axial TI C+ FS MR shows a non enhancing CSF-like mass expanding the 4th ventricle. The "scalloped" expansion of the 4th ventricle suggests epidermoid.


c:

.... '"

a!

"c: '"

less Common • Neurocysticercosis • Central Neurocytoma • Ependymoma • Subependymoma • Epidermoid Cyst • Cavernous Malformation • Ependymal Cyst Rare but Important • Choroid Plexus Papilloma • Choroid Plexus Carcinoma • Parasites, Miscellaneous • Astroblastoma

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Purely cystic intraventricular masses are usually benign o Xanthogranulomas> > ependymal or inflammatory cysts • Only truly common "bubbly-appearing" intraventricular masses = choroid plexus cysts (xanthogranulomas) Helpful Clues for Common Diagnoses • Choroid Plexus Cysts o Benign xanthogranulomas o Choroid plexus glomi, bilateral o Increased prevalence with age o Usually asymptomatic (rarely cause obstruction) o Histologically most are xanthogranulomas • Benign degenerative process • Typically FLAIR hyperintense • May restrict on DWI • Inhomogeneous enhancement common

I 3 36

Helpful Clues for less Common Diagnoses • Neurocysticercosis o Often show rim enhancement o Look for characteristic scolex, parenchymal/cisternal lesions o Small intraventricular cysts best seen on FLAIR • Central eurocytoma o Who grade II neoplasm o Younger age patients

•

•

•

• Nearly 1/2 occur in the 3rd decade • 75% between 2nd-4th decades o Location • Arises from septum pellucid urn or lateral ventricle wall • Anterior (near foramen of Monro), mid-body> > atrium, temporal horn • Less common: 3rd ventricle • Rare: Extraventricular central neurocytoma • 13% bilateral o Imaging • Cyst-like areas seen in 2/3 of cases • Moderate enhancement is typical • Punctate calcifications in up to 1/2 • Hemorrhage not uncommon Ependymoma o WHO grade II neoplasms o Arises from differentiated ependymal cells lining ventricles, central canal of the spinal cord o Mean age - 6 years o Location • 58% 4th ventricle • 42% lateral, 3rd ventricles • Less common: Extraventricular ependymoma o Imaging • Ca++ in 40-80% • Occasional intra tumoral hemorrhage yields blood-fluid levels • Contrast-enhancement varies; usually intense but spares the cyst-like regions • Extension beyond ventricular margins (paraventricular) not uncommon Subependymoma o Middle-aged, older adults o Most located within the 4th, frontal horn of lateral ventricles o Varied enhancement: None to intense, calcification, cyst formation may occur o Extension of a subependymoma beyond the ventricular margins is rare, unlike for ependymoma Epidermoid Cyst o DWl most specific: Restricted diffusion o FLAIR next most helpful sequence, showing "gray" CSF or incomplete CSF suppression Cavernous Malformation o Intraventricular location is uncommon

"BUBBLY-APPEARING" INTRAVENTRICULAR MASS o Imaging appearance like cavernous malformations elsewhere oGRE or SWI sequence helpful to assess for susceptibility due to blood products • Ependymal Cyst o Lacks enhancement o CSF signal all sequences (FLAIR most specific) Helpful Clues for Rare Diagnoses • Choroid Plexus Papilloma o Nearly half present in 1st decade o WHO grade I (carcinoma is WHO grade III) o Presentation with hydrocephalus common; can be due to mechanical obstruction and/or overproduction of CSF o Locations: Lateral ventricle most common site (50% of cases) > 4th ventricle (40%; most common in adults) > 3rd ventricle (5%) o Imaging • Cauliflower-like lobulated tumor, usually with moderate or intense enhancement • Hemorrhage, cyst formation may occur • Necrosis and/or parenchymal invasion suggest choroid plexus carcinoma • Flow voids common • Pure "cystic" variant may occur within ventricles, subarachnoid spaces • Astroblastoma o "Bubbly" appearance common o Parenchymal> > intraventricular

Choroid

Plexus Cysts

Axial T1 C+ MR shows multiple rim-enhancing cysts some with solid-appearing nodules 8l in atria of both laleral venlricles. llislologically these cysts are

=,

xanthogranulomas.

Other Essential Information • Enhancing intraventricular tumors may require MR neuraxis screening for drop metastasis, particularly when choroid plexus tumors and ependymoma are suspected • Nonenhancing cystic lesions with DWI restriction characteristic for epidermoid cysts • Neurocysticercosis can rarely mimic other intraventricular cysts, such as colloid cyst o Cryptococcal infection can present in a similar fashion to cysticercosis

SELECTED REFERENCES

< CD ;;.

:0. Q. CD (j)

;0 CD

(LeFt) Axial T2WI FS MR shows multiple cysts in the quadrigeminal cistern ~ and atrium of righllareral ventricle ~. Note trapped temporal horn '2>, (Courtesy E. Bravo, MOJ. (Right) Axial T2WI MR shows multiple "bubbly" intraventricular cysts in a patient with known NCe. (Courtesy B. Villarreal, MOJ.

=

Central Neurocytoma (Left) Coronal T2WI MR shows a typical MR case of central neurocytoma with a classic "bubbly"

-=

muJUcyslic appearance.

These tumors are typically attached to the septum pellucidum. (Right) Coronal Tl C+ MR in the same case as previous image shows patchy enhancement 82 within the partly cystic, "bubbly-appearing" mass

that arises from the septum

=

pellucidum.

(Left) Sagittal T2WI MR shows a large, "bubbly-appearing" 4th ventricle/cisterna magna mass in a 9 year old with a 2 month history of morning vomiting and worsening headaches. (Right) Sagittal T2WI MR shows a large, "bubbly-appearing" mixed cystic and solid 4th ventricular/cisterna magna mass in a 40 year old female with headaches.

=

=

I 3 38

MASS

"BUBBLY-APPEARING"

INTRAVENTRICULAR

MASS

CJ)

c: """

III

:3 Co

lD .., III

(Left) Axial FLAIR MR shows

:3

an inhomogeneous

< CO

mass filling the 4th ventricle =:II.

Incomplete suppression on FLAIR gives this epidermoid cyst a "cauliflower" or "bubbly" appearance. (Right) Axial T2WI MR shows a lobulated fluid signal intensity cyst in the 4th ventricle =:II. Although an arachnoid cyst is a possibility, the insinuating margins are more typical (or epidermoid.

Cavernous Malformation

~ ::!. ()

roVI

Cavernous Malformation (LeFt) Axial T1WI MR shows typical findings of a cavernous malformation in the atrium of the left lateral ventricle 1m. Note the classic mixed signal appearance, with intrinsic -f 1 shortening.

(Right) Axial T2WI MR in the

same case as previous image shows a mixed signal

=

with areas of high and low T2 signal, intensity

characteristic

of cavernous

malformation.

Choroid Plexus Papilloma

Choroid

Plexus Papilloma (Leh) Coronal T1WI MR in a 43 year old female with headaches shows a well-delineated inhomogeneously hypointense mass in the 4th ventricle (Right) Axial T2WI MR in the same case shows the "bubbly" appearance of mass caused by multiple small cysts =:II. Choroid plexus papilloma

cz.

was confirmed

at surgery.

I 3 39

en c

EPENDYMAL

ENHANCEMENT

.Q 0> OJ

0::

~

.!!l ::J

U

·C

C OJ > ·C OJ

0..

vi OJ

~ C OJ

> C 1tI

~ CO "t:l

c 1tI

DIFFERENTIAL DIAGNOSIS Common • Normal Variant • Developmental Venous Anomaly • Multiple Sclerosis Less Common • Ventriculitis • Opportunistic Infection, AIDS • Neoplasm with CSF Seeding • Lymphoma, Primary CNS • Tuberculosis Rare but Important • Subependymal Venous Congestion o Sturge- Weber Syndrome o Thrombosis, Deep Cerebral Venous o Arteriovenous Malformation or Dural A-V Fistula • Vasculitis • Neurosarcoid • Langerhans Cell Histiocytosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Pre-operative neuraxis MR (imaging) recommended in patients suspected of having CSF seeding of tumor

I 3 40

Helpful Clues for Common Diagnoses • Normal Variant o Subependymal veins enhance normally & may be mistaken fur pathol9GY • Developmental VenousAnomaly o Enhancing "Medusa head" (dilated medullary white matter veins) o May have enlarged subependymal veins o Almost always unilateral, focal lesion o Angle of ventricle common location • Multiple Sclerosis o Common locations: Subependymal, peri ventricular, posterior fossa o Ovoid or round enhancing lesion with no significant mass effect o "Horseshoe" (incomplete ring enhancement) characteristic of demyelination o Tumefactive MS may mimic neoplasm, and enhancement may extend to ependyma

Helpful Clues for Less Common Diagnoses • Ventriculitis o Ventriculomegaly with fluid-debris level & enhancement characteristic o Associated DWI restriction typical o May complicate meningitis, abscess, or shunt • Opportunistic Infection, AIDS o CMV commonly causes ventriculitis o TB may cause ventriculitis o Toxoplasmosis may extend to ependyma & mimic lymphoma • Neoplasm with CSF Seeding o Many parenchymal tumors result in ependymal spread as they abut ventricular surfaces o Ependymal spread most common in childhood tumors: Medulloblastoma> ependymoma, pineal & choroid plexus tumors o Malignant gliomas in adults (GBM, anaplastic astrocytoma/ oligod en drogli oma) commonly spread along ependyma o Metastases from extra cranial primary: Breast & lung most common • Lymphoma, Primary CNS o Enhancing lesion(s) within basal ganglia, periventricular WM o Frequently abut, extend along ependymal surfaces o Often involves, crosses corpus callosum • Tuberculosis o Typically basal meningitis, may be complicated by ventriculitis o Dural & parenchymal disease common Helpful Clues for Rare Diagnoses • Sturge-Weber Syndrome o May cause subependymal venous congestion o Cortical Ca++, atrophy, & enlarged ipsilateral choroid plexus o UsuaJly a sporadic congenital malformation in which fetal cortical veins fail to develop normally • Thrombosis, Deep Cerebral Venous o Hyperdense internal cerebral veins on ECT o Usually affects bilateral internal cerebral veins and variably involves vein of Galen & straight sinus

EPENDYMAL

•

•

•

•

o Deep gray nuclei, internal capsule, medullary WM typically affected o Venous stasis in deep WM (medullary) veins seen as linear enhancing foci radiating outwards from ventricles o May cause subependymal venous congestion Arteriovenous Malformation or Dural A-V Fistula o AVM: Vascular malformation with arteriovenous shunting • Tightly packed mass of enlarged, enhancing vascular channels • May cause subependymal venous congestion o DAVF: Network of tiny vessels in wall of thrombosed dural venous sinus • Transverse sinus> cavernous sinus • May thrombose, resulting in venous infarct • May cause subependymal venous congestion Vasculitis o Linear enhancement along course of penetrating vessels o Enhancement often extends to ventricular margins o Extensive T2 hyperintense white matter common Neurosarcoid o Leptomeningeal & dural enhancing masses o May occur intraventricularly or along ependyma Langerhans Cell Histiocytosis

Developmental

Axial

n

Venous Anomaly

C+ MR shows an enlarged seplal vein

Rare subependymal involvement perivascular space infiltration o May affect choroid plexus o

by

Alternative Differential Approaches • Neoplasm with CSF seeding: Medulloblastoma, ependymoma, germinoma, GBM, metastases, lymphoma, anaplastic astrocytoma, anaplastic oligodendroglioma, choroid plexus tumors, pineoblastoma, leukemia • Ependymal enhancement in a child: Medulloblastoma, ependymoma, choroid plexus or pineal tumor, leukemia • Ependymal enhancement in an adult: High-grade gliomas, metastases, lymphoma, multiple sclerosis • All ages: Normal variant, developmental venous anomaly, ventriculitis

SELECTED 1. 2.

< C1l ~

Q: C1l

en

;:0 C1l



in

'"

tuberculosis.

Arteriovenous

::lJ

C1l

'C QJ

Il.

en QJ

U 'C

C QJ

> c:

.. 01

III "C

c:

01

Common • Aging Brain, Normal • Encephalomalacia, General • Obstructive Hydrocephalus o Meningitis o Subarachnoid Hemorrhage, NOS o Intraventricular Hemorrhage • Cerebral Atrophy, NOS o Chronic Hypertensive Encephalopathy o Multiple Sclerosis o Alcoholic Encephalopathy o Radiation and Chemotherapy o Diffuse Axonal Injury (DAI) o Post-Meningitis o Drug Abuse Less Common • Alzheimer Dementia • Normal Pressure Hydrocephalus • Multi-Infarct Dementia • Frontotemporal Dementia Rare but Important • Choroid Plexus Papilloma • Megalencephaly Syndromes • Huntington Disease • Creutzfeldt-]akob Disease (C]D) • Inborn Errors of Metabolism (End-Stage)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Imaging most important to distinguish acutely obstructive causes from non-obstructive causes • Dementias best diagnosed clinically

I 3 44

Helpful Clues for Common Diagnoses • Aging Brain, Normal o Ventriculomegaly in proportion to sulci o Reflects atrophy from parenchymal loss • Encephalomalacia, General o Volume loss from many causes (prior stroke, trauma, surgery) o Focal, in areas of parenchymal tissue loss (with focal ventricular enlargement), or diffuse when global • Obstructive Hydrocephalus o Surgically emergent condition o Types of obstructive hydrocephalus

• Intraventricular obstructive hydrocephalus (IVOH) = "non-communicating hydrocephalus": Due to obstructed CSF at level of ventricles from focal mass effect • Extraventricular obstructive hydrocephalus (EVOH) = "communicating hydrocephalus": Due to obstructed CSF resorption at level of sulci, meninges/arachnoid granulations • CSF overproduction (choroid plexus tumors) o Meningitis • Mild hydrocephalus typical, may be earliest imaging finding (EVOH) • Leptomeningeal enhancement • Complications: Cerebritis/abscess, effusions, ischemia o Subarachnoid Hemorrhage, NOS • Impaired CSF resorption (EVOH) • Subarachnoid blood, often aneurysmal o Intraventricular Hemorrhage • Impaired CSF resorption (EVOH) • Ventricular blood, often related to trauma or AVM • Cerebral Atrophy, NOS o Chronic Hypertensive Encephalopathy • Brain parenchymal changes due to long-standing effects of untreated or poorly treated systemic hypertension • May result in vascular dementia • Diffuse white matter (WM) atrophy with low density or high T2 signal • May have hemorrhagic foci on GRE (basal ganglia, thalamus, cerebellum) o Multiple Sclerosis • Periventricular WM pattern of T2 hyperintensities ± enhancement • Often dramatic callosal volume loss & ventriculomegaly • Lesions generally lack mass effect o Alcoholic Encephalopathy • Chronic alcohol abuse results in symmetric lateral ventricle enlargement & superior vermian atrophy • Wernicke involvement: Mamillary bodies, medial thalami, hypothalamus, periaqueductal gray matter o Radiation and Chemotherapy • Late volume loss & diffuse T2 hyperintensity WM

,.-c: CJl

LARGEVENTRICLES

o

o

o

• Spares subcortical "U" fibers Diffuse Axonal Injury (DAI) • DAI best seen on GRE, FLAIR,& DWI • Classic locations: Gray-white matter junctions, callosum, deep nuclei • Accompanied by late WM volume loss Post-Meningitis • Late WM volume loss diffusely • May have encephalomalacia related to abscess, ischemia Drug Abuse • Consider in young patients with ischemic or hemorrhagic strokes • Chronic: Volume loss

Helpful Clues for Less Common Diagnoses • Alzheimer Dementia o Parietal & temporal cortical atrophy with/disproportionate hippocampal volume loss is suggestive • Normal Pressure Hydrocephalus o Clinical triad of dementia, gait apraxia, & incontinence o Ventriculomegaly disproportionate to sulcal prominence, normal hippocampus o CSF flow studies can detect increased velocity • Multi-Infarct Dementia o Multifocal infarcts involving cortical gray matter, subcortical WM, & basal ganglia o Strokes of multiple ages & lacunes common o Often associated with arteriolosclerosis, WM hyperintensity

• Frontotemporal Dementia o Anterior frontotemporal atrophy with WM hyperintensity; "knife-like gyri"

III

::l

0-

..•III

lD ::l

Helpful Clues for Rare Diagnoses • Choroid Plexus Papilloma o Intraventricular enhancing mass in child o Hydrocephalus due to obstruction &/or CSF overproduction • Megalencephaly Syndromes o Ventricular enlargement ipsilateral to enlarged hemisphere • Huntington Disease o Focal enlargement of frontal horns due to caudate atrophy • Creutzfeldt-jakob Disease (CJD) o Hyperintensity involving deep nuclei &/or cortex on DWI > FLAIR • Inborn Errors of Metabolism (End-Stage) o Chronic ventriculomegaly from parenchymal volume loss




;0 (1)

to 0' ::l CJ>

Alternative Differential Approaches • Ventriculomegaly may represent atrophy or "compensated" hydrocephalus • Compensated hydrocephalus: Compressed or small sulci, little/no transependymal CSF migration, relatively stable over time • Acute hydrocephalus: Small or compressed sulci, transependymal CSF migration (T2 hyperintensity along ventricular margins), ventricles enlarge over short time period o Acute obstruction usually requires urgent treatment

Obstructive Hydrocephalus

Axial FLAIR MR shows mild ventricular enlargement ~ in proportion to the mild sulcal enlargement in an elderly patient with expected atrophy, Note lack of

Coronal T2WI MR shows massive acute obstructive hydrocephalus, with ballooned ventricles & transependymal CSF migration due to a tectal

significant

glioma

a

white maller

disease.

m obstrucUng

a

the cerebral aqueduct.

I 3 45

LARGE VENTRICLES

C/)

c::

a

OJ Q)

IX

~ ell

:::J .;::

'-'

C Q)

> .;:: Q)

a.. C/) Q)



(Left) Sagittal T1 C+ MR shows a dilated 4th ventricle & extensive enhancement obliterating the basal cisterns & Filling the cisterna magna ~ Meningitis may be complicated by hydrocephalus, usually due to impaired CST resorption (EVOH). (Right) Axial NECT shows blood in the basal cisterns E1 & subarachnoid spaces ~. Note blood levels in the occipital horns & ventricular dilation due to acute ("communicating") hydrocephalus ([vOH).

m

Multiple Sclerosis (Left) Axial T2WI MR shows marked parenchymal volume loss evidenced by ventricular prominence 8lI & marked white matter volume foss. Note multiple while maller T2 hyperintense plaques related to the patient's MS. Marked corpus callosum atrophy is typical. (Right) Axial FLAIR MR shows lateral ventricle enlargement & diFFuseparenchymal volume 1055in a patient with chronic alcohol abuse. White matter disease is also noted, likely arteriolosclerosis.

=

Radiation and Chemotherapy (LeFt) Axial T2WI MR shows diFFusehyperintensity throughout perivenlricular white matter sparing the subcortical U-Fibers & corpus callosum, in this young patient who underwent radiation & chemotherapy. (Right) Coronal T2WI MR shows marked venlriculomegaly in a patient with a history of coccidioides meningitis. Lack of transependymal CSF migration suggests the obstruction is likely chronic ("compensated") or low grade.

=

=

I 3 46

Post-Meningitis

,..c:

en

LARGE VENTRiClES

Ql

::l

a. OJ ...•

Multi-Infarct Dementia

Ql

(Lefl) Axial T2WI MR shows multiple high signal foci in the basal ganglia !::ill & white maller caused by vasculitis related to drug abuse. In young patients with ischemia, drug use should be considered. Street drugs such as amphetamines may cause chemical vasculitis with secondary infarcts. (Right) Axial NECT shows multiple

hypoinlensilies

::l


right o Septum may be displaced across the midline o 0 associated mass effect, herniation, or parenchymal atrophy o Must exclude underlying mass or obstructing lesion • Extrinsic Mass Effect o Etiologies include mass, hemorrhage, infarct, infection o Mass can cause ventricular deformity, subfalcine herniation • Encephalomalacia, General o Parenchymal loss results in compensatory ventricular enlargement o Common etiologies include chronic infarct, trauma, surgery

• Intraventricular Hemorrhage o Involved ventricle may dilate early from mass effect o Chronic dilation may be due to scarring from adhesions o Etiologies include trauma, AVM, basal ganglia hemorrhage • Herniation Syndromes, Intracranial o Subfalcine herniation: Cingulate gyrus herniates under falx • Ipsilateral lateral ventricle compressed • Foramen of Monro obstructs, causes contralateral lateral ventricle enlargement o Unilateral descending transtentorial herniation (uncal): Herniation of medial temporal lobe inferiorly • Contralateral temporal horn becomes entrapped & enlarges o Entrapped ventricle: Typically temporal horn, by extrinsic mass effect • Surgical Defects o Look for calvarial defect or "tract" o Typically related to resection of mass o Ventricle enlarged unilateral to defect • Obstructive Hydrocephalus o Typically acquired & bilateral o May be unilateral if shunt complication or obstructing tumor is cause o Rare: Colloid cyst may obstruct unilateral foramen of Monro & cause unilateral ventriculomegaly • Choroid Plexus Cyst o Nonneoplastic, noninflammatory cyst of the choroid plexus o Common incidental finding in older patients (40% prevalence) o Typically bilateral, may be unilateral & enlarge lateral ventricle Helpful Clues for Less Common Diagnoses • Ventriculitis o Ventriculomegaly with debris level, enhancing ependyma o May affect lateral ventricles asymmetrically, particularly if related to shunt placement or abscess rupture • CSF Shunts and Complications o Common complications include shunt obstruction or breakage, infection, overdrainage

ASYMMETRIC LATERALVENTRICLES Asymmetric ventricles may result from overdrainage or underdrainage of an "isolated" ventricle • Meningioma o Intraventricular meningioma rare, typically left lateral ventricle o Associated with choroid plexus o Smooth enhancing intraventricular mass • Choroid Plexus Papilloma o Enhancing, lobulated intraventricular mass in a child o 50% in lateral ventricle atrium, left> right o May obstruct CSF flow or overproduce CSF o May have CSF spread of tumor • Neurocysticercosis o Intraventricular disease uncommon o Rarely may obstruct unilateral foramen of Monro & cause asymmetric lateral ventricle o Cyst with "dot" representing scolex characteristic o Tl & FLAIR best show intraventricular cysts o

Helpful Clues for Rare Diagnoses • Intraventricular Synechiae/Adhesions o May be congenital or acquired (prior bleed, infection, tumor) o Look for enhancing septae, intraventricular cysts within ventricle • Choroid Plexus Carcinoma o Enhancing intraventricular mass & ependymal invasion in young child o CSF seeding common

• Ependymal Cyst o Nonenhancing thin-walled cyst with CSF density/intensity o Lateral ventricle most common location • Dyke-Davidoff-Masson o Antenatal unilateral hemispheric infarction causes cerebral hemiatrophy o Ipsilateral calvarial thickening & hyperpneumatized frontal sinuses, temporal bones o Dilated ventricle from volume loss is ipsilateral to small hemisphere • Hemimegalencephaly o Unilateral hemispheric enlargement o Dilated, usually dysmorphic ventricle ipsilateral to enlarged hemisphere o Ipsilateral extra calvarial soft tissues may be larger

acrossmidline~.

::::l

a.

ro ...• III

::::l

;:0 C1> C 01

...

al "C

c

01

of the lateral

=

ventricles in addition to colpocephaly (enlargement of the posterior portions of lateral ventricles). Colpocephaly refleclS the predominantly posterior volume 1055. (Right) Axial NECT shows irregular enlargement of the left frontal horn 81 due 10 focal regional parenchymal volume los5 in this patient with remote

MCA

infarct.

(Left) Axial CECT shows a low density outpouching from the right lateral ventricle 1::1. While a thin rim of cortex seems intact, the cyst nearly reaches brain surface & can be considered a porencephalic dilation or porencephalic lateral ventricle cyst. (Right) Axial NfCTshowsirregu~r~ dilated occipital horns 1::1 with interdigitation of parietal & occipital parenchyma across midline PJ:ll due 10 a falx deficiency.

(Left) Axial T1 WI FS MR shows multifocal nodularity along ependymal margins of both lateral ventricles 1:12. These nodules follow gray matter signal on all sequences & do not enhance or change over time. (Right) Axial T2WI MR shows multiple calcified subependymalnodules (SEN) 1:12 lining ventricles. Note also subcortical tubers PJ:ll. SEN calcify much more commonly than

cortical/subcortical tubers.

I 3 56

Approximately 50% SfN are calcified by 10 years of age.

IRREGULAR lATERAL VENTRiClES

CIl

""c: Ql

:J Co

tll .., Ql

CMV, Congenital (Left) Axial T2WI MR shows

:J

near complete coating of the ependymal lining of both lateral

=

venlricles

with tumor

nodules due to metastatic seeding of anaplastic oligodendroglioma. (Right) Axial NECT shows periventricuJar calcification ~ particularly along the

cauda-striatal groove in the context of microcephaly & developmental delay. This strongly suggests congenital CMV inFection. Note smooth ventricular margins, unlike calciFied nodules in TSC complex.

(Left) Axial NECT shows Focal outpouchings of CSF From both lateral ventricles with a CSF cleFt extending From lateral ventricles to the subpial surface. The "pial-ependymal seam" is gray matter-lined. (Right) Axial T2WI MR shows cortical dysplasia & open-lip schizencephaly Schizencephaly is closed-lip with a Fusedgray matter lined pial-ependymal seam or open-lip with large, gray matter-lined & Fluid-Filled CSF cleFts.

=

=.

(Left) Axial T2WI MR shows enlargement of leFt cerebral hemisphere accompanied by an irregular ipsilateral ventricle The body of the leFt hemispheric white matter is bulky. Note leFt Fornix ~ overgrowth. (Right) Axial TlWI MR shows a large

=.

/I

horseshoe*shaped"

monovenlricle with fused basal ganglia. There is no interhemispheric fissure & no identiFiable lobulation or formation of ventricular horns in this a/abar holoprosencephaly patient.

I 3 57

PERIVENTRICULAR

IJ)

c:

o

ENHANCING

LESIONS

Cl Q)

0::

DIFFERENTIAL DIAGNOSIS Common • Multiple Sclerosis • ADEM • Lymphoma, Primary CNS

IJ)

Q)

U 'C

C Q)

> c: III

'm "C

c:

III

Less Common • Glioblastoma Multiforme • Abscess • Toxoplasmosis, Acquired • Germinoma • Metastases, Parenchymal • Vasculitis • Lyme Disease • Ependymoma Rare but Important • Leukemia • Susac Syndrome • Alexander Disease • Ependymal/Subependymal

o May be identical to MS • Lymphoma, Primary CNS o Enhancing periventricular WM or BG mass o Often extend along ependymal surfaces o Often crosses corpus callosum o Solid appearing mass with low T2 signal, mild DWI restriction o Hyperdense on CT

Helpful Clues for Less Common Diagnoses • Glioblastoma Multiforme o Peripherally enhancing WM mass with central necrosis o Surrounding T2 hyperintensity & significant mass effect common o Often crosses corpus callosum • Abscess o Ring enhancing mass in peri ventricular

WM Veins (Mimic) •

ESSENTIAL INFORMATION

•

•

•

•

I 3 58

Smooth, thin, linear enhancement DWI restriction characteristic Toxoplasmosis, Acquired o Multiple WM & BG ring enhancing masses o May show "target" sign o DWJ restriction variable o Typically seen in HIV patients Germinoma o Enhancing midline mass (pineal, suprasellar) typical o Occurs in BG or thalamus 5-10% o Hyperdense on CT o CSF spread common Metastases, Parenchymal o Gray-white junctions & multiple enhancing lesions typical o May occur in periventricular WM o Primary tumor often known Vasculitis o Irregularities, stenosis & vascular occlusions o Multifocal cortical/subcortical & BG T2 hyperintensities; DWI restriction if acute o Patchy enhancement typical o Angiography remains gold standard for diagnosis Lyme Disease o Periventricular T2 hyperintensities + enhancement in patient with skin rash & flu-like illness o Cranial nerve enhancement may occur • eN? often involved o May be identical to MS o o

PERIVENTRICULAR • Ependymoma o Majority (2/3) infra tentorial • 4th ventricle in a child • ± Extension through lateral recesses into CPA cisterns o 1/3 are supratentorial • Most are extraventricular • Typically periventricular WM o Heterogeneous enhancing mass o 50% are calcified o Cysts, hemorrhage common Helpful Clues for Rare Diagnoses

• Leukemia o Typically involves dura o May see along penetrating vessels or ependyma o Enhancing mass(es) in a child • Susac Syndrome o Clinical triad: Encephalopathy, retinal artery occlusions, hearing loss o Corpus callosum, BG, posterior fossa lesions o May be identical to MS • Alexander Disease o Diffuse symmetric bifrontal WM signal abnormality & enhancement o ear total lack of myelin o Infant with macrocephaly, seizures, developmental delay • Ependymal/Subependymal Veins (Mimic) o Normal periventricular venous structures may become engorged with various pathologies

Multiple Sclerosis

Axial Tl C+ MR shows numerous enhancing MS plaques in the periventricular ~ & subcortical white matter. Note typical lack of mass effect. ADEM & Lyme disease may be idenUcal.

ENHANCING

LESIONS

• Venous thrombosis, vascular malformations (AVM, DVA) Alternative

Differential

Approaches

• Mass involving corpus callosum: GBM, lymphoma, MS, ADEM • Mass in immunocompromised patient: Lymphoma, abscess, toxoplasmosis, metastases • Single enhancing mass: MS (tumefactive), ADEM (tumefactive), lymphoma, GBM, abscess, germinoma, ependymoma • Multiple enhancing masses: MS, ADEM, lymphoma, abscess, toxoplasmosis, metastases, vasculitis, Susac syndrome

ell

:J

0OJ

.., ell

:J

< CD ~ .., ~ CD

(f)

;:0 CD to

o· :J

(f)

SELECTED REFERENCES 1.

2.

3.

Lucchinetti CF et al: Clinical and radiographic spectrum of pathologically confirmed tumefactive multiple sclerosis. Brain. 131(Pt 7):1759-75, 2008 Hunt MA et al: Distinguishing primary central nervous system lymphoma from other central nervous system diseases: a neurosurgical perspective on diagnostic dilemmas and approaches. Neurosurg Focus. 21 (5):E3, 2006 Do TH et al: Susac syndrome: report of four cases and review of the literature. AJNR Am J Neuroradiol. 25(3):382-8, 2004

Multiple Sclerosis

Axial T1 C+ MR shows characteristic tumefaClive MS plaque with i((egula, thick, partial ring enhancement & mass effect These lesions may cross the corpus callosum & mimic tumors.

=.

I 3 59

PERIVENTRICULAR

(/)

c .Q

ENHANCING

LESIONS

Ol .;: Q)

0...

en Q)

"0 .;:

C Q)

>

:::J .>0:

C/)

Common • Physiologic Calcification, Choroid Plexus • Choroid Plexus Cyst • Neurocysticercosis • Neurofibromatosis Type 2 • Tuberous Sclerosis Complex less Common • Meningioma • Ependymoma • Intraventricular Hemorrhage (Mimic) • Choroid Plexus Papilloma • Subependymal Giant Cell Astrocytoma • Subependymoma • Central Neurocytoma • Cavernous Malformation • TORCH, General (Mimic) Rare but Important • Medulloblastoma (PNET-MB) • Choroid Plexus Carcinoma • Craniopharyngioma

ESSENTIAL INFORMATION

I 3 62

• Nodular calcified (healed) stage: Small, Ca++ nodules o Typically subarachnoid spaces; may involve cisterns> parenchyma> ventricles o Intraventricular cysts are often isolated; 4th ventricle most common o Most common cause of cerebral Ca++ under 30 years • Neurofibromatosis Type 2 o Nonneoplastic cerebral Ca++ is uncommon manifestation o Extensive choroid plexus Ca++ > cortical surface Ca++ > ventricular lining Ca++ • Tuberous Sclerosis Complex o Ca++ subependymal nodules (SEN), 98% of patients • Along caudothalamic groove> atrial> > temporal • 30-80% of SEN enhance, best seen on MR o Cortical/subcortical tubers, WM lesions 70-95% Helpful Clues for less Common Diagnoses • Meningioma o Calcified (20-25%): Diffuse, focal, sand-like, sunburst, globular, rim o Approximately 1% are intraventricular o Most common in left lateral ventricle • Ependymoma o Soft or "plastic" tumor: Squeezes out through 4th ventricle foramina o Ca++ common (50%) o 2/3rd infratentorial, arise from floor of 4th o Hydrocephalus common; ± cysts, hemorrhage • Intraventricular Hemorrhage (Mimic) o Typically associated with trauma o May be primary presentation of AVM o Acutely, hyperdense blood may mimic intraventricular Ca++ o May result in Ca++ in chronic phase • Choroid Plexus Papilloma o Intraventricular, papillary neoplasm derived from choroid plexus epithelium o Child with strongly enhancing, lobulated intraventricular mass; Ca++ in 25% o 50-70% - atrium of lateral ventricle o 4th ventricle most common site in adults • Sub ependymal Giant Cell Astrocytoma o Enhancing mass at foramen of Monro o Ca++ common; hydrocephalus common o Occurs in 15% of TSC patients

INTRAVENTRICULAR

CALCIFICATlON(S)

(J)

""r::

• Subependymoma o Rare, benign, well-differentiated, and intraventricular, ependymal tumor o T2 hyperintense lobular, nonenhancing intraventricular mass o May see cysts, hemorrhage, Ca++ o Inferior 4th (60%) > lateral ventricle • Central Neurocytoma o Typical "bubbly" appearance; Ca++ common o Lateral ventricle, attached to septum pellucidum o Moderate to strong enhancement • Cavernous Malformation o Rarely intraventricular, 2.5-11 % of cases o Ca++ & T2 hypointense hemosiderin rim common o Enhancement variable • TORCH, General (Mimic) o Acronym for congenital infections caused by transplacental transmission of pathogens o Taxa, CMV, HIV, & rubella cause parenchymal &/or periventricular Ca++ Helpful Clues for Rare Diagnoses • Medulloblastoma (PNET-MB) o Malignant, invasive, highly cellular embryonal tumor o 4th ventricle tumor, arise from roof (superior medullary velum) o Hydrocephalus common (95%) o 90% hyperdense related to high nuclear:cytoplasmic ratio

Physiologic

Calcification,

Choroid

Plexus

Axial NECT in a padent who presented following trauma. Note symmetric physiologic Ca++ ~ in the auia of the lateral ventricles in this young patient.

Ca++ in up to 20% Small tumor cysts/necrosis in 40-50% • Choroid Plexus Carcinoma o Child < 5 y, with enhancing intraventricular mass & ependymal invasion o Ca++ in 20-25% o Almost all in lateral ventricle o May see necrosis, cysts & hemorrhage • Craniopharyngioma o Partially Ca++, partially solid, cystic suprasellar mass in a child o Typically sellar & suprasellar o Rare within third ventricle o o

Alternative Differential Approaches • Calcified intraventricular mass: Adult o Meningioma (lateral ventricle) o Subependymoma (4th> lateral ventricle) o Central neurocytoma (lateral ventricle) o Cavernous malformation o Neurocysticercosis (4th ventricle) • Calcified intraventricular mass: Child o Ependymoma (4th ventricle) o Choroid plexus papilloma (lateral> 4th ventricle) o Subependymal giant cell astrocytoma (foramen of Monro) o Medulloblastoma (4th ventricle) o Craniopharyngioma (3rd ventricle)

Choroid

Plexus Cyst

Axial CECT shows bilateral choroid plexus cysts (xanthogranulomas), a common incidental finding in older patients. The cysts are calcified =::I & show mild rim-enhancement.

I 3 63

INTRAVENTRICULAR

C/)

c

.Q OJ Q)

0:::

(Left) Axial T2' CRE MR shows mullifocal

C/) Q)

u ·C C Q)

> C nl

Ca++

in

this patient with nodular calcified NCe. Note focal intraventricular Ca++ Ca++ typically occur at convexity subarachnoid spaces. (Right) Axial N[CT shows globular Ca++ within the ventricles in unusual

•.... 1IJ

locations

"C

the presence of extensive &/o( unusual intraventricular Ca++ suggests NF2.

c nl

Monro).

(foramen In

a

of

young patient,

(Left) Axial NECT shows bilateral Ca++ subependymal nodules in this tuberous sclerosis patient. These occur along caudothalamic groove, atria, & temporal horns. 50% calcify; progressive after I year. (Right) Axial NECT shows a hyperdense mass with central ~ & rim Ca++ in the left lateral ventricle.

Note associated

ventricular enlargement Approximately I % of meningiomas

~.-

are

intraventricular.

(Left) Axial NECT shows a partially calcified mass within the 4th ventricle. Ependymomas often partially calcify (50%) & characteristically extrude through the 4th ventricular foramen. (Right) Axial N[CT shows a lobulated mass in the atrium of the lateral ventricle with focal Ca++ 81. Note the marked expansion & septation of the lateral ventricle

=.

I 3 64

CAlCiFICATION(S)

I NTRAVENTRICU

LAR CALCIFICATION

(5)

C/l

" c: Ql

:J

Co

..,

lJl Ql

(Left) Axial NECT shows a calcified

foramen

or Monro

mass 81. Note dilated lateral ventricle

indicating

ventricular obstruction. Often, hydrocephalus is first presentation of tuberous sclerosis. (Rigl1t) Axial NECT shows a densely calcified 4th ventricular mass. Although

:J


2 months old! o If congenital infection is diagnostic consideration, obtain NECT to detect Ca++ CMV, Congenital o Most common cause of intrauterine infection in USA o Timing of infection predicts pattern of damage o Hypomyelination o Cortical gyral anomalies o Microcephaly o Symmetric periventricular Ca++ in 30-70% Toxoplasmosis, Congenital o Periventricular & scattered Ca++ o Hydrocephalus (colpocephaly-like) Herpes Encephalitis, Congenital o Calcification pattern varies in HSV2 • Asymmetric periventricular • Scattered periventricular and deep gray • Subcortical white matter & cortex • Calcification pronounced in foci of hemorrhagic ischemia • Like rubella, rare cause of "stone brain" o Brain atrophy or cystic encephalomalacia • Focal or diffuse HIV, Congenital o Vertical HIV infection o Basal ganglia Ca++, atrophy o Consider congenital HIV if bilateral symmetric basal ganglia C++ identified in child> 2 months old! Rubella, Congenital o Periventricular and scattered o Scattered or hazy basal ganglia Ca++ o Rare "stone brain" • Extensive gyral calcification & gliosis o Micro-infarcts Tuberous Sclerosis Complex o Look for cutaneous markers of TS o Subependymal nodules • Variable-sized periventricular calcifications o Cortical tubers also calcify o

DIFFERENTIAL DIAGNOSIS

•

•

•

Helpful Clues for Less Common Diagnoses • Neurocysticercosis o Best clue: Dot inside cyst o Usually convexity subarachnoid space o Also gray-white junction, intraventricular o Nodular calcified (healed) stage

PERIVENTRICULAR

• Shrinks to small Ca++ puncta or nodule • Tuberculosis o Best diagnostic clue: Basal meningitis and pulmonary TB o Acute • Typically basal meningitis • ± Localized CNS tuberculoma o Chronic • Residual pachymeningeal • ± Localized Ca++ o "Target sign" • Calcification surrounded by enhancing rim (not specific) • Ventriculitis (Chronic) o Areas of prior hemorrhagic infarction prone to dystrophic calcification • Germinal Matrix Hemorrhage o Occasional ependymal, germinal matrix calcific foci Helpful Clues for Rare Diagnoses • Radiation and Chemotherapy o History! o Mineralizing microangiopathy • Pseudo-TORCH o Aicardi-Goutieres Syndrome • "Mendelian mimic of congenital infection" • Multifocal punctate calcifications • Variable locations including periventricular white matter, basal ganglia, dentate nuclei • Elevated CSF interferon (IFN-a) • TREXI mutations in some

CMV, Congenital

within

cortex

1m

in this deaf child,

o

C/l

c: "

Coats-Plus Syndrome • a.k.a., cerebroretinal microangiopathy with calcifications and cysts (CRMCC) • Ocular coats: Retinal telangiectasia & exudate • CNS small blood vessel calcification • Extensive thalamic and gyraJ calcification • Defects of bone marrow & integument • Growth failure

SELECTED 1.

2.

3.

4. 5.

6.

7.

8.

III

:l

Q.

...

OJ III

:l

REFERENCES

Briggs TA et al: Cerebroretinal microangiopathy with calcifications and cysts (CRMCC). Am J Med Genet A. I 46A(2): 182-90, 2008 Crow YJ et al: Aicardi-Goutieres syndrome: an important Mendelian mimic of congenital infection. Dev Med Child Neural. 50(6):410-6, 2008 Rice G et al: Clinical and molecular phenotype of Aicardi-Goutieres syndrome. Am J Ilum Genet. 81(4):713-25,2007 Linnankivi T et al: Cerebrorelinal microangiopathy with calcifications and cysts. Neurology. 67(8):]437-43, 2006 Abdel-Salam GM et al: Aicardi-Goutieres syndrome: clinical and neuroradiological findings of ]0 new cases.Acta Paediatr. 93(7):929-36, 2004 Malinger Get al: Fetal cytomegalovirus infection of the brain: the spectrum of sonographic findings. AJNR Am J Neuroradiol. 24(1):28-32, 2003 Numazaki K et al: Intracranial calcification with congenital rubella syndrome in a mother with serologic immunity. J Child Neurol. 18(4):296-7, 2003 Tanaka F et al: Association of osteopontin with ischemic axonal death in periventricular leukomalacia. Acta Neuropathol. 100(1):69-74,2000

;;u Cll

(Q

o· :l

(/)

CMV, Congenital

Coronal NECT shows classic findings of TORCH. Note linear periventricular Ca++ ~ with scattered Ca++ foci

intrauterine CMV exposure.

CALCIFICATION

suggesting prior

Sagittal T2WI MR shows a thick cortex with small gyri, hyperintense white maNer and a thin layer of calcification!J:.:l in the same 18 month old deaf toddler.

I 3 67

PERIVENTRICUlAR

'"c:o OJ Ql

0:::

'"

Ql

U 'C

C Ql

>

(Left) Axial NECT shows basal ganglia SII and perivenuicular calcifications ~ in a child with typical colpocephalic dilation of the ventricles. (Right) Coronal T2WI MR shows marked ventriculomegaly and loss of the perivenlricular while

c:

malter.

III

and basal ganglia calcifications are occult on MR but do involve the right choroid plexus glomus

•....

al

"0

c: III

The periventricular

(Left) Axial NECT shows scattered and peri ventricular calcifications. In this child, there is unilateral left-sided colpocephaly~. Note severe cortical mantle thinning SII over the cofpocephalic ventricle. (RighI) Axial T2' GRE MR shows similar findings, although the calcifications

e:I are not as well-visualized.

(Left) Axial NEeT in child who survived congenital herpes encephalitis shows scattered parenchymal calcifications ~. (Right) Axial NECT in same patient shows calcifications of the infarcted Rolandic cortex SII. They can be variable, predominantly involving damaged brain.

I 3 68

CALCIFICATION

PERIVENTRICUlAR

CALCIFICATION

CJl

" C

Rubella, Congenital (Left) Axial NECT shows hazy, symmetric basal ganglia calcification with diffusely prominent sulci and cisterns consistent with volume loss. In this one year old, the findings are highly suggestive of congenital I II V. (Right) Axial NEeT shows basal ganglia calcifications 81 and diffuse white matter

=

hypoinlensily.

There are faint

bilateral subependymal calcifications lining the

posterior horns

=.

Tuberous Sclerosis Complex (Left) Sagittal ultrasound in child with TSC, subependymal giant cell astrocytoma shows mass indenting lateral ventricle B. Tumor shows increased echogenicity (Right) Axial NECT shows variable

=.

calcification

in the

subependymal nodules. Calcification in these lesions progresses over lime.

(Left) Axial CECT shows disseminated "miliary" form of neurocysticercosis (NCC).

Note numerous cysts, each with a hyperdense central "dot" representing scolex small calcific foci, some of which are peri ventricular Eel cause

=. Innumerable

classic "starry sky" appearance of healed NCe. (Right) Axial T2' CRE MR show scattered calcifications throughout the brain. A few are in the deep gray structures and one is

=

intraventricular ~.

I 3 69

en c

PERIVENTRICULAR

CALCIFICATION

.Q Ol Q)

0:: ~ ro :J

U

Tuberculosis

.0:

C Q)

> .0: Q)

CL

en

Q)

u E

c Q)

>

Tuberculosis

(Left) Axial NECT shows nodular calcification E2 along the postero-medial temporal lobe on the tentorial surface. (RighI) Axial CECT in same patient shows the calcification to be largely obscured by the thick rind of pachymeningeal and leptomeningeal thickening and enhancement

=

H2.

:J

-'"

III

(Leh) Axial T7 WI MR early in the course of the disease shows hemorrhagic infarction H2 of the ependyma and subependymal brain. (RighI) Axial NECT shows subependymal tissue necrosis and calciFication

the same areas

in

m.

Germinal aeft)Ax~/N[CTshows while matter deficiency

due

to perivenlricular

leukomalacia. The gray matter I!:'J nearly approximates the ventricular surface. Small perivenlricular calcifications Ea are present at the site of prior germinal matrix hemorrhage. (Right) Axial NECT shows bilateral symmetric calcifications at the gray-white junction H2 due to mineralizing microangiopathy following radiation and chemotherapy.

I 3 70

Matrix

Hemorrhage

Radiation and Chemotherapy

PERIVENTRICULAR

en

CALCIFICATION

:0:r::

III

::s

Q.

OJ .,

Radiation and Chemotherapy

Aicardi-Goutieres

Syndrome

III

(Left) Axial T2WI MR from the same patient shows while mailer demyelination l:l:I. The calcificalions are occult. (Right) Axial NECT shows brain alrophy and bilaleralsymmelrical calcifications in the basal ganglia ~. Extension into the corona radiata (nol shown) was also present

::s

< en ;:!. ::::!. Cl

CD (f)

;;u en to

o ::J

(f)

Aicardi-Goutieres

Syndrome

Aicardi-Goutieres

Syndrome (Left) Axial PO FSEMR shows extensive abnormal signal of white maller and volume 1055of gray & while matter. Faint calcifications ~ are presenl, allhough they are less well seen on MR lhan on NECT (Right) Coronal T2WI MR again shows severe volume loss. Faint perivenlricular

calcificalions ? and basal ganglia calcificalions ~ are present, mimicking the appearance of TORCH infections.

Coats-Plus

Syndrome

Coats-Plus

Syndrome (Left) Axial NECT shows extensive Byra!, brainstem, and perivenlricular calcifications. The brainstem is also swollen ~ and low density. Note post-operative change of lhe righl globe. (Right) Axial NECT shows dense perivemricular calcification that extends to involve the sparse subcortical white maller posleriorlya lhe fronlal while maller, cortex, and lhalami~. The pal/ern of calcification is lypical, although swelling occurs

I

first.

3 71

PERIVENTRICUlAR

CI)

c

o

T2/HAIR

HYPERINTENSE

lESIONS

Ol (!)

0:: ~

DIFFERENTIAL DIAGNOSIS

C1l

:::J

U

·C

C (!) >

·C (!)

0.. CI) (!)

u E c (!)

>

Common • Aging Brain, Normal • Arteriolosclerosis • Multiple Sclerosis • ADEM • Diffuse Axonal Injury (DAI) • Metastases, Parenchymal

c:

less Common • Radiation and Chemotherapy • Periventricular Leukomalacia • Lyme Disease

'"

• Vasculitis

c:

~ '"

aJ

"0

• • • •

(PVL)

Obstructive Hydrocephalus Drug Abuse CADASIL Susac Syndrome

Rare but Important • Metachromatic Leukodystrophy • X-Linked Adrenoleukodystrophy • Mucopolysaccharidoses • TORCH Infections

(MLD)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Peri ventricular T2/FLAIR hyperintense lesions are often nonspecific, with significant overlap among etiologies • These guestions help narrow differential o How old is the patient? o Volume loss vs. mass effect? o Are there T2 * GRE "black dots"? o Is there enhancement? o Is the corpus callosum (CC) involved? o Are the basal ganglia involved?

I 3 72

Helpful Clues for Common Diagnoses • Aging Brain, Normal o Smooth, thin rim of peri ventricular hyperintensity, wide sulci, prominent ventricles o Sparing of cortex, subcortical/deep white matter (WM) & basal ganglia (BG) • Arteriolosclerosis o Patchy confluent & focal lesions; subcortical/deep WM & BG involved; ± cortical infarcts oGRE: Associated "black dots" (overlap with chronic hypertension & amyloid)

• Multiple Sclerosis o Linear/ovoid callosal & perpendicular caIJososeptallesions • Infratentorial (esp. brachium pontis, brainstem), optic nerve, spinal cord o T1 MR: Hyperintense rim: Chronic plague o T1 C+ MR: Enhancement with active disease: Nodular> ring> semilunar • ADEM o Lesions have less mass effect than expected for size; BG lesions common o T1 C+ MR: Enhancement & appearance may mimic MS; often need flu exam o Clinical: Viral prodrome or recent vaccination; monophasic • Diffuse Axonal Injury (DAI) oGRE: Multiple "black dots" at gray/white interface, CC, deep gray matter, brainstem o Clinical: Trauma patient • Metastases, Parenchymal o T1 C+ MR: Multiple enhancing masses at gray/white interface o T2/FLAIR: Hyperintensity has mass effect (vasogenic edema) Helpful Clues for less Common Diagnoses • Radiation and Chemotherapy o Numerous appearances based on injury • Periventricular leukoencephalopathy: Confluent T2 hyperintensity, spares subcortical V-fibers & CC • PRES: Symmetric posterior circulation subcortical/peri ventricular T2 hyperin tensi ty • Radiation necrosis: Vasogenic edema surrounds irregular, enhancing lesion(s) • Periventricular Leukomalacia (PVL) o Early: Periventricular cystic changes o Late: Undulating ventricular borders, ventriculomegaly, WM volume loss o Clinical: Pre term birth, spastic diplegia, visual & cognitive impairment • Lyme Disease o T1 C+ MR: Multiple enhancing cranial nerves; CN7 common o WM lesions may be identical to MS o Clinical: Meningoencephalitis, ± history of skin rash (erythema migrans); higher prevalence in New England • Vasculitis o Restricted diffusion in acute phase

PERIVENTRICULAR

T2/FLAIR

HYPERINTENSE

LESIONS

CIl

~ c:

T2/FLAIR MR: Ranges from normal to patchy asymmetric hyperintensity in multiple small vessel territories o DSA: Regions of alternating stenosis & dilatation primarily involving 2nd, 3rd order branches Obstructive Hydrocephalus o Periventricular "halos": Fingers of CSF-like hyperintensity most pronounced at ventricular horns o Ventricles dilated without sulcal widening or cortical volume loss Drug Abuse o Confluent peri ventricular WM; corticospinal tract & deep grey matter; often hemorrhagic o Cerebellar involvement in absence of hypertension, characteristic of inhaled heroin ("chasing the dragon") o Can cause a vasculitis CADASIL o Subcortical lacunar infarcts & leukoencephalopathy in young adult o Anterior temporal pole & external capsule lesions highly sensitive/specific o Frontal lobe has highest lesion load Susac Syndrome o Central CC > callososeptallesions o WM lesions may be identical to MS o Clinical triad: Encephalopathy, hearing loss, branch retinal artery occlusions o

•

•

•

•

Axial FLAIR MR shows prominent venlric/es, wide cortical sulci, and a thin rim of periventricular while matter hyperintensity 1:::1 in an elderly individual.

III

Helpful Clues for Rare Diagnoses

• Metachromatic Leukodystrophy (MLD): Confluent "butterfly-shaped" cerebral hemispheric WM T2 hyperintensity • X-Linked Adrenoleukodystrophy: Enhancing peri-trigonal WM demyelination • Mucopolysaccharidoses: T2 hyperintensity surrounds dilated MPS-filled PVS • TORCH Infections: Variable WM T2 hyperintensity, ± calcification Alternative

Differential

::l

Co tll

....•

III

::l

< CD ~ ....• ~ CD

'"

Approaches

• Patient age o Elderly: Normal aging, arteriolosclerosis, metastases o Young adult: MS, ADEM, vasculitis, drug abuse, CADASIL o Infant to child: ADEM, PVL, MLD, TORCH • Volume loss vs. mass effect o Volume loss: Normal aging, arteriolosclerosis, MS, PVL, CADASIL o Mass effect: MS (active), ADEM, metastases, obstructive hydrocephalus • T2 * GRE "black dots" present o Arteriolosclerosis, DAI, periventricular leukoencephalopathy (+ radiation-induced vascular lesions), chronic hypertension • Enhancement: MS, ADEM, Lyme disease, metastases, radiation necrosis • Corpus callosum involved: MS, ADEM, DAI, Susac syndrome • Basal ganglia involved: Arteriolosclerosis, ADEM, DAI, vasculitis, drug abuse

Axial FLAIR MR shows confluent periventricular and subcortical hyperintensity, focal right thalamus SI and left putamen I!:ll hyperintensity with diffuse white malLer volume 1055.

;0 CD

0, ~0> UJ

"0

0> ()

CD

en

0>

::J

C.

UJ

c

C-

.., O>

0> ()

::T ::J

o

Ci

o weD .., ::J

en

I 4 5

en c ~

EPIDURAL

MASS, BRAIN

Q)

~

U "0

·0 C £ U

co ~ co

.n ::J (f) "0 C

co en Q)

u

co

Q. (f)

Dural Metastasis (Left) Axial T7 C+ MR shows an enhancing

= related

epidural

mass

to a calvarial metastasis in this patient with renal cell carcinoma. (Right) Coronal T7 C+ MR shows a dural-based enhancing mass in a patient with systemic lymphoma.

=

co

·x

co, co ~

X

w C III

"-

CO "t:l

c III

Neurosarcoid (Left) Axial T7 C+ MR shows a lobulated, dural-based mass that infiltrates the brain, causing underlying edema. Note subtle sulcal enhancement~. (Right) Coronal T7 C+ FS MR shows two epidural fluid collections with rim-enhancement Note the underlying sinusitis

=

=.

~

Tuberculoma (Left) Axial NEeT a hyperdense dural-based mass =:I that enhanced following

contrast

administration (not shown). Dura/tuberculoma was found at surgery. (Right) Axial T2WI MR shows a solitary osteolytic skull plasmacytoma with a large tumoral component that displaces the relatively normal dura ~

=

I 4 6

Lymphoma

EPIDURAL

,..

en

MASS, BRAIN

c: III

:J Co

Meningioma,

Ol ....•

Atypical and Malignant

III

(Left) Sagillal T1 C+ MR shows a heterogeneously enhancing mass with extension through the calvarium and into the scalp and a "mushrooming" pattern of brain invasion with associated edema. (Right) Axial T1 C+ MR shows a large hemangiopericyloma with transcalvarial extension ~ and heterogeneous

=

=

enhancement.

:J

m

~ ....• OJ , OJ

x

or UJ

-0

OJ ()

C1>

(f)

OJ

:J 0.

UJ

c:

0-

OJ ....• OJ ()

:T :J

o

a: o (ii' CD ....• Extramedullary

Hematopoiesis

:J

leukemia

(f)

(Left) Axial NECT shows a lobulated, hyperdcnse, dural-based mass 1::1. The mass was profoundly hypointense on T2WI and enhanced strongly following contrast administration. (Right) Axial NEC r shows a hyperdense bifrontal mass 1::1 with adjacent calvarial destruction and frontal sinus invasion

Gliosarcoma

langerhans

Cell Histiocytosis (Left) Axial T1 C+ MR shows

a left frontal mass with heterogeneous, thick, irregular enhancement and central necrosis, typical for gliosarcoma. Note the dural invasion SII. (Right) Axial T1 C+ FS MR shows a destructive, avidly enhancing, mastoid lesion with epidural extension

=.

I 4 7

ENLARGED SULCI, GENERALIZED

(/)

c: ~ Q)

~

U

DIFFERENTIAL DIAGNOSIS

"0

·0 c: .!: u

ro ~ ro .0 :J CfJ

"0

c: ro (/)

Q)

u ro

Q.

CfJ

ro

·x ro

ro~ xw

.=~ Ol

al

"0

c: Ol

:J

-"III

Common • Aging Brain, Normal • Dementias o Alzheimer Dementia o Vascular Dementia o Dementia with Lewy Bodies o Frontotemporal Dementia • Chronic Alcoholic Encephalopathy • HIV Encephalitis Less Common • Chronic Hepatic Encephalopathy • Remote Generalized Insult o Trauma o Hypoxic Ischemic Encephalopathy o Meningitis o Encephalitis (Miscellaneous) o Multiple Sclerosis (Longstanding) o Radiation and Chemotherapy o Other Toxic/Metabolic Insults • Enlarged Subarachnoid Spaces (Benign Macrocrania of Infancy) Rare but Important • Steroids • Volume Loss Secondary to Nutrition or Hydration Status • Miscellaneous Neurodegenerative Disorders o Corticobasal Degeneration o Parkinson Disease o Huntington Disease o Multiple System Atrophy • Creutzfeldt-]akob Disease (ClD)

ESSENTIAL INFORMATION

I 4 8

Key Differential Diagnosis Issues • Some age-related volume loss (especially cortical) normal • Location helpful o Generalized or disproportionately affecting some parts of brain more than others? o Parieto-temporal/hippocampal (Alzheimer), frontotemporal (FTD or Lewy body disease) vs. parieto-occipital (Heidenhain variant of C]D) • Clinical information helpful o History of trauma, drug abuse, stroke, infection o

Dehydration, steroids may cause temporary

sulcal enlargement

o

Metabolic/demyelinating disorders (inherited or acquired, longstanding) may cause volume loss, sulcal enlargement

Helpful Clues for Common Diagnoses • Aging Brain, Normal o White matter volume decreases o Mild/moderate ventricular, sulcal enlargement o Thin periventricular hyperintense rim o Scattered white matter hyperintensities increase with age, normal o "Black dots" on GRE/SWI are NOT normal • Chronic hypertensive encephalopathy • Cerebral amyloid angiopathy • Dementias o Evaluate for other treatable (potentially treatable) causes of dementia (e.g., repeated trauma with subdural hematoma) • Endocrinopathy (e.g., hypothyroidism) • Alcohol/drug abuse • Depression ("pseudodementia") o General imaging findings • Differentiation solely on basis of CT, standard MR difficult • PET, fMRI helpful o Alzheimer Dementia • Temporal (especially hippocampal), parietal atrophy • Hypometabolic areas, perfusion deficits o Vascular Dementia • Second most common dementia • Volume loss, multiple chronic infarcts, lacunes • Multifocal white matter disease, often confluent (arteriolosclerosis) o Dementia with Lewy Bodies • Visual/a uditory hallucinations, delusions • Entire brain hypo metabolic (including visual cortex, cerebellum) o Frontotemporal Dementia • Anterior frontotemporal atrophy • "Knife-like" gyri • Up to 40% familial (tau mutations) • Chronic Alcoholic Encephalopathy o Generalized & cerebellar (superior vermian) atrophy o Hyperintense basal ganglia on Tl WI suggests chronic hepatic encephalopathy o Polydrug abuse common o Methanol less common; causes hemorrhagic putaminal necrosis

ENLARGED SULCI, GENERALIZED

en ;;r:: c:

• HIV Encephalitis o Most common imaging finding in brains of HIV/AIDSpatients o Diffuse atrophy, "hazy" white matter hyperin tensi ty Helpful Clues for Less Common Diagnoses • Chronic Hepatic Encephalopathy o History of alcohol abuse, liver disease common o Atrophy (especially cerebellum), T1 shortening (especially globi pallidi) • Remote Generalized Insult o Any longstanding, sufficiently severe disease may cause brain atrophy, sulcal prominence o Trauma, infection, demyelination, radiation/ chemothera py, toxic/metabolic/hypoxic insult • If patients survive, brain often shrinks and sulci enlarge • Very chronic MS causes severe white matter loss, sulci enlarge, basal ganglia become hypointense • Enlarged Subarachnoid Spaces (Benign Macrocrania of Infancy) o Enlarged SASscommon in infancy • Bifrontal, symmetric • Peaks about 7 months, tends to resolve after age 1 o Danger signs • Rapid t OFC or signs of t ICP • Asymmetric, persisting after 1 year • Asymmetric

Helpful Clues for Rare Diagnoses • Steroids o May cause transient, reversible sulcal enlargement • Volume Loss Secondary to Nutrition or Hydration Status o Starvation, dehydration (may be reversible) • Miscellaneous Neurodegenerative Disorders o Multiple system atrophy (midbrain, corticobasal degeneration) o Parkinson-associated dementia (midbrain with loss of pars compacta) • Creutzfeldt-]akob Disease (ClD) o Early findings • Hyperintensity in anterior basal ganglia • "Pulvinar sign" (hyperintensity in posterior thalamus) • FLAIR,DWI positive o Later findings • Rapidly progressive atrophy, ventricular dilatation o Heidenhain variant • Peripheral cortex, especially occipital

':" l Q.

..• OJ

'"

:l

m ~ ..•OJ , OJ

x

Qj' Ul

'0 OJ

()

l1>

(f>

OJ :l Q.

Ul C

CT OJ .., OJ ()

:::T :l

o

a: o (f>

CD .., ::J (f>

I Axial T2Wf MR shows mild sulcal prominence with minimal while matter hyperinlensilies in this high-functioning 76 year old man. No/e normal sylvian fissures,/emporal horns, hippocampi =:11.

Axial T2WI MR in a 63 year old man with Alzheimer dementia shows large sylvian fissures, la/eral ventricles. The parie/o-occipital sulci are lessseverely affected.

4 9

ENLARGED SULCI, GENERALIZED

VJ C

~

(f) 1:l C CO VJ

subdural blood in Ihis child with repealed

trauma.

I 4 10

nonaccidental

Frontotemporal Dementia

ENLARGED SULCI, GENERALIZED

(fl

"

c: III

:J

Co

tll ., III

(Left) Axial T2WI MR in a patient with longstanding MS shows classic peri ventricular plaques

("Dawson

fingers")

>< 0;.

ventricular, sulcal White matter

(fl

volume loss, steroids can cause sulcal enlargement. (Right) Axial T2WI MR following whole brain XRT shows diffuse, symmetric white matter hyperintensily, enlarged ventricles and sulci.

=

Two focal hypointensities

are probably radiation-induced malformations.

m

~ ., OJ , OJ

IIJI. Note generalized enlargement.

:J

vascular

-0 OJ Cl C1l

en OJ

:J

C. (fl

TS as cause for diffuse brain swelling o TS + vein of Labbe may cause extensive venous ischemia, hemorrhage, frank infarct

EFFACED SULCI,

en

GENERALIZED

~ c:

NECT shows hyperdense sinus; CECT ~ "empty delta sign" o Beware: Hyperacute thrombus is isointense on 1'1WI, hypointense on T2WI (may mimic "flow void")! o T2* (GRE, SWI) best MR sequence to show blooming clot • Thrombosis, Deep Cerebral Venous o Hyperdense ICVs, straight sinus o Hyperdense thrombosed rcvs can make NECT look like CECT scan! o Hypodensity in thalami, basal ganglia, internal capsules, deep periventricular white matter • Acute Hypertensive Encephalopathy, o

PRES

Bioccipital cortical/subcortical edema, sulcal obliteration most common o May affect brainstem, cerebellum, basal ganglia, watershed (sometimes ONLY these areas without classic posterior cerebral territory involvement) o Hypodense on NECT, hyperintense on T2WI/FLAIR o Typically does not restrict on DWI • Status Epilepticus o Prolonged seizure causes hypermetabolic state, blood-brain-barrier leakage o Imaging within 24 hours after ictus • Cerebral edema (gyraJ swelling, sulcal obliteration) • May cause transient enhancement • May cause DWI restriction o

May mimic encephalitis, ischemic stroke, even neoplasm! o Follow-up scan shows resolution • Intracranial Hypertension, Idiopathic o Severe "pseudotumor cerebri" may cause diffuse brain swelling, papilledema, small ventricles o Look for "empty sella" plus dilated optic nerve sheaths indenting posterior globe o

:J

C.

OJ ., III

:J

m ~ OJ

0, ~,

III

en

" III ()

Helpful Clues for Rare Diagnoses • Contrast Complications o Contrast overdose may cause diffuse cerebral edema o Renal failure may cause gadolinium-based agents to accumulate in CSF, show sulcal enhancement on FLAIR • Cerebral Hyperperfusion Syndrome o Rare complication following carotid endarterectomy o Defined as a> 100% increase in CBF • Occurs in 10-15% of patients but minority become symptomatic • Can develop immediately or within first few days (mean = 5 days) although some reports up to a month • Triad of ipsilateral headache, focal seizure, neurologic deficit in absence of cerebral ischemia • Most symptomatic patients are hypertensive • Unilateral cerebral edema with gyral swelling, vascular enhancement; decreased MTT on perfusion CT, MR Toxic/Metabolic

Cerebral

III

Edema, Traumatic



en Q)

:J

0.

en c:

0Q)

.,

Q)

()

::r

:J

o

Ci

o iii'

CO

3

en

Encephalopathies (Many)

I Axial NECT shows diffuse brain swelling with loss of gray·while differentiation, diffuse sulcal effacement.

Small subdural hematoma is present ~.

Axial NECT in a padent with chronic hepadc encephalopathy and acute exacerbation shows diffuse cerebral edema, obliterated sulci, and effaced gray-while

matler.

4 13

EFFACED SULCI, GENERALIZED

(/l

c

'-Q)

u;

o -0

'0 C

~

Subdural Hematoma, Subacute

u

ro '-ro

.n ::J (fJ

-0 C

ro

(/l Q)

u

ro

n. (fJ

ro

'x ro,

ro '-X w C l'Cl

...

Acute Obstructive

Hydrocephalus

(Left) Axial NEeT shows perfeclly isodense subdural hematomas ~ same attenuation as cortex. All sulci are obliterated except one where CSF is seen in a sulcus displaced away Irom inner table ffi (Right) Axial NECT shows absence of visualized cerebral aqueduct ~ with enlarged 3rd, lateral ventricles and diffuse brain swelling. "Blurred" margins of lateral ventricles indicate transependymal CSF flow.

al "C

c l'Cl

Meningitis (Left) Axial NECT shows sulcal ell a cement over /elt convexity (contrast with normal-appearing right sulci) secondary to pyogenic meningitis &. Asymmetric involvement is unusual. (Right) Axial TlWI MR shows basal cisterns sulci I:llI appear effaced because they are lilled with isointense acute blood, not normal hypointense CSF Note acute obstructive hydrocephalus with blood-fluid levels in dilated lateral ventricles

Metastases, Skull and Meningeal (Left) Axial FlAIR MR in a patient with prostate cancer, headaches, shows normal right-sided sulci, thickened dura and infiltrated sulci m over entire left hemisphere. (Right) Coronal T I C+ MR in a patient with viral encephalitis shows diffuse right hemisphere swelling, especially temporal lobe. All surface sulci are obliterated. Note subIa/cine herniation from mass effect

I 4 14

Aneurysmal Subarachnoid Hemorrhage

,..c:

EFFACED SULCI, GENERALIZED

(Jl

Ql

:J

a. III ...• Ql

(Left) Axial NEeT shows 555 occlusion SlI with parenchymal subarachnoid hemorrhage PJ:iil. Note near-complete effacement of right hemisphere sulci compared to more normal left side. (Right) Axial NEeT shows hyperdensity in both internal cerebral veins and straight sinus =:I. Hypodensity in bilateral thalami SlI is

=-

consistent

edema

with

and/or venous ischemia . Most sulci, cisterns appear effaced by brain swelling.

:J

m

~ ...• OJ, OJ

~. OJ

UJ

-0 OJ

(1

CO

rJl

OJ

::J

a. UJ

c

rr

...•

OJ

OJ ()

:::r ::J

o

a: o Acute Hypertensive

w' eD ...•

Encephalopathy,

::J

PRES

rJl

(Left) Axial NECT in renal transplant patient on cyclosporin shows bilateral parieto-occipital sulcal effacement with hypodense

cortical/subcortical lesions

=:I consistent

with PRES. (Right) Axial T2WI MR obtained after status epilepticus shows temporal lobe (and, to a lesser extent, parietal lobe) gyral hyperintensity CO> and mass effect mimicking encephalitis. Cyral swelling has effaced adjacent sulci.

Intracranial

Hypertension,

Idiopathic (Left) Axial T2WI MR shows dilated optic nerve sheaths elevation of optic nerve head liB Suprasellar cistern, sylvian fissure are small; superficial sulci almost effaced. (Right) Axial NECT in

a patient

with

right

arm/leg weakness 24 hours after left carotid endartereclOmy, shows swollen gyri with generalized decrease in left hemispheric sulci. Note hypodense parietal whitemaller=:l.MR

showed hyperintense cortex/while matle" decreased MTT

I 4 15

EFFACED SULCI, FOCAL

(/)

c ~ Q)

115

U :2 o C

.!: ()

ro ~ ro

.0

::> CfJ -0 C

ro

(/)

Q) ()

ro

0-

CfJ

ro 'xro , ro ~ X W

r:: III

~ r:c -0

r::

III

::>

-"1Il

DIFFERENTIAL DIAGNOSIS Common • Cortical Contusion • Cerebral Ischemia-Infarction, Acute • Spontaneous Intracranial Hemorrhage • Subdural Hematoma • Epidural Hematoma • Neurocysticercosis Less Common • Primary CNS Neoplasm o Meningioma o Oligodendroglioma o Ganglioglioma o Diffuse Astrocytoma, Low Grade o DNET o Pleomorphic Xanthoastrocytoma • Metastases, Parenchymal • Metastases, Skull and Meningeal • Abscess • Meningitis • Focal Cortical Dysplasia • Tuberous Sclerosis Complex • Thrombosed Cortical Vein(s) Rare but Important • Extra-Axial Empyema • Meningioangiomatosis • Superficial Siderosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Focal = one or several sulci (not hemisphere or whole brain) • Key concept: Is sulcal effacement caused by lesion within sulcus itself or underlying gyrus? o Intra- vs. extra-axial causes o Parenchymal> > sulcal disease • Imaging o Sulcal, gyral masses can be isodense on NECT, isointense on Tl-weighted MR difficult to detect!! o CECT, T2WI, FLAIR, Tl C+ scans most helpful

I 4 16

Helpful Clues for Common Diagnoses • Cortical Contusion o History of closed head injury o Heterogeneous hyper-/hypodense swollen gyri

Look for focal traumatic SAH adjacent to contusions • Cerebral Ischemia-Infarction, Acute o Cortical branch occlusion - gyral swelling o Difficult to see on ECT, Tl/T2WI o DWI helps distinguish ischemia (restricts) from neoplasm (usually doesn't) • Spontaneous Intracranial Hemorrhage o Children/young adult • Vascular malformation, venous occlusion, drug abuse o Middle-aged, older adults • Amyloid angiopathy, hypertension • Hemorrhagic neoplasm (metastasis, o

GBM)

• Subdural Hematoma o Usually crescentic, spreads over hemisphere - more generalized sulcal effacement o Occasionally focal, mimics EDH • Epidural Hematoma o Focal, biconvex extra-axial hematoma o Severe compression of underlying sulci o Mimics: Plasmacytoma, extra-medullary hematopoiesis, etc. • Neurocysticercosis o NCC cysts typically in subarachnoid spaces, depths of sulci o Intense pial inflammatory reaction may efface sulci Helpful Clues for Less Common Diagnoses • Primary CNS Neoplasms o Any cortical, subcortical neoplasm causes local mass effect, expanded parenchyma/compressed sulci o Age, history helpful • Child, young adult with longstanding seizures: Ganglioglioma (cyst, Ca++ common), DNET ("bubbly" appearance), low grade astrocytoma • Adult: Meningioma (dural-based, often Ca++), oligodendroglioma (Ca++ common, variable enhancement), PXA (look for "dural tail") • Metastases, Parenchymal o May cause focal mass, variable edema o Almost always enhances • Metastases, Skull and Meningeal o Dural-based, usually isodense/isointense with brain o Look for skull lesions

,.. CJl

EFFACED SULCI, FOCAL

C

• Abscess o Gray-white junction common site o Early stage (cerebritis) typically does not enhance o Late cerebritis/capsule stages ring-enhancement o Sulci compressed but don't enhance unless meningitis also present o DWI shows restriction early, helps distinguish abscess from neoplasm • Meningitis o Diffuse> focal, symmetric> asymmetric o Rarely affects solitary sulci; multiple adjacent sulci typically involved o FLAIR, Tl C+ stans best for detecting subtle disease • Focal Cortical Dysplasia o History of longstanding seizures o Perisylvian most common location o Follows gray matter on all sequences (occasionally slightly hyperintense on FLAIR) o Does not enhance o MRS usually normal • Tuberous Sclerosis Complex o Cortical tubers expand gyri, blur gray-white interface o Cortical/subcortical hyperintensity on FLAIR, T2WI o Tubers typically don't enhance o Taylor-type cortical dysplasia • Considered "forme fruste" of TSC • Solitary tuber • Caution: Can mimic neoplasm!

Cortical

Contusion

• Thrombosed Cortical Vein(s) o Usually occurs with dural sinus occlusion o May be isolated, solitary o Clinically devastating if vein of Labbe occluded o Can mimic hemorrhagic neoplasm/stroke/vascular malformation o T2* scan (GRE, SWI) helpful • Petechial hemorrhage in cortex ± focal SAH • Look for occluded dural sinus • Look for "cord-like" blooming in thrombosed vessel Helpful Clues for Rare Diagnoses • Extra-Axial Empyema o Look for sinusitis, mastoiditis ± underlying meningitis o Subdural> > epidural • Meningioangiomatosis o Usually child/young adult with seizure o Consider MA if calcified cortical lesion ± cysts o Typically hypointense "serpentine" cortical lesion o Enhances o May extend along PVSs, mimic neoplasm • Superficial Siderosis o History of repeated SAH helpful but not always present o Serpentine pial/cortical hypointensity on T2* scan> mass-like lesion o Posterior fossa> supratentorial brain

Cerebral

Ischemia-Infarction,

III

:l C.

III ., III

:l

m ~ .,

,

0> 0> X

Qi"

en

"0

0> ()

CD

en

0> :l

a.

en c

00> ., 0> ()

-::r :J o

c: o en

CO ., :J en

Acute

I Axial NEG scan shows a left frontal hyperdensity with surrounding hypodensily typical of cortical contusion. Note effaced frontal sulci from focal mass effect.

Axial TIWI MR in patient "found down" several hours after "doing cocaine" shows a subtle, mostly isointense mass with adjacent sulcal effacement. Acute

=

drug·reJaled

cortical

inFarct.

4 17

EFFACED SULCI, FOCAL

(/)

c ~ OJ

Ul U

:2 o c

.r:

Spontaneous

II

~

(Left) Axial T1 WI MR in 68 yo man with sudden onset of

:J

right-sided weakness shows

CO .0 (f)

" C

CO

(/)

OJ II

CO 0. (f) CO

·X CO, CO ~ X w c

~ '"

aJ

mostly isoinlense cortical/subcortical mass 6> effacing adjacent sulci. T2 showed numerous peripherally-located microbleeds consistent with amyloid angiopathy. (Right) Axial NECT shows almost perfectly isodense right posterior

frontal mass

=.

Only indication of presence of mass is focal effacement of the underlying sulci. This is an easy lesion to miss.

"c '"

:J .:.; (f)

(Left) Axial NECT shows effacement of left posterior frontal sulci by calcified mass (Right) Coronal FLAIR MR shows inhomogeneously hyperintense left temporal lobe mass that infiltrates hippocampus, compressing temporal horn and effacing the collateral sulcus (compare with normal right side).

=-

=

(Left) Axial T1 WI MR shows hypointense left posterior parietal cortical/subcortical mass ~ with adjacent sulcal effacement. Mass was hyperintense on T2WI, FLAIR. WHO grade II fibrillary astrocylOma was found at surgery. (Right) Axial T1WI MR shows slightly "bubbly"

cOrLical-based mass ~ with focal gyral expansion, sulcal effacement.

I 4 18

Intracranial

Hemorrhage

EFFACED SULCI, FOCAL

(fl

;>

a.

en c

CT OJ ...•• OJ (')

:::,::>

o

0.: Q rJl

co...•• ::>

rJl

CPA-lAC

I Axial T1 C+ MR ,eveals enhancing mass filling the CPA & internal auditory canal 81. Note the cochlear

=

nerve canal is involved hearing preservation

=

difficult.

making resection with

Axial T1 C+ FS MR reveals an enhancing dural-based

mass centered over the lAC but with minimal lAC

=.

involvement The shape and the associated dural tail meningioma diagnosis.

B make

4 25

CPA MASS, ADULT

IJl C

~ OJ

u; U "0

·0 c o

.r:

~ ro :J

.0

en "0

c ro IJl

OJ

o ro

C>-

en ro

·x

ro, ro ~

X

w

Epidermoid

Cyst, CPA-lAC

Aneurysm,

CPA-lAC

Arachnoid

Cyst, CPA-lAC

Metastases,

CPA-lAC

Sarcoidosis,

CPA-lAC

(Left) Axial TI WI MR shows a low signal mass in the right CPA cistern that insinuates and enlarges the Foramen of Luschka and scallops the ventral cerebellar hemisphere 81. (Right) Axial TI C+ MR demonstrates a large enhancing distal vertebral artery aneurysm projecting up into the CPA cistern and compressing the area where CN? and CN8 exit the brainslem ~.

=

=

C

•.. III

aJ

"0 C III

(Left) Axial T2WI FS MR shows a high signal lesion in low CPA cistern. Note the anterior displacement of proximal CN8 by arachnoid cyst 81. The high signal results From absence of CSF (Jaw. (Right) Axial TI C+ FS

=

MR reveals an in homogeneously enhancing metastatic focus arising from dura along the prepontine

cistern. This metastasis reaches the anterior margin of the porus acuslicus

=.

Neurofibromatosis (Left) Axial T1 C+ MR shows bilateral enhancing CPA-tAC schwannomas The leFt

=.

schwannoma involves the intra temporal facia! nerve HJ indicating it is mosllikely a facial nerve scl1wannoma. (RighI) Axial TI C+ MR shows heaped up, dural-based, sarcoid deposit in right CPA that enters the internal auditory canal !l::I. Meckel cave is also aFFected81. This lesion

=

mimics

I 4 26

meningioma.

2, CPA-lAC

CPA MASS, ADULT

Ul

c: " III

::l

Co III

.., lipoma,

III

CPA-lAC (Left) Axial TI C+ MR reveals a pear-shaped inhomogeneously enhancing papilloma projecting from the lateral recess of the 4th ventricle through the foramen of Luschka into the low CPA cistern 82. (Right) Axial T1WI MR shows a

=

varianllhree-part

lipoma

=-

affecting the CPA cistern high anterior jugular foramen 82 and the vestibule of the inner ear P.:Z. No surgery is done for these lesions.

::l

m ~ .., OJ

0, x

Cli'

en

"0 OJ ()

(lJ CJ>

OJ

::l 0-

en c

0OJ

OJ ()

::T ::l

o

c: o CJ>

CD Pseudotumor,

3

Intracranial

CJ>

(Left) Axial TI C+ MR demonstrates an aggressive mixed cystic-solid enhancing ependymoma of the right CPA cistern 4th ventricle 8l and cerebellar hemisphere 1J:!ll. (Right) Axial T1 C+ MR demonstrates an extensive area of enhancing dural thickening along the right low CPA cistern. The intracranial pseudotumor also involves the subjacent jugular foramenB.

=-

=

Schwannoma,

Facial Nerve, CPA-lAC

Schwannoma,

Jugular Foramen (Left) Axial T I C+ MR shows

a variant facial nerve schwannoma with enhancing CPA-lAC

component II] extending into the geniculate ganglion

82. Note associated arachnoid cystlJ:!ll. (Right) Coronal TI + MR reveals a schwannoma projecting cephalad from the jugular foramen 82 into the CPA cistern. Note the normal lAC IJ:!ll is at the level of upper margin of the tumor.

rs

=

I 4 27

CYSTIC CPA MASS

I/l C

~ OJ

]2 U -0

DIFFERENTIAL DIAGNOSIS

·0 C

.r::

()

co ~ co

.0

Common • Epidermoid Cyst, CPA-lAC • Arachnoid Cyst, CPA-lAC

OJ

rJ) -0 C

co

I/l

OJ

()

co

Q.

rJ)

co

·x co,

co ~ X

W

r:: III

~ 1IJ "C

r:: III

Less Common • Vestibular Schwannoma with Intramural Cyst(s) • Neurocysticercosis, CPA • Hemangioblastoma • Large Endolymphatic Sac Anomaly (IP-2) Rare but Important • Vestibular Schwannoma with Arachnoid Cyst • Schwannoma, Facial Nerve, CPA-lAC with Cyst • Neurenteric Cyst • Schwannoma, Jugular Foramen with Intramural Cyst

ESSENTIAL INFORMATION

I 4 28

• Also sorts out solid and cystic components of lesions • May help with associated cranial nerve and arterial anatomy Helpful Clues for Common Diagnoses • Epidermoid Cyst, CPA-lAC o Congenital rest of epithelial tissue in CPA o Imaging • Insinuating ± scalloping brainstem margin • Tl C+ MR: Nonenhancing, cystic appearing; may be difficult to see • DWI: Restricted diffusion (high signal) makes diagnosis • Arachnoid Cyst, CPA-lAC o Congenital lesion resulting from failure of embryonic meninges to merge with cyst between split in arachnoid membrane o Imaging: Fills cistern with rounded margins • Tl C+ MR: No enhancement • Other MR: FLAIRattenuates; DWI: No restricted diffusion Helpful Clues for Less Common Diagnoses • Vestibular Schwan noma with Intramural Cyst(s) o Vestibular schwannoma may have either intramural or extramural (arachnoid cyst) cysts o Imaging • Solid CPA-lAC mass with intramural cysts • Tl C+ MR: Enhancing solid tumor component ± intramural cysts (common) ± arachnoid cyst (rare) • Neurocysticercosis, CPA o Intracranial infection caused by pork tapeworm (Taenia solium) o Imaging • Cysts with "dots" inside • Appearance varies with stage • Tl C+ MR: Cysts with enhancing thin or thick wall • Hemangioblastoma o Adult with intra-axial posterior fossa mass abutting pia o Imaging • Cerebellar cystic & solid tumor • Tl C+ MR: 60% of tumors with solid enhancing & cystic components (40% solid only)

CYSTIC CPA MASS

CJl

'"

c:

• Large Endolymphatic Sac Anomaly (IP-2) o Bilateral congenital S HL that appears in child with cascading hearing loss pattern o Most common congenital imaging abnormality o Imaging • CT: Enlarged bony vestibular aqueduct • T2 high-resolution MR: Enlarged endolymphatic sac + mild cochlear aplasia (modiolar deficiency, bulbous apical turn, scalar chamber asymmetry) Helpful Clues for Rare Diagnoses • Vestibular Schwannoma with Arachnoid Cyst o Vestibular schwannoma with extramural (arachnoid cyst) cyst o Neuro-otologist refer to as "herald cyst" o Imaging • CPA-lAC mass with extramural cyst • Tl C+ MR: Enhancing solid tumor component rare ± arachnoid cyst • Schwannoma, Facial Nerve, CPA-lAC with Cyst o Rare CPA-lAC mass with "labyrinthine tail" involving labyrinthine segment of facial nerve canal o Often present with hearing loss before facial nerve symptoms o Imaging • CT: Labyrinthine segment CN? may be enlarged

Epidermoid

• Tl C+ MR: Enhancing tubular mass in CPA-lAC & labyrinthine segment of facial nerve; intramural or extramural cyst visible • Neurenteric Cyst o Incidental rounded to ovoid mass in prepontine cistern o Imaging • MR shows intermediate to high signal T1 prepontine mass • Schwannoma, Jugular Foramen with Intramural Cyst o Presents with some mixture of 9-12 cranial neuropathy o Imaging • Bone CT: Enlarged sharply marginated jugular foramen • Tl C+ MR shows enhancing mass with intramural cysts arising from jugular foramen & projecting superomedially into CPA cistern often with brainstem compression

III

::::l

Co

III .., III

::::l

m

~ .., OJ, OJ X

0;. CJl

-0 OJ ()

CD (f>

OJ

::::l

a. CJl

c:

0OJ OJ

..,

()

:T :::J

o

0: ()

(f>

CO

3 (f>

Cyst, CPA-lAC

=

Axial T7 C+ MR reveals a low signal epidermoid cyst lhat insinuates into foramen of Luschka and cerebellar hemisphere E:I. OWl MR sequence would show restricted diffusion.

Axial T7 C+ FS MR demonstrates a right CPA cistern arachnoid cyst displacing the proximal facial and vestibu/ocochlear nerves anteriorly H2.

=

I 4 29

CYSTIC CPA MASS

(/)

E ell

en

u -0

·0

Vestibular

C

~ U < 0;' (f)

" OJ

(1 (l)

subdural

en OJ ;,

The anterior

C.

acule-an-chronic frontoparietal hematoma.

;,

right

portion shows the hypodense chronic component I!:i'l with associated mass effect. The more acute blood layers posteriorly,

(f) C

0-

m ~

OJ

(1

::T :J

o

1i

o iii'

CD Dandy-Walker Continuum

3 en

Arachnoid Cyst (Left) Sagittal T2WI MR shows a large posterior fossa cyst continuous with the 4th ventricle. Note also the superiorly rotated vermian remnanlldl. classic for Dandy-Walker malformation. Patient a/so has macrocrania & hydrocephalus. (RighI) Axial T1 WI MR shows CSF

intensity extra-axial lesion

=-

causing thinning of the adjacent calvarium arachnoid cyst. Arachnoid cysts follow CSF signal on all MR sequences.

Intracranial Hypotension (Left) Coronal T1 C+ FS MR shows small bilateral subdural

effusions

=

over

the cerebral convexity. Note the diffuse dural thickening & enhancement characteristic for intracranial hypotension, (Right) Axial T1 C+ MR shows a peripherally enhancing subdural empyema in this sinusitis patient. OWl MR (not shown) shows restricted diffusion which can help differentiate empyema from more benign extra-axial fluid collections.

a

=

I 4 51

CSF-L1KE EXTRA-AXIAL

VJ C

MASS

L-

Q)

~

() "0

DIFFERENTIAL DIAGNOSIS

·0 C £ U Cll L-

Cll

.n ::::J CfJ

"0 C Cll VJ Q) U Cll Q.

CfJ Cll

·x 'P Cll L-

X

W

c:

Common • Arachnoid Cyst • Neurocysticercosis less Common • Pineal Cyst • Schwannoma (Cystic) • Epidermoid Cyst Rare but Important • Neurenteric Cyst • Leptomeningeal Cyst • Callosal Dysgenesis • Holoprosencephaly (Dorsal Cyst)

III L-

a! 'tl

c:

III

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Enhancement is helpful to differentiate CSF-like extra-axial masses Helpful Clues for Common Diagnoses • Arachnoid Cyst o Nonenhancing CSF-like mass, bone remodeling • Neurocysticercosis o Cyst with a scolex is pathognomonic o Racemose (grape-like) in basal cisterns: No scolex is typical o Subarachnoid & intraventricular disease often symptomatic from hydrocephalus &/or meningitis (enhancing)

Arachnoid

I 4 52

Helpful Clues for less Common Diagnoses • Pineal Cyst o Lies dorsal to midbrain at pineal gland o Usually asymptomatic, less than 2 cm • Schwannoma (Cystic) o Commonly located in cerebellopontine angle (CPA) cistern o Enhancement typical • Epidermoid Cyst o Lobular, insinuating nonenhancing mass o Restricted diffusion & FLAIR hyperintensity differentiates from arachnoid cyst Helpful Clues for Rare Diagnoses • Neurenteric Cyst o Posterior fossa: Anterior to brainstem, CPA o Nonenhancing midline or paramedian cyst o MR signal variable (protein content) • Leptomeningeal Cyst o Underlying brain shows encephalomalacia o Communicates with subarachnoid space o Well-marginated skull defect at site of cyst • Callosal Dysgenesis o Interhemispheric cyst common o Parallel lateral ventricles, colpocephaly, high riding 3rd ventricle • Holoprosencephaly (Dorsal Cyst) o Hydrocephalus is almost always present o Look for fused thalami, absence of interhemispheric fissures, septum pellucidum o May see corpus callosum agenesis

Arachnoid

Cyst

Sagittal T1WI MR shows an extra-axial mass causing thinning of the inner table of the skull Arachnoid cysts are benign & usually found incidentally. They follow CSFon all MR sequences.

'-=.

=

Cyst

Sagittal T1WI MR shows a large frontal arachnoid cyst with associated mass errect. Vast majority of

arachnoid cysts are incidentally found treatment.

&

require no

CSF-liKE

EXTRA-AXIAL

MASS III

::::l C.

...

OJ

Neurocysticercosis

III

Pineal Cyst (Left) Axial T1 C+ MR shows multiple hypointense cysts with mild peripheral enhancement. Note interhemispheric I:] & sylvian fissure E!lI cysts. Subarachnoid spaces are the most common location for NCC cysts. Cisternal NCC may be complicated by meningitis, hydrocephalus, or vasculitis. (RighI) Sagillal T1 WI MR shows a cystic mass in the pineal region. These are typically less than 2 em & incidental. Enhancement of compressed pineal gland may be seen.

=

::::l

m ~ ... Ql

Q, ~. Ql

(fJ "t)

Ql (') (l)

en Ql

:J

C. (fJ C 0Ql

...

Ql

(')

::T ::::l

o

c: o (jj' CD ...

Neurenteric

:J en

Cyst (Left) Axial T2WI MR shows wel'·circumscribed extra-axial mass ~ which is isointense to CSF. FLAIR & OWl MR can differentiate this lesion from an arachnoid cyst. (Right) Sagittal T1 C+ MR shows a mildly hyperintense non enhancing lesion in the prepontine cistern typical location for neurenteric cyst. MR signal is dependent on protein content of cyst. They are typically T I hyperintense or isointense & T2 hyperintense (to CSf).

=-

Callosal Dysgenesis (Left) Axial T2WI MR shows corpus callosum dysgenesis with a large dorsal interhemispheric cyst"" & prominent azygous artery The large dorsal cyst & the parallel lateral ventricles E!lI are typical of callosal dysgenesis. (Right) Axial NECT shows a large dorsal cyst associated with alobar holoprosencephaly~. Note absence

of septum

pellucidum

artiFacts ~

1:]. Streak are due to shunt

(not shown) inserted into the cyst.

I 4 53

SULCAL/CISTERNAL

rJJ

E

ENHANCEMENT

Q)

]2 U -0

'0 C

.L:

U l\l l\l .0

~ :J

en -0

c

l\l

rJJ

Common • Meningitis • Meningeal Carcinomatosis • Lymphomatous Meningitis • Neurocysticercosis • Tuberculosis Meningitis

•

Q)

U l\l

n.

en l\l

'xl\l

, ~ X l\l

w

c

~ '"

llJ -0

c

=':J" -'en "

less Common • Neurosarcoid • Sturge-Weber Syndrome • Fungal Diseases • Aneurysmal Subarachnoid Hemorrhage (Subacute May Enhance) • Opportunistic Infection, AIDS • Leukemia Rare but Important • Neurocutaneous Melanosis • Meningioangiomatosis • Contrast Leakage

•

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • All meningitides (infectious, granulomatous, neoplastic) have similar imaging appearance (enhancing pia ± sulcal/cisternal enhancement) • Location, pattern only minimally helpful • Nodular "leptomeningeal" (pial) enhancement o Meningeal carcinoma tosis o Lymphomatous meningitis o Tuberculosis meningitis o Leukemia o eurosarcoid o Fungal diseases • Thick basal cistern enhancement o Tuberculosis meningitis o Fungal diseases o eurosarcoid o Pyogenic meningitis o Lymphoma o Neurosyphilis

I 4 54

Helpful Clues for Common • Meningitis o Clinical-laboratory (not • Positive CSF by lumbar o Imaging may be normal helpful)

Diagnoses imaging) diagnosis puncture early (FLAIR

Use imaging to detect complications (e.g., ventriculitis, hydrocephalus, subdural empyema, cerebritis/abscess, secondary ischemia, dural venous thrombosis) Meningeal Carcinomatosis o CNS neoplasms (e.g., GBM, medulloblastoma, pineal tumors, choroid plexus tumors), extra-CNS primary tumors (breast, lung, melanoma common) o Look for other lesions (parenchyma, bone) Lymphomatous Meningitis o Involvement of leptomeninges or dura, more commonly in secondary lymphoma • Primary CNS lymphoma: Typically periventricular parenchymal disease o Often affects both brain, spine Neurocysticercosis o Cysts often in deep sulci, may incite intense inflammatory reaction o Cisternal NCC may appear racemose (multilobulated, grape-like), typically lacks scolex • Complications: Meningitis, hydrocephalus, vasculitis o Cisterns> parenchyma> ventricles o Best diagnostic clue: Cyst with "dot" (scolex) inside Tuberculosis Meningitis o Most common presentation of active CNS o

DIFFERENTIAL DIAGNOSIS

•

TB

Predilection for basal cisterns Complications: Hydrocephalus, ischemia common o Look for extracerebral TB (pulmonary) o TB often mimics other diseases like neoplasm

o

o

Helpful Clues for less Common Diagnoses • Neurosarcoid o Dural, leptomeningeal> > parenchymal disease o Lacy leptomeningeal enhancement typical o Look for infundibular stalk involvement o CXR may be helpful to assess for hilar/paratracheallymphadenopathy (most have systemic disease) • Sturge-Weber Syndrome o Atrophy of affected hemisphere o Pial angioma enhances o Ipsilateral choroid plexus often enlarged o Abnormally prominent medullary (deep white matter), ependymal veins

en

SULCAL/CISTERNALENHANCEMENT

""C • Fungal Diseases o Coccidioidomycosis, cryptococcus often basilar • Aneurysmal Subarachnoid Hemorrhage (Subacute May Enhance) o 1'2* GRE: Hypointense hemosiderin deposition in 70-75% of patients with prior SAH • Opportunistic Infection, AIDS o Meningeal involvement in AIDS (HIV or opportunistic infection> tumor) • Acute aseptic HIV meningitis • Cryptococcal or TB meningitis • Lymphoma: Extension of parenchymal disease • Other fungal: Candidiasis, aspergillosis, coccidiosis • Consider neurosyphilis • Leukemia o Meningeal disease, usually with acute lymphoblastic leukemia (ALL) o Multiple lesions at multiple sites are suggestive of diagnosis Helpful Clues for Rare Diagnoses • Neurocutaneous Melanosis o Giant or multiple cutaneous melanocytic nevi (GCMN) and o Benign, malignant CNS melanotic lesions occur o Foci of 1'1 hyperintensity (parenchymal melanosis) in amygdala or cerebellum

Diffuse/focal pial enhancement; may extend into parenchyma via perivascular spaces o Pre-contrast 1'1WI sulci/cisterns may be normal, iso-, or hyperintense • Meningioangiomatosis o Neurofibromatosis found in Yz of patients (particularly NF2) o Rare, hamartomatous cortical/leptomeningeal malformation o Best diagnostic clue: Cortical mass with Ca++ (with or without cysts) • Contrast Leakage o Increased signal in CSF on 1'1WI and FLAIR o Dialysis-dependent patient with end-stage renal disease o Contrast overload o Leakage from tumor o

Cll

~ Co

...

OJ Cll

~ m ~ ... 0>

dJ

>< 00·

en

-0 0>

()



::J Co

en c C-

...

O>

0>

()

::r ::J

o

Ci

Q rn

ro... ::J

Other Essential Information • Thin, curvilinear enhancement over brain surface reflects pial disease • Predilection for basal cisterns in inflammatory, granulomatous meningitis

'"

SELECTED REFERENCES 1. 2.

Fukui MB et al: MR imaging of thc mcningcs. Part II. Neoplastic disease. Radiology. 20] (3):60S-12, 1996 Meltzer CC et al: MR imaging of the meninges. Part I.

orrnal anatomic

features and nonneoplastic

Radiology. 201(2):297-308,

Meningeal

disease.

] 996

Carcinomatosis

I Axial T1 C+ MR shows extensive leptomeningeal enhancement of the sulci

Axial T1 C+ MR reveals extensive leplOmeningeal carcinomatosis with a basal predominance. There is diffuse coaUng of the cerebellar folia with additional nodular areas of enhancement E2.

4 55

SULCAL/CISTERNAL

(/)

c ~ Ql

~

o "0

'6 c J::

()

ro ~ ro --"::J

(/)

(Left) Sagittal T1 C+ MR shows extensive leptomeningeal carcinomatosis with diffuse coating of the cerebellar folia ffi Scattered nodular areas

Ql

of enhancement

(f) "0 C

ro

()

ro

n. (f)

ro

'x ro, ro ~ X w c

~ '"

are evident

=.

in the supratenlorium (RighI) Axial T I C+ FS MR shows enhancement in the internal auditory canal and in Meckel cave on the

=

right !G. Note extensive fetro-orbital

enhancement

in

this patient with lymphoma

ffi

III "0

c

'::J" en "" (Left) Axial T1 C+ FS MR shows ring·enhancing right CPA cistern cysts 1:;;1 and thickened enhancing meninges 81, (RighI) Axial T1 C+ FS MR shows small areas of ring-enhancement

in

the subarachnoid space 1:;;1.

(Left) Axial T1 C+ MR shows intense basal meningeal enhancement ffi (RighI) Axial T 1 C+ MR shows linear and nodular coating of the midbrain 1:;;1, Note thickening of the infundibular stalk PJ:J:l,

I 4 56

ENHANCEMENT

SULCAl/CISTERNAL

ENHANCEMENT III

::l

a. Sturge-Weber

Syndrome

Fungal

CD .,

Diseases

III

(Left) Axiat T7 C+ MR shows serpentine leptomeningeal enhancement ffi feft cerebrat atrophy, thickening o( the catvariat diptoic space =:1 and hypertrophy of the ipsilateral choroid plexus •. (Right) Axiat T7 C+ MR shows thick enhancement of the basal cisterns in this patient with coccidioidomycosis meningitis.

=

::l

m ~ ., III o III X

Qj.

en

-0

III

o < l1J

c III

~

al

"0

c

III

:J

Common • Normal (Normal Arteries, Veins) • CSF Pulsation • Saccular Aneurysm • Fusiform Aneurysm, ASVD • Arteriovenous Malformation • Developmental Venous Anomaly Less Common • Dural A-V Fistula • Thrombosis, Dural Sinus • Fusiform Aneurysm, Non-ASVD • Dissecting Aneurysm • Pseudoaneurysm Rare but Important • Vein of Galen Malformation • Venous Varix

-"(f)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Vascular vs. CSF flow void (FV) o Vascular FVs sharply demarcated from surrounding CSF o If large, vascular FVs may cause phase artifact • Vascular FV vs. acutely thrombosed artery/vein o Thrombus iso- on Tl, hypointense on T2WI, can mimic FV o Do T2* (GRE/SWI) - clot "blooms"

Normal

I 4 60

(Normal

Arteries,

a.

Helpful Clues for Less Common Diagnoses • Dural A-V Fistula o Older; usually prior dural sinus thrombosis o Direct AV shunt • Thrombosis, Dural Sinus o Prominent collateral veins • Fusiform Aneurysm, Non-ASVD o Often more distally located than ASVD o Vasculopathy, vasculitis, mycotic, oncotic • Dissecting Aneurysm o Extra- > intracranial; VA > supra clinoid ICA Helpful Clues for Rare Diagnoses • Vein of Galen Malformation o t VOG, feeding/draining vessels • Venous Varix o Seen with AV shunting, venous strictures

Normal

Veins)

Axial T2WI MR shows paired ACA flow voids "on end" curvilinear MCA flow voids internal cerebral veins 1'71 proximal straight sinus ~ & superior sagittal sinus !:ll.

.2b

Helpful Clues for Common Diagnoses • CSF Pulsation o Ill-defined signal loss near artery • Saccular Aneurysm o Typically involve major branch points • Fusiform Aneurysm, ASVD o Long segment & focal outpouching (BA > ICA/branches) • Arteriovenous Malformation o Extra-axial feeding, draining vessels o Look for aneurysms (feeding arteries, intranidal), venous varices • Developmental Venous Anomaly o Draining vein & enlarged medullary veins o Tl C+ best sequence

=-

(Normal

Arteries, Veins)

Axial T2WI MR shows superior sagittal sinus flow void cortical veins entering sinus ~ .•. & superficial

cortical veins over the convexities ~.

,...

Ul

EXTRA-AXIAL FLOW VOIDS

c: III

::l

Co III .,

CSF Pulsation

III

Saccular Aneurysm (Left) Axial T2WI MR shows localized signal loss in the prepontine cistern CSF ~ due to pulsations from the basilar artery =:II. (Right) Axial T2WI MR shows a rounded flow void in the fissure It] representing

a

Q)

Q, ~. Q)

Ul Q) ()

ro

(f)

anterior

communicating

m ~ .,

-0

lower interhemispheric saccular

::l

artery

aneurysm.

Q)

::J 0Cf)

c

0-

., Q)

Q) ()

::T ::J

o Ci

o (jj. CD ., Fusiform Aneurysm, ASVD

Arteriovenous

::J

Malformation

(f)

(Left) Axial T2WI MR shows an ovoid mass that involves the horizontal segment of the left middle cerebral artery =:II. Note tortuous, elongated "flow voids" in both middle cerebral arteries. (Right) Axial PO FSEMR shows enlargement

of the internal

cerebral veins ~ prominent

as well as

areas of flow void

in an AVM nidus located in the lateral basal ganglia 8:1.

Developmental

Venous Anomaly

Dural A-V Fistula (Left) Axial T2WI MR shows

a

solitary prominent

flow

void near the vertex ~ that is substantially larger than other vascular flow voids at this level =:II. (Right) Axial T2WI MR shows high signal in the left transverse sinus & a number punctate &

or

curvilinear

signal voids

within it These small flow voids are part of a dural AVF within a chronically thrombosed dural sinus. Compare with the normal flow void of right transverse

sinus=.

I 4 61

11 HYPERINTENSE

rn

c ~

CSF

OJ

U; U "0

'0 C

.r:: u

~

Cll ..Q

::J (/J

"0 C Cll

rn

DIFFERENTIAL DIAGNOSIS Common • MR Artifacts, Flow-Related • MR Artifacts, Magnetic Susceptibility • Subarachnoid Hemorrhage • Intraventricular Hemorrhage • Meningitis

OJ

u Cll

a.

(/J

Less Common • Ventriculitis

Cll

'xCll

ro~

x

w

C ltl

~

Rare but Important • Dermoid Cyst (Ruptured) • Carcinomatous Meningitis • Contrast Complications, NOS • Retained Pantopaque

al

"t:l C ltl

::J

...:

(/J

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • MR artifact common at high field strengths • CSF hemorrhage & infection often causes "dirty CSF", hyperintense to CSF & isointense to brain parenchyma o CSF FLAIRhyperintensity more common than true T1 CSF hyper intensity Helpful Clues for Common Diagnoses • MR Artifacts, Flow-Related o Pulsation artifact in phase encoding direction o Confirm artifact when seen outside skull • MR Artifacts, Magnetic Susceptibility o "Black holes" with T1 bright rim o Changing phase encode direction confirms

MR Artifacts,

• Subarachnoid Hemorrhage o May be traumatic, aneurysmal, or nonaneurysmal perimesencephalic • Location helps determine etiology o Typically isointense to brain, "dirty CSF" • Intraventricular Hemorrhage o Typically hyperintense to CSF & isointense to brain with a fluid level o May be T1 hyperintense, related to age • Meningitis o Typically isointense to brain, "dirty CSF" o Meningeal enhancement classic Helpful Clues for Less Common Diagnoses • Ventriculitis o Debris in ventricles from sediment, cells o Typically hyperintense to CSF & isointense to brain with a fluid level Helpful Clues for Rare Diagnoses • Dermoid Cyst (Ruptured) o Fat droplets within CSF spaces o Suppress with fat-saturation • Carcinomatous Meningitis o Rare, related to blood, cells, melanoma • Contrast Complications, NOS o Chronic renal failure causes delayed excretion & hyperintensity from recirculation o Gadolinium leak from lack of intact blood-brain barrier: Infection, PRES • Retained Pantopaque o Often focal T1 hyperintensity in CSF o Older adults (not used since 1980s)

Flow-Related

I 4 62

=

=

Axial TlWI MR shows CSFpulsation artifact on this spin echo Tl sequence (3T magneO. Anifact is confirmed by periodic high SII and low !l:?Jl signal

Axial T I C+ MR shows localized magnetic susceptibility artifact from an aneurysm clip. This results in localized Tl hyperintensity within the suprasellar cistern

artifacts in phase encoding

SII.

direction.

T1 HYPERINTENSE

CSF Ql

::I Q.

I:D ..,

Subarachnoid

Ql

Hemorrhage (Left) Axial TI WI MR shows "dirty" CSF in the suprasellar cistern, isointense with brain, related to aneurysm rupture. Note hydrocephalus with blood-fluid level ~ in lateral ventricle. (Right) Axial TI WI MR shows heterogeneous hyperintense signal anterior to the medulla. This is a typical distribution for nonaneurysmal perimesencephalic subarachnoid hemorrhage, which tends to collect around the midbrain & anterior to the pons.

::I

m

~ .., Ql , Ql

X

Oi (j)

-0 Ql ()

C1l V> Ql

:J

Q.

(j)

c:

0Ql

Q] ()

::T :J

o

Ci

o V>

CD .., Intraventricular

::J

Hemorrhage

V>

(Left) Axial TI WI MR shows hyperintense hemorrhage layering in the occipital horns 11II] & 3rd ventricle. Focal clot is seen in the frontal horn ~ in this patient with posterior fossa AVM rupture. (Right) Axial TlWI MR shows "dirty" CSF, isointens€

to brain

parenchyma in the basal cisterns ~ in this fungal meningitis patient. The CSF is also FLAIR hyperintense & enhances. Meningitis is a clinical-laboratory diagnosis.

Ventriculitis (Left) Axial TI WI MR shows debris layering posteriorly within the occipital horns in this 2 year old with

=

ventriculitis.

Note signal is

mildly hyperintense to CSF & isointense to brain. (Right) Sagittal TI WI MR shows numerous hyperintense foci in the subarachnoid spaces & supraselJar cistern SI related to rat droplets

=

from dermoid

rupture.

Hydrocephalus is caused by associated chemical meningitis.

I 4 63

en c ~

FLAIR HYPERINTENSE CSF

Q)

Ul

U "0 " C

J::

U

~ '"

':::J"

.0 (f)

" C

'e"n Q)

u

'" '", '~" '" X

Cl. (f)

Common • Subarachnoid Hemorrhage, OS • Intraventricular Hemorrhage • Meningitis • MR Artifacts, Magnetic Susceptibility • MR Artifacts, Flow-Related • MR Artifacts, Patient-Related • Metastases, Meningeal • Ventriculitis

•

";;:

w

c: t'll

~

In

" C t'll

Less Common • Gadolinium in CSF due to o Blood-Brain Barrier Leakage o Chronic Renal Failure • Cerebral Ischemia-Infarction, Acute

•

Rare but Important • Dermoid Cyst (Ruptured) • Moyamoya •

ESSENTIAL INFORMATION

•

•

I 4 64

May be complicated by hydrocephalus, ventriculitis, abscess, vasculitis o Remains a clinical-laboratory diagnosis MR Artifacts, Magnetic Susceptibility o Regionally adjacent metal, blood, air-bone interfaces causes FLAIRhyperintensity o Distorts local magnetic field, altering null point for fluid (Tl), resulting in inappropriate high signal o Often seen close to aerated frontal sinuses & temporal bones o Common surrounding aneurysm clips MR Artifacts, Flow-Related o CSF flow artifacts are common in basal cisterns, foramen of Monro, aqueduct, & 4th ventricle o Periodic artifacts extending outside skull in phase encoding direction is diagnostic o Usually absent on spin echo sequences (Tl, T2); helpful to confirm artifact MR Artifacts, Patient-Related o Diffuse FLAIRhyperintensity o Common etiologies: Head motion, Propofol, 50% or greater supplemental oxygen (4-5x t signal with 100% 0,) Metastases, Meningeal o Usually due to cellularity &/or increased protein content within CSF o May be focal or diffuse o Meningeal enhancement typical o Adjacent bone changes common o Breast & lung most common distant primary tumors Ventriculitis o Ventriculomegaly with debris level o OWl bright & ventricular enhancement o Complication of meningitis, abscess, ventricular catheter o

DIFFERENTIAL DIAGNOSIS

Helpful Clues for Less Common Diagnoses • Blood-Brain Barrier Leakage o Etiologies include: Infection/inflammation, ischemia, tumor • Cerebritis, posterior reversible encephalopathy syndrome (PRES)may cause BBBleak • Acute/subacute stroke (poor prognostic sign suggests hemorrhagic transformation) • Neoplasms uncommon, usually with delayed imaging

FLAIR HYPERINTENSE CSF

(/I ;YC

r::

Gadolinium accumulates in CSF due to BBB leakage o May cause focal or diffuse FLAIR hyperintensity & enhancement • Chronic Renal Failure o Increased FLAIR related to delayed gadolinium clearance from circulation o May augment other pathologic causes of FLAIR hyperintensity o Usually seen with delayed imaging (may also be seen in normal patients) • Cerebral Ischemia-Infarction, Acute o May see hyperintense CSF related to vessel occlusion or slow flow o "Dot sign" related to occluded MCA branches in Sylvian fissure o Enhancement related to slow flow

o

o

Helpful Clues for Rare Diagnoses • Dermoid Cyst (Ruptured) o Fat-containing lesions are FLAIR bright from Tl shortening effects o Tl foci in subarachnoid spaces pathognomonic • Moyamoya o Progressive narrowing of distal ICA & proximal circle of Willis with collateraIs, anterior> posterior circulation o "Ivy sign": Bright FLAIR signal related to slow-flowing engorged pial vessels, thickened arachnoid membranes • More commonly seen in frontal & parietal lobes

Axial flAIR MR shows abnormal hyperinlensily wilhin lhe lefl-sided sulci The pauern of peripheral sulcal blood is more characteristic (or traumatic hemorrhage

=.

than aneurysm rupture.

Leptomeningeal "ivy sign")

enhancement

(contrast

Other Essential Information • Causes of pathologic FLAIR hyperintense CSF: Blood, elevated protein, or cells • FLAIR hyperintensity can be due to T2 prolongation or Tl shortening • "Fast" FLAIR can cause artifactual FLAIR hyperintensity Alternative Differential Approaches • FLAIR hyperintensity with enhancement: Meningitis, metastases, ventriculitis, blood-brain barrier leakage, chronic renal failure, acute ischemia, moyamoya

Q)

:l

C. OJ .., Q)

:l

m ~ .., Ql , Ql X

oj" (fJ

"CD Ql

()

en Q)

:l 0. (fJ

r::

0-

..,

Ql Ql ()

::r :l

o

SELECTED 1.

2. 3.

4.

S.

REFERENCES

Morris JM et ai: Increased signal in the subarachnoid space on fluid-altenuated inversion recovery imaging associated with the clearance dynamics of gadolinium chelate: a potential diagnostic pitfall. AJNR Am J Neuroradiol. 28(10): 1964-7,2007 Stuckey SL et al: Hyperintensity in the subarachnoid space on FLAIR MRI. AJR Am J Roentgenol. ]89(4):913-21,2007 Cian[oni A et al: Artifact simulating subarachnoid and intraventricular hemorrhage on single-shol, fast spin-echo fluid-attenuated inversion recovery images caused by head movement: A trap for the unwary. AJNR Am J Neuroradiol. 27(4):843-9,2006 Frigon C et al: Supplemental oxygen causes increased signal intensity in subarachnoid cerebrospinal fluid on brain FLAIR MR images obtained in children during general anesthesia. Radiology. 233(1):S]-S, 2004 Bozzao A et al: Cerebrospinal fluid changes after intravenous injection of gadolinium chelate: assessment by FLAIR MR imaging. Eur Radiol. 13(3):592-7,2003

Axial flAIR MR shows high signal in lhe basal cislerns & along the sylvian fissure !:ll caused by subarachnoid blood relaled La aneurysm rupWre. Note also acule hydrocephalus 81.

=

c: o 00·

m ..,

~ en

I 4 65

FLAIR HYPERINTENSE CSF

Cfl

E

OJ

§ U "0

'0 C

.r:: u

~

Intraventricular Hemorrhage

Cll

(Left) Axial FLAIR MR shows

Cll ..0

increased signal surrounding

en

the midbrain & in the suprasellar cistern 81. A

:J

"0 C Cll Cfl

OJ

u Cll Cl.

en Cll

·x

, ~ X Cll Cll

w

C III

Intraventricular Hemorrhage

=

small amount

of

intraventricular hemorrhage is presenl p:;J layering in the occipital horns. (Rigl1t) Axial fLAIR MR shows a basal ganglia hematoma in a patient with a hypertensive hemorrhage. Hyperintensity in the atrium of the left lateral ventricle B is indicaUve of intraventricular extension.

=

~

aJ

"0 C III

MR Artifacts, Magnetic Susceptibility (Left) Axial FLAIR MR shows diffusely abnormal signal throughout the sulci 81 & pial surfaces caused by pyogenic meningitis. Hyperintensity in the choroid plexi p:;J suggests choroid plexitis. FLAIR hyperintense CSF may be more apparent than abnormal enhancement on contrast images in meningitis. (Right) Axial T2* GRE MR shows magnetic susceptibility artifact due to aneurysm clip placement in this patient with recent subarachnoid hemorrhage.

=

=

MR Artifacts, Flow-Related (Left) Axial FLAIR MR shows prominent round hyperinlense focus in the 4th ventricle Periodic artifacts in the phase encoding direction EJ confirm the suspicion of CSF pulsation artifact. (Rigl1t) Axial FLAIR MR shows hyperintensity within the CSf due to high levels of inspired oxygen at the time of imaging. This is a relatively

=.

=

common

artifact

requiring

sedation

study.

I 4 66

in patients for an MR

MR Artifacts, Patient-Related

flAIR

HYPERINTENSE

en

CSF

""c:

'Co" :J

..,

lJl Metastases, Meningeal

Ventriculitis (Left) Axial FLAIR MR shows scattered hyperintense signal at the sulci PJ:J:l & along the dura 1::1 related to meningeal metastatic disease. Enhanced images (not shown) revealed thickened, enhancing dura wilh subtfe sulcal enhancemenl. (Right) Axial FLAIR MR shows hyperintense material with the righllaleral venlricle ~ in this patient with meningoencephalitis & ventriculitis . Ventriculomegaly with debris level is most common imaging appearance.

'"

:J

m ~ .., OJ

0, 1:5. OJ

en

"D

OJ ()

CD

'":J

OJ 0..

en c rr

..,

OJ OJ

()

::r :J

o

c: o

'"10.., Blood-Brain

Barrier leakage

Blood-Brain

:J

Barrier leakage (Left) Coronal FLAIR MR shows focal hyperintense CSF 1::1 from local conlrast accumulation overlying a small parenchymal mass E!llI due 10 focal cerebritis. Contrast accumulation is relaled 10 blood-brain barrier leakage. (Rigl1t) Axial FLAIR MR shows diffuse CSf hyperinlensity due 10 gadolinium leakage in PRES. Note classic vasogenic edema in bOlh occipilal lobes ~ & extensive right temporal involvement. Renal

'"

=

function

Chronic

was normal.

Renal Failure (Left) Axial FLAIR MR shows diffuse hyperinlensity within the sulci in a patient with brain MR 2 days post-gadolinium injection for abdominal MRA (patient had a creatinine of 3.0). If history not known, would consider other meningeal processes. (Right) Axial FLAIR MR shows brighl CSF 1::1 in lhis patient with a hyperacute right MCA infarct. This abnormal signal is thoughllo be relaled 10 slow flow (luxury perfusion).

=

I 4 67

rn

c ~

12 HYPOINTENSE

EXTRA-AXIAL

LESIONS

90% enhance homogeneously & intensely on CECT • Metastases, Meningeal o NECT: Hypercellular or hemorrhagic o Skull/dura often/but not always infiltrated o Often known extra cranial malignancy Helpful Clues for less Common Diagnoses • Thrombosis, Dural Sinus o Hyperdensity along expected location of dural sinuses o May be associated with venous infarcts • Neurosarcoid o Multifocal dural-based foci, presence of leptomeningeal enhancement additional clue o Abnormal CXR, raised ESR, ACE levels

Epidural Hematoma

Axial NECT shows a classic epidural hematoma EB

biconvex

hyperdense

HYPERDENSE

EXTRA-AXIAL

,..

MASS(ES)

(JJ

c: III

:J 0llJ

Meningioma

..,

Metastases, Meningeal

III

(Left) Axial NECT in a patient with multiple meningiomalosis syndrome shows several hyperdense, lobulated, dural-based masses Bt,. (Right) Axial NECT shows a mildly hyperdense extra-axial mass overlying the cerebral convexity with adjacent calvaria/thickening [;8 in a patient with a prostate metastasis.

:J

m

~ ~ III x

'"

iii'

en

-0 III (") (1)

en

III

:J 0-

en c: CT III

~

III (")

::T :J Q, 0-

o en

ro~ Thrombosis, Dural Sinus

::J

Tuberculosis

en (Left) Axial NECT shows dural sinus thrombosis with hyperdensity along the expected location of the right transverse sinus ffi (Right) Axial NECT shows a

hyperdense

=:J found

extra-axial mass to be a dural

tuberculoma at surgery (Courtesy R, Ramakantan, MD)

Extramedullary Hematopoiesis

leukemia (Left) Axial NECT shows the typical appearance of extramedullary hematopoiesis with hyperdense, dural-based masses mimicking subdural hematomas in a patient with myelofibrosis. (Right) Axial NECT shows multiple hyperdense extra-axial masses (chloromas) ~ in a patient with leukemia, CECT showed

=

homogeneous enhancement.

I 4 75

en c ~

HYPODENSE

EXTRA-AXIAL

MASS(ES)

Cll

Ul U "0

'0 C

.. .r: u c

~ Q)

CIl

D...

c

~ co c: ra~

co "'C

c ra

(Left) Coronal T7 C+ MR shows a left frontal tuberculoma ~. Meningitis occurs in approximately 50% of patienlS with CNS TB. TB is more common in children &, young adullS. (Right) Axial CECT shows an irregular, ring-shaped mass in the suprasellar cistern Note adjacent pial enhancement extending around the suprasellar cistern & into the sylvian fissure m in this patient with suprasel1ar tuberculoma with tuberculous meningitis.

=.

Aneurysm (Thrombosed)

Aneurysm

Arteriovenous Malformation (Thrombosed)

Arteriovenous

(Thrombosed)

(Left) Coronal T7 C+ MR shows a large extra-axial

basilar artery aneurysm anterior to the pons & medulla =:I with some nodular & rim enhancement. This mass is markedly hypointense on T2 MR. A laminated appearance may help with the diagnosis. (Right) Axial CECT shows ring enhancement in this partially thrombosed "giant" aneurysm (> 2.5 em) =:I. Giant aneurysms are more likely to thrombose.

(Left) Axial CECT shows a

heterogeneous,

ring-enhancing mass =:I with a fluid level SlI related to recent hemorrhage. Note surrounding edema. Thrombosed AVMs account for only 1-2% of all AVMs of the brain. When they occur, they often mimic neoplasm. (Right) Coronal T7 C+ MR shows a partially treated

right parietal arteriovenous malformation

that contains

serpentine flow voids typical of AVM.

I 5 10

ffi

Malformation

(Thrombosed)

RING-ENHANCING

lESION,

SOLITARY

VI

" c: Cll

:l

Co llJ

., Cll

(Left) Coronal T1 C+ FS MR shows a large partially

rim-enhancing cystic mass 8lI in the frontal lobe, compressing the frontal horn of the left lateral ventricfe. There is a strongly enhancing mural nodule within this cystic mass (not shown), typical of ganglioglioma. (Right) Axial T1 C+ MR

Pilocytic Astrocytoma

:l llJ

~

OJ :l

"U OJ

ro:l ()

::r

'
-

.r:

c Q)

~ a.. co

c .~

co c ..

abnormalities

should suggest congenital CMV inFection. (Right) Axial T2WI MR in another inFant with congenital CMV inFection shows multiple perivenlricular

cysts

CD

::::l

CD

Q]

germinolytic

ffi

(Left) Coronal fLAIR MR in a patient with inFantile ReFsum disease shows bilateral perivenlricular

germinolytic

a.."

cysts mimicking Zellweger syndrome. (Right) Axial T2WI MR in an inFant with Zellweger syndrome shows germinolytic cysts at the caudothalamic groove The hyperintense white maller

is indicative

demyelination.

of

Also note the

perisylvian polymicrogyria

Ii8

Miscellaneous

Congenital Malformations

Miscellaneous

Congenital Malformations (Left) Axial T2WI MR in a child with congenital muscular dystrophy shows multiple small cystic lesions in the dysplastic cerebellum The pons is hypoplastic with dorsal cleFting ~ Hypomyelination of the temporal lobes is present 81. (Right) Coronal FLAIR MR in an 78 month old inFant with

=.

van der Knaap

leukoencephalopathy shows cystic changes in both temporal lobes

=.

characteristic

condition.

of this

I 5 27

CYST WITH NODULE

['(l Q)

c Q)

(9

DIFFERENTIAL DIAGNOSIS Common • Neurocysticercosis • Pilocytic Astrocytoma • Ganglioglioma • Hemangioblastoma Less Common • Metastases, Parenchymal • Glioblastoma Multiforme • Pleomorphic Xanthoastrocytoma • Abscess • Opportunistic Infection, AIDS, Toxoplasmosis • Parasites, Miscellaneous • DNET Rare but Important • Desmoplastic Infantile Ganglioglioma • Schwannoma, Intraparenchymal • Arteriovenous Malformation (AVM)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Cystic lesions with solid nodular components can be divided into 2 categories o Lesions that typically demonstrate cyst with nodule morphology • Neurocysticercosis (NCC), pilocytic astrocytoma, ganglioglioma, hemangioblastoma, pleomorphic xanthoastrocytoma (PXA), desmoplastic infantile ganglioglioma (DIG), intraparenchymal schwannoma o Lesions that may demonstrate cyst with nodule morphology • Metastases, glioblastoma multiforme (GEM), abscess, toxoplasmosis, parasites, DNET, thrombosed AVM • Although metastases, abscesses, & GEMs do not classically present as "cysts with nodules", they are included because of their overall prevalence o Statistically, the atypical form of these common diseases may be more likely than some of the other "classic" cyst with nodule lesions

I 5 28

Helpful Clues for Common Diagnoses • Neurocysticercosis o Cyst with "dot" inside representing scolex

Imaging appearance varies with stage; increased enhancement & edema when organism dies (inflammatory host response) o Location: Convexity subarachnoid space> > cisterns> parenchyma> ventricles • Pilocytic Astrocytoma o Cerebellar cystic mass with mural nodule in a child; rarely supratentorial o Tl C+: Nodule shows intense but heterogeneous enhancement • Ganglioglioma o Cortically based, slow-growing enhancing mass in older child or young adult o Cyst with nodule most common, may be solid o Most common tumor to cause temporal lobe epilepsy • Hemangioblastoma o Parenchymal posterior fossa cyst with nodule mass in an adult o Tl C+: Nodule abuts pial surface & shows intense, homogeneous enhancement o Multiple in von Hippel-Lindau syndrome (VHL) (25-40% of hemangioblastomas) o

Helpful Clues for Less Common Diagnoses • Metastases, Parenchymal o Discrete, gray-white interface mass(es) with adjacent vasogenic edema o Multiplicity, history of primary malignancy, helpful if present o Solitary metastasis may mimic GEM • Glioblastoma Multiforme o Malignant white matter mass with central necrosis o Predilection to spread across midline along corpus callosum; "butterfly glioma" o Tl C+: Thick, irregular, nodular enhancing margins o T2/FLAIR: Surrounding hyperintensity & mass effect reflect edema + infiltrative tumor • Pleomorphic Xanthoastrocytoma o Cortically based cyst + nodule ± involvement of adjacent meninges o Tl C+ • Enhancing nodule • Look for thickening, enhancement of adjacent meninges • 70% have "dural tail" o Temporal lobe predominance; young adult

CYST WITH NODULE

C/I

c: ""

• Abscess o T2 Hypointense rim with surrounding edema classic o Tl C+: Enhancing capsule thinnest at ventricular side o DWI: Cystic component bright (diffusion restriction) • Opportunistic Infection, AIDS, Toxoplasmosis o Toxoplasmosis: Enhancing central nodules with peripheral rim = "target" lesions o Location: Basal ganglia> hemispheres o Clinical: Immunocompromised patient • Parasites, Miscellaneous o Multiple enhancing lesions typical o May mimic brain tumor o Travel history critical • DNET o Bubbly, wedge-shaped, cortically based mass "points" toward lateral ventricle o T2: Very hyperintense; nodular, septate; no surrounding edema o Tl C+: No to minimal enhancement, may be nodular o Temporal lobe predominance Helpful Clues for Rare Diagnoses

• Desmoplastic Infantile Gangiiogiioma o Supratentorial cystic/nodular mass with dominance of the cyst o Cortically based nodule with intense enhancement & dural tail o May be massive o Peak age 3-6 months

• Schwan noma, Intraparenchymal o Only 1-2% of schwannomas are parenchymal o Cyst with strongly enhancing nodule • Arteriovenous Malformation (AVM) o When hemorrhagic with partial or complete thrombosis, may present as cyst with nodule o Blood breakdown products of various ages; fluid-fluid levels Alternative

Differential

Approaches

Dl

::l Q.

lJl ...• Dl

::l lJl ...• Q)

::l -0

...•

Q)

-

..c:: t.l c

~

Ql

ro

0..

c

ro ~ co c 'iij ~

co 't:l

c III

DIFFERENTIAL DIAGNOSIS Common • Choroid Plexus Xanthogranuloma • Lipoma • Craniopharyngioma • Teratoma • Dermoid Cyst • Ossified Falx less Common • Asymmetric Marrow, Petrous Apex • Cholesterol Granuloma, Petrous Apex Rare but Important • "White" Epidermoid Cyst • Meningioma, Lipomatous • Encephalocraniocutaneous • Retained Pantopaque

Lipomatosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Fat vs. cholesterol-containing lesion o Fat (lipoma, dermoid, teratoma) o Cholesterol (craniopharyngioma, xanthogranuloma, cholesterol granuloma) • Fat vs. mimic (lesions with short Tl) Helpful Clues for Common Diagnoses • Choroid Plexus Xanthogranuloma o Common (70% of autopsies) o Incidental MR finding o Older patient with bilateral choroid plexus cysts • Hypodense, Ca++ on NECT

I 5 32

Axial N[CT shows bilateral hypodense, calcified choroid plexus cysts ~ in an elderly paUent. Cysts are xanthogranulomas and look more like CSFthan fat.

• Usually Tl hypointense • Lipoma o Subpial mass (-SO to 100 HU, short Tl) o 50% interhemispheric ± agenesis CC • Craniopharyngioma o Cyst contains high cholesterol fluid o Variable signal on MR • Teratoma o Midline mass with Ca++, adipose tissue • Dermoid Cyst o ± Cisternal fat droplets o NECT: 20-40 HU ± Ca++ o MR: Heterogeneously hyperintense • Ossified Falx o Osseous metaplasia, fatty marrow Helpful Clues for less Common Diagnoses • Asymmetric Marrow, Petrous Apex o Asymmetric aeration o Fatty marrow, no expansile change • Cholesterol Granuloma, Petrous Apex o Expansile PA mass o Tl/T2 hyperintense Helpful Clues for Rare Diagnoses • "White" Epidermoid Cyst o t Protein - short Tl/T2 • Meningioma, Lipomatous o Rare, inhomogeneously hyperintense • Encephalocraniocutaneous Lipomatosis o Scalp lipoma, hemispheric atrophy, variable intracraniaillpomas • Retained Pantopaque o Tl hyperintense; T2 iso-/hypointense o Spine> > > brain

Sagittal T1WI MR shows a small curvilinear interhemispheric lipoma =:I above the corpus callosum.

FAT-LIKE lESION(S),

en ,.-

GENERAL

c: IU

::::l Co

...IU

III

Teratoma (Left) T1WI MR shows classic adamantinomatous craniopharyngioma with striking T 7 shortening caused by thick, brownish ("crankcase") fluid containing high cholesterol. (Right) Sagillal T1 WI MR demonstrates hyperintense fat hypointense focal calcification and soft tissue ~ components in a suprasellar teratoma.

=-

=- =-

Dermoid

::::l

...OJ

OJ ::::l -U OJ CD

...

::::l ::r

()

'< 3 OJ

G) CD

::::l

CD

Q]

Ossified Falx

Cyst

(Left) Sagillal Tf WI MR demonstrates a lesion of mixed signal in the quadrigeminal cistern Q in keeping with a dermoid cyst. There is evidence of rupture with lipid droplets noted throughout the subarachnoid space PJ:?]. A fat-fluid level was present in the lateral ventricle (not shown). (Right) Sagittal T1 WI MR shows hyperintense foci in the midline caused by fatty marrow in the osseous metaplasia i:l2.

Asymmetric

Marrow, Petrous Apex

Cholesterol V

Granuloma,

Petrous Apex (Left) Axial T1 WI MR shows increased signal within leFt petrous apex without expansion. Compare to the normal aerated right petrous apex 81. This is a "leave me alone" pseudolesionl (Right) Axial Tf WI FS MR shows expansile, hyperintense lesion in pelrous apex Lesion did not saturate, which lipoma or fat in asymmetric, unaerated petrous apex would have done.

=

=.

I 5 33

~ solitary lesions o Most NCC cysts are actually cisternal (within depths of superficial sulci) > brain parenchyma, ventricles • Tuberculosis o Healed gran uloma • Can be single or multiple • Many fewer lesions than CC • Occasionally solitary tuberculoma can be mass-like, mimic neoplasm • Cavernous Malformation o Solitary> multiple o Ca++ can be dot-like, clumped, or scattered within single lesion o Do MR with T2* scan (GRE, SWI) to look for hemorrhage, multiplicity • Oligodendroglioma o Cortical/subcortical mass o Slow-growing; may erode adjacent skull o 70-90% calcify (nodular, clumped) o Adult> child • Ganglioglioma o Slow-growing, cortically based neoplasm o Child/young adult with epilepsy o Common: Ca++ nodule, ± cysts o May erode/remodel adjacent skull • Diffuse Astrocytoma, Low Grade o Hemispheres> posterior fossa o Solid> > cystic mass o 10-20% calcify o Infiltrates brain o Intrinsic tendency to undergo malignant degeneration • Pilocytic Astrocytoma o Cerebellum> optic nerve/chiasm, 3rd ventricle> pons o Cyst with nodule (cerebellum) o Solid mass (optic chiasm/hypothalamus, pons) o Ca++, hemorrhage uncommon (unless pilomyxoid variant) Helpful Clues for Less Common Diagnoses • Arteriovenous Malformation o Little/no mass effect unless hemorrhage o Look for enlarged feeding arteries, draining veins o Occasional Ca++ in nidus, draining veins (phlebolith)

SOLITARY PARENCHYMAL

CALCIFICATION

C/)

~ r::

• Ependymoma o 3rd most common posterior fossa neoplasm in children (after medulloblastoma, pilocytic astrocytoma) 02/3 infra tentorial (4th ventricle) o 1/3 supratentorial (extra-ventricular, hemispheric WM) • Large, extensively calcified cystic/solid hemispheric mass in young child? Think ependymoma first! o 50% of all ependymomas calcify o Cysts, hemorrhage also common • Parasites, Miscellaneous o Except NCC, parenchymal Ca++ rare o Any healed parasitic infection can calcify Helpful Clues for Rare Diagnoses • Physiologic Calcification, Brain o True solitary, unilateral normal parenchymal Ca++ unusual • Basal ganglia usually bilateral, occasionally unilateral • Habenular commissure may Ca++ • "Brain Rock" o Dense globular parenchymal Ca++ o No infection, neoplasm, degeneration • Calcified Embolus o In artery within sulcus, not brain parenchyma • Saccular Aneurysm o Huge, bizarre-appearing, extensively calcified mass in adult? Think partial/completely thrombosed giant saccular aneurysm

• Metastasis, Parenchymal o Untreated metastases rarely calcify o Breast, mucinous carcinoma, osteosarcoma metastasis may calcify spontaneously • TORCH Infection o Multiple> > solitary o CMV most common o Cortical • DNET o Almost all patients < 20 years o Chronic epilepsy o Well-delineated, "bubbly" appearing cortical mass • May remodel overlying skull • Gross Ca++ uncommon, hemorrhage rare • < 20% enhance • May have adjacent cortical dysplasia • Meningioangiomatosis o Child/young adult with seizures o Hamartomatous cortical/leptomeningeal malformation o Meningovascular proliferation along perivascular spaces (PVSs) o 50% associated with neurofibromatosis o Cortical mass with Ca++ (often gyriform) o T2 hypointense o Plaque-like pial, linear enhancement along PVSs

Neurocysticercosis

=-

Nee. No

other brain lesions were identified.

j

C-

..,ll>

OJ j

OJ

OJ :J -U OJ

Cil :J (")

::r

'< 3 OJ

Gl

:J

.., OJ

Neurocysticercosis

Axial N[CT shows solitary calcified NCC cyst probably in depths of sulcus. This was an incidental finding in an immigrant from endemic area who has systemic

ll>

Axial NECT shows small right medial frontal calcification in a patient with known neurocysticercosis. Although lesion looks intraparenchymal, it is most likely within a deep sulcus.

=

I 5 35

SOLITARY PARENCHYMAL



::J () ::r

'< 3 Q)

G) C1>

::J

C1>

OJ

TORCH

Infection

DNET (Left) Axial NECT shows subtle lefl perivenlricular calcificalion Note broad, flal, fronloparielal gyri, suggesling a corlical neuronal migrational abnormalily ~ Note moderate ventricular dilatalion 1!:lI. (Right) Axial NECT shows a hypodense, right posterior fronlallobe, corlically based mass with adjacenl remodeling of lhe calvarium and a dOL of faint calcificalion ~ The diagnosis was ONET.

=-

(Left) Axial NECT in a 75 year old with chronic epilepsy shows dense gyriform calcificalion enlargement of adjacent subarachnoid space m. Meningioangiomalosis found at surgery. (Right) Axial NECT in young adult wilh chronic epilepsy shows

=-

superficial

cortical

=.

calcificalion MR demonstrated enhancing mass in adjacent pia that infiltrated

deep into brain

along perivascular spaces. Meningioangiomatosis identified

I

at surgery.

5 39

[1:1

MUlTIPLE PARENCHYMAL CALCIFICATIONS

OJ C

OJ

19 ro

E

>u c

.c

~ OJ

ro

0..

c

ro ~

co

C ltl

~ l%l "t:l

c

ltl

DIFFERENTIAL DIAGNOSIS Common • Normal • Neurocysticercosis • Cavernous Malformation

(Multiple)

Less Common • Tuberculosis • Tuberous Sclerosis Complex • Sturge- Weber Syndrome • Metastases, Parenchymal Rare but Important • Remote Brain Injury • Opportunistic Infection, AIDS • TORCH Infections • Lymphocytic Choriomeningitis • Metabolic (Inherited or Acquired) o Fahr Disease o MELAS o Hypothyroidism o Hyperparathyroidism o Hypoparathyroidism o Pseudohypoparathyroidism oX-linked Adrenoleukodystrophy • Pseudo-TORCH Syndromes • Radiation and Chemotherapy

ESSENTIAL INFORMATION

I 5 40

Key Differential Diagnosis Issues • Discrete, multifocal/scattered Ca++ • Hyperdensities on NECT, variably "blooming" hypointensities on T2*/GRE • Location helpful in differential diagnosis o Basal ganglia (physiologic in adults) • Abnormal Ca++ can be congenital, acquired • End result of toxic/metabolic (e.g., thyroid/parathyroid disorder), inflammatory/infectious etiologies (e.g., TORCH) o Cortex: Neurocysticercosis (sulci), TB, Sturge-Weber o Gray-white junction • Fahr disease • Tuberous sclerosis complex • Metastases (treated> > untreated) • Radiation/chemotherapy o Periventricular • Fahr disease • TORCH, pseudo-TORCH

• Tuberous sclerosis complex Helpful Clues for Common Diagnoses • Normal o Microscopic brain Ca++ ("calcospherocytes") • Ca++, iron deposits in microvessels • Common in elderly, especially basal ganglia (BG) • Except for BG, macroscopic brain parenchymal calcifications usually abnormal o Basal ganglia • Ca++ common in adults • Physiologic> > metabolic derangement (e.g., thyroid/parathyroid disorders) • Uni-/bilateral • Symmetric or asymmetric • Neurocysticercosis o Nodular calcified stage of neurocysticercosis (NCe) o Multiple, small ("starry sky" pattern) > solitary, large Ca++ o Lesions appear to be parenchymal but most actually in depths of sulci! • Cavernous Malformation (Multiple) o Multiple (familial) CM syndrome o 10-30% of cases o Variably-sized hyperdense/Ca++ lesions • Can be small/almost invisible, occasionally very large • Homogeneous or "salt and pepper" o T2* (SWI > GRE) best to detect Helpful Clues for Less Common Diagnoses • Tuberculosis o Ca++ uncommon ('" 20%) • Represents healed granuloma • Solitary> multiple small Ca++ more common • Ca++ often somewhat larger (can be giant) compared to NCC • Few scattered, larger Ca++ (TB) vs. numerous multiple small (NCe) o "Target sign" = central Ca++ surrounded by enhancing rim • Tuberous Sclerosis Complex o 98% have Ca++ subependymal nodules • Most along caudothalamic groove • 30-80% enhance • Enhancing lesion near foramen of Monro needs follow-up (growth indicates subependymal giant cell astrocytoma)

MULTIPLE

PARENCHYMAL

CALCIFICATIONS

CIl

" c:

Tubers in cortex, subcortical white matter • Up to 50% show some Ca++ by age 10 • Enhancement less common (10-15%), does not presage malignancy • Sturge-Weber Syndrome o Gyral (cortex, subcortical white matter) Ca++ (not in pial angioma!) o Atrophy/prominent subarachnoid spaces o Look for enlarged, enhancing ipsilateral choroid plexus, prominent medullary veins o 20% bilateral • Metastases, Parenchymal o Typically post-treatment (e.g., XRT for breast metastases) o Untreated metastases rarely Ca++ o Exceptions • Mucinous adenocarcinoma • Malignant bone neoplasms • Breast (rare) o

Helpful Clues for Rare Diagnoses • Remote Brain Injury o Rare cause of Ca++ o Can occur with trauma, infarction • Opportunistic Infection, AIDS o Most acute, not chronic; Ca++ rare o Co-infection with TB may cause Ca++ if patient survives • TORCH Infections o CMV most common intrauterine infection in developed countries o Others rare (e.g., toxoplasmosis, rubella, herpes)

• Lymphocytic Choriomeningitis o Rodent-borne o Causes necrotizing ependymitis, aqueductal obstruction o Can be indistinguishable from CMV • Fahr Disease o Cerebrovascular ferrocalcinosis o Extensive bilateral BG Ca++ o Can involve dentate nuclei, cerebral white matter • MELAS o Stroke-like cortical, basal ganglionic lacunar infarcts o Basal ganglia Ca++ • Hypothyroidism o May cause BG, cerebellar, subcortical white matter Ca++ • Hyperparathyroidism o Rare; BG Ca++ • X-Linked Adrenoleukodystrophy o Chronic lesions may Ca++ • Pseudo-TORCH Syndromes o Types • Baraister-Reardon • Aicardi-Goutieres o BG, cerebellar> periventricular Ca++ • Radiation and Chemotherapy o Mineralizing microangiopathy o BG, gray-white junction Ca++

Ql

:J C-

OJ ..... Ql

:J OJ ..... III

:J lJ

III

CO

:J () ::T

'< 3

III

Gl C1>

:J C1> ..... III

Neurocysticercosis

Axial NEeT shows multiple calcifications typical for healed cysticercosis. While most lesions look as if they

are in brain parenchyma, many are actually within cerebral sulci.

Axial NEeT scans in same patient at low ventricular fleft), high left frontal (right) regions show healed, calcified TB granulomata 1::1.

I 5 41

MUlTIPLE

OJ OJ

~

PARENCHYMAL

CAlCIFICATIONS

c OJ

(9

Tuberous Sclerosis Complex

Sturge-Weber

Syndrome

(Left) Axial CECT shows multiple parenchyma/l:lll and subependymal calcifications 811. (RighI) Axial NECT shows variant case of Swrge-Weber syndrome with focal sulcal enlargement

ffi

linear

calcifications in underlying thinned cortex SlI. Most patients show much more extensive atrophy and calcification.

Metastases,

Parenchymal

(Lefl) Axial NECT shows untreated calcified metastases in a patient with breast carcinoma, decreased mental status. Multiple lesions enhanced on CECT scan, including these lesions. (RighI) Axial NECT shows focal right temporal lobe infarct as a wedge-shaped area of low density encephalomalacic, gliotic brain 1:llI. Associated dystrophic calcification !J:gI is very rare. Ipsilateral ventricle is mildly enlarged related to volume 1055SlI.

=

TORCH (Lefl) Axial NECT shows extensive perivenlricular. basal ganglia cerebellar IaI calcification. The "primitive" appearance of sylvian cisterns are due to bilateral opercular polymicrogyria ~ (RighI) Axial NECT shows periventricular, thalamic calcifications with venlriculomegaly. Lymphocytic choriomeningilis can mimic cytomegalovirus.

I 5 42

Infections

Remote Brain Injury

MUlTIPLE

PARENCHYMAL

CALCIFICATIONS III

:J

a.

..,

OJ

Fahr Disease

MELAS

III

(Left) Axial NECT shows mulliple nearly symmeuic calcifications in basal ganglia, gray-while malter junclions. (Right) Axial NECT shows bilaleral basal ganglia calcifications

=..

bioccipilal

encephafomalacic

areas

m

in a child with MELAS, mulliple strokes.

:J CD .., OJ

:J "U

.., OJ Ctl

::J

()

::r

'
parenchymal lesions o Mildly hyperdense (rim> solid) ± edema o Healed granulomas may calcify • Neurosarcoid o Infiltrates along perivascular spaces -> parenchymal mass o May cause focal patchy hyperdense mass(es)

Cerebral Contusion

• Leukemia o Most parenchymal hyperdensities are hemorrhages o Hypercellular parenchymal masses (chloromas) < extra-axial tumor • Thrombotic Microangiopathies (HUS/TTP) o Thrombocytopenia, intravascular hemolysis characteristic of 3 disorders • Malignant hypertension (often with HUS) • Disseminated intravascular coagulation (DIC) • Thrombocytopenic thrombotic purpura (TIP) o Patchy petechial hemorrhages, predominately cortical • Thrombolysis Complications o 10-lS% hemorrhage • Petechial> gross lobar o Post-procedural T1 C+ MR may predict hemorrhagic transformation (HT) • If present, risk of HT t • Parasites, Miscellaneous o Cysts> hyperdensities o Consider travel history, especially in endemic area o Beware: Conglomerate parasitic masses can mimic brain tumor! • Acute Hemorrhagic Leukoencephalopathy o Fulminant variant of ADEM o Hyperintensities in/along perivascular spaces o Microhemorrhages > gross lesions oCT, MR may not show hemorrhage

Ql

:I

a. III ..., Ql

:I III ..., Q)

:I

-U

..., Q)

CD :I ()

:r '
,

-'u= c QJ

~ co 0-

c

co ~

[D

c co •...

[JJ

"tl

c

III

(Left) Axial NECT shows a large high density mass in the leit cerebellar hemisphere =:I. The right cerebellar hematoma oi slightly lesser increased attenuation ~ indicates active hemorrhage. (Right) Axial NECT in a hypertensive patient shows patchy pontine =:I and cerebellar hemorrhages PJ:].

Cerebral (Left) Axial NECT shows spontaneous leitlobar hemorrhage =:I in a demented, normotensive patient. (Right) Axial NECT at a higher level in the same patient shows a right lobar hemorrhage =:I. Multiple lobar hemorrhages suggest amyloid angiopathy.

(Left) Axial NECT shows a heterogeneous, slightly hyperdense lesion in the leit temporal lobe, with a central iocus oi hemorrhage ~ and surrounding vasogenic edema. This patient has metastatic

=

bronchogenic

carcinoma.

(Right) Axial NECT in the same patient shows 2 other slightly hyperdense lesions =:I in the leit iron tal lobe, one with central hemorrhage

ffi

Significant

vasogenic

I 5 52

surrounding

edema is present.

Amyloid

Disease

Cerebral Amyloid

Disease

MUlTIPLE

HYPERDENSE

PARENCHYMAL

en ,..

LESIONS

c: III

::::l Q.

..,

OJ Cavernous Malformations

III

(Left) Axial NECT shows faint hyperdensities in the septum pe//ucidum and left medial frontal cortex MR with SWI showed multiple cavernous malformations mixed with large venous malformation. (Righi) Axial NECT in a child with known multiple cavernous malformation syndrome shows 2 faint hyperdense lesions in left parietal lobe.

=.

=

::::l

..,

OJ Ql

::::l II

..,

Ql

posterior fossa o Often in a single vascular distribution o May appear as multiple lesions if embolic • Trauma o DAI & cerebral contusions typically hemorrhagic (hyperdense)

o Trauma history is usually known • Cerebral Contusion o Brain surface injuries involving superficial gray matter (GM) & contiguous subcortical white matter (WM) o Classic location: Anterior inferior frontal lobes & inferior temporal lobes o Hemorrhagic> nonhemorrhagic o Soft tissue injury in 70% of patients • Diffuse Axonal Injury (DAI) o Punctate hemorrhages at corticomedullary junction, corpus callosum, deep GM, & upper brainstem classic oCT often normal acutely (50-80%) o May see small hypodense edematous foci o Petechial hemorrhage in up to 50% • Metastases, Parenchymal o Multifocal enhancing lesions with edema at corticomedullary junctions Helpful Clues for Less Common Diagnoses • Multiple Sclerosis o Multiple hypodense periventricular lesions o Variable enhancement o Young adult presentation common • Infection o Pattern of brain involvement may help differentiate various etiologies o Fungal & parasitic infections less common • Encephalitis (Miscellaneous) o Viral agents most common o Many involve deep gray nuclei o Hypodense lesions with patchy enhancement common o Herpes encephalitis most common agent • Predilection for limbic system • Involves cortex and subcortical WM • Bilateral, asymmetric involvement • Abscesses o Four pathologic stages: Early cerebritis, late cerebritis, early capsule, late capsule o Imaging varies with abscess stage o Bacterial> > fungal/parasitic o Multiple often related to septic emboli o Frontal, parietal lobes commonly involved • Opportunistic Infection, AIDS o Toxoplasmosis: Multiple ring-enhancing lesions of varying size with surrounding edema in deep & superficial brain o PML: Large multifocal subcortical WM lesions without mass effect, enhancement

MULTIPLE

HYPODENSE

PARENCHYMAL

en

LESIONS

'"

r::

TB & fungal: Solid, mildly hyperdense or hypodense masses Tuberculosis o Basilar meningitis + parenchymal lesions highly suggestive o Tuberculomas: Hypodense parenchymal masses with solid or ring enhancement o Meningitis is most frequent manifestation of CNS TB & is more common in children ADEM o Multifocal WM &/or basal ganglia (BG) lesions after infection or vaccination o Hypodense flocculent, asymmetric lesions o Initial CT normal in 40% Acute Hypertensive Encephalopathy, PRES o Patchy cortical/subcortical PCA territory lesions in a hypertensive patient o Posterior parietal, occipital lobes > BG, posterior fossa o Usually bilateral, often asymmetric Vasculitis o Characterized by non-atheromatous inflammation & blood vessel wall necrosis o May see multifocallow density areas in subcortical WM, BG o Initial CT often normal; angiography remains gold standard o

•

•

•

•

Helpful Clues for Rare Diagnoses • Glioblastoma Multiforme o Single hypodense mass with central necrosis & rim enhancement common o Multifocal or multicentric disease rare

• Osmotic Demyelination Syndrome o Acute demyelination caused by rapid shifts in serum osmolality o 50% in pons (CPM): Central fibers involved; peripheral fibers spared o 50% extra-pontine sites (EPM): BG, WM • Tuberous Sclerosis Complex o Cortical/subcortical tubers, WM lesions o Frontal> parietal> occipital> temporal o Calcified subependymal nodules typical • Lyme Disease o Small hypodense periventricular lesions o Cranial nerve enhancement common • Systemic Lupus Erythematosus o Small multifocal hypodense WM lesions o Focal infarcts of various sizes; symptomatic "migratory" edematous areas o Frontal, parietal subcortical WM common • CADASIL o Characteristic subcortical lacunar infarcts & leukoencephalopathy in a young adult o Anterior temporal pole & external capsule lesions (high sensitivity & specificity) o Subcortical hypodense lesions typical, may be confluent • Rickettsial Diseases o Rocky Mountain spotted fever most common (skin rash) o III-defined areas of WM & GM hypodensity ± petechial hemorrhage o Variable enhancement • Lymphoma, Intravascular (Angiocentric) o Multifocal WM lesions + enhancement o May mimic chronic small vessel ischemia

Cerebral

Axial

NECT

hypodensities

shows

muldple

wedge-shaped

= related to chronic ischemia in this

multi-infarct dementia patient. The multiple distributions suggest a central embolic source.

vascular

-=

::J

0-

lD ., Ql

::J

....

lD Q)

:::J

-u Q) ...• CD

:::J () ::T '
-

J:::

::l ()

or

'


::l C1> .., Ol

(Left) Axial NECT shows multiple infarcts in this patient with angioinvasive fungal vasculitis related to aspergillosis. Multiple low density lesions in the subcortical white matter & deep gray nuclei is common. OWl MR may be positive acutely. (Right) Axial N[CT shows multiple parenchymal hypodensities I:] in the cortex & subcortical white

maller related to tubers. Note the multiple calcified subependymal nodules, characteristic of tuberous sclerosis complex.

Rickettsial Diseases (Left) Axial NECT shows multiple hypodense lesions in the while maller related to hypertensive encephalopathy secondary to severe renal involvement in this patient with lupus. (Right) Axial CECT shows low density in the deep gray nuclei bilaterally, with areas of petechial hemorrhage 1:]. White maller hypodensity is also seen. Rickettsial diseases often a((ect the basal ganglia & show small infarct-like lesions in both the deep gray & white matter.

I 5 63

MULTIPLE BRAIN HYPERINTENSITIES

ell

~

(T2/FLAIR),

COMMON

Q)

c Q)

t?

Common • Aging Brain, Normal • ormal Myelination • Reactive Astrocytosis (Gliosis) & Encephalomalacia • Atherosclerosis, Intracranial • Neurofibromatosis Type 1 o Myelin Vacuolization • Enlarged Perivascular Spaces o Mucopolysaccharidoses • Lacunar Infarction • Chronic Hypertensive Encephalopathy • Acute Hypertensive Encephalopathy, PRES • Cerebral Infarct, Subacute • Cerebral Infarct, Chronic • Hypotensive Cerebral Infarct • Cerebral Edema, Traumatic • Cerebral Contusion • Diffuse Axonal Injury (DAI) • Multiple Sclerosis • Metastases, Parenchymal • Lymphoma, Primary CNS • Radiation and Chemotherapy • Periventricular Leukomalacia

ESSENTIAL INFORMATION

I 5 64

Helpful Clues for Common Diagnoses • Aging Brain, Normal o White matter (WM) hyperintensities are normally seen • Rule of thumb: 1 per decade to age SO o Increase in number & size is exponential from age SO to 100 years o Due to gliosis, leukoariosis, & enlarged perivascular spaces (PVS) • Normal Myelination o T2 hyperintense myelin at birth, except posterior fossa, optic radiations, & corticospinal tracts o Corpus callosum (CC) myelinates from 4 to 9 months, splenium to genu o Parietal & frontal myelination from center to periphery until around 2 years of age • Reactive Astrocytosis (Gliosis) & Encephalomalacia o Brain's only response to insults: Infectious, stroke, trauma o

Gliosis is T2 hyperintense without mass effect, encephalomalacia

often associated

Encephalomalacia is a "hole" that follows CSF signal, often surrounded by gliosis Atherosclerosis, Intracranial o Results in distal emboli or hypoperfusion infarcts o Variable infarct location, depends upon vessel involved Neurofibromatosis Type 1 o Nonenhancing T2 hyperintensities in basal ganglia (BG) & deep cerebellum most commonly (myelin vacuolization) o No mass effect, unlike astrocytoma, the main differential in NFl o Develops in early childhood, peaks around age 8, & usually regresses by late teens Enlarged Perivascular Spaces o Commonly symmetric & peripheral in WM, but can be unilateral focal & deep o Inferior BG, near anterior commissure common location o Sharp margins & lentiform, follows CSF on T2/FLAlR in young patients o Often associated with gliosis in the elderly (FLAIRhyperintense) o MucopoIysaccharidoses • Dilated PVS usually with surrounding gliosis presenting in infancy • CC & peri atrial WM most common Lacunar Infarction o Usually in lenticular & caudate nuclei, thalamus, internal capsules, periventricular o

DIFFERENTIAL DIAGNOSIS •

•

•

•

WM

Acute: T2 hyperintense, diffusion positive o Chronic: Focal encephalomalacia with surrounding gliosis • Chronic Hyperintensive Encephalopathy o Usually deep & periventricular WM confluent hyperintensities o Often associated with T2 hypointensities from microhemorrhage on GRE images • Acute Hypertensive Encephalopathy, PRES o Peripheral subcortical confluent hyperintensities, mild mass effect o Bilateral occipital parietal is common, but many variations including hemorrhage • Cerebral Infarct, Subacute o Embolic infarcts usually cortical, wedge-shaped with mass effect o Microembolic infarcts are usually peripheral centrum semiovale or BG o

MULTIPLE

BRAIN HYPERINTENSITIES

Enhancement typical Cerebral Infarct, Chronic o Results in focal encephalomalacia & gliosis o Typically in a major vascular distribution Hypotensive Cerebral Infarct o Watershed infarcts • Parasaggitallinear "string of pearls" in the centrum semiovale • Wedge-shaped regions in the border zone between vascular distributions o Diffuse or multifocal cortical infarcts & BG o Diffusion positive acutely Cerebral Edema, Traumatic o Cerebral swelling without T2 change early, may develop hyperintensities o Contusion & DAI commonly with hemorrhage Cerebral Contusion o Cortical, subcortical hyperintensities with developing hemorrhage o Regions of injury: Temporal, frontal lobe, superficial brain with direct trauma Diffuse Axonal Injury (DAI) o Shear stress deceleration injury: Gray-white, midbrain hemorrhage; diffusion positive early o Typically in older children to young adults, as there is minimal subarachnoid space & brain movement Multiple Sclerosis o CC & peri 4th ventricular involvement characteristic o Radiating periventricular location, "Dawson fingers"

•

•

•

•

•

COMMON

Acute tumefactive lesion: Large with T2 hypointense ring that enhances, usually little mass effect Metastases, Parenchymal o Hyperintensities may be punctate to massive, with variable surrounding edema, mass effect o Hyperintensity, edema, & mass effect less prominent in posterior fossa, but risks higher Lymphoma, Primary CNS o Central region nearly T2 isointense due to high nuclear to cytoplasmic ratio o Surrounding edema variable, usually crossing or around CC in immunocompetent o Immunocompromised PCNSL will have multifocal ring-like "glioblastoma" look Radiation and Chemotherapy o Radiation leukomalacia: Confluent poorly marginated regions in the radiation field without enhancement o Radiation necrosis: Irregular ring-enhancing lesions with variable mass effect, may grow, CBV/choline low Peri ventricular Leukomalacia o WM volume loss, gliosis, & focal cystic lesion in the periatrial WM o Associated with prematurity o

o

•

(T2/FLAIR),

•

•

•

•

III

::J

a.

..•

lJl III

::J OJ

~. ::J II

..•

OJ CD

:::J () :::J"

'< 3 OJ

Gl CD

:::J

..• CD OJ

Aging Brain, Normal

Axial FLAIR MR shows minimal deep while maIler hyperintensilies I:'.] & minimal gyral atrophy in this healthy 76 year old patient. These hyperinlensilies may be seen as parI of the aging process.

Axial FLAIR MR shows more extensive & confluent regions of hyperintensity including perivascular "leukoariosis" in this 96 year old healthy individual. Note the minimal atrophy.

I 5 65

MUlTIPLE

ro ~

BRAIN HYPERINTENSITIES

(T2/FlAIR),

COMMON

Q)

c Q) (9

ro

E

>.

.-

.L:

U C Q) L

ro

[L

c

~ co c ro •... In "'C

C C'Il

Less Common • Cerebral Amyloid Disease • ADEM • Vasculitis • Sickle Cell Disease • Leigh Syndrome • Thrombosis, Cortical or Deep Venous • CMV, Acquired • CMV, Congenital • Cerebritis • Encephalitis (Miscellaneous) • Herpes Encephalitis • Septic Emboli • Neurocysticercosis (NCC) • Parasites, Miscellaneous ·PML • Opportunistic Infection, AIDS • Glioblastoma Multiforme • Gliomatosis Cerebri • Osmotic Demyelination Syndrome • CO Poisoning • Drug Toxicity, NOS • Tuberous Sclerosis Complex • Susac Syndrome

•

•

•

•

ESSENTIAL INFORMATION

I 5 70

Helpful Clues for Less Common Diagnoses • Cerebral Amyloid Disease o Multifocal juxtacortical small infarcts & hemorrhages of varying ages o Little to no deep white matter (WM) or basal ganglia (BG) involvement o Acute lobar hemorrhage, the usual presenting symptom, typically large o May see confluent WM hyperintensity • ADEM o Multifocal WM lesions, punctate to flocculent, with enhancement, faint & fuzzy early, ring-like later o May mimic MS, but lesions are often more peripheral WM & all at same stage o Usually 10-14 days following infection or vaccination • Vasculitis o Multiple hyperintensities typical; pial & subarachnoid hemorrhage common o Less cortical involvement & more enhancement than embolic stroke

Granulomatous (PACNS), drug-induced, & infectious vasculitis usually moderate-sized vessels: M1 to cortical surface, may involve basal structures o Lupus & radiation-induced vasculitis are small vessel & usually angiographically occult with punctate to confluent hyperintensi ties Sickle Cell Disease o Creates a moyamoya pattern of vascular stenosis & occlusion with infarcts in MCA territory or watershed o Demographic & family history differentiate it from classic moyamoya Leigh Syndrome o Symmetric hyperintensity in regions of oxidative activity o Putamina & periaqueductal gray> caudate > globi pallidi, brains tern, thalami, dentate Thrombosis, Cortical or Deep Venous o T2 hyperintensity without diffusion restriction unless infarction has developed o Lesions usually solitary when isolated cortical venous o Dural sinus: Multiple lesions o Deep venous: Bilateral thalamic CMV, Acquired o Opportunistic infection with periventricular (4th> lateral) & cerebellar > cortical hyperintensity with mild enhancement CMV, Congenital o Multifocal deep band-like T2 hyperintensity with microcephaly & calcifications o Cortical dysplasia, agyria, myelination delay, periventricular cysts Cerebritis o Early stage of bacterial infection, prior to cavitation & enhancement seen in abscess o Peripheral, poorly marginated large lesion with mass effect Encephalitis (Miscellaneous) o Most non-herpes encephalitides involve the BG, thalamus, midbrain, & WM o Variable enhancement Herpes Encephalitis o Cortical & subcortical WM with bilateral, asymmetric involvement of the medial temporal & inferior frontal lobes & insula o Pial-cortical enhancement; OWl positive o

DIFFERENTIAL DIAGNOSIS

•

•

•

•

MULTIPLE

BRAIN HYPERINTENSITIES

(T2/FLAIR),

LESS COMMON

en

" r::

• Septic Emboli o Scattered small juxtacortical hyperin tensi ties o Develop into small ring-enhancing micro-abscesses • Neurocysticercosis (NCC) o Vesicular phase: Small 10 mm cysts with central dot- or comma-shaped scolex, no edema, follows CSF o Colloidal phase: Cyst may enlarge, is hyperintense to CSF,+ surrounding edema, enhancement o Granular nodular & calcified phase: Cyst retracts, wall thickens, edema resolves, calcifies • Parasites, Miscellaneous o Cystic mass or masses with hypointense rim & surrounding edema o Many with hemorrhage, which is uncommon in bacterial infection

•

•

•

•

·PML Multifocallarge WM lesions that lack mass effect, rarely enhance o Involves subcortical U-fibers • Opportunistic Infection, AIDS o Toxoplasmosis: Peripheral ring-enhancing "abscesses" o Cryptococcus: Enlarged perivascular spaces o CMV: Subtle ventriculitis, pial inflammation o Tuberculosis: Meningitis, tuberculous abscesses • Glioblastoma Multiforme o Rarely multifocal or multicentric

Heterogeneous mass with irregular enhancement o May cross the corpus callosum Gliomatosis Cerebri o Extensive multilobar or diffuse cerebral hyperintensity with mild mass effect o Preservation of underlying architecture Osmotic Demyelination Syndrome o Central pontine hyperintensity sparing the periphery & cortical spinal tract, round or trident-shaped (CPM) o BG & WM lesions with extra-pontine myelinolysis (EPM) CO Poisoning o Bilateral globi pallidi hyperintensity ± adjacent hemorrhage o May see putamen, caudate, & WM hyperintensity Drug Toxicity, NOS o WM multifocal strokes: Cocaine, amphetamine o Diffuse leukoencephalopathy: Inhaled heroin Tuberous Sclerosis Complex o Cortical tubers: juxtacortical hyperintensities o Calcified subependymal nodules Susac Syndrome o Callosal involvement always; central rather than at callosal septal margin seen in MS o Will leave "holes" in central callosum in chronic cases o Involves BG in 70%, much more than MS o

o

•

•

III

::J a. III ., III

::J OJ ., III

::J -U III

ro::J ()

::r

'< 3 III

I Axial FLAIR MR shows patchy & confluent T2 hype,intensities 1:2 in the deep and subcortical white matter bilaterally. The lesion distribution is often more peripheral than in arteriolosclerosis.

Axial FLAIR MR shows numerous peripheral hyperintensities generally sparing the cortex & extending around the subcortical U-fibers typical for AD[M.

=-

Bilateral, asymmetric involvement is common.

5 71

MULTIPLE BRAIN HYPERINTENSITIES

(T2/FLAIR),

LESSCOMMON

(Lefl) Axial FLAIR MR shows confluent

while maller

hyperinlensity primarily affecling the fronlal lobes with a small amounl of old hemorrhage in the right hemisphere due to granulomatous angiitis. (Right) Axial PO FSEMR shows bilateral subfrontal infarctions with increased

=-

-=

flow voids in paramedian

sulci ~

due to pial collateral

engorgement in this African American child. The Findings

are similar to moyamoya differenl demographic.

in a

Thrombosis, (Left) Axial T2WI MR shows bilaleral putaminal hyperintensity & swelling classic for acute Leigh syndrome with periatrial signal abnormality~. (Right) Axial T2WI MR shows hyperinlensity & swelling in the lhalami, putamina, & caudate heads bilaterally with hypointensity of the internal cerebral & thalamOSlriate

=

=

veins due to deep venous thrombosis.

(Left) Coronal FLAIR MR shows thin regular linear hyperintensities in the immediate

perivenlricular

while maller & caudate rim of the lateral & 3rd ventricles typical for

=

acquired

=

CMV

ventriculitis

in

this AIDS patient. (RighI) Axial T2WI MR shows extensive periventricular hyperintensity with germinal matrix cysts ~ & perisylvian cortical dysplasia ~. Microcephaly &

=

calcifications

I 5 72

are also

common in congenital CMV.

Cortical

or Deep Venous

MUlTIPLE

BRAIN HYPERINTENSITIES

(T2/FLAIR),

,.-c:

LESS COMMON

CIl

Dl

:l Q.

l:D ....• Dl

Cerebritis (Left) Axial T2WI MR shows abnormal hyperintense signal in the cerebellar hemispheres ~ due to cerebellitis. Enhanced images showed

marked enhancement. Cerebellitis is often a disease of children & is typically bilateral. (Right) Axial FU\IR MR shows symmetric hyperintense signal within the thalami with involvement of the deep WM E!lI in this EBVencephalitis patient. Viral encephalitis typically involves the BG, thalami, cortex, &/o{

=

:l OJ ....• OJ :l

-U OJ ....• CD :l ()

::r

'< 3 OJ

Gl CD :l CD ....• OJ

brainstem.

(Left) Axial FU\IR MR shows symmetric hyperinlensily in the medial temporal lobes & hippocampi bilaterally Sparing of the basal ganglia & brainstem is typical of herpcs enccphalitis. (RighI) Axial T2WI MR shows the typical appearance of a small brain abscess with a

=.

=-

hypointense rim central necrosis, & modest surrounding edema, occurring in a patient with streptococcal endocarditis with an associated cervical

cord abscess.

Neurocysticercosis

(NCC)

Parasites, Miscellaneous (Left) Sagittal T2WI MR shows numerous CSF isoinlense cysts with a

discrete, eccentric,

=

hypoinlense scolex in each & lack of edema, due to disseminated or "miliary" form of NCe. (Right) Axial FU\IR MR shows mixed hypo-/hyperintense right frontal mass with multiple smaller supratentorial masses

=

due

to

amoebiasis.

Hypoinlense hemorrhage or calcification, common in parasitic infections, is atypical for other infections.

I 5 73

MULTIPLE BRAIN HYPERINTENSITIES

~

(T2/FLAIR),

LESSCOMMON

Q)

c Q)

CJ

ro

E

>.

.r:

()

c

~ Q)

ro n.. c

ro ~

III

c ell

~

CO 't:l C

ell

(Left) Axial T2WI FS MR shows confluent, high signal in the fronlallobes wilhout significant mass effect. The subcorlical U-fiber involvement leads to a "scalloped" appearance to the gray-white junction (;8 (Right) Axial FLAIR MR shows numerous mixed hyperintense lesions commonly seen with

m

toxoplasmosis, the most opportunistic eNS infection in AIDS. Ring enhancement is a/so typical. common

(Left) Axial T2WI MR shows mu/tifocal high signa/lesions in the BG midbrain E!:l & subcortical WM characteristic of gelatinous "pseudocysts" caused by

= =

cryptococcosis

due to

dilated PVS filled with fungi, mucoid material, & infiammalOry cells. (Right) Axial FLAIR MR shows extensive hyperintensity infiltrating the cerebral WM & corpus callosum 1::1 wilh mass effect due 10 atypical GBM.

Gliomatosis (Left) Axial T2W/ MR shows mullifocal hyperinlensily infiltrating Ihe thalamus, basal ganglia, insula, & fronla/lobe while & gray matter with mild associated enlargement

of the involved

structures, typical for gliomatosis cerebri. Involvement

of more than

one lobe is common. (Right) Axial T2WI MR shows high signal intensity in the pons with characteristic symmetric geographic pal/ern typical for centra! pontine myelinolysis (CPM).

=

I 5 74

Cerebri

Osmotic

Demyelination

Syndrome

MULTIPLE BRAIN HYPERINTENSITIES

(T2/FLAIR),

LESSCOMMON III

:J

0-

III .,

Osmotic

Demyelination

Syndrome

III

CO Poisoning (Left) Axial FLAIR MR shows hyperintensity in the bilateral putamina E:II and caudate nuclei !:l'l due to osmotic demyelination, extra-pontine. Central and extra-pontine myelinolysis are often seen in the same patient. (Right) Axial T2WI MR shows hyperintensity 8. decreased size of the globus pallidi =.1 surrounded by a hypointense rim Sltypical for chronic carbon monoxide poisoning.

:J OJ

03 :J

-U OJ

CD

:J ()

::r

'< 3 OJ

G) CD :J CD ., OJ

Tuberous Sclerosis Complex (Left) Axial T2WI MR shows multiple hyperintense foci involving the basal ganglia 8. cerebral white maUer !:l'l caused by amphetamine-induced vasculitis. (Right) Axial T2WI MR shows multiple subcortical hyperinlensilies =.1 due to peripheral tubers. The hypointense subependymal nodules!:l'l 8. heterogeneous giant celt astrocytoma at the foramen of Monro E:II are diagnostic of tuberous sclerosis.

=.1

Tuberous Sclerosis Complex

Susac Syndrome (Left) Axial T2WI MR shows normal

immature

myelin in

this infant with subtle premature hypointensity in a tuber of the medial left frontal white maUer along with multiple low signal intensity subependymal nodules 81. (Right) Axial FLAIR MR shows hyperintensities in the

=-

white maller

=-

involvement

with

of the corpus

callosum always associated with Susac syndrome. Imaging often mimics multiple sclerosis.

I 5 75

ro ~

MUlTIPLE

BRAIN HYPERINTENSITIES

(T2/FLAIR),

RARE BUT IMPORTANT

QJ

c QJ

.

.r: u

c

~ QJ

ro

Cl..

c

ro ~

OJ C ltl

~

OJ

" C

ltl

Rare but Important • CADASIL • Neurosarcoid • Hashimoto Encephalopathy • Granulomatous Angiitis • Lyme Disease • West Nile Encephalitis • Wegener Granulomatosis, Brain • Paraneoplastic Syndromes • Lymphoma, Intravascular (Angiocentric) • Olivopontocerebellar Degeneration • Subacute Sclerosing Panencephalitis • Rasmussen Encephalitis • Kernicterus

•

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Lesion location is critical: Gray vs. white matter (WM), basal ganglia (BG) vs. periphery, or specific locations • Treatment in these diagnoses is often specific & consideration of these rare diagnoses is important • Enhancement helps separate inflammatory from noninflammatory lesions

I 5 76

Helpful Clues for Rare Diagnoses • CADASIL o Subcortical bilateral anterior temporal poles involved early o Diagnosis age 20-40 years is common, unique to CADASIL o External capsule involvement somewhat specific, but other WM regions, thalamus, BG, pons also commonly involved o Frontal lobe predominant involvement developing into confluent lesions will become more prominent after age 50 o Migraine-like symptoms common, but CADASILlesions larger than typical punctate lesions in migraineurs o Can have a multiple sclerosis-like appearance early in the disease, although callosal involvement is rare • Neurosarcoid o Pial & leptomeningeal involvement with extension via perivascular spaces o Peripheral WM hyperintensities, intense enhancement

Parenchymal lesions can extend to the periventricular WM; usually confluent o Associated T2 hypointensity in dura & leptomeninges is characteristic, but can be seen with secondary lymphoma & metastasis Hashimoto Encephalopathy o MR positive in 25%, involves hippocampus, WM, cerebellum o Lesions usually ill-defined, no enhancement o May mimic olivopontocerebellar degeneration (OPCD) Granulomatous Angiitis o Multiple subcortical & cortical infarcts, often with peripheral subarachnoid hemorrhage o Peripheral segmental symmetric stenoses typical, not seen in CADASILor chronic hypertensive disease Lyme Disease o Scattered lesions 2-3 mm typical, usually less than 10 mm o May be DWI + & may enhance o Cortical involvement unusual o Myalgia, arthralgias, petechial rash of the palms & soles suggest Lyme disease West Nile Encephalitis o Midbrain, substantia nigra, cerebellum, & anterior horn of the spinal cord involvement typical o Moderate-sized lesions, ill-defined, leptomeningeal enhancement Wegener Granulomatosis, Brain o Similar to neurosarcoid in distribution, T2 signal, & enhancement o Necrotizing vasculitis with paranasal sinus & orbital involvement Para neoplastic Syndromes o Limbic encephalitis: Hyperintensity in amygdala, hippocampus, cingulate gyrus, & inferior frontal lobe WM o Paraneoplastic cerebellar degeneration: Bilateral peripheral cerebellar & pontine involvement o Mild edema in the acute phase; atrophy in the chronic phase Lymphoma, Intravascular (Angiocentric) o Multifocal, often confluent periventricular hyperintensity o

DIFFERENTIAL DIAGNOSIS

•

•

•

•

•

MULTIPLE

BRAIN HYPERINTENSITIES

(T2/FlAIR),

RARE BUT IMPORTANT

en ,... c:

Radiating enhancement pattern along deep medullary veins Olivopontocerebellar Degeneration a Cruciate T2 hyperintensity in lower pons a Cerebellar hemispheres more involved than vermis, with "fine comb" cerebellar folia in dominant form a Lateral cerebellar hemisphere atrophy with "fish mouth" deformity in recessive form Subacute Sclerosing Panencephalitis a Multifocal large or diffuse T2 hyperintensity extending into the gyri with callosal involvement; no enhancement a Similar features to progressive multifocal leukoencephalopathy with differing past medical history a Diffuse atrophy with severe WM volume loss late a Presents in childhood or early adolescence Rasmussen Encephalitis a Early focal cortical swelling & gray-white differentiation loss, usually does not enhance o Atrophy of the cerebral hemisphere or a lobe late a Begins in childhood, progressive seizures, hemiparesis, cognitive deterioration Kernicterus o Globus pallidus, hippocampi, substantial nigra & dentate nuclei, T2 & T1 hyperintensity o Encephalopathy due to deposition of unconjugated bilirubin a

•

•

•

•

III

Alternative Differential Approaches

• Characterize lesions by enhancement a Enhancing multiple rare T2 lesions • Neurosarcoid • Wegener granulomatosis • Granulomatous angiitis • Lymphoma, intravascular a Nonenhancing multiple rare T2 lesions • CADASIL • Hashimoto encephalopathy • Lyme disease • West Nile encephalitis • Paraneoplastic syndromes • Olivopontocerebellar degeneration (OPCD) • Subacute sclerosing panencephalitis • Rasmussen encephalitis • Kernicterus • Characterize lesions by location a Anterior temporal lobe: CADASIL,trauma o Limbic system/cerebellum: Paraneoplastic syndromes, herpes a Olive, pons, cerebellum: OPCD, multisystem atrophy a Unilateral hemisphere: Rasmussen encephalitis, Sturge-Weber, Dyke-Davidoff-Mason o Deep white matter: Granulomatous angiitis, intravascular lymphoma, Hashimoto, multiple sclerosis, arteriolosclerosis a Basal ganglia: Kernicterus, hypoxia, West Nile, Leigh, Wilson

;, Cl. O::J ....• III

;, O::J OJ :::J lJ Q) ....• CD

:::J :::r

()

'
J:: U C

~ Q)

ell

(L

c ell

~

[!J

.. C III

[!J

"C

c

III

Neurosarcoid

Neurosarcoid

(Left) Axial FLAIR MR shows unusual signal abnormality along the corpus callosum caudate nucleus, a thickened septum pellucidum & bilateral parieto-temporal white mailer. (Right) Coronal T1 C+ MR shows enlargement of the choroid plexus I:] & enhancement in the cerebellum. The left convexity lesion has typical pial-leptomeningeal enhancement with extension into the parenchyma ~ via

m

=-

perivascular spaces.

Granulomatous

Angiitis

(Left) Axial T2WI MR shows multiple confluent hyperintensities in the frontal & parietal white matter that extend into the gyri but spare the immediate juxtacortical white maller

=

related

to

Ilashimoto encephalopathy (Rigl1t) Axial T2WI MR show confluent

while matter

hyperintensity primarily affecting the (rontallobes with smaller regions on the right posteriorly. Old hemorrhage in the right hemisphere I:] suggests vasculitis.

Lyme Disease (Left) Axial fLAIR MR shows small white maller

I 5 78

hyperintensity in the deep, peripheral, & juxtacortical white malter. The scattered peripheral nature with small foci is typical for Lyme disease. (Right) Axial FLAIR MR shows multiple hyperinlensities surrounding the red nuclei !:ll & in the basal ganglia 1:]. The combination of basal ganglia & midbrain involvement is lypical for a viral encephalitis, in this case due to West Nile virus.

West Nile Encephalitis

MUlTIPLE BRAIN HYPERINTENSITIES (T2/FlAIR), RAREBUT IMPORTANT

en

'c":

III

:3

.. C.

lXl III

(Left) Coronal T2WI MR shows typical limbic encephalitis involving the medial temporal lobes =:I & right insular cortex PJ:I. This mimics herpes encephalitis, but lack of hemorrhage as we/J as cingulate involvement (not shown) favors limbic encephalitis. (Right) Axial FLAIR MR shows multiple, poorly marginated, (.f/.- confluent hyperintensilies in the periventricular, deep, & peripheral white mailer =:I with an outwardly radiating pattern seen in lymphoma.

:3

(Left) Axial T2WI MR shows disproportionate cerebellar =:I & pontine atrophy with cruciform T2 signal within t.he lower pons, the" hot cross bun" sign E±I characteristic for OPCD.

Note the normal supratentorial brain. (Right) Axial T2WI MR shows subcortical white maller hyperintensities III which have ill-defined margins &

spare the cortex. This is atypical for MS or stroke. SSPEusually ocwrs after a clinically silent period of months to years.

Rasmussen Encephalitis

Kernicterus (Leh) Axial T2WI MR shows ill-defined whit.e matter hyperintensities in the {rontal lobe within a larger region of striking atrophy of the frontal & parietal lobes. Rasmussen encephalitis. I-femicranium hypoplasia of Dyke-Davidoff-Mason & cortical hypointensity of Sturge-Weber are absent. (Right) Coronal T2WI MR

shows abnorrnal hyperintensity in the hippocampus =:I & globus pallidi PJ:I in a patient with age·appropriale immature myelin.

I 5 79

MULTIPLE HYPOINTENSE FOCI ON 12

ro

E

>-

£

()

C

~ ro

CL

c ro ~

co

r:: ell

~ III "'C

r:: ell

DIFFERENTIAL DIAGNOSIS Common • Neoplasm o Lymphoma o Metastases, Parenchymal o Multifocal Glioma • Atypical Infection o Bacterial (TB, Nocardia) o Fungal Diseases o Toxoplasmosis, Acquired Less Common • Neurosarcoid • Neoplasm-like Conditions o Post-Transplant Lymphoproliferative Disorder (PTLD) o Lymphomatoid Granulomatosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • These lesions show mild T2 hypointensity or "intermediate" signal intensity (51) o Lesions are often isodense or mildly hyperdense to gray matter (GM) on CT • Lesions in this ddx often associated with vasogenic edema & "bright" on T2/FLAIR, but are centrally iso- or hypointense to GM • Neoplasms included are generally small round blue-cell tumors (e.g., lymphoma) or highly cellular metastases with high nuclear-to-cytoplasmic ratio • DWI variable; may be mildly reduced due to t cellularity of some of these lesions

Helpful Clues for Common Diagnoses • Lymphoma o Both primary & secondary CN5 lymphoma may present as intermediate 51masses • PCN5L often limited to brain parenchyma • 5CN5L more likely to involve leptomeninges, dura, bone • Metastases, Parenchymal o Highly cellular, non-necrotic metastases o Breast & lung mets often T2 intermediate • Atypical Infection o Pyogenic abscesses typically have central t 51on T2WI because of pus o Atypical non-pyogenic "abscesses" often have intermediate 51on T2WI • In TB, due to caseous material • Fungal: Due to absence of pus, concentration of paramagnetic ions • Toxo: May show "eccentric target sign" o Variable reduced diffusion Helpful Clues for Less Common Diagnoses • Neurosarcoid o Parenchymal nodules & masses often intermediate T2 51due to high cellularity o Look for dural/leptomeningeal disease • Post-Transplant Lymphoproliferative Disorder (PTLD) o Parenchymal lesions resemble lymphoma • Lymphomatoid Granulomatosis o Rare lymphoproliferative disorder o Typical: Punctate & linear enhancement o Large coalescent nodules T2 intermediate

Metastases, Parenchymal

I 5 80

Axial T2WI MR shows multiple

brain parenchymal

masses lID with intermediate SI & variable associated vasogenic edema. The lesions enhanced intensely 8.. homogeneously- typical of primary eNS lymphoma.

Axial T2WI MR shows multiple lesions with associated

vasogenic edema. The 2 posterior lesions 1:.1 show fairly homogeneous intermediate 51, while the left frontal lesion I:i.'.l has a rim of low SI.

MULTIPLE HYPOINTENSE FOCI ON 12 III

::l

a. [ll .,

Multifocal

III

Glioma (Left) Axial T2WI MR shows areas of vasogenic edema in the right frontal & left temporal lobes, with central intermediate 51 ~ & associated mass effect The T2 hypointense central masses enhanced post-gadolinium. (Right) Axial T2WI MR shows multiple lesions that are intermediate in 5/ I:] & associated with vasogenic edema. These lesions showed ring enhancement. This patient had evidence for pulmonary TB as well as epididymo-orchitis.

Fungal Diseases

::l OJ

OJ ::J \J

., OJ

CD

::J () ::T '
. . peripheral) • Cerebral Amyloid Angiopathy o Elderly normotensive demented patients o Hemorrhages of different age, peripheral microbleeds on T2* • Demyelinating Disease oMS> > ADEM • History of viral illness, recent immunization suggests ADEM o Susac Syndrome • Rare; often mistaken for MS! • Young to early middle-aged females • Progressive encephalopathy, sensorineural hearing loss, visual symptoms • "Holes" in middle of corpus callosum Helpful Clues for Less Common Diagnoses • Primary Brain Tumor o Most primary brain neoplasms typically hypointense on Tl WI, hyperintense on T2WI; may be difficult to distinguish neoplastic from nonneoplastic etiologies

T1 HYPOINTENSE,12

•

•

•

•

HYPERINTENSE

• DWI helpful (neoplasms generally don't restrict; ischemia/infarction, infection typically do) • MRS helpful in some cases (t Cho) o Presence/absence/pattern of enhancement helpful but often nonspecific o Tend to be infiltrative rather than discrete, round masses Metastases, Parenchymal o Tend to be round rather than infiltrative o Gray-white junction common location o Almost always enhance (ring, punctate, solid) o May cause multifocal white matter hyperintensities, mimic "small vessel disease" o Difficult to detect or differentiate from vascular disease without contrast Abscess o Early cerebritis stage can be difficult to distinguish from ischemia, neoplasm o Late cerebritis to late capsule stages show ring enhancement o DWI restriction at all stages typical o MRS often shows lactate, amino acid peaks Cerebral Amyloid Disease o Can be multifocal, diffuse (amyloid angiopathy) • Do T2* (GRE/SWI) to detect micro bleeds • Peripheral> central (basal ganglia) o Lobar (hemorrhages of different ages) o Mass-like ("amyloidoma" rare) Herpes Encephalitis o Affects limbic system

Enlarged Perivascular

not enhance.

c: "

• Temporal lobes, insular cortex • Cingulate gyrus, subfrontal cortex o Look for "sequential bilaterality" in temporal lobes o Preferentially involves cortex o FLAIR,DWI most sensitive for early detection o Hemorrhage with TI shortening in late acute/subacute stages • Vasculitis o Can be primary CNS or secondary to systemic disorder o Combination of cortical/subcortical, basal ganglia disease suggestive o Punctate/linear enhancement common • Neurofibromatosis Type 1 o Foci of abnormal signal intensity best seen on T2WI, FLAIR o Hypointensities on TI WI less common; basal ganglia may have hyperintensity o Typically represent myelin vacuolization, not demyelination; are transient (rarely seen in adults) o No enhancement; if present, suggests possibility of astrocytoma (usually pilocytic) • Tuberous Sclerosis Complex o Cortical/subcortical tubers hypointense on TI, hyperintense on T2WI (similar signal to WM lesions of NFl) o Look for other stigmata of TSC (e.g., subependymal nodules, lesions along radial glial bands)

Spaces

Axial T2WI MR shows bizarre va,iable-sized hyperintense white matter cysts with gyral expansion cortical sparing lesions followed CSFon TI WI, did

en

PARENCHYMAL lESIONS

Gl CD

:J CD

~

Q)

Arteriolosclerosis

Sagittal TI WI MR in a patient with clinical diagnosis of Binswanger

vasculaNype

dementia

shows

mu/tjfocal

discrete and confluent lesions in subcortical, deep perivent/ieu/ar white maller _

I 5 91

T1 HYPOINTENSE,12

HYPERINTENSE

PARENCHYMAL

lESIONS

co

E

>. .s:: u c

•... Q)

co

0..

c

co •...

[]:J

c

•... l'Cl

aJ "'C

c l'Cl

(Leh) Axial T2WI MR shows several types o( T2 hyperintense lesions: Chronic hypertensive encephalopathy (typically periatrial changes) 1C>1 lacunar infarcts [;>1 prominent perivascular spaces ffi (RighI) Axial T2WI MR shows multifocal hyperintensities in subcortical white matter Presence of acute chronic 81 hemorrhage plus

= =.

peripherallocalion

is

characteristic for CAA.

(Lefl) Sagittal T7 WI MR in this patient with known MS shows deep perivenlricular hypointense lesions oriented perpendicular to the ventricular margin These lesions are perivenular demyelinating MS plaques. (RighI) Axial T7WI MR shows discrete, ill-defined hypointense foci ~ in a patient with a history of

recent viral illness. Many additional lesions were present on fLAIR, T2WI.

Susac Syndrome (Lefl) Sagittal T7 WI MR shows multifocal hypoinlensilies in the middle of the corpus callosum I:] in this 31 year old man with encephalopathy,

sensorineural hearing loss, visual symptoms. (Courtesy P. Rodriguez, MO). (RighI) Axial T2WI MR in a patient with decreasing mental status shows mulliFocal white maller

hyperinlensilies

lID.

Severa/lesions enhanced with contrast. Breast carcinoma

I 5 92

was found on

Further evaluation.

Metastases,

Parenchymal

11 HYPOINTENSE,12

HYPERINTENSE

PARENCHYMAL

lESIONS III

::l

Co

..,

OJ III

(Left) SagiLral T1 WI MR in polydrug abuser shows 2 inhomogeneously hypointense lesions that enhanced slrongly with contrast and showed reSlriction on DWI. (RighI) Axial T1WI MR shows diffuse cortical swelling, hypointensity in left temporal lobe with less prominent involvement of right temporal lobe SI. Bilateral disease suggests herpes encephalitis.

=

=

Cerebritis

::l

..,

IJl tlJ

::J \J

.., tlJ C1l

::J () :::r

'< 3 tlJ

Gl C1l

::J

.., C1l tlJ

Vasculitis (Lefl) Axial T1 WI MR in a 16 yo with headache, nausea developing 2 weeks after URI shows in homogeneously hypointense mass in right temporal lobe T1 C+ scan (nol shown) demonstrated poorly delineated enhancing rim characteristic for early cerebritis stage of abscess. (RighI) Axial T2WI MR shows hyperintense basal ganglia, thalami in this young female patient with known systemic lupus erythematosus and probable SLE vasculitis.

(Lefl) Axial T1 WI MR shows an optic chiasm astrocytoma hypointense foci in pons [;8 Pontine lesions were hyperintense on T2WI. (RighI) Axial T1 WI MR shows a large, flat gyri with hypointense juxtacorlical lesions in muflipfe tubers and white matter, as well as numerous calciried hyperintense subependymal nodules ffi Subcortical lesions were hyperintense on T2WI, fLAIR.

=-

I 5 93

~

11/12 IsOINTENsE PARENCHYMAL lESIONS

Q)

c Q)

c.9 l\l

E

>.c u

c

~

Q)

l\l

Cl.. C

l\l

~ co C ltl

~ co "'0 C

'"

DIFFERENTIAL DIAGNOSIS Common • Cerebral Ischemia-Infarction, Hyperacute • Intracerebral Hematoma (Hyperacute) • Capillary Telangiectasia • Developmental Venous Anomaly • Meningioma

•

less Common • Metastases, Parenchymal • Lymphoma, Primary CNS Rare but Important • Neurosarcoid • Heterotopic Gray Matter • Tuber Cinereum Hamartoma • Tuberous Sclerosis Complex • Cerebral Infarction, Subacute

•

ESSENTIAL INFORMATION

•

•

I 5 94

• Look for "dot sign" (intravascular high signal intensity caused by occlusion/slow flow) • Found in 10% of patients with acute stroke Intracerebral Hematoma (Hyperacute) o Clot contains intracellular oxyhemoglobin, which is diamagnetic o Although hyperacute clot can be isointense on Tl WI, most hematomas are inhomogeneous, often hyperintense on T2WI Capillary Telangiectasia o Can be anywhere • Pons, medulla> supratentorial cortex, white matter o Imaging • Unless unusually large, typically invisible on Tl/T2WI • Use T2* sequence (become hypointense on GRE, SWI) • Tl C+ shows "brush-like" enhancement • May see tiny central draining vein within lesion Developmental Venous Anomaly o Most common cerebrovascular anomaly o Imaging • If small, often invisible on Tl/T2WI • Larger DVAsmay have discernible flow void or flow-related enhancement • If slow flow in "Medusa head" (medullary veins), may become hypointense on T2* (GRE/SWI) • Best seen on Tl C+ Meningioma o Not truly a parenchymal lesion although some may invaginate into brain o Included because often isointense to cortex, difficult to detect on nonenhanced TlWI, T2WI o Look for signs of extra-axial location • Gray-white matter "buckling" • CSF-vascular "cleft" o Most enhance on Tl C+

Helpful Clues for less Common Diagnoses • Metastases, Parenchymal o Most hyperintense on FLAIR,T2WI o Gray-white matter junction distortion • Few are isointense on both Tl/T2WI • Most (not all) have detectable edema

T1/12

ISOINTENSE

PARENCHYMAL

lESIONS

(J)

""c:

• Look for subtle alteration in gyral shape, sulcal effacement o Most enhance • Lymphoma, Primary CNS o Hypercellular tumor, high nuclear:cytoplasm ratio • Isointense (cortex, basal ganglia) on both Tl/T2WI • Hemorrhage, necrosis rare unless HIV/AIDS o Look for anatomic distortion of deep periventricular structures o Almost always enhances Helpful Clues for Rare Diagnoses

• Neurosarcoid o Can be anywhere, look like almost anything! o Dural-based masses> > parenchymal lesions o Infiltration along perivascular spaces parenchymal masses o Isointense on Tl WI • Typically hyperintense on T2WI, FLAIR • Exception: Lesions in infundibular stalk usually isointense on all sequences o Enhance strongly, sometimes heterogeneously • Heterotopic Gray Matter o Isointense to cortex on all sequences, no enhancement o Can be cortical, subcortical white matter, subependymal

Cerebral

Ischemia-Infarction, Hyperacute

Axial T2WI MR shows very subtle focus of white matter hyperintensity in right posterior frontal lobe ~ tI,at is isointense with gray maHer. OWl showed anterior MCA division

infarct.

Beware: Masses of heterotopic gray matter can distort ventricle, mimic tumor! • Tuber Cinereum Hamartoma o Typical clinical presentation • Young male with isosexual precocious puberty • Gelastic seizures o Imaging • > 90% isointense with cortex on all sequences • 10% cystic, slightly hyperintense on PD, FLAIR,T2WI • Tuberous Sclerosis Complex o Cortical "tubers" • Thickened gyri • "Blurred" gray-white interface • Mostly isointense with cortex, occasionally hyperintense o Subependymal nodules • Mostly isointense with white matter • Variable, often heterogeneous intensity if densely calcified • May enhance on Tl C+ • If enhancing SEN at foramen of Monro, surveillance to watch for giant cell astrocytoma warranted • Cerebral Infarction, Subacute o Imaging • 10 days to 2 weeks after ictus • MR "fogging effect" may render stroke isointense on Tl/T2WI • DWI may pseudonormalize • Lesion typically enhances o

Intracerebral

Hematoma

III

:l Co

..•

OJ III

:l

..• OJ III

:J

-u III

CD

:J ()

::T '
:J ct> ~ III

(Hyperacute)

Axial T7WI FS MR in a patient with AML, acute clinical deterioration with normal NEeT minutes before this scan shows left frontal lesion ~ isointense with cortex. T2W/showed expanding hematoma.

I 5 95

11/12

ro ~

ISOINTENSE

PARENCHYMAL

LESIONS

Q)

c Q)

o ro E >.r: () c

~ ro

0...

c ro ~

CO

c

~ '"

CO

"tl

c

ro

Developmental

Metastases, (Lefl) Axial T1WI MR shows left parietal sulcal effacement by an isointense, dural-based mass ~ (RighI) Axial T1 WI MR in

a

patient

with known

metastatic breast cancer shows expansion of left posterior frontal gyri by mass that is so completely ;sointense with brain that it can't be identified separately from surrounding

normal

parenchyma.

(Lefl) Axial T1WI MR shows corpus callosum thickening and expansion by an ;sointens€ mass that demonstrated strong homogeneous enhancement (not shown). Primary CNS lymphoma was documented on stereotaxic biopsy. (RighI) Axial T2WI MR in the same

=

as previous image shows corpus callosum patient

splenium

lesion

remains

mostly isointense with cortex but is slightly hyperintense to

I S 96

Venous Anomaly

(Left) Axial T2WI MR shows no discernible abnormality. T2' CRE scan (not shown) disclosed hypointense pontine lesion with "brush-like" enhancement following contrast administration. Most capillary telangiectasias are not detectable on either T1 or T2Wls. (RighI) Axial T1 WI MR shows flow void of OVA transmantle draining vein. Enlarged medullary radicles constituting OVA ~ are almost invisible but enhanced strongly on T1 C+ scan.

white maller.

Adjacent

edema Ell is hyperintense.

Parenchymal

11/12

ISOI NTENSE PARENCHYMAL

en

lESIONS

c: " III

:l Co

OJ .,

Heterotopic

Gray Malter

Heterotopic

III

Gray Malter (Left) Axial TI WI MR shows

:l

bilaleral

OJ .,

subependymal nodules of heterotopic gray mailer 8 that are isointense with cortex. (RighI) Axial T2WI MR in the same patient as the previous image shows the nodules of heterotopic

OJ :l

extensive

gray maller

isointense

.:=

lJ

.,

OJ

(1)

:l ()

:r '
basal ganglia) o Hypotension - cortical laminar necrosis (gyriform Tl shortening) o Heat stroke - thermal injury, Tl shortening in external capsules, paraventricular thalami, cerebellum • Acute Hypertensive Encephalopathy,

PRES Gross hemorrhage rare; petechial uncommon o Typically occipital lobes • Encephalitis o Herpes encephalitis • Hemorrhagic cortical necrosis • "Sequential bilaterality" in temporal lobes highly suggestive • May also involve cingulate gyrus, subfrontal region o Other: West Nile may cause basal ganglionic necrosis, Tl shortening o

Ql

:;j

a.

..• OJ

Ql

:;j

...

OJ OJ :;j

\J

...

OJ (l)

:;j

n ::r

'
-

.-

.r:: u

c

~ Ql

CIl

c.. c CIl (lJ

~ C

III

~ CO "'C

c:

III

Glioblastoma

Multiforme

(Left) Axial T2WI MR in this 6 week old infant shows a markedly heterogeneous bifrontal mass lesion with hemorrhages of various ages §. There is obstruction of both foramina of Monro and enlargement of the lateral ventricular trigones. (Righi) Axial T7 C+ MR shows extensive enhancement of thislumor.

Choroid

Plexus Carcinoma

(Left) Axial T7 C+ MR in this 9 month old infant shows a large, bulky, avidly enhancing left intraventricular tumor ~ with invasion of the overlying brain ED. There are multiple intraventricular metastases ~ (Right) Anteroposterior angiography performed as a part of pre-operative embolization shows hyper vascularity ~ and multiple areas of contrast puddling ~.

Atypical Teratoid-Rhabdoid (Left) Sagittal T2WI MR in this 7 month old inFant shows hydrocephalus and a complicated solid & cystic tumor filling the 4th ventricle, supravermian cistern and extending through the tentorial incisura E!llI. (Right) Coronal T1 C+ MR in the same 7 month old shows a right frontal metastatic deposit B.

I 5 110

Tumor

BRAIN TUMOR IN NEWBORN/INFANT III

~ C-

Neurocutaneous Melanosis (Melanoma/ Melanocytoma)

..•

Neurocutaneous Melanosis (Melanoma/ Melanocytoma)

O:! III

(Left) 5agiltal T1WI MR

:l

...OJ

shows increased signal

OJ

intensity of the hippocampus E!l:I in this 70 month old with

~

a large cutaneous

nevus.

Pachymeningealthickening

= is present

prior to

contrast administration. (Right) Coronal T1 C+ MR

"U

... OJ

(1)

~ ()

::r

'< 3

during the same examination

OJ

shows diffuse pachy· and leptomeningeal metastatic melanoma.

Gl (1)

:l

...

(1)

OJ

Pineoblastoma

Pineoblastoma

(Left) Sagittal T2WI MR in a 7 month old infant shows a mass in the pineal region traversing the tentorial incisura into the supravermian

cistern. There

;s compression

of the aqueduct of 5ylvius with resultant hydrocephalus. Acute edema along the fiber tracts of the corpus callosum renders a striated pattern El (Right) Axial OWl MR in the same patient shows typical diffusion

Brainstem

Glioma,

Pediatric

restriction.

Medulloepithelioma (Left) 5agiltal T1 C+ MR in

this newborn shows massive expansion of the pons and medulla by a nonenhancing mass. (Right) 5agiual T1WI MR in a 5 day old infant shows a massive

hemorrhagic tumor replacing and expanding the upper cervical

spinal cord, the

brainslem, and the cerebellum. The tumor protrudes through the incisura and displaces the straight sinus E!l:I.

I 5 111

~

BRAIN TUMOR IN CHILD> 1 YEAR

QJ C QJ

~ ro

,., E

£ U C QJ

~ ro a.. c

~ (]J

C III

~ III "0

c

III

DIFFERENTIAL DIAGNOSIS Common • Pilocytic Astrocytoma o Cerebellar JPA o Optic Pathway Glioma o Pilomyxoid Astrocytoma (Rare) • Medulloblastoma (PNET-MB) • Ependymoma • Brainstem Glioma, Pediatric • Diffuse Astrocytoma, Low Grade • Subependymal Giant Cell Astrocytoma • DNET • Craniopharyngioma less Common • Germinoma • Choroid Plexus Papilloma • Ganglioglioma • Oligodendroglioma • Neurofibromatosis Type 2 o Meningioma o Schwannoma • Pineoblastoma • Pleomorphic Xanthoastrocytoma • Anaplastic Astrocytoma • Glioblastoma Multiforme • Gliomatosis Cerebri • Supratentorial PNET • Teratoma Rare but Important • Astroblastoma • Choroid Plexus Carcinoma • Atypical Teratoid-Rhabdoid Tumor • Primary CNS Sarcoma • Metastases o Metastases, Skull and Meningeal o Metastases, Parenchymal o Leukemia o Neuroblastoma, Metastatic o Neurocutaneous Melanosis (Melanoma, Melanocytoma) • Central Neurocytoma • Dysplastic Cerebellar Gangliocytoma

ESSENTIAL INFORMATION

I 5 112

Key Differential Diagnosis Issues • Diffusion weighted imaging helpful • All of the following restrict on DWI o PNET-MB o Pineoblastoma (pineal PNET)

Atypical teratoid-rhabdoid tumor (ATRT) o Germinoma o Epidermoid • May present with hemorrhage into tumor o Primary CNS sarcoma o Supratentorial PNET o Neuroblastoma metastatic to brain tissue o Pilomyxoid variant of pilocytic astrocytoma o

Helpful Clues for Common Diagnoses • Pilocytic Astrocytoma o Low density NECT o High signal T2 • Medulloblastoma (PNET-MB) o Hyperdense 4th ventricle (V) mass on NECT o Restricts on DWI • Ependymoma o 60% posterior fossa • "Plastic" tumor in 4th ventricle, extrudes through foramina o 40% supratentorial • Mixed cystic, solid mass with Ca++ • Brainstem Glioma, Pediatric o Location predicts pathology, prognosis • Infiltrating pontine glioma worst • Diffuse Astrocytoma, Low Grade o Hemispheres, thalami (can be bithalamic), tectum, brainstem (pons, medulla) • 50% of brainstem "gliomas" are low grade, diffusely infiltrating astrocytomas o Poorly marginated o Hypo- on Tl WI, hyperintense on T2WI o No enhancement • Subependymal Giant Cell Astrocytoma o Location at foramina of Monro typical o Look for cortical/subcortical tubers o Look for subependymal nodules • DNET o Almost all in patients < 20 years o Chronic epilepsy o "Bubbly appearing" cortically based mass o Ring sign on FLAIR • Craniopharyngioma o Nearly half of pediatric suprasellar masses o 90% Ca++/cystic/enhance Helpful Clues for less Common Diagnoses • Germinoma o Suprasellar + pineal masses together best clue o Early ependymal infiltration

BRAIN TUMOR IN CHILD> 1 YEAR • Choroid Plexus Papilloma o Densely enhancing o Cotyledon- or frond-like surface • Neurofibromatosis Type 2 o If multiple schwannomas, think NF2+ o Look for "hidden", dural-based meningiomas with C+ • Pineoblastoma o Restricts on DWI o Look for CSF spread (ventricles, ependyma) • Pleomorphic Xanthoastrocytoma o Cortically based tumor (temporal lobe most common site) o Dural reaction ( "tail") common o Enhancing ill-defined mass plus cyst • Anaplastic Astrocytoma o Diffusely infiltrating o Classic do not enhance • Glioblastoma MuItiforme o Typically arises from lower grade astrocytoma • Gliomatosis Cerebri o Less likely to enhance o More likely bilateral o More likely to spread across callosal tracts • Supratentorial PNET o Infant with large, bulky, complex hemispheric mass o Ca++, hemorrhage, necrosis common o Peritumoral edema sparse/absent • Teratoma o Neonate with large bulky midline mass o Ca++, soft tissue, cysts, fat

Cerebellar

Helpful Clues for Rare Diagnoses • Astroblastoma o Large, hemispheric o Well-circumscribed o "Bubbly" solid and cystic • Choroid Plexus Carcinoma o Similar to CPP • Invades ependymal surface & brain • Less homogeneous than CPP • Atypical Teratoid-Rhabdoid Tumor o Heterogeneous intracranial mass in infant o 50% infra tentorial, early CSF spread • Metastases o Pial, leptomeningeal • PNET • Ependymoma • Anaplastic astrocytoma • Germinoma • Choroid plexus carcinoma o Falx • Leukemia involves both sides of the falx o Bone & dura: Neuroblastoma> leukemia • CT: Bone spiculation, "hair on end" • MR: Bone expanded and marrow replaced • Central Neurocytoma o "Bubbly" lobulated mass in body of lateral ventricle • Dysplastic Cerebellar GangIiocytoma o Look for evidence of Cowden disease o Striated cerebellum • Enlarged low signal cerebellar folia

Cerebellar

JPA

Axial NEG shows typical midline cystic tumor with large low density mural nodule There is hydrocephalus with interstitialedema.

=.

G) CD ::J CD

~

Q)

JPA

Axial T2WI MR shows the nodule to be high signal intensity, a clue to the high nuclear-to-cytoplasm ratio in cerebellarIPAtumors.

I 5 113

BRAIN TUMOR IN CHILD>

1 YEAR

co

E

>-

.r: u

c

~ (1)

co

a.. c

co ~

(D

c::

~ Cll

(D "0

c:: Cll

Optic Pathway Glioma

Pilomyxoid

Astrocytoma

(Rare)

(Left) Axial T2WI MR shows poorly marginated hyperintensity =:I that extends posteriorly from optic chiasm/hypothalamus along both optic radiations. (Right) Axial T2WI MR shows a large, hyperintense, well-circumscribed mass. It arises from the hypothalamic region and demonstrates no edema of adjacent structures.

Medulloblastoma

(PNET-MB)

Medulloblastoma

(PNET-MB)

(Left) Axial T2WI MR shows a Jow signal midline tumor. There is an associated cyst =:1_ (Right) Axial OWl MR shows diffusion restriction within the tumor nodule, an excellent clue to the aggressive nature of the lesion.

Brainstem (Left) Sagittal T2WI MR shows a large, heterogeneous, low signal mass that widens the tegmenta-cerebellar angle and extends through the inferior recesses of the 4th ventricle. There is extension into the upper cervical spinal canal =:1_ (Right) Sagittal T2WI MR shows diffuse expansion of the pons and medulla

glioma_

I 5 114

due to an infiltrating

Glioma, Pediatric

BRAIN TUMOR IN CHILD>

en ,.-

1 YEAR

c::

ll>

:J Q.

OJ ., Subependymal

Giant Cell Astrocytoma

ll>

DNET (Lcfl) Coronal T1 C+ MR shows bilateral, asymmetric enhancing lesions at the foramina location

of Monro.

The

is characteristic

for

subcpendymal giant cell astrocytoma. The child also had skin and other brain lesions typical of tuberous sclerosis. (RighI) Coronal FLAIR MR in a child with

tAl ., III

:J lJ

III ., CD

:J ()

::r

'< 3

III

Gl CD

seizures shows an

=-

insular·based

:J

lesion with a

partial bright ring the ONET FLAIR ring sign.

:J CD .,

III

Germinoma (Lcfl) Sagittal T1WI MR shows a suprasellar collection of cysts of many signal intensities. One!:] is very high signal intensity, likely due to protein; another extends behind the clivus 81; and the remainder herniate

into Jrd ventricle.

Calcification 1:1:1 is noted in the solid component above the dorsum sella. (RighI) Sagittal T1 C+ MR shows a medium-sized pineal mass with central necrosis 1m. There is a very small enhancing

infundibular

Choroid

mass in the

recess

e=.

Plexus Papilloma (Lefl) Coronal T1 C+ MR shows a large enhancing mass within the right lateral venlricle. The surface is frond-like, and there is no brain invasion. appearance

The

is typical for a

choroid plexus papilloma. (RighI) Axial TI C+ MR shows a cystic and solid thalamic mass. This lesion was heavily calcified on NECT (not shown).

I 5 115

BRAIN TUMOR IN CHILD>

ro ~

1 YEAR

Ql

c Ql

o ro

E

>.

.r: u

c

~ Ql

ro

a.. c ro ~

co C

III

~

CO "'C

c

III

Neurofibromatosis

Type 2

(Left) Coronal T2WI MR shows multiple dural-based meningiomas ED at the vertex. There are a/50 bilateral, asymmetric, vestibular schwannomas ~ in this teen with NF2. (Right) Sagittal T2WI MR shows a low signal pineal mass that obstructs the aqueduct. This lesion was dense on NEeT and restricted on DWI.

(Left) Coronal T1 C+ MR shows a cortically based temporal lobe tumor. It is ill-defined, invades adjacent brain tissue, enhances, and contains

a rim-enhancing

cyst ~. (Right) Axial T2WI MR shows bithalamic involvement by

homogeneous

lUmor,

did not enhance

which

on T I C+

image (not shown).

Supratentorial (Left) Coronal T1 WI MR shows marked expansion of the left temporal lobe by a hemorrhagic ED mass. (Right) Sagittal T2WI MR shows a mixed solid, cystic, and calcified

pineal

region

mass Blthat obstructs the aqueduct of Sylvius. This teenaged patient presented with Parinaud

phenomenon.

There is acute edema involving the septal-callosal interface =:II.

I 5 116

PNET

Pineo blastoma

BRAIN TUMOR IN CHILD>

Choroid

Plexus Carcinoma

1 YEAR

Atypical Teratoid-Rhabdoid

Tumor (Left) Axial T1 C+ MR shows a large heterogeneously enhancing trigonal mass with brain invasion and

ependymal spread 811. (RighI) Axial T2WI MR shows a mixed signal mass obstructing both the right 811 and left foramina of Monro.

Gl

ct> ::J ct> ~ OJ

Atypical Teratoid-Rhabdoid

Tumor (Left) Axial OWl MR in the same patient shows extensive diffusion restriction in the left frontal ATRT. (RighI) Axial CECT in metastatic PNET-MB shows "comb-like" enhancement of the interfoliate sulci ~ Note moderately enlarged lateral ventricles 1:1 caused by

extraventricular obstructive hydrocephalus

from diffuse

cisternal metastases.

leukemia

Neuroblastoma,

Metastatic (Lefl) Axial T1 C+ FS MR in a child with ALL shows involvement of the posterior and anterior 811 falx by densely enhancing tissue. Both sides of the falx are involved ventrally. (RighI) Coronal FLAIR MR shows expansion of the lesser wing of sphenoid by neuroblastoma. There is an

=

additional

calvarial

and

dural-based focus at the vertex EJ.

I 5 117

EPILEPSY, GENERAL

•... CIl

OJ

c OJ

(9 CIl

E

>,

.s;;: u

c

~ CIl

0..

c

~ co C t'll

"co

"c: t'll

Common • Acquired Causes o Trauma o Remote Stroke o Remote Infection o Neoplasms o Mesial Temporal Sclerosis (MTS) o Vascular Malformations o Toxic/Metabolic Insult, NOS o Drug Abuse • Heterotopic Gray Matter • Perisylvian Dysplasia • Schizencephaly • Septo-Optic Dysplasia • Tuberous Sclerosis Complex (TSC) • Focal Cortical Dysplasia, Taylor Type (Balloon Cell Dysplasia) • Focal Cortical Dysplasia • Pachygyria-Polymicrogyria • Lissencephaly Type 1 • Band Heterotopia • Hemimegalencephaly Less Common • Neuronal & Mixed Neuronal-Glial Tumors o DNET o Ganglioglioma • Pleomorphic Xanthoastrocytoma

•

•

•

•

Rare but Important • Sturge-Weber Syndrome • Status Epilepticus

I 5 118

MTS: Small, hyperintense hippocampus associated with temporal lobe epilepsy o Causative vascular malformations include AVM & cavernous malformations o Toxic-metabolic & drug abuse patients may present with seizures Heterotopic Gray Matter o Gray matter (GM) nodules, follow GM signal on all MR sequences o Subependymal most common location o Can be found incidentally in patients without seizures Perisylvian Dysplasia o Common site for cortical dysplasia o Typically bilateral o ± Septo-optic dysplasia, schizencephaly Schizencephaly o CSF cleft extending to ventricular ependyma, GM-lined o Outpouching or "dimpling" of lateral ventricular contour "points" to cleft o Two morphologic varieties • Closed lip: GM ependymal seams touch • Open lip: GM seams separated by cleft o May be unilateral or bilateral o Absent septum pellucidum common o Associated with septo-optic dysplasia Septo-Optic Dysplasia o Some consider mildest form of holoprosencephaly o Septum pellucidum absence + optic nerve hypoplasia, ± pituitary dysfunction o Common associated malformations: Schizencephaly, perisylvian dysplasia Tuberous Sclerosis Complex (TSC) o T2 hyperintense cortical/subcortical tubers o Subependymal nodules follow white matter (WM) signal until calcified o 10-15% develop giant cell astrocytoma Focal Cortical Dysplasia, Taylor Type (Balloon Cell Dysplasia) o Imaging & histology = tubers in TSC • Histology shows "balloon cell" dysplasia o Solitary dysplasia; lack other TSC features o T2 hyperintense "comet tail" from cortex to ventricle; best seen on FLAIR> T2 > T1 Focal Cortical Dysplasia o Thickening &/or nodular cortex o Blurred gray-white junction Pachygyria-Polymicrogyria o Pachygyria: Thick, smooth cortex o

DIFFERENTIAL DIAGNOSIS

ESSENTIAL INFORMATION

•

Key Differential Diagnosis Issues • Generalized seizure disorders usually nonlocalizing • Partial complex (focal) epilepsy usually due to focal structural abnormality (i.e., MTS) • High-resolution MR necessary to fully evaluate epilepsy

•

Helpful Clues for Common Diagnoses • Acquired Causes o Trauma is most common cause in adults o Trauma, remote stroke, or infection results in encephalomalacia &/or gliosis, which may cause epilepsy o Benign, malignant tumors

•

•

,... C/)

EPILEPSY, GENERAL

c:

Polymicrogyria: Small, "pebbly", cobblestone or micronodular appearing gyri (cortical dysplasia) • Lissencephaly Type 1 o "Smooth" brain lacking normal gyral infolding; thick cortex o Spectral continuum with po Iymicrogyria -pach ygyr ia • Band Heterotopia o Most genetic; X-linked inheritance o Most (90%) are female • Males severely affected, rare survival o Band of incompletely migrated GM between cortex & ventricle (double cortex) o GM band size inversely proportional to overlying cortex thickness • Hemimegalencephaly o Unilateral hemispheric overgrowth o Dysplastic enlarged ipsilateral ventricle o Overlying skull & soft tissues overgrown o

Helpful Clues for Less Common Diagnoses • DNET o Discrete T2 hyperintense "bubbly" cortical mass, low grade neuronal neoplasm o Associated cortical dysplasia common o Medial temporal lobe most common • Ganglioglioma o Cystic/solid enhancing, cortically based mass, mixed neuronal-glial tumor o Temporal lobe most common site o Associated cortical dysplasia common • Pleomorphic Xanthoastrocytoma o Cyst + enhancing nodule classic

Mesial Temporal Sclerosis (MTS)

Coronal FlAIR MR shows high signal in the right hippocampus 1:2 related to this paUent's MTS. The primary MR features are T2 hyperintense signal, atrophy of the hippocampus, & loss of internal architecture.

o o

Well-circumscribed, no surrounding edema Involvement of adjacent meninges typical

III

:J Co

OJ .., III

:J

Helpful Clues for Rare Diagnoses • Sturge-Weber Syndrome o Malformation of cortical & pial veins o Clinical diagnosis by trigeminal distribution facial "port-wine" stain o Earliest intracranial finding = ipsilateral enlarged choroid plexus o Later = ipsilateral hemiatrophy • Status Epilepticus o Focal cortical (& subcortical) edema, T2 hyperintense • Varied cortical enhancement • Usually DWI & FLAIR bright o Persistent seizures, often 2: 24 hours o May show hyperperfusion: High CBV & CBF, delayed MTT o Most resolve in days-weeks o Long term atrophy may result

OJ .., OJ

:J "U OJ .., C1l

:J

n ::r

'< 3 OJ

Gl C1l :J C1l .., OJ

Other Essential Information • "New onset seizures" require routine brain MR with & without contrast o Rule out acute lesions: Hemorrhage, tumor, infection, & stroke • "Epilepsy" high resolution MR evaluation o High resolution Tl/T2 (3D techniques at 1 mm slices preferred) through entire brain o IR techniques improve gray-white matter contrast (STIR, FLAIR, & Tl FLAIR) o High field strength (3T) preferred

Mesial Temporal Sclerosis (MTS)

Coronal T1WI MR shows typical decreased parenchymal volume 1:2 of U,e hippocampus in MTS.

I 5

Internal architecture remains preserved in this case. Mild enlargement of the adjacenllemporal

horn is common.

119

EPILEPSY, GENERAL

.c () c Q)

~ ," E

CEREBRAL

HEMISPHERES

.!:

U C

J signal increase and swelling in a child with proven Mycoplasma encephalitis.

• Glioblastoma Multiforme o White matter> > gray matter o Tumor infiltration of cortex, subpial extension may occur late o Hemorrhage, enhancement common o Primary GBM (older patient) 95% necrotic with thick irregular enhancing rim o Secondary GBM (younger patient) shows enhancing focus within lower grade tumor • Gliomatosis Cerebri o Tumor infiltrates but preserves underlying brain architecture o Two or more lobes affected o T2 hyperintense infiltrating mass enlarges cortex, basal ganglia o MRS shows elevated myo-inositol (mI) o Most are WHO grade II or III diffusely infiltrating astrocytoma • Meningioangiomatosis o Cortical mass with variable Ca++ o Linear &/or gyriform enhancement o Perivascular proliferation of vessels in meninges, cortex o May infiltrate along perivascular spaces, cause mass effect • Congenital Muscular Dystrophy o Cobblestone lissencephaly (overmigration) o Z-shaped brainstem o Hypoplastic rotated cerebellum (similar to Dandy-Walker continuum)

Coronal FLAIR MR shows swollen, hyperintense temporal lobe cortex ~ with relative sparing 01 the underlying white matter. OWl (not shown) revealed restricted diffusion in insular cortex, cingulale gyri.

III

::::l

Co

..•

OJ III

::::l

en c

"0

OJ CD OJ

0OJ. Ql

CD

OJ OJ

\J Ql

CD OJ ()

::T '
.r: u

c

~ OJ

co

ll.

c

~ co co

'C

o C OJ

ro~ c.

:J CJ) C

CO

~

al

"0

c CO

(Left) Axial NECT in a 4 month old with hypomyelination ~ shows decreased volume and while matter density. The thin arbors of while maller give a false impression that the cortex, especially in occipital poles, is thickened 81. (Right) Coronal T2WI MR in an 18 month old with Pelizaeus-Merzbacher disease (PMD) shows white maller hypomyeJinalion in occipital lobes 81 and cerebellum giving the appearance of prominent thick cortex.

=-

Tuberous Sclerosis Complex (Left) Axial FLAIR MR shows multiple large, (fat, thickened gyri with classic subcortical hyperinlensilies

E1

characteristic for cortical tubers. (Right) Axial T2WI MR in an 8 month old shows two maniFestations of tuberous sclerosis complex: Densely calcified, thickened transmantle hamartoma in the right parietal lobe and 2) characteristic "tubers" ~ in the left. Note multiple subependymal nodules 81.

=

(Left) Coronal PO FSf MR shows focaf cortical thickening with high signal of the expanded gyrus 81. (Right) Axial CECT in the same child shows a focal low density, noncalcified cortical/subcortical mass Ea. There is no enhancement, and there are neither subependymal nodules nor a foramen

of Monro

astrocytomas.

I 6 10

giant cell

Tuberous Sclerosis Complex

en

TH ICK CORTEX

c" : III

::l

Q.

..• OJ

III

(Left) Axial T2WI MR in a 10 month old with refractory seizures shows bilateral perisylvian foci of polymicrogyria giving the appearance of thick cortex. Note abnormal veins !:ll and subtle laminar heterotopia 81. (Right) Sagittal T1WI MR shows a thick cortex ~ lining the sylvian fissure in another child with bilateral primitive sylvian fissures and perisylvian polymicrogyria.

=-

::l (j)

c

"... III

ro::l

o ... ~

...

OJ III

::l -U

...

Q)

Ctl

:J

(')

:r

'
, £ U C

~

Q)

co

0..

c

co ~

(])

co o C Q)

'C

(Left) Axial T1 WI MR in a 2 week old shows layered appearanCe of cortex with thick inner band of gray SI mailer and thin outer layer

ro~

~.

:::l

=::I.

a.

(/)

c

•.. C1l

(])

"0 C C1l

In between ;s the "cell while matter zone

sparse!1

(Right) Coronal T1 WI

MR shows a thickened "cobblestone" cortex ~ and a hypoplastic cerebellum . The 4th ventricle =::I is opened inferiorly due to vermian hypoplasia and cephalad rotation.

DNET (Left) Axial FLAIR MR shows thickened, hyperintense cortically based mass with "rim sign" of hyperintensity

on FLAIR =::I. Lack of edema also is characteristic for ONET. (Right) Axial T7WI MR shows typical multinodular low signal intensity mass SI focally expanding the cortical mantle and remodeling the inner cortex ~ of the calvarium.

(Left) Axial PO rSf MR shows thickened, hyperintense cortex in a S year old with epilepsy. Without contrast-enhanced scan, this image would be indistinguishable from Taylor cortical dysplasia. (Right) Axial T7 C+ MR in the same patient shows several small

=

enhancing

foci

Ganglioglioma

surgery.

I 6 12

=.

was found at

,..

en

THICK CORTEX

c:

(Left) Axial T2WI MR shows a striated ;50- and hypointense posterior fossa mass E!l2 that displaces the

4th ventricle~.

There is an

additional epidermoid cyst 1:11. (Right) Coronal T2WI MR shows thickened, striated-appearing cerebellar {olia ~ in a patient with Lhermiue·Ouc/os disease. In

this case, there was no association with Cowden syndrome.

Glioblastoma Multiforme (Left) Coronal T2WI MR in a 74 year old shows iso- & hyperintense right temporal lobe & insular mass 1:11 involving both gray & white maller. Note necrosis, Focal hemorrhage liB Tumor spread across anterior commissure thickens the left temporal lobe cortex ~ (Right) Axial FLAIR MR shows a typical case of meningioangiomatosis,

most

commonly found in NF2. Fine gyriform increased

density was present on NECT FLAIR MR shows linear increased

signal ~.

(Left) Axial T2WI MR in an adult shows involvement of the temporal pole cortex Sl hippocampus ffi & mesencephalon Involvement

of more

than

one lobe or region is typical of gliomatosis cerebri. (Right) Axial T2WI F5 MR in a 12 year old shows hyperintense, swollen gyri

I:]

with involvement

of the

midbrain E!l2 related to gliomatosis cerebri. WI 10 grade III diffusely infiltrating astrocytoma was found. (Courtesy M.

WarmUlh·Metz, MOr

I 6 13

THIN CORTEX

ell

E

>.r: u

c Q)

~

DIFFERENTIAL DIAGNOSIS

ell

0..

c ell (D

~ ell

.t:

o C Q)

Til

Common • Aging Brain • Prematurity • Obstructive Hydrocephalus • Cerebral Infarction, Chronic • Encephalomalacia, General

Q.

::J (f)

C Ol

~

CO

"'C C Ol

::l

-" en

Less Common • Multiple Sclerosis • Alzheimer Dementia • Multi-Infarct Dementia • Frontotemporal Dementia Rare but Important • Microcephaly • Subcortical Laminar Heterotopic Gray Matter • Inborn Errors of Metabolism (Gray Matter Disorders)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Is cortical thinning focal (typical for encephalomalacia) or generalized? • Is cortex thin but normal signal intensity? o If abnormal, consider infection, infarction, trauma, etc. • Child vs. adult o Child: History important • Prematurity, family history of inborn error of metabolism • Seizures (heterotopias, encephalomalacia) o Adult: Normal cognitive function or demented?

I 6 14

Helpful Clues for Common Diagnoses • Aging Brain o White matter (WM), not gray matter (GM) volume loss predominates in normal "successfully aging" brain • Posterior vermis, cerebellum> cerebral hemispheres • Cortical thinning minimal o "Black line" in visual, motor/sensory cortex common in normal older patients • Prematurity o Hemispheric WM almost completely unmyelinated ("wet brain") o Cortex always appears thin

• Pre- and post-central gyri myelinate early • Hyperintensity on Tl WI, hypointensity on T2WI normal o Note: White matter injury of prematurity spares GM • Undulating ven tricular borders, ventriculomegaly • Generalized volume loss due to " WM • Obstructive Hydrocephalus o "Maximal" hydrocephalus thins cortical mantle o May be difficult to distinguish from hydranencephaly on NECT • MR diagnostic • Cerebral Infarction, Chronic o Usually wedge-shaped, involves both cortex & underlying WM o "Hierarchy" of vulnerability to territorial or hypotensive ischemia • CAI hippocampus most sensitive • GM generally more vulnerable than WM o Collateral flow across pial watershed (border zones) may permit cortex within ischemic penumbra to survive o Thin rim of cortex may persist adjacent to densely ischemic core of infarct o Often hyperintense on T2/FLAlR, reflecting spongiosis/gliosis • Encephalomalacia, General o Trauma, infection, toxic-metabolic insults o May primarily affect GM, WM, or both o Can be generalized (e.g., following global hypo perfusion) or focal Helpful Clues for Less Common Diagnoses • Multiple Sclerosis o Multiple T2/FLAlR hyperintensities perpendicular to callososeptal interface o Chronic, severe multiple sclerosis (MS) causes variable brain atrophy • WM»GM • But normal-appearing GM may have abnormal metabolic profile with" NAA • Cortical loss in secondary-progressive MS common • Alzheimer Dementia o Alzheimer dementia (AD) is most common of all dementias o Best diagnostic clue = temporoparietal cortical atrophy + disproportionate hippocampal volume loss • Perihippocampal fissures widen

THIN CORTEX • Hippocampal, entorhinal cortex thins • Temporal horns enlarge • Perfusion MR, FDG, & PET can identify hypometabolic areas • Multi-Infarct Dementia o Also known as "vascular" dementia o Second most common dementia after AD • 10-30% of all dementing disorders o Imaging findings vary • Generalized, diffuse atrophy • Large ventricles, superficial sulci • Generalized cortical thinning • Focal territorial &/or lacunar infarcts • Subcortical WM T2/FLAIR hyperintensities • Diffuse bilateral, confluent deep WM hyperintensity secondary to arteriolosclerosis • Frontotemporal Dementia o One of several tauopathies, also known as Pick disease o Frontotemporal dementia (FTD) causes disproportionate frontotemporal atrophy o "Knife-like" gyri with very thin cortex o Subcortical WM usually hyperintense o Parietal, occipital lobes relatively spared Helpful Clues for Rare Diagnoses • Microcephaly o Small head size, • craniofacial ratio o Sutural overlap common o Simplified gyri with thin cortex o Shallow sulci o Many causes

Axial FLAIR MR in an intellectually normal 65 year old shows mild ventricular, sulcal enlargement. Thin rim of periventricular hyperintensity =::I is normal. Very mild cordcal thinning E1 is present.

,.-c: C/l

• Primary (genetic) microcephaly (e.g., microlissencephaly, many syndromes) • Secondary (nongenetic) microcephaly (e.g., TORCH infection, fetal alcohol syndrome) • Subcortical Laminar Heterotopic Gray Matter o "Band" heterotopia ("double cortex"): LlS1 or LISX1 • Thick inner band of dysplastic GM in subcortical WM • Overlying cortex thin (not all neurons "arrive") o Classic lissencephaly: (LIS1) • Shallow sylvian fissure ("hourglass" configuration of hemispheres) • Thin outer layer of GM • "Cell sparse" WM zone • Thick inner band of GM • Inborn Errors of Metabolism (Gray Matter Disorders) o Includes inborn errors of metabolism that affect WM > > GM o Many "poliodystrophies"; all uncommon o All have similar imaging appearance • Generalized atrophy with t sulci, thinned cortex • Cortical signal generally normal • BUT WM often hyperintense due to secondary axonal degeneration o Lysosomal (example: Neuronal ceroid lipofuscinosis) clue • Hypointense thalami (best seen on standard T2WI, not FSET2WI)

Axial T2WI MR in an elderly demented patient with su/xordcal arteriosclerodc leukoencephalopathy shows diffuse confluent hyperintensity in hemispheric white matter but only mild cortical thinning E1.

I 6 15

THIN CORTEX

co

E

>-

J::

U C Q) L

co

0..

c

co L

co

co ·C

o C Q) 115 a. L

:J

CfJ

c:

.. III

CO

"C

c:

III

Prematurity

Prematurity

(Left) Sagittal T2WI MR in a normal 28 week premalUre infant shows thin cortical

ribbon 81. The brain is smooth, and only the central ~,

calcarine

and

It] fissures

parielOoccipital

are present. (Right) Axial T2WI MR in the same patient shows age-appropriate, undersulcated brain. The shallow, "squared" sylvian fissures are normal, as is the very thin cortical mantle overlying almost completely unmyelinated hemispheric while matter.

Prematurity (Left) Axial T2WI MR in a 32 week normal but premature infant shows more advanced 5ulcaliofl,

with deepening

of

the sylvian fissures. WM is stiff largely unmyelinated, and cortex appears thin 81. (Right) Axial T2WI MR in the

same premature baby shows thin cortical

mantle

overlying

almost completely unmyelinated white matter with the exception of hypointense WM Ii8 deep to the central sulci. Mild hypointensity of the cortex of pre-, post-central gyri E±I is normal.

Obstructive (Left) Coronal NECT in an 11 week old infant shows

"maxima/" hydrocephalus. Note massively enlarged ventricles

within

cranium.

Very thin, almost

imperceptible

am surrounds

huge

cortical mantle ventricles.

Posterior fossa appears

comparatively actually

small but is

normal

in size.

(Right) Coronal T2WI MR in the same patient shunting remain

large, cortical

very thin

I 6 16

after

shows ventricles

E±J.

mantle

Hydrocephalus

Obstructive

Hydrocephalus

,..c:

THIN CORTEX

CII

01

:J

C. OJ

Obstructive

Hydrocephalus

Obstructive

... 01

Hydrocephalus (Left) Axial T2WI MR in a patient with severe congenital hydrocephalus after shunting shows stenogyria with thinned, "crenelated"

:J

cortex along

interhemispheric fissure. (Right) Coronal T2WI MR in

the same patient shows more clearly the stenogyria ~ with thinned cortex along lhe interhemispheric fissure.

Cerebral

Infarction,

Chronic

Cerebral

Infarction,

Chronic (Left) Axial T2WI MR, obtained many years after near-tolallefl hemisphere infarction

secondary

to

internal carotid artery occlusion, shows thin rims of gliolic hyperintense cortex ~ surrounding cystic encephalomalacia. (Right) Axial FLAIR MR in a patient with systemic lupus erylhemalosus and multiple old infarcts shows diffusely atrophic right hemisphere wilh enlarged sulci, shrunken gyri, and markedly lhinned

cortexB.

Cerebral

Infarction,

Chronic

Cerebral

Infarction,

Chronic (Left) Axial NEeT in a child wilh Slurge-Weber syndrome shows small left hemisphere with very atrophic, calcified cortex. Dystrophic Ca++ is in brain (nolleptomeningeal angioma),

and cortical

thinning is secondary chronic

to

venous (not arteria/)

ischemia. (Right) Axial T2WI MR in the same patient shows how thin the affeeled cortex is compared to the normal

-=

right side.

I 6 17

ro

THIN CORTEX

E

>J::: ()

c:

~ Q)

ro

Il.

c:

ro ~

OJ

ro

'C

o ~ c: Q)

CO ~

n.

:J

CJJ

c: 01

~ 1IJ "l:l

c:

Encephalomalacia, General

Encephalomalacia, General

Multi-Infarct Dementia

Frontotemporal Dementia

(Left) Coronal T2WI MR obtained in a child 5 months after initial neonatal

group

B

Streptococcal meningitis shows generalized volume loss with gliosis and thinned cortex ~ in the leFt temporal lobe. (Right) Coronal T2WI MR in child with Rasmussen encephalitis shows thinned cortex around the left sylvian Fissure=:I compared to the normal right side.

01

:J 1Il ""

(Left) Axial T2WI MR shows hypointense bodies of caudate nuclei confluent plaques and thin cortex 81. (Right) Axial T2WI MR shows disproportionate atrophy of occipital lobes with striking cortical thinning [;8 The Heidenhain variant of Alzheimer dementia primarily a(Fects the occipital cortex.

=

=..

(Left) Axial NECT shows classic mulli·infarct dementia with multi-territorial infarctions.

cortical

Peri ventricular

white matter hypodensity, multiple cortical infarcts EB thinned cortex, shrunken parielooccipilal

gyri

E:II

are

all seen. (Right) Axial FLAIR MR shows predominate

I 6 18

Frontal lobe atrophy with striking cortical thinning. Some gyri demonstrate a classic" knife-like II appearance =:I. There is also associated white matter T2 hyperintensity 81.

THIN CORTEX

Microcephaly (Left) Axial T2WI MR in an infant wlhead circumference 3 standard deviations below mean shows simplified gyral pattern, thin corlex i7 ~ shallow sulci, & broad flat gyri. The infant had familial

autosomal recessive microcephaly. fRight) Axial T2WI MR in an 8 month old with microcephaly related to congenital CMV shows thin cortex [;8 delayed myelination. Germinolytic cysts ffi periventricular calcifications & large

a

subarachnoid spaces are also seen.

Subcortical

laminar Heterotopic Gray Matter

Subcortical

laminar Heterotopic Gray Matter (Left) Axial T2WI MR in a 2 week old with Miller-Dieker syndrome shows

"hourglass-shaped"

=-

brain,

smooth thin cortex thick band of subcortical laminar heterotopic gray matter [;8 and primitive veins in sylvian fissures !:ill. (Right) Sagiltal T1 WI MR shows subcortical "bands II or II ribbons II of heterotopic gray matter ~ separated from thinned overlying cortex S'I by a strip of myelinated white maller

Inborn Errors of Metabolism (Gray Matter Disorders)

Inborn Errors of Metabolism (Gray Matter Disorders) (Left) Axial T2WI MR in a child with neuronal ceroid lipofuscinosis (CLN3 or Batten variant) shows markedly thinned cortex S'I throughout both hemispheres. Thalami are shrunken, very hypointense fRight) Axial T2WI MR in a child with lysosomal storage disorder (CLN 7 ) shows generalized atrophy with very thin cortex !:ill, classic "dark"thalamiG & basal ganglia S'I.

=.

I 6 19

FOCAL CORTICAL MASS

DIFFERENTIAL DIAGNOSIS Common • Cerebral Ischemia-Infarction, Acute (Cortical) • Metastases, Parenchymal • Oligodendroglioma • Cerebritis • Diffuse Astrocytoma, Low Grade Less Common • Venous Infarction • Pleomorphic Xanthoastrocytoma • Tuberous Sclerosis Complex • Pachygyria-Polymicrogyria (Focal Cortical Dysplasia) • DNET • Ganglioglioma Rare but Important • Pilocytic Astrocytoma • Cavernous Malformation • Desmoplastic Infantile Ganglioglioma • Viral Encephalitis • Astroblastoma

ESSENTIAL INFORMATION

I

Usually solid, may be complex with central cystic or necrotic areas o May be hemorrhagic with increased Tl SI o May be solitary but frequently are multiple & bilateral • Oligodendroglioma o T2 hyperintense mass, variable enhancement o Calcification is common o Frontal> other lobes; usually a single mass • Cerebritis o Gray & white matter are often involved together o T2 hyperintense with variable enhancement & variable DWI appearance o Cerebritis essentially represents a developing brain abscess & is commonly caused by pyogenic bacteria o May be solitary or multifocal • Diffuse Astrocytoma, Low Grade o T2 hyperintense WM mass, may involve gray matter o May mimic stroke; however ADC values typically normal to elevated o No or minimal enhancement is typical o Usually a solitary mass o Bilateral disease may be seen in gliomatosis cerebri, a rare infiltrative process o

Helpful Clues for Less Common Diagnoses • Venous Infarction o T2 hyperintense lesion o Associated hemorrhage is very common, often at gray-white junctions o Typically related to dural sinus thrombosis o May be multiple & bilateral if the superior sagittal sinus is involved • Pleomorphic Xanthoastrocytoma o Cortical enhancing mass with adjacent cyst, classic appearance o Enhancement extends to meninges, causing a "dural tail" o Temporal lobe is most common location o Occurs in young adults • Tuberous Sclerosis Complex o Multiple cortical "tubers" = cortical hamartomas are T2 hyperintense & nonenhancing o Calcified subependymal nodules ± enhancing giant cell astrocytoma at the

foramen of Monro is classic o

6 20

Usually a multiple & bilateral process

FOCAL CORTICAL

en

MASS

" s::

When solitary, consider Taylor cortical dysplasia • Pachygyria-Polymicrogyria (Focal Cortical Dysplasia) o Limited to gray matter; focal or regional thickening of the cortex o Variable T2 appearance; no enhancement o Many have deep sulci with thickened cortex that mimics a mass o Occasionally a linear region of increased T2 signal connects the focal cortical dysplasia with the ependymal surface • DNET o Multicystic cortical mass, frequently seen in the temporal lobe o "Bubbly" appearance classic o Variable enhancement o Solitary lesion in a young adult typical • Ganglioglioma o Enhancing (multi)cystic mass; may be solid or have a cyst & nodule appearance o Calcification is common o Temporal lobe is most common location o Solitary lesion o

Helpful Clues for Rare Diagnoses • Pilocytic Astrocytoma o Enhancing nodule with or without an associated cyst, most common appearance o Children> adults o Cerebellum & optic pathways are frequent locations o May rarely occur in the cortex o Solitary lesion Cerebral

Ischemia-Infarction, (Cortical)

• Cavernous Malformation o Heterogeneous mass with a "mulberry" appearance related to blood products o Hemosiderin ring "blooms" on GRE; Tl bright locules o May have increased CT density &/or punctate calcifications o Sometimes associated with a developmental venous anomaly o May be deep as well as cortical o May be solitary or multiple, bilateral • Desmoplastic Infantile Ganglioglioma o Frontal/parietal locations common o Cystic mass with enhancement o May be massive, occupy majority of hemisphere o Presentation occurs when younger than 6 months • Viral Encephalitis o Cortical swelling; minimal enhancement o Not in a typical vascular territory o Temporal, frontal, cingulum are often seen in herpes simplex virus • Astroblastoma o Large hemispheric solid & cystic mass with heterogeneous enhancement of solid portion o Superficial mass involves cortex & subcortical WM typical o Children & young adults

III

:l C.

..•

tll III

:l (J)

s::

"0

Q)

CD :::J 8" 00. Ol

..•

CD Ol

:::J -U

..•

Ol

(t)

:::J

o ::T '
-

.r: u

c

~ co

a.. Cerebritis

c

~

(lJ

co o

'C

C OJ

1§a. :::J

(/)

C III

'III "0

c III

(Left) Axial FLAIR MR shows a high signal mass SI containing a {ocal area of lower signal:±" representing a calcification within the tumor. A calcified frontal lobe mass involving the cortex & subcortical while maller is typical of oligodendroglioma. (Right) Coronal T7 C+ MR shows patchy enhancement significant edema, & mass effect. A mature abscess wall & central cavity are not yet

present, differentiating cerebritis from abscess.

Diffuse Astrocytoma,

Low Grade

Venous Infarction

(Left) Axial T2WI MR shows a well-circumscribed frontal lobe diffuse astrocytoma, low grade Ea. There was no significant enhancement of the mass following contrast injection. (Right) Axial NECT shows ill-defined low density ~ associated with subcortical hemorrhages and a hyperdense superior

=

sagittal sinus E:I. Ilemorrhage is common in venous infarction. The parenchymal findings can mimic a primary tumor or

metastases.

Pleomorphic (Left) Axial T7 C+ MR shows enhancing parenchymal nodule SI associated with a cyst in the temporal lobe. These features are nonspecific but are typical of PXA. (Right) Axial T2WI MR shows several areas of high T2 signal & slight mass effect representing cortical hamartomas ("tubers")~. There are several subependymal nodules, some with dark signal suggesting calcification ~ Subependymal nodules often enhance, while cortical

=

I 6 22

tubers rarely do.

Xanthoastrocytoma

Tuberous Sclerosis Complex

FOCAL CORTICAL MASS

Pachygyria-Polymicrogyria Cortical Dysplasia)

CJ)

:0:c:

(Focal

DNET (Left) Axial T2WI MR shows bilateral deep sulci lined with pebbly dysplastic cortex Band-like heterotopic gray mailer is also seen bilaterally E2. The lack of normal-appearing gyri & unusual cortex makes this a mimic of focal mass. (Right) Sagittal T1 WI MR shows a mass in the parieto-lemporal-occipital junction with a central cystic area liB The mass did not enhance with contrast

=.

material.

A mullicystic

"bubbly" appearance is common.

Pilocytic Astrocytoma (Left) Coronal T I C+ MR shows an enhancing nodule ~ associated with a tumor cyst E2. The findings are not specific but are typical of ganglioglioma. The temporal lobe is a very common location for ganglioglioma. Patients typically present with seizures. (Right) Axial T7 C+ MR shows an occipital lobe enhancing nodule E2 associated with a small cyst The findings are not specific but are typical of pilocytic

=.

astrocytoma.

Cavernous Malformation (Left) Coronal T2 CRE MR shows typical hypointense appearance of a cavernous malformation [;8 The lesions may be calcified but usually "bloom" 0/1 CRE due to contained blood products. They may be associated with developmental venous anomaly. (Right) Coronal T7 C+ MR shows a very large right hemispheric, predominantly cystic mass with an enhancing mass along the medial wall Findings are nonspecific but typical of this entity.

=.

I 6 23

co

E

CORTICAL HYPERINTENSITY

T2/FLAIR

>.r: l> c Q)

~ co

0...

c

co ~

I:!l

co o C Q)

·C

CO ~

DIFFERENTIAL DIAGNOSIS Common • Cerebral Ischemia-Infarction, Acute • Cerebral Contusion • Hypotensive Cerebral Infarction • Status Epilepticus • Herpes Encephalitis

a.

:::J (/)

C CO

'-

I:!l "t:l C CO

Less Common • Diffuse Astrocytoma, Low Grade • Acute Hypertensive Encephalopathy, PRES • Vasculitis • Oligodendroglioma • Anaplastic Oligodendroglioma • Hypoxic-Ischemic Encephalopathy, NOS • DNET • Pleomorphic Xanthoastrocytoma • Tuberous Sclerosis Complex • Cerebritis • Hypoglycemia Rare but Important • MELAS(Acute Presentation) • Creutzfeldt-jakob Disease (C]D) • Dysplastic Cerebellar Gangliocytoma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Vast majority of cortical lesions are related to ischemia & trauma • Remainder of lesions much less common and include primarily tumors & infections • DWI may help differentiate lesions

I 6 24

Helpful Clues for Common Diagnoses • Cerebral Ischemia-Infarction, Acute o T2 hyperintensity in a typical vascular distribution (ACA, MCA, PCA) o Wedge-shaped, involves gray matter (GM) & white matter (WM) o DWI restriction • Cerebral Contusion o T2 hyperintensity in inferior frontal & temporal lobe GM & subcortical WM o Blood products nearly always present oCT: Patchy superficial hemorrhages with surrounding edema o History of trauma • Hypotensive Cerebral Infarction o "Border zone" or watershed infarct related to insufficient cerebral blood flow

T2 hyperintense cortically based, wedge-shaped lesions at border zone between vascular territories o Edematous gyri with local mass effect o May involve basal ganglia (BG) & thalamus o DWI positive acutely • Status Epilepticus o T2 hyperintensity in GM &/or subcortical WM with mild mass effect o May focally involve hippocampus or corpus callosum o DWI positive acutely; variable enhancement • Herpes Encephalitis o T2 hyperintensity in the limbic system & temporal lobes; DWI positive o Subtle blood products, patchy enhancement common o Typically bilateral, but asymmetric o Acute onset, often with fever; may present with seizures o

Helpful Clues for Less Common Diagnoses • Diffuse Astrocytoma, Low Grade o Infiltrating T2 hyperintense WM mass o May extend to involve cortex o No enhancement typical • Acute Hypertensive Encephalopathy, PRES o Patchy cortical/subcortical PCA territory lesions in a patient with severe acute/subacute hypertension (HTN) o Parietooccipital T2 hyperintense cortical lesions in 95% o DWI: Usually normal o Variable patchy enhancement o Diverse causes, clinical entities with HTN • Vasculitis o Multiple small areas of T2 hyperintensity in deep & subcortical WM, often bilateral o GM involvement common o DWI positive in acute setting o Variable enhancement • Oligodendroglioma o Calcified T2 hyperintense frontal mass o Slowly growing but diffusely infiltrating cortical/subcortical mass o Variable enhancement • Anaplastic Oligodendroglioma o Calcified frontal lobe mass involving cortex/subcortical WM, ± enhancement o May appear discrete, but always infiltrative

CORTICAL

HYPERINTENSITY

T2/FlAIR

C/l ;J("

c:

Difficult to differentiate from oligodendroglioma • Hypoxic-Ischemic Encephalopathy, NOS o Bilateral cortical involvement common o Oeep gray nuclei often involved o OWl positive in acute setting • DNET o Well-demarcated, wedge-shaped "bubbly" cortical mass o Temporal & parietal lobes most common o May remodel overlying bone o Typically a young patient with longstanding seizures • Pleomorphic Xanthoastrocytoma o Supratentorial 1'2 hyperintense cortical mass with adjacent enhancing dural "tail" o Enhancing nodule abuts pia o Temporal lobe most common site o Found almost exclusively in young adults • Tuberous Sclerosis Complex o 1'2 hyperintense cortical & subcortical tubers o Calcified subependymal nodules nearly always present o Subependymal giant cell astrocytoma 15% o Taylor cortical dysplasia: Solitary tuber in cortex & subcortical WM • Cerebritis 01'2 hyperintense "mass" with mass effect o Typically DWI positive o Patchy enhancement • Hypoglycemia .. o Severe parietooccipital edema or mfarcts m a newborn with seizures o

Axial T2WI MR shows a local cortical hyperintensity & edema ~ in the medial posterior Iron tal lobe. OWl restriction

&

history

cerebral artery inlarct.

confirmed

this

acute

anterior

Parietal, occipital lobes > temporal or BG o OWl: Restricted diffusion, decreased AOC (may be transient) o

Helpful Clues for Rare Diagnoses • MELAS (Acute Presentation) o Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes o Multifocal bilateral 1'2 hyperintensities, typically reversible o Predominantly GM involvement, may involve subcortical WM o MRS shows lactate peak • Creutzfeldt-jakob Disease (CjD) o Rapidly progressing, fatal, potentially transmissible dementing disorder o Progressive 1'2 hyperintensity of BG, thalamus, & cerebral cortex (gyriform) o OWl positive o Frontal & temporal lobe cortex most commonly involved o Occipital lobe involvement in Heidenhain variant • Dysplastic Cerebellar Gangliocytoma . o Enlarged 1'2 hyperintense cerebellum with preservation of folia o Striated, laminated, or "tigroid" appearance o Associated with Cowden syndrome

Ql

~ c.

..,

OJ Ql

~ C/l C

.., 10

'0 OJ

::J

8' .., 0;' OJ

OJ ::J -0 OJ

CD ::J

o

::r

'< 3 OJ

Alternative Differential Approaches • Temporal lobe cortical lesions: Ischemia, contusion, status epilepticus, herpes encephalitis, ONET, PXA

Coronal T2WI MR shows a large hyperintense

involving the cortex

&

subcortical

=

while

matter ~

central blood products related to a Additional contusions are also present.

lesion

with

I 6

contusion.

25

co

CORTICAL

E

HYPERINTENSITY

T2/FLAIR

>-

.r: u

c

~ co

11.

c

co ~

(lJ

co o C Q)

·C

ro~

a. :::l

(f)

c:

•.. Ol

10 "0

c: Ol

:::l

..I
~ u

c

~ CIl a.. Q)

c

~ co CIl 'C

o C Q) CO ~ Cl.

::J

(fJ

c: ns ~

CO

"tl

c: ns

• Status Epilepticus o Patchy or gyriform enhancement o Underlying white matter (WM) spared • Acute Hypertensive Encephalopathy,

DIFFERENTIAL DIAGNOSIS Common • Cerebral Infarction, Subacute • Herpes Encephalitis • Hypotensive Cerebral Infarction • Status Epilepticus • Acute Hypertensive Encephalopathy, • Cerebritis

PRES

PRES

Less Common • Malignant Gliomas • Vasculitis • Hypoglycemia Rare but Important • MELAS • Cerebral Hyperperfusion • Osmotic Demyelination

Syndrome Syndrome

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Cerebral Infarction, Subacute o Gyriform enhancement characteristic o Petechial hemorrhage or pseudolaminar necrosis often seen (Tl hyperintense) o DWI has typically normalized • Herpes Encephalitis o Predilection for limbic system o Typically bilateral, asymmetric; DWI + o Enhancement patchy or gyriform • Hypotensive Cerebral Infarction o Commonly at cortical "border zones" o Gyriform enhancement subacutely

Cerebral

Infarction,

Patchy cortical/subcortical PCA territory lesions in a patient with hypertension o Patchy enhancement, may be gyriform • Cerebritis o T2 hyperintense lesion with mass effect & patchy enhancement; DWI + o

Helpful Clues for Less Common Diagnoses • Malignant Gliomas o May involve cortex or have subpial spread • Vasculitis o Multiple small areas of T2 hyperintensity in deep & subcortical WM, often bilateral o Enhancement patchy or gyriform • Hypoglycemia o Severe parietooccipltal edema/infarcts o Patchy enhancement Helpful Clues for Rare Diagnoses • MELAS o Multifocal bilateral T2 hyperintensities o Patchy enhancement • Cerebral Hyperperfusion Syndrome o Carotid endarterectomy, angioplasty, or post-stenting patient o Increased vessel & patchy enhancement • Osmotic Demyelination Syndrome o May rarely involve cortex o Pseudolaminar necrosis &/or gyriform enhancement rare

Subacute

I 6 28

Axial T7 C+ MR shows marked gyri/arm enhancement in this subacute infarct. Remember the "2-2-2 rule" for strokes: Enhancement begins at 2 days, peaks at 2 weeks, & generally disappears by 2 months.

Coronal T7 c+ MR shows gyri/arm enhancement in the temporal lobes & insular cortex in this herpes

encephalitis involvement

patient.

Bilateral

=but

asymmetric

of the limbic system is most common.

CORTICAL

ENHANCEMENT

,.c: Ul

Status Epilepticus (Lcft) Coronal T7 C+ MR shows diffuse gyriform cortical enhancement & basal ganglia enhancement ~. T7 hyperintensity representing pseudolaminar cortical necrosis is common in this type of ischemia. (Right) Coronal T7 C+ MR shows gyriform & meningeal enhancement in the right parietal & occipital lobes, related to status epileplicus. Ten days after imaging, once the patient's seizures were controlled, there was resolution of enhancement

Acute Hypertensive

Encephalopathy,

PRES (Left) Axial T7 C+ MR shows multifocal areas of punctate enhancement

=..

active blood-brain

indicating barrier

disruption in this case of PRES. PRESis typically completely reversible but may become complicated by hemorrhage or infarcts. (Right) Axial TI C+ MR shows patchy enhancement SII within an ill-defined "mass ". The lesion showed restriction

on OWl (not

shown), typical of cerebritis. This represents the early cerebrilis stage of abscess {ormation.

Vasculitis (Left) Axial T7 C+ MR shows gyriform & patchy enhancement. OWl images (not shown) reveal bright diffusion indicating

restriction acute ischemia.

Multiple vascular distributions are commonly involved. (Right) Corolla I T 1 C+ MR shows increased vascularity in the left hemisphere with ill-defined punctate enhancement suggesting blood-brain barrier leakage in this carotid endarterectomy patiellt. OWl is normal, & there is increased perfusion (rCBT).

=.

I 6 29

ctl

E

SOLITARY WHITE MATTER LESION

>-

.r: u

-

L

U C

~ Q)

Cll

CL

c

~

(() Cll

·C

o C Q) iii ~

Q.

:J

(fJ

C ltl

~

(()

"t:l

Arteriolosclerosis

=

c

while matler

:J

a linear isointense rim an isointense juxta cortical core ~ & mass effect due to a

ltl

(fJ ""

Multiple

Sclerosis

(Left) Axial T2WI MR shows hyperintensity in the pons without mass effect =:I related to arterioloscferosis. These WM lesions are most common in peri ventricular & subcortical WM. Arteriolosclerosis is expected in patients with a history of hypertension &lor diabetes. (Right) Axial FLAIR MR shows a large hyperintense

lUmefactive

lesion

=

with

MS lesion.

Metastasis

ADEM

(Left) Axial FLAIR MR shows a solitary T2 hyperintense lesion in the juxta cortical right frontal lobe white maller. There is a small central focus of isointensity =:I that may be due to hemorrhage in this testicular embryonal carcinoma metastasis. (Right) Axial FLAIR MR shows a large, tumefactive ADEM lesion =:I with hyperinlensily sparing the cortex. The mass effect is less than expected for lesion size. Gadolinium

enhancement was at the peripheral margin.

Reactive Astrocytosis (Gliosis) (Left) Axial FLAIR MR shows increased signal intensity in the medial left temporal lobe =:I (gliosis), with dilatation of the left temporal horn !J:il in this seizure patient

mesia/temporal

with

sclerosis.

(Right) Axial T2WI MR shows a heterogeneous,

discrete appearing mass

I 6 32

=

in the posterior temporal/occipital region. Lack of surrounding edema is very unusual for CBM. The hypointensity is likely related to blood products, common in CBM.

Glioblastoma

Multiforme

en

SOLITARY WHITE MATTER LESION

~ r:: III

::l

a. III .,

Encephalitis

III

(Miscellaneous) (Left) Coronal T2WI MR shows edema & hyperintensity of the temporal lobe & insula with involvement of gray & white matter with significant mass effect due to a viral encephalitis. The lateral neocortical location is rare in herpes. (Right) Axial FLAIR MR shows a hyperintense white maller mass involving the cortex with mild mass effect Although this may mimic acute stroke, extension into the ACA distribution makes that diagnosis unlikely

=

=

Diffuse Astrocytoma,

low Grade

Anaplastic

::l

en

c u ., OJ

CD ::J

o ., 0;' OJ ., OJ

::J -0 OJ ., (!l

::J () ::r

'
.r::

CONFLUENT WHITE MATTER LESIONS

u

c

~ Q)

ro

CL

c

ro ~

co

ro o

·C

C Q)

ro~

0.

:J

(f)

c:

0-

OJ ., III

::> Ul

c:

-0

.,

OJ

CD ::> 8" ., iij" CD ., OJ

::> "U OJ

co::>

()

::T

'< 3 OJ

Alternative Differential Approaches • Inherited metabolic disorders o Macrocephaly: Canavan, van der Knaap, Alexander disease, mucopolysaccharidoses o Frontal: Alexander disease o Occipital: XLD

I Axial T2WI MR shows diffuse hyperintensity with sparing of the juxlacorlical & deep central while

=

matter E:I. Findings are typical for extensive age-related changes in this elderly gentleman.

=

Axial T2WI MR shows diffuse patchy hyperintensily in the perivenlIicular while matter due to elderly microangiopathy, a mixed eUology of arteriolosclerosis,

venous collagenosis, and amyloid.

6 35

CONflUENT

Cll

E

WHITE MATTER lESIONS

>-

-'u= c OJ

~ Cll

D-

c

~

CJ

ro

Multiple Sclerosis (lefl) Axial T2WI MR shows patchy & conlluentloci 01

'C

hyperintensity in the centrum

C

semiovale & atrophy. Although nonspecilic, these

o

OJ

ro~ Cl.

:J

(/)

C Cll

~

CJ "C

c nl

:J

-'"

(/)

=

findings are characteristic

of

chronic hypertensive encephalopathy. Associated basal ganglia inlarcts &

hemorrhage are common. (RighI) Axial T2WI MR shows significant, predominantly while maller atrophy and confluent

==

periventricular

&

juxta cortical hyperintense plaques of severe chronic multiple sclerosis.

Multi-Infarct Dementia

Hypotensive Cerebral Infarction

Cerebral Amyloid Disease

Glioblastoma Multiforme

(Left) Axial FLAIR MR shows confluent

periventricular

(.~

subcortical while malter hyperintensities It] with minimal

callosal involvement

PJ::I

& significant atrophy. typical for arteriolosclerosis in this multi-infarct

dementia

patient. (RighI) Axial FLAIR MR shows confluent

linear

hyperintensity of the cortex, the subcortical "U-fibers" I.r: u c

~ Q)

DIFFERENTIAL DIAGNOSIS

C1l

0..

c

~ (])

C1l 'C

o C Q)

ro~

c. ::J

(fJ C

'" "-

III

"c '"

Common • Normal Variant • Callosal Dysgenesis • Callosotomy • Neoplasm o Lipoma o Glioblastoma Multiforme o Lymphoma, Primary CNS • Decreased White Matter Volume o Hypomyelination o Periventricular Leukomalacia o HIE, Term o Cerebral Infarction, Chronic o Diffuse Axonal Injury (DAI) o Multiple Sclerosis o Radiation and Chemotherapy • Obstructive Hydrocephalus Less Common • Holoprosencephaly • Holoprosencephaly

Variants

Rare but Important • Hypertensive Intracranial Hemorrhage • Marchiafava-Bignami

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Normal corpus callosum (CC) varies in thickness, shape • Isolated callosal dysgenesis not common o Look for second lesion o Associated CNS anomalies in > 50% • Heterotopia • Cortical dysplasia • Noncallosal midline anomalies • Abnormal brainstem or cerebellum • If not congenital, history crucial!

I 6 46

Helpful Clues for Common Diagnoses • Normal Variant o Size, shape, thickness of normal CC vary • Splenium, genu are largest parts of corpus callosum • Narrowing between body, splenium ("isthmus") is normal • Dorsal surface of fully developed, normally myelinated corpus callosum often "wavy" o Immature corpus callosum is thin

• Pre-myelination • Gradually thickens with progressive myelination • Callosal Dysgenesis o One or all segments absent • Rostrum, splenium most likely deficient • Remnants vary in size, shape, configuration o "Micro" CC • Small, but well-formed • Often syndromic o "Mega"CC • Isthmus usually absent • Megalencephalic (bulky white matter) • Or small to normal brain (syndromic) • Callosotomy o Surgical disruption • Focal: Approach to 3rd ventricle or suprasellar tumor • Diffuse: Surgery for intractable seizures o Best seen on sagittal or coronal MR • Neoplasm o Can be benign/focal or malignant/diffusely infiltrating o Lipoma • 40-50% interhemispheric fissure • Common in callosal dysgenesis • Can be bulky, mass-like ("tubonodular" type, usually associated with CC agenesis; may extend through choroidal fissures into lateral ventricles) • Thin mass curving around CC body/splenium ("curvilinear" type, CC present but may be dysgenetic) o Glioblastoma Multiforme • "Butterfly" glioma • Central necrosis + thick irregular rim enhancement o Lymphoma, Primary CNS • Hyperdense on NECT • Strong, uniform enhancement o Decreased White Matter Volume • Many causes (congenital, acquired) • All may result in focal or diffuse callosal thinning o Hypomyelination • Chromosomal, inborn errors of metabolism o Peri ventricular Leukomalacia • Premature infant • "Scalloped" lateral ventricles

ABNORMAL SHAPE/CONFIGURATION

OF CORPUS CALLOSUM

(J)

c: ""

HIE, Term • Term infant with profound partial asphyxia - WM/cortex damaged o Cerebral Infarction, Chronic • Axonal loss - focal/diffuse thinning CC o Diffuse Axonal Injury (DAI) • 20% involve CC (splenium, undersurface posterior body) o Multiple Sclerosis • Chronic, late • Obstructive Hydrocephalus o Acute • Corpus callosum (CC) stretched • CC bowed upwards • Forniceal columns bowed downwards o Chronic • Post-shunt encephalomalacia • Sequela of acute callosal impingement against falx

• Middle CC body "dips" • Gray matter crosses at dip • If severe, add bilateral perisylvian polymicrogyria

o

Helpful Clues for Less Common Diagnoses • Holoprosencephaly o Corpus callosum absent in alobar • Large dorsal "cyst" often present o Semilobar may have residual splenium • Frontal fusion & hypoplasia • Splenium may be present o Lobar • Genu mayor may not be present • Gray matter often crosses with genu • Holoprosencephaly Variants o Middle interhemispheric variant • a.k.a., syntelencephaly • Splenium, genu present, body deficient

III

:J C.

CD ., III

:J (J)

Helpful Clues for Rare Diagnoses • Hypertensive Intracranial Hemorrhage o CC rare primary site • Marchiafava-Bignami o Middle-aged alcoholic o CC demyelination, necrosis, atrophy

c:

.,

1:l

III

CD :J 8' ., III

OJ ., III :J

"U III

SELECTED REFERENCES

CD

:J

(")

].

2.

3.

4.

5.

6. 7.

8.

9.

Pierson TM et al: Mega-corpus callosum, polymicrogyria, and psychomotor retardation: confirmation of a syndromic entity. Neuropediatrics. 39(2):123-7, 2008 Samaranch Let al: SPGll compound mutations in spastic paraparesis with thin corpus callosum. Neurology. 71(5):332-6, 2008 Matar6 M et al: Functional and magnetic resonance imaging correlates of corpus callosum in normal pressure hydrocephalus before and after shunting. J Neurol Neurosurg Psychiatry. 78(4):395-8,2007 Hetts SW et al: Anomalies of the corpus callosum: an MR analysis of the phenotypic spectrum of associated malformations. AJRAm J Roentgenol. 187(5):1343-8,2006 Rollins N: Semilobar holoprosencephaly seen with diffusion tensor imaging and fiber tracking. AJNR Am J Neuroradiol. 26(8):2]48-52, 2005 Kinsman SL: White matter imaging in holoprosencephaly in children. CUff Opin Neurol. ] 7(2):1 ]5-9,2004 Barkovich AJ et al: Callosal agenesis with cyst: a better understanding and new classification. Neurology. 56(2):220-7,200] Kier EL et al: The normal and abnormal genu of the corpus callosum: an evolutionary, embryologic, anatomic, and MR analysis. AJNR Am J Neuroradiol. 17(9):1631-41, 1996 Mendelsohn DB et al: Corpus callosum lesions after closed head injury in children: MR], clinical features and outcome. Neuroradiology. 34(5):384-8, 1992

Normal Variant

::r

'< 3

III

Normal Variant

Sagittal Tl WI FSMR with a close-up view of the corpus callosum shows normal "wavy" dorsal surface. Note the focal thinning along posterior body a common normal finding.

=-

=-

Sagittal TlWI MR shows a normal neonatal corpus callosum thin due to age-appropriate lack of myelin maturation. The cingulale gyrus ~ is normal.

I 6 47

ABNORMAL

Cll

E

:>.

..r: u c OJ

~ co

a.. c

co ~

co co

'C

o C OJ

ro~ 0..

:J (f) C

co ~

III "C

c co :J

-"en

DIFFERENTIAL DIAGNOSIS Common • Multiple Sclerosis • Diffuse Axonal Injury (DAI) Less Common • Post-Surgical • ADEM • Obstructive Hydrocephalus • Lacunar Infarction Rare but Important • Enlarged Perivascular Spaces • Marchiafava-Bignami Disease • Susac Syndrome

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Multiple Sclerosis o Callososeptal interface T2 hyperintensities o "Burned out" chronic lesions have Tl hypointense center, very slight hyperintense rim (lesion within lesion) • Diffuse Axonal Injury (DAI) o Punctate hemorrhages at gray-white interfaces & corpus callosum (CC) typical o "Blooming" on T2*, GRE, SWI common o May result in focal encephalomalacia Helpful Clues for Less Common Diagnoses • Post-Surgical o Small CC "holes" common after shunt o Defects may result from transcallosal surgery (e.g., for colloid cyst)

HOLES

• ADEM o Both subcortical white matter (WM), deep gray nuclei often involved o May mimic multiple sclerosis • Obstructive Hydrocephalus o Dorsal, middle layers may show Tl hypointense & T2 hyperintense signal o May be related to CC compression against falx during acute ventricular obstruction • Lacunar Infarction o Uncommon; rich blood supply to CC o Focal ischemia with surrounding gliosis o Supplied by anterior communicating artery, peri callosal artery, & posterior pericallosal artery Helpful Clues for Rare Diagnoses • Enlarged Perivascular Spaces o Follow CSF on all sequences o When CC involved, adjacent brain often involved • Marchiafava-Bignami Disease o Rare complication of chronic alcoholism; CC demyelination & necrosis o T2 hyperintense CC (middle layers) virtually pathognomonic o Sudden onset of altered mental status, seizures, dysarthria, ataxia, hypertonia, pyramidal signs • Susac Syndrome o Classic clinical triad = encephalopathy, visual changes, hearing loss o Multifocal supratentorial WM lesions + CC o "Holes" in CC middle layers characteristic

Diffuse Axonal Injury (DAI)

I 6 52

Sagittal Tf WI MR shows mulUple hypointense lesions in U,e CC & deep white mailer perpendicular to the lateral ventricle in this young adult. These lesions may have a mildly hyperintense rim.

=

Sagittal T2' eRE MR shows muMocal hypointensilies at the gray-white interfaces & CC related to OAi. The CC lesion will likely result in focal encephalomalacia, causing a "ce hole".

CORPUS

CALLOSUM

HOLES III

::l

a. III ., Obstructive

ADEM

III

Hydrocephalus (Left) SagiLtal FLAIR MR shows multifocal hyperintensiLies within the CC & pons in this ADEM patient with a recent flu-like illness. Imaging mimics MS. These lesions often result in "CC holes" chronically. (Rigl1t) Axial T2WI MR

shows a peculiar transverse "striated" appearance of the CC body resulLing from

prior severe obstructive hydrocephalus. In about 15% of patients with shunted hydrocephalus, CC signal abnormalities may be

::l

en c

-0

., Q)

CD

~

o:0. Q)

OJ ., Q)

~ -U Q)

~ CD ~ ()

::T

'< 3 Q)

seen.

(Left) SagiLtal T1 WI MR shows a CC hole Il::l related to

a

lacunar

infarct in

a

moyamoya patient. Note the T1 shortening related to additional anterior circulation ischemia. Lacunar infarcts are uncommon as there is a rich CC blood supply. (Right) Sagittal T1 WI MR shows mulLiple "cysLic" lesions that follow CSF in the CC & cingulate gyrus. When perivascular spaces are in the CC, there is often involvement of the adjacent brain, cingulate gyrus in this case.

Marchiafava-Bignami

Disease

Susac Syndrome (Lelt) Sagittal T1WI MR shows cla.5sic findings (or Marchiafava-Bignami disease with a thinned CC & hypoinlensily in the middle layers l:llI. NOle that the genu, body, & splenium are all involved. T2 hyperintensity that extends to the deep white matter is also common. (Right) SagiLtal T2WI MR shows a

subtle hyperintense" hole" in the central CC l:llI in this young adult with Susac syndrome. Iioies in the middle layers of the CC are characteristic.

I 6 53

co

CORPUS CAllOSUM

E

lESION WITHOUT MASS EFFECT

>. .£ l)

C

DIFFERENTIAL DIAGNOSIS

~ Q)

co

0-

c

co ~

CD

CO 'C

o C Q)

ro~ Cl.

:J

en c

co ~

co

"coc :J

-" en

Common • Multiple Sclerosis • Diffuse Axonal Injury (DAI) less Common ·PML • ADEM • Periventricular Leukomalacia Rare but Important • Enlarged Perivascular Spaces • Vasculitis • Lyme Disease • Susac Syndrome • X-Linked Adrenoleukodystrophy • Metachromatic Leukodystrophy (MLD)

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Multiple Sclerosis o Multiple perpendicular callososeptal T2 hyperintensities characteristic o Corpus callosum (CC) almost always involved, subcallosal striations early • Diffuse Axonal Injury (DAI) o Punctate hemorrhages at corticomedullary junction & CC typical o CC involvement in 20%; 75% involve splenium/undersurface of posterior body Helpful Clues for less Common Diagnoses

·PML o

I 6 54

Bilateral, asymmetric involvement typical

Large multifocal subcortical white matter (WM) lesions without mass effect • ADEM o 10-14 days after viral illness/vaccination o Involves subcortical WM, deep gray nuclei o May mimic multiple sclerosis • Periventricular Leukomalacia o Small CC typical, ± T2 hyperintensity o Peritrigonal WM loss & "wavy" ventricular margins o

Helpful Clues for Rare Diagnoses • Enlarged Perivascular Spaces o Cystic lesions follow CSF on all sequences o May involve CC • Vasculitis o Subcortical WM commonly affected o DWI bright & enhancement typical • Lyme Disease o May mimic multiple sclerosis o Cranial nerve enhancement common • Susac Syndrome o Classic triad: Encephalopathy, retinal artery branch occlusions, hearing loss o Multifocal supratentorial WM lesions + CC • X-Linked Adrenoleukodystrophy o Enhancing peritrigonal demyelination o Involves CC splenium early, followed by peritrigonal WM & WM tracts • Metachromatic Leukodystrophy (MLD) o Confluent "butterfly-shaped" cerebral hemisphere WM T2 hyperintense signal o Late involvement of CC, V-fibers, pyramidal tracts, internal capsule

Multiple Sclerosis

Diffuse Axonal Injury (OAf)

Sagittal fLAIR MR shows mu/tjfocal hyperinlense lesions wilhin the CC & sulx:orlical while mailer. typical {or MS. Sagillal FLAIR MR helps idenlily sulx:allosal

Sagiual T2WI MR shows hyperinlensily in lhe CC body & local hypoinlensily in lhe splenium E!ilI relaled 10 OAI. Correialion with eRE or SWI sequences lypically shows mulliple addilionallesions.

=

striations seen in early disease stages.

=

CORPUS

CALLOSUM

LESION WITHOUT

,.-c:

MASS EFFECT

(J)

'a.:"l ...

OJ (Left) Axial FLAIR MR shows confluent, high signal in the frontal lobes that crosses the CC without significant mass effect.

There is involvement

of the subcortical U-fibers, typical of PML. No enhancement is characteristic. (Right) Axial T2WI MR shows a "wavy" ventricular

margin

m& a

small corpus callosum, typical of PVL. Note also perilrigonal while matter 1055 & deep sulci. PVL often occurs in premature

infanl5

related to a hypoxic-ischemic

':"l (J)

c:

... m :l o...

"0 Ql

iii'

...

OJ Ql

:l

lJ

...

Ql

CD :l (")

:::r

'< 3 Ql

event

(Left) Axial T2WI MR shows innumerable clusters of CSF-signal cysts in the corpus callosum & occipital white matter related to perivascular spaces. These are rare in the corpus callosum. (Right) Sagittal FLAIR MR shows hyperintensities in the middle layers of the CC, typical of Susac syndrome. Central CC involvement is more common than callososeptal interface involvement.

Imaging

may

mimic MS, so clinical history is important for diagnosis.

(Left) Axial FLAIR MR shows marked hyperintensity in the CC splenium & peritrigonal white maller related to demyelination

in this patient

with X-ALD. CC splenium is involved early. Enhancement is cfassic. (Right) Axial T2WI MR shows confluent hyperintense periventricular white matter~ (butterfly pattern) related to demyelination. Note the preservation of subcortical U-fiber myelination SlI. Hyperintensity & volume loss of the

CC is common.

I 6 55

ro

CORPUS CAllOSUM

E

MASS

>L U C Q) L

ro CL

c ro L

co ro

·C

o C Q)

ro L

Cl.

::J (/J

C

ro "CO

"cro

DIFFERENTIAL DIAGNOSIS Common • Glioblastoma Multiforme • Lymphoma, Primary C S • Anaplastic Astrocytoma less Common • Oligodendroglioma • "Tumefactive" Multiple Sclerosis • Gliomatosis Cerebri • Lipoma Rare but Important • "Tumefactive" ADEM • Enlarged Perivascular Spaces

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Glioblastoma Multiforme o Heterogeneously enhancing mass o Classically crosses corpus callosum (CC), results in a "butterfly glioma" o Central necrosis, blood products typical • Lymphoma, Primary CNS o Homogeneously enhancing, 1'2 hypointense mass o Usually involves basal ganglia, periventricular white matter (WM) o Often crosses CC, extends along ependymal surfaces • Anaplastic Astrocytoma o 1'2 hyperintense WM mass with variable enhancement

Glioblastoma

o

Often involves, crosses CC

Helpful Clues for less Common Diagnoses • Oligodendroglioma o Calcified frontal lobe mass involving cortex/subcortical WM o May extend into CC o Heterogeneous enhancement 50% • "Tumefactive" Multiple Sclerosis o CC lesions characteristic o Single tumefactive lesion common o Often incomplete, "horseshoe-shaped" enhancement, open toward cortex • Gliomatosis Cerebri o 1'2 hyperintense infiltrating mass with enlargement of involved structures o May cross CC o Typically nonenhancing at presentation • Lipoma o Often associated with CC dysgenesis o 1'1 hyperintense mass along CC Helpful Clues for Rare Diagnoses • "Tumefactive" ADEM o 10-14 days after viral illness/vaccination o Often involves subcortical WM & deep gray nuclei o Incomplete ring enhancement characteristic • Enlarged Perivascular Spaces o May cause mass effect, particularly in midbrain o Follow CSF signal on all sequences o No enhancement

Multiforme

lymphoma,

Primary eNS

I 6

T1

mass

involving

perialfial

56

C+ M R

Axial

while

shows

the

a

corpus

maller.

helerogeneously callosum

Cenlfaf

of these malignanllumors.

necrosis

enhancing

splenium

& left

is characteristic

Axial

T1 C+ MR shows

a homogeneously

enhancing

mass involving t.he corpus callosum splenium perialrial hypointense

while

malter.

&, enhances

Lymphoma homogeneously.

is

typically

& T2

CORPUS CALLOSUM MASS

CJl

" c:

Anaplastic

Astrocytoma (Left) Axial FLAIR MR shows a hyperintense mass that involves the corpus callosum splenium & parietal lobes. Anaplastic astrocytomas occur in hemispheric

white

malter, and neoplastic cells are almost always found beyond the signal abnormality. (Right) Axial T2WI MR shows a heterogeneous frontal lobe mass that involves the corpus callosum genu, cortex, & subcortical white matter. These tumors are typically calcified, which is

OJ

~ Ql

:J lJ Ql

ii3

:J (')

::r

'
£ U C Q) L

ctl Q..

c ctl L OJ

ctl

'C

o

C 10 C. ~ Q) L

(/)

r:: C'.r: ()

c

~ a.. '" (l)

Vasculitis

c

~ co

'o"

'C

C (l)

ro~ Cl.

:J (/) C

'"

L-

CO

"c '"

(Leh) Coronal T' C+ MR shows multiple punctate & linear enhancing

foci

m

along the penetrating perivascular spaces in this TB meningitis patient. TB may cause a true vasculitis with muflifocallacunar & cortical infarcts as sequelae. (Right) Axial T' C+ MR shows striking enhancement in the brain parenchyma & perivascular spaces of the basal ganglia in this HIV patient. I-{IV vasculitis is

=

increasing

in incidence,

particularly

in children.

Glioblastoma

Multiforme

(Left) Axial TI C+ F5 MR shows multifocal glioblastoma multiforme with involvement of the PV5 as patchy contrast enhancement s::I in the basal ganglia. (Right) Coronal TI C+ MR shows linear enhancement along the

perivascular spaces ED representing lymphoma. enhancement of T2 white abnormality.

intravascular This occurs in areas mailer signal The linear

enhancement

along PVS can

help suggest the diagnosis in a dementia patient.

Cerebral (Left) Axial TI C+ MR shows nodular enhancement representing intravascular lymphoma involving the perivascular spaces. Enhancement patterns are variable in intravascular lymphoma & may be linear, punctate, patchy, nodular, ring-like, gyriform, or homogeneous. (Right) Axial TI C+ MR shows nodular

=

enhancement

I 6 78

in the basal

ganglia ~ related to amyloid in the perivascular spaces. Amyloid deposits are typically interstitial, vascular, or perivascular.

Amyloid

Disease

PERIVASCULAR

SPACE ENHANCING

lESIONS III

::l

a.

..,

III III

(Left) Coronal T1 C+ MR shows linear enhancement along the perivascular spaces of the frontal lobes. Imaging mimics sarcoid & intravascular lymphoma. Biopsy disclosed granulomatous angiitis. (Right) Axial T7 C+ MR

=.2

shows punctate

&

linear

enhancement in the tempora/lobe & pons =.2 representing involvement of

the perivascular spaces. Biopsy disclosed Langerhans cell histiocytosis in this young patient.

::l (fJ

c:

..,

"0

OJ

CD ::J

0" ..,

Qi. III .., III

::J -U OJ CD

.., ::J

()

::r

'< 3 OJ

(Left) Coronal T1 C+ MR

shows irregular enhancement in the frontal lobes of this patient with Wegener granulomatosis of the paranasal sinuses. Invasion of the meninges & brain from the sinuses occurs in up to 30% of these patients. (Right) Axial T7 C+ MR shows enhancing lenticulostriate collateral vessels in the basal ganglia related to the patienes dista//CA stenosis bilaterally. These colfalerals mimic

=

perivascular space enhancement.

(Left) Coronal T1 C+ MR shows linear enhancement =.2 related to a calcified pial-based mass seen on CT. Meningioangiomatosis infiltrating

the brain

parenchyma via the PVS was identified at surgery. (Right) Axial T7 C+ MR shows a strongly enhancing superficial mass that fills the adjacent sulci & extends into the underlying brain. Surgery disclosed exlensive melanosis that had invaded the brain via the perivascular spaces.

I 6 79

Cll

E

BILATERAL BASAL GANGLIA

LESIONS

>.r:: u

c -

-'o=

c OJ

~

'c" ~ '" CO 'o" Cl..

'C

C OJ

ro~

a. ::>

(fJ

c

•... '"

ell

-0

c

'::>" -"(fJ

Mineralization (Left) Axial NEeT shows stippled Ca++ of the bila!eral putamina i:llI & fron!al subcortical WM as well as subtle Ca++ of the caudate nuclei, in a patient

=

with

pseudohypoparathyroidism. Ca++ associated with normal aging affec!s the Cp, usually symmetrically. (Right) Axial T1WI MR shows symmelrical t 51 in the CP in a patient with end·scage liver disease from hepatic cirrhosis. After liver transplantation, the signal abnormality regressed over time.

(Left) Axial OWl MR shows symmetrical diffusion in the caudate nuclei 81 & putamina in a patient who suffered cardiac arrest & was comatose. There is also ~ diffusion in the cortical ribbon, most evident in the occipital lobes ~ (Right) Axial CECT shows contrast-enhancing masses with associated vasogenic edema involving the caudate nuclei i:llI & the ependymal surfaces of bilateral fron!al horns. An enhancing mass E1 is also seen in the atrium.

*

=

Trauma (Left) Axial T2 CRE MR shows severe traumatic injury, with scalp hemalomas, 5AH, fVH, bifrontal hemorrhagic contusions, & hemorrhagic shear injury of the BG i:llI & !halamus 81. Edema is also present in the putamina & frontal lobes. Swelling of the right temporal cortical ribbon ~ was due to vascular injury & MCA infarct (Right) Axial T2WI MR shows t 51 in the CP & lef! > right thalami 81 in a child with Nfl, representing myeNn vacuolization.

=

I 6 82

Neurofibromatosis

Type 1

BILATERAL BASAL GANGLIA

,,-c:

LESIONS

CJl

III

~ Q.

...III

OJ (LeFt) Axial FLAIR MR shows fairly symmetric t 51 in the GP I:] & hemispheric WM in a severely altered patient days after being found in a mobile home with a faulty propane heater. Imaging typical of CO poisoning. (Right) Axial PO F5f MR shows "fluffy" irregular t 51 without mass effect involving bilateral caudate nuclei & putamina. diffusion

There was no

J..

or enhancement

in

this IIIV+ patient with cryptococcal

meningitis

&

gelatinous pseudocys15.

~ Ul C

...

"0 OJ

CD :J

o::!. OJ

aJ ...

OJ

:J lJ

... OJ CD

:J ()

::r

'< 3 OJ

(Left) Axial T2WI MR shows diffuse symmetrical t 51 in bilateral caudate nuclei & putamina in a patient who had rapid correction of hyponatremia. Diffuse t 51 of the inner cortex/subcortical WM is also seen. (Righi) Axial OWl MR shows asymmetrical J. diffusion in the caudate

nuclei

&

Anterior>

putamina ED. posterior

putamina! abnormality is typical of C/O. Note also asymmetrical

~ diffusion

in

the frontal & temporal lobe cortical ribbon 1:].

(LeFt) Axial FLAIR MR shows patchy t 51 in bilateral caudate & putamina in a young child with pyruvate dehydrogenase complex deficiency & an acute clinical

decompensation. These lesions showed J. diffusion & no post-gadolinium enhancement. (Right) Coronal FLAIR MR shows fairly symmetric t 51 in the bilateral caudate nuclei & putamina in this patient with Wilson disease, a rare

autosomal recessive disorder characterized by impaired biliary excretion of copper.

I 6 83

co

PUTAMEN lESION(S)

E>,

.r:: u

c

~

OJ

co

a.. c

co ~

CD

CO

.'B" c

OJ



Co III .., III

:> (f)

c

"0 OJ

..,

ro-

:J ~

o

:::!.

OJ

OJ ..,

OJ

:J \J

..,

OJ

CD

:J o ::T

'< 3 OJ

HIE, Neonate

I Axial FLAIR MR shows hyperintensity in lhe GP bilaterally E1 related to an acute hypoxic·ischemic event. Imaging mimics CO fXJisoning or other drug

Axial T1WI MR shows brighl signal wilhin lhe Gp, putamen, & latera/thalamus. Imaging pattern is typical for profound acute HIE, seen in an acute event such as

abuse. DWI is positive in the acute setting.

uterine rupture or cord prolapse.

6 B7

GLOBUS

PAlliDUS

CO Poisoning (Left) Axial FlAIR MR shows heterogeneous hyperintensity within the globus pallidus 81 bilaterally related 10 CO poisoning. The heterogeneity is likely related to necrosis &/o(

c: IV •...

al "'C

c: IV

blood

produc15. (Right) Axial FlAIR MR shows extensive Focal

areas of increased signal intensity (FASI) 81 in the GP in this NFl patient most common

GP is

location

for

FASI. Enhancement of these lesions is worrisome but does nol always signal neoplastic change.

(Left) Axial PO FSEMR shows hyperintense GP 81 related to heroin abuse in this young adult, likely related to ischemia. MOMA would mimic this appearance. (Right) Axial T7 WI MR shows bilateral, symmetric hyperintensity in the BC, predominanlly in the GP ~. This hyperintensity resolved after therapy. The patient's movement disorder also resolved, showing that both clinical & imaging findings of hepalOcerebral degeneration can be reversible.

(Left) Axial T2WI MR shows bilateral,

symmetric

hyperintensilies in the putamina & CP The (;ndings are suggestive of mitochondrial encephalopathy. (Right) Axial T2WI MR shows symmetric hyperintensities in the CP bilaterally in this adult patient with a history of cyanide poisoning history.

=.

=

Differential

considerations

in

an adult would include CO poisoning, drug abuse, & hypoxia.

I 6 BB

lESION(S)

Neurofibromatosis

Type 1

(fl

GLOBUS PALLIDUS LESION(S)

" c: Q)

:l

Cl. lJl

.., Q)

Kernicterus (Left) Axial T1WI MR shows hyperintensity in the GP in this child with acute kernicterus. There are many causes for elevation of bilirubin to toxic levels; the most common worldwide is erythroblastosis fetalis. (Right) Axial T2WI MR shows hyperintensity in the GP bilaterally in this child with treated hyperbilirubinemia. MR obtained at 6 month follow-up shows typical GP hyperintensity of chronic

=

=

kernicterus.

:l

en c: .,

"D OJ

CD :l

8" :0. OJ OJ ., OJ :l

\J

OJ ., C1l

:l ()

::T '
,

J::

II C

~ Q)

ro D-

c

ro ~

en

ro 'C o C Q)

ro~

c. :J

en C Cll

co"'tl

l:: Cll

DIFFERENTIAL DIAGNOSIS Common • Lacunar Infarction • Hypertensive Intracranial Hemorrhage • Neurofibromatosis Type 1 Less Common • Diffuse Astrocytoma, Low Grade • Glioblastoma Multiforme • Anaplastic Astrocytoma • ADEM Rare but Important • Multiple Sclerosis • Thrombosis, Deep Cerebral Venous • Germinoma

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Lacunar Infarction o Small, < 1.5 em T2 hyperintensity in thalamus or basal ganglia (BG) o DWI restriction if acute o Related to ischemia of penetrating vessels • Hypertensive Intracranial Hemorrhage o BG > thalamus> pons/cerebellum> hemisphere bleed in a hypertensive patient o 15-25% in thalamus o May enhance subacutely o Intraventricular hemorrhage common • Neurofibromatosis Type 1 o Focal areas of signal intensity (FAS!)in deep gray matter characteristic (60-85%)

o o o

Globus pallidus, white matter (WM), thalami, hippocampi, brainstem Bilateral> > unilateral No enhancement!

Helpful Clues for Less Common Diagnoses • Diffuse Astrocytoma, Low Grade o Nonenhancing T2 hyperintense mass o May be bilateral • Glioblastoma Multiforme o Peripherally enhancing WM mass typical o May involve thalamus or BG • Anaplastic Astrocytoma o T2 hyperintense mass ± enhancement • ADEM o Muitifocal WM &/or BG lesions following infection/vaccination o Thalamic involvement common o Typically bilateral, but asymmetric lesions Helpful Clues for Rare Diagnoses • Multiple Sclerosis o Periventricular WM, corpus callosum T2 hyperintense lesions most common o Rarely involves thalamus • Thrombosis, Deep Cerebral Venous o Typically bilateral, related to internal cerebral vein (ICV) thrombosis o T2 hyperintensity in thalamus o Hyperdense lCV on CT • Germinoma o Enhancing mass in pineal or suprasellar region; 5-10% involve BG or thalamus

Lacunar Infarction

I 6 90

Axial FlAIR MR shows a focal hyperintensity within the thalamus

=

related to an acute lacunar infarct. Note abnormal perivenlricular hyperintensity related to

chronic small vessel ischemia 81.

Axial NEeT shows a hypertensive hemorrhage p:J with associated intraventricular hemorrhage, a common complication. The thalamus is the second most common location for hypertensive hemorrhages.

UNILATERAL THALAMIC

en

LESION

t: "" Dl

::l Co

..,

llJ

Hypertensive

Intracranial

Hemorrhage

Neurofibromatosis

Dl

Type 1 (Left) Axial T2' eRE MR shows muttiFocal areas of "blooming" related to hemosiderin in this chronic hypertension patient. Note large area in left thalamus ~ related to a prior hypertensive hemorrhage. (Right) Axial FLAIR MR shows multiple foci of abnormally increased signal in the globus pallidus & thalamus typical of NFl. They are related focal areas of signal intensity (FAS/), which are most common in the deep gray nuclei.

=

Diffuse Astrocytoma,

::l (f) C

-

"0

OJ C1l

::J

o ::!.

OJ

..,OJ

llJ ::J \J

.., OJ C1l

::J () ::T

'


II

...

Ql

Ctl

::::>

o or '
,

.s:: u c

~ ro a.. c

ro ~

OJ

ro o

·C

C Q)

ro~

c. :J

(fJ

C

~ '"

OJ

"0 C

':J" -"en

DIFFERENTIAL DIAGNOSIS Common • Creutzfeldt-]akob Disease (C]D) • Creutzfeldt-]akob Disease, Variant (vC]D) Less Common • Fabry Disease • Thalamic Infarct (Mimic) • Neoplasms (Mimic) • ADEM (Mimic) Rare but Important • Periventricular Leukomalacia • Status Epilepticus

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • "Pulvinar sign": T2 hyperintensity in bilateral pulvinar, most sensitive for vC]D • T1 hyperintensity in pulvinar also called "pulvinar sign" (Fabry disease) Helpful Clues for Common Diagnoses • Creutzfeldt-]akob Disease (C]D) o Rapidly progressive, fatal neurodegenerative disease o Prion protein accumulates in neurons o 85% of cases sporadic; 15% genetic or familial o Infectious/iatrogenic cases, including vC]D, < 1% o , T2 in basal ganglia (BG), thalamus, cortex o FLAIR& DWI MR most sensitive

I 6 96

=-

=

Axial FU\/R MR shows abnormal hyperintensity involving the pulvinar medial thalami, putamen & caudate, characterisUc for C/D. Thalamic involvement is less commonly seen than in velD.

SIGN" • Creutzfeldt-]akob Disease, Variant (vC]D) o Bilateral T2 pulvinar hyperintensity o ± , T2 dorsomedial thalami, periaqueductal gray, caudate nuclei Helpful Clues for Less Common Diagnoses • Fabry Disease o Multisystem X-linked disorder with renal & cardiac dysfunction and stroke o T1 hyperintensity in bilateral pulvinar o CT may show mineralization in pulvinar o May see ischemia, white matter (WM) lesions, & vertebrobasilar dolichoectasia • Thalamic Infarct (Mimic) o Artery of Percheron infarct & internal vein thrombosis: Bilateral T2 hyperintensity o HIE may affect only deep gray nuclei o DWI bright in acute setting • Neoplasms (Mimic) o Lymphoma or astrocytoma may cause bilateral thalamic T2 hyperintensity • ADEM (Mimic) o T2 hyperintensity in bilateral thalami o WM lesions typically also present Helpful Clues for Rare Diagnoses • Periventricular Leukomalacia o Pulvinar hyperintensity may be seen in association with PVL o Thalamic involvement suggests more severe motor & mental disabilities • Status Epilepticus o Peri-ictal T2 hyperintensity, DWI restriction in bilateral pulvinar, often with hippocampal & cortex involvement

=

Axial FU\/R MR shows bilateral hyperintensities in the posterior UJa/ami, "pulvinar sign" of vCID. FU\IR & OWl MR are most sensiUve for diagnosis. vCIO is primarily seen in the United Kingdom.

"PULVINAR

,..c:

SIGN"

CIl

III

='c. Creutzfeldt-jakob Disease, Variant (vCjD)

OJ .., III

(Left) Axial OWl MR shows

='

in

(JJ

the pulvinar bilaterally EE characteristic for velD. vClO is caused by ingestion of beef produc15 infected with

C

symmetric

bovine

OWl restriction

spongiform

encephalopathy. It is rare, making up < 1% of all Clo cases. (Right) Axial TI WI MR shows symmetric hyperintensity in the pulvinar the "pulvinar sign" of Fabry disease. Hyperintensity is also noted in the basal ganglia.

..,

"0 OJ

ro::0 8"

"'. OJ

=-

(Left) Axial FlAIR MR shows hyperinlensily in the medial thalami classic location

=-

for major penetrating

artery

of Percheron stroke. Some patients have a dominant large posterior perforating artery instead of multiple

smaller ones. When these arteries are occluded, devastating midbrain & thalamic

infarcts may occur.

OWl is positive in the acute selling. (Right) Axial T2WI MR shows asymmetric bithalamic hyperintensity

H2.

Astrocytoma

was found

at biopsy.

ADEM (Mimic)

Periventricular leukomalacia (Left) Axial FlAIR MR shows symmetric

hyperinlensity

in

the pulvinar 1:]. Note involvement of the occipital subcortical white matter E:I. ADEM involves the deep gray structures more often than other demyelinating processes. 1l is typically bilateral but asymmetric. (Right) Axial T2WI MR shows hyperintensity in the pulvinar I:] of the thalamus bilaterally in this patient with spastic quadriparesis & PVL. Note wavy ventricular margins, typical of PVL.

I 6 97

ro

TECTAl (QUADRIGEMINAL PLATE) lESION

E >,

.r: u c Q)

~ ro a.. c

~ III

ro

·C

o C Q)

ro~ Cl.

:J

CI) C

~

tn'"

"'C

c

':J" ""CI)

DIFFERENTIAL DIAGNOSIS Common • Diffuse Astrocytoma, Low Grade • Brainstem Glioma, Pediatric less Common • Lipoma • Neurofibromatosis Type 1 • Chiari 2 Rare but Important • Cavernous Malformation • Progressive Supranuclear Palsy

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Tectum is dorsal portion of midbrain, dorsal to cerebral aqueduct • Tectum includes superior & inferior colliculi & periaqueductal gray matter Helpful Clues for Common Diagnoses • Diffuse Astrocytoma, Low Grade o Nonenhancing T2 hyperintense mass o Supratentorial 2/3, infratentoriall/3 o 50% of "brainstem gliomas" are diffuse astrocytomas • Brainstem Glioma, Pediatric o Heterogeneous group of gliomas o Tectal glioma: Most indolent, often only need CSF diversion • Expands tectum & obstructs aqueduct • T2 hyperintense mass ± enhancement

Helpful Clues for less Common Diagnoses • Lipoma o Well-delineated lobulated extra-axial mass with fat attenuation/intensity o Interhemispheric fissure most common location (30-40%) o 20-25% pineal region (attached to tectum) • Neurofibromatosis Type 1 o Focal areas of signal intensity (FASI) in white matter & deep gray matter • Typically involve globus pallidus • May involve brainstem o Tectal gliomas are associated with Nfl • Chiari 2 o Complex malformation of hindbrain associated with neural tube closure defect, usually lumbar myelomeningocele o Small posterior fossa, "beaked" tectum o "Towering" cerebellum protrudes up through incisura, compresses tectum Helpful Clues for Rare Diagnoses • Cavernous Malformation o Heterogeneous "popcorn" mass with T2 hypointense rim (hemosiderin) o Brainstem lesions common when multiple • Progressive Supranuclear Palsy o Midbrain, superior colliculi, & superior cerebellar peduncle atrophy o T2 hyperintensity in periaqueductal gray o Midbrain atrophy described as "penguin" & "hummingbird" sign on sagittal MR o "Morning glory sign": Concave lateral tegmentum on axial images

I 6 98

Sagittal T2WI MR shows a hyperintense mass involving the tectal plate along the posterior 3rd ventricle ~ in this young adult. Sagittal imaging is helpful 10 define

lesions in this location.

Axial T2WI MR shows a hyperintense mass involving the tectal plate Lesions in this location often cause

obstruction shunting.

of

=_

the

cerebral aqueduct,

requiring

TECTAL (QUADRIGEMINAL

PLATE) LESION Ql

::::l Co

...

OJ Ql

(Left) Sagittal TI WI MR shows a homogeneous mass arising from the superior colliculus a tectal glioma. Tectal gliomas are the most benign of the brainstem gliomas. They often have an indolent course & usually only require CSF diversion. They are most often pilocytic astrocytomas. (Right) Sagittal T1WI MR shows a hyperintense mass along the inferior collicu/us typical location for a collicular lipoma. Fat suppression confirms the diagnosis.

=-

=-

Neurofibromatosis

Type 1

::::l

en

c u

..•tlJ CO ::J

o::l. tlJ

..•tlJ

OJ ::::l \J

., tlJ CD

::::l

()

::T '
.r: () c

~ Ql

Cl.. C III

~

CO

III 'C

o C Ql CO ~ 0.

:J (/)

C III

"CO

" C

III

:J

-"

(/)

Common • Cerebral Ischemia-Infarction, Acute • Trauma (Diffuse Axonal Injury, Contusion) • Demyelinating Disease (MS, ADEM) • Metastasis • Cavernous Malformation • Enlarged Perivascular Spaces • Wallerian Degeneration less Common • Aqueductal Stenosis • Brainstem Tumor o Tectal Glioma o Low Grade Neoplasm • JPA, Diffuse Fibrillary Astrocytoma o High Grade Neoplasm • Anaplastic Astrocytoma, GBM, PNET • Wernicke Encephalopathy • Mitochondrial Cytopathy Rare but Important • Infection o Progressive Multifocal Leukoencephalopathy (PML) o Abscess, Encephalitis • Vasculitis • Intracranial Hypotension • Progressive Supranuclear Palsy (PSP) • Parkinson Disease • Amyotrophic Lateral Sclerosis (ALS) • Drug Toxicity

•

•

•

•

•

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Most common midbrain lesions are ischemic, traumatic, demyelinating, vascular, or neoplastic • Hemorrhage usually due to trauma, vascular malformation, or hemorrhagic metastasis; hypertensive hemorrhage rare in midbrain

I 6 100

Helpful Clues for Common Diagnoses • Cerebral Ischemia-Infarction, Acute o Acute onset of clinical symptoms, often hemiparesis (corticospinal tracts), cranial neuropathy (nuclei of III, IV; a nucleus of V), &/or ataxia (red nucleus) o Presence of reduced diffusion: High SI on DWI, low SI on ADC map

Often accompanied by lesion of basilar artery, so consider MRA or CTA Trauma (Diffuse Axonal Injury, Contusion) o Appropriate clinical history; FLAIR,DWI particularly helpful to assess for edema (cytotoxic &/or vasogenic); GRE to assess for hemorrhage o Brainstem DAI typically dorsolateral, usually seen with hemispheric & callosal involvement; check for additional sites of injury Demyelinating Disease (MS, ADEM) o T2 bright lesions typically without reduced diffusion or GRE abnormality, often enhance post-gadolinium o Assess rest of brain for additional white matter (WM) lesions o Consider MR of optic nerves, spinal cord Metastasis o Typically enhance, associated with vasogenic edema; additional lesions often present in brain, meninges, or bone o May be hemorrhagic Cavernous Malformation o Often bright on T1 & T2WI; "mulberry-like" morphology; >SI on GRE o Associated developmental venous anomaly (DVA)may be present Enlarged Perivascular Spaces o Usually seen at base of cerebral peduncles o Follow CSF on all MR seq uences Wallerian Degeneration o Acute: Variable> diffusion and t SI on T2 o Chronic: Volume loss; variable T2 SI o

DIFFERENTIAL DIAGNOSIS

III

Helpful Clues for less Common Diagnoses • AqueductaI Stenosis o Cause of "congenital" hydrocephalus: May be due to a web or adhesion; often post-infJammatory or post-intraventricular hemorrhage o Assess tectum carefully on axial T2 & FLAIRto exclude subtle nonenhancing tectal glioma • Brainstem Tumor o Multiple histologies can affect midbrain & other parts of brainstem o Imaging varies with tumor histology o "Tectal gliomas": Typically confined to tectum, nonenhancing, present with chronic hydrocephalus

MIDBRAIN

en ,..

LESION

c:

• Generally better prognosis then other brainstem tumors; associated with NFl • Wernicke Encephalopathy o Thiamine deficiency; most commonly seen in alcoholics; also malnutrition, malabsorption, HIV/AIDS o Classic clinical triad: Ataxia, encephalopathy, oculomotor dysfunction o Symmetrical t T2 SI variably involves periaqueductal gray matter, dorsomedial thalami, mamillary bodies o • Diffusion, post-gad enhancement variably present acutely • Mitochondrial Cytopathy o Typically affects deep gray nuclei of cerebrum &/or gray matter structures of brainstem in symmetrical fashion o • Diffusion, t T2 SI typically present with acute flare of disease o t Lactate peak may be seen with MR spectroscopy Helpful Clues for Rare Diagnoses • Infection o Progressive multifocal leukoencephalopathy (PML) • Usually severely immunocompromised patients (AIDS, organ transplant, chemotherapy) • Classic: WM lesions without enhancement or mass effect • May cause pattern of "small dots" in WM or brainstem that eventually coalesce into more typical geographic lesions

Cerebral Ischemia-I nfarction,

Acute

Pyogenic abscess: Central. diffusion; also ring enhancement, vasogenic edema Vasculitis o Nonspecific t SI on T2WI; often I diffusion Intracranial Hypotension o Downward displacement of midbrain, loss of cisterns; "folding" if severe Progressive Supranuclear Palsy (PSP) o Atypical Parkinsonian syndrome: Supranuclear ophthalmoplegia, pseudobulbar palsy, dysarthria, postural instability, frontotemporal dementia o Neuropathological hallmark: Midbrain atrophy; tau + aggregates o MR: Midbrain atrophy; variable midbrain T2 hyperintensity Parkinson Disease a Imaging findings typically subtle; possible • volume of substantia nigra, • hypointensity of lateral margin of substantia nigra Amyotropic Lateral Sclerosis (ALS) o Degenerative disease of upper and lower motor neurons in the motor cortex, brainstem, and spinal cord o Imaging hallmark: t T2 SI of corticospinal tracts; no mass effect, enhancement Drug Toxicity o Notably metronidazole; symmetrical t T2 SI, variable. diffusion o Dentate nuclei usually involved o

• •

•

•

•

•

Trauma (Diffuse Axonal Injury, Contusion)

I Axial OWl MR in a 71 year old shows high signal intensity representing reduced diffusion in the midbrain 1GB This lesion sharply respects midline An AOC map confirmed lrue reduced diffusion.

Axial NEG shows a shear hemorrhage I:!lI in the right dorsolateral midbrain. This paUent with severe head trauma has evidence of scalp injury 8J and post-traumatic SAIl ffi among other injuries.

6 101

MIDBRAIN lESION

. .-

. thalamus> pons Helpful Clues for Less Common Diagnoses • Intracranial Hypotension o Downward displacement of brain through incisura ("slumping" midbrain) • "Fat pons" can mimic neoplasm! o ± Dural enhancement, SDH

Brainstem

Glioma

• Osmotic Demyelination Syndrome o Typically involves central pons 01'2 hyperintense, ± enhancement, DWI • Cerebral Ischemia-Infarction, Acute o "Top of the basilar": Midbrain & thalamic infarcts ± temporal & occipital lobes o May have midbrain, pons, or medulla ischemia related to vertebrobasilar perforator or cerebellar artery disease 01'2 hyperintense edema, DWI bright • Demyelination o Includes multiple sclerosis & ADEM o Brainstem enlargement with acute lesions o Focal 1'2 hyperintensity ± enhancement • Encephalitis 01'2 hyperintensity & enhancement typical o Etiologies include Listeria monocytogenes, enterovirus, West Nile virus, herpes, EBV, adenovirus, Japanese encephalitis • Cavernous Malformation o Heterogeneously bright on 1'1 & 1'2 o Hemosiderin rim classic Helpful Clues for Rare Diagnoses • Metastases, Parenchymal o Enhancing mass with edema o Multiple lesions common • Syringobulbia o Extension of cervical syrinx into brainstem • Hypertrophic Olivary Degeneration o Unilateral or bilateral 1'2 hyperintensity & enlargement of medullary olives • Hemangioblastoma o Nodular enhancement ± cyst

Hypertensive

Intracranial

Hemorrhage

I 7 2

Axial T2WI FS MR shows expansion and hyperintensity of the pons by a diffusely infiltraUng glioma. Note that the pons engulfs the basilar artery 1:;'.1 typical of these

tumors.

Axial NEeT the pons

shows a hypertensive hemorrhage within Note that ale blood has dissected into the

=.=.

4th ventricle Extension of blood into the venlJicular system is common.

LARGE BRAINSTEM

en

c" : III

:l

Co OJ

Intracranial Hypotension

..•

Osmotic Demyelination Syndrome

III

(Lefl) Sagillal T7 c+ MR shows classic intracranial hypotension with a "slumping midbrain" ffi dural engorgement, & downward tonsillar displacement. Signal in the brainstem is normal, which helps differentiate this from other etiologies. (RighI) Axial T2WI MR shows high signal in the centra! pons with peripheral sparing. Preservation

Cerebral

Ischemia-Infarction,

Acute

..•tll CO ::J

o::!. tll

OJ

iil ::J \J

..• tll C1l

::J ()

'
-

£

(.)

C

~ Q)

ro

0..

c

ro ~

co

ro 'C

o C Q)

-

ro~ c C III

~ IJJ "C

c

III

Common • Lateral Medullary Infarct • Wallerian Degeneration • Demyelinating Lesion (MS, ADEM) • Vascular Lesion o Cavernous Malformation; AVM • Brainstem Glioma, Pediatric o Diffuse Fibrillary Astrocytoma o Exophytic Cervicomedullary Glioma Less Common • Brainstem Neoplasm, Adult o Glioma, High or Low Grade o Hemangioblastoma o Metastasis, Lymphoma • Vasculitis • Medial Medullary Infarct • Infection (Abscess, Tuberculoma, • Syringobulbia

Rare but Important • Hypertrophic Olivary Degeneration • Infiltrative Disorders (Langerhans Cell Histiocytosis, Neurosarcoid) • Mitochondrial Disorder • Viral Encephalitis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Acute onset of cranial nerve deficits and Horner syndrome in an older patient suggests medullary infarction o CT suboptimal for evaluation of medulla; MR with diffusion is indicated o Posterior circulation should be assessed intra- & extracranially with CTA or MRA o Vertebral artery dissection a consideration in younger patient; add Ax Tl with fat-sat • Reduced diffusion in focal medullary lesion usually due to acute medullary infarction • Volume loss of medullary pyramides) usually due to wallerian degeneration o Look for remote infarct • Expanded medulla? Neoplasm> infarction, demyelination, infection

I 7 10

•

•

PML)

Helpful Clues for Common Diagnoses • Lateral Medullary Infarct o Reduced diffusion; often subtle T2 abnormality in acute phase

Typically dorsolateral, due to occlusion of vertebral artery or PICA; check CTA or MRA o Wallenberg syndrome: Deficits in pain/temperature sense, dysphagia, hoarseness, vertigo, diplopia, Horner syndrome Wallerian Degeneration o Acute wallerian degeneration may lead to medullary pyramid T2 hyperintensity, mildly reduced diffusion o Chronic infarction along corticospinal tract leads to volume loss of medullary pyramid; variable T2 signal Demyelinating Lesion (MS, ADEM) o Usually associated with WM lesions in other parts of brain, may enhance, diffusion typically not reduced Vascular Lesion o Cavernous malformation may be associated with developmental venous anomaly; GRE hypointense o CTA or MRA may help to evaluate for high flow vascular malformation Brainstem Glioma, Pediatric o Diffuse infiltrative astrocytoma: Medullary expansion, t T2 SI, usually nonenhancing o Pediatric astrocytoma may also be exophytic from cervicomedullary junction • Dorsal or ventral; often enhancing o

DIFFERENTIAL DIAGNOSIS

•

•

Helpful Clues for Less Common Diagnoses • Brainstem Neoplasm, Adult o Medullary expansion, areas of irregular enhancement likely high grade glioma o Hemangioblastoma presents as nodular enhancement ± cyst • Usually in setting of VHL; look for other lesions in cerebellum, spinal cord o Focal enhancing lesion + associated edema: Consider metastasis, lymphoma • Vasculitis o Multifocal T2 lesions, variable ~ DWl o CTA or MRA may show vascular irregularity, but catheter angiography generally indicated o Often associated with systemic symptoms, abnormal CSF • Medial Medullary Infarct o Less common vertebrobasilar stroke syndrome

MEDULLA lESION

Classic Ipsilateral hypoglossal palsy, contralateral hem iparesis, contralateral lemniscal sensory loss • Infection (Abscess, Tuberculoma, PML) o Medullary pyogenic abscess rare; reduced diffusion, peripheral enhancement o Tuberculoma: Ring or nodular enhancement, central T2 hypointensity, diffusion variable o PML: Multifocal T2 abnormality, no mass effect, immunocompromised patient • Syringobulbia o Cervical syrinx may extend cephalad into medulla o Assess for Chiari 1 malformation, spinal cord tumor, other obstruction to CSF flow o

Helpful Clues for Rare Diagnoses • Hypertrophic Olivary Degeneration o Insult to dentato-rubro-olivary pathway o Classic symptom: Palatal tremor o Uni- or bilateral enlargement, T2 hyperintensity of inferior olivary nucleus o No reduced diffusion, no post-gad enhancement o Chronic phase: Possible volume loss • Infiltrative Disorders (Langerhans Cell Histiocytosis, Neurosarcoid) o T2 abnormality, irregular linear and nodular enhancement o Diffusion typically not reduced, vascular imaging studies normal • Mitochondrial Disorder o Symmetrical t T2 51, often ! diffusion

lateral

Medullary

May mimic medullary encephalitis, or vice versa • Viral Encephalitis o Typically symmetrical, nonspecific t 51on T2WI; variably! diffusion o Specific diagnosis usually made with CSF analysis o

Other Essential Information • MR is always the imaging study of choice for medullary pathology

=

Axial OWl MR shows high signal intensity consistent with reduced diffusion in the left lateral medulla of a young man with acute onset of dysphagia and lefl vocal cord paralysis.

:J

a.

..•III

OJ :J

-

:J

...

OJ

ro:J

o..• Qj. ...OJ

OJ

:J -U

Alternative Differential Approaches • Medullary lesion with reduced diffusion o Typically medullary infarct; assess vertebrobasilar circulation o Occasionally seen with demyelination: Look elsewhere for typical lesions o May occur with mitochondrial disease or brainstem encephalitis (more diffuse, symmetrical) • Medullary lesion with GRE hypointensity o Typically cavernous malformation; give gadolinium to look for DVA o Other possibilities: Hemorrhage due to AVM,neoplasm, infection, prior trauma • Medullary lesion with gadolinium enhancement o Neoplasm, infection, demyelination • Medullary expansion o Usually seen with diffuse infiltrative astrocytoma in a child or young adult

lateral

Infarct

III

Medullary

...ro OJ

:J

()

::r

'
.c o c > enlarged perivascular spaces)

I 7 14

o

Helpful Clues for Common Diagnoses • Mega Cisterna Magna o Enlarged posterior fossa CSF space o Normal vermis completely covers 4th ventricle (rules out Dandy-Walker malforma tion/varian t) o May show striking scalloping of skull (due to CSF pulsations) • Arachnoid Cyst o Sharply demarcated extra-axial cyst o Follows CSF attenuation/signal

o

Suppresses on FLAIR,no DWI restriction Size varies from few millimeters to giant Often asymptomatic, found incidentally

Helpful Clues for Less Common Diagnoses • Neurocysticercosis o Best clue: Cyst with "dot" inside • ± Discrete eccentric scolex • Cyst slightly hyperintense to CSF o Cisterns> 4th ventricle • Dandy-Walker Continuum o DWC: Broad spectrum of cystic posterior fossa malformations o DW malformation: Large posterior fossa + large CSF cyst, normal 4th ventricle absent, lambdoid-torcular inversion o DW variant: Failure of "closure" of 4th ventricle, vermian hypoplasia o Includes persistent Blake pouch cyst, mega cisterna magna 02/3 have associated CNS &/or extracranial anomalies • Obstructive Hydrocephalus ("Trapped" or "Encysted" 4th Ventricle) o Due to obstructing lesions of 4th ventricle; all foramina must be involved (Magendie, Luschka, aqueduct) o May be from hemorrhage, infectious, inflammatory, or neoplastic causes o Ventricle enlarged but maintains basic shape o CSF intensity/attenuation • Pilocytic Astrocytoma o Cystic cerebellar mass with enhancing mural nodule o Cerebellum> vermis, 4th ventricle o Child> adult • Hemangioblastoma o Best diagnostic clue: Adult with intra-axial posterior fossa mass with cyst, enhancing mural nodule abutting pia o Size varies from tiny to several centimeters o 1-2% of primary intracranial tumors, 7-10% of posterior fossa tumors o May be associated with von Hippel-Lindau syndrome • Epidermoid Cyst o Congenital inclusion cyst o Lobulated, irregular, insinuating CSF-like mass with "fronds" o CerebeUopontine angle cistern> 4th ventricle

INFRATENTORIAl FLAIR usually doesn't completely null; restricts on DWI • Dermoid Cyst o Congenital inclusion cyst o Looks like fat • Use fat-suppression sequence to confirm • ± Rupture (fat droplets in cisterns, sulci, ventricles) • May cause chemical meningitis, extensive enhancement • Enlarged Perivascular Spaces o Pial-lined interstitial fluid-filled structures that accompany penetrating arteries but do not communicate directly with subarachnoid space o Cluster of variably sized intra-axial cysts o Off-midline (dentate nuclei) > midline (vermis, pons) o Follow CSF • Suppress completely on FLAIR • No restriction on DWI • No enhancement o "Leave me alone" lesion that should not be mistaken for serious disease o

Helpful Clues for Rare Diagnoses • Congenital Vermian Hypoplasia o Prototype = Joubert syndrome o Inherited hypoplasia or aplasia of vermis characterized by transient episodic hyperpnea, oculomotor abnormalities, ataxia, variable mental retardation

Mega Cisterna

MIDLINE

CYST

"Molar tooth" brainstem; "bat wing" or "umbrella" shaped 4th ventricle; vermian remnant variable size o Midline anomalies common (holoprosencephaly, frontonasal dysplasia, facial clefting) • Ganglioglioma o Best diagnostic clue: Partially cystic, enhancing, cortically based mass in child/young adult o Cortical dysplasia commonly associated o Excellent prognosis if surgical resection complete o Malignant degeneration rare, approximately 5-10% (glial component) • Pleomorphic Xanthoastrocytoma o Supratentorial cortical mass with adjacent enhancing dural tail o Cyst and enhancing mural nodule typical o 98% supratentorial, rarely found in cerebellum o Despite circumscribed appearance, tumor often infiltrates • Neurenteric Cyst o Benign malformative endodermal C S cyst o Round/lobulated nonenhancing mass o Anterior to pontomedullary junction, slightly off-midline o Slightly/moderately hyperintense compared to CSF o

Arachnoid

Magna

III

:l

a.

..,

OJ III

:l

OJ

m

::J "U

.., Ql

ct> ::J

()

::T

'< 3 Ql

Cyst

I Sagittal TI WI MR in the midline shows a very large CSF·imensity space behind an intact vermis a=. Note the thinned inner table of the occipital bone 81.

Coronal TlWI MR demonstrates a sharply demarcated cyst in the midline posterior fossa just behind the vermis =:l. Contents followed CSF signal intensity on all

sequences.

7 15

INFRATENTORIAl

III

E

MIDLINE CYST

>. .J:: u C

~ Q)

III

0..

c

~ III

IJ) III

·C

o C Q)

ro~ "-c:

Neurocysticercosis

Dandy-Walker

Continuum

(Left) Coronal T7 C+ MR shows a nonenhancing cyst with a nodule inside the 4th ventricle Itl. The protoscofex is the viable larva within the smooth thin-walled cyst SI. NOle

associated mild

obstructive hydrocephalus with transependymal CSF flow!:iJ. (Right) Sagillal T2WI MR demonstrates a markedly enlarged posterior fossa with cephalad rotation of superior vermian remnant ~ and a thinned inner table of the occipital

calvarium

~

Obstructive Hydrocephalus ("Trapped" or "Encysted" 4th Ventricle) (Left) Axial NECT shows a CSF-filfed mass in the posterior fossa midline, in the expected location o( the 4th ventricle m. This is the typical imaging appearance of a "trapped" fourth ventricle. Also note encephalomalacia in the le(t temporal lobe SI. (Right) Sagittal T2WI MR demonstrates a cystic mass ~ that expands the vermis Note compression,

=.

anterior

displacement

of 4th

ventricfe ~.

Hemangioblastoma (Left) Sagillal T7 C+ MR shows a cystic-appearing midline mass II] with enhancing mural nodule B of hemangioblastoma. (Right) Axial T2WI MR demonstrates a typical MR appearance of a large epidermoid cyst as a mildly lobulated lesion that expands the 4th ventricle,

=

which

is nearly isoinlense

CSF but shows mild heterogeneity.

I 7 16

to

Epidermoid

Cyst

INFRATENTORIAl

MIDLINE

CYST

CIl

" c:

Dermoid

Cyst

Enlarged Perivascular Spaces (Left) Axial NECT shows a midline, fat-density,

extra-axial mass

= that

extends into the middle cranial fossa ~. Low density foci are scattered in the subarachnoid spaces, indicative of rupture~. (Right) Coronal T2WI MR shows enlarged perivascular spaces in left dentate nucfeus with extension toward midline~.

=

-. :J

OJ

ro :J

8" ~

'OJ" ~ '" :J

\J OJ

~ CD :J

()

::r

'< 3

'"

Congenital

Vermian

Hypoplasia (Left) Axial TI WI MR reveals of a large posterior fossa midline CST space a tiny vermian remnant and the typical" molar tooth" appearance of the brainstem 1::1. (Right) Coronal T1 C+ MR at 0.6 T reveals a cystic-appearing lesion of the cerebellum 1::1 demonstrating thick ring-like enhancement and ventricular enlargement from obstructive hydrocephalus

=-

a portion

a.

81.

Neurenteric

Cyst

Neurenteric

Cyst (Left) Sagittal T2WI MR shows hyperintense extra-axial ovoid mass 1m anterior

to

ponlomesencephalic junction. (Right) Sagittal T 1 C+ MR shows a large well-delineated extra-axial mass elevating and displacing the pons and medulla.

=

I 7 17

ro

CEREBEllAR ATROPHY

E

>-

.r:. u

c Q) L

ro CL

c ro L

(D

ro

·C

o C Q)

ro

.•... L

C

c III L

aI "C

c III

DIFFERENTIAL DIAGNOSIS Common • Aging Brain, Normal • Encephalomalacia, NOS • Progressive on-Familial Adult Onset Cerebellar Degeneration o Chronic Vertebrobasilar Insufficiency o Alcoholic Encephalopathy o Phenytoin (Dilantin) Use, Chronic o Paraneoplastic Syndromes o Lithium Intoxication o Radiation and Chemotherapy o Hypothyroidism less Common • Cerebellitis, NOS Rare but Important • Multiple System Atrophy • Ataxia, Hereditary, NOS • Ataxia Telangiectasia • Cerebellar Atrophy, Hereditary, OS • Congenital Vermian Hypoplasia (Mimic)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Clinical history often more important in making diagnosis than imaging findings

I 7 18

Helpful Clues for Common Diagnoses • Aging Brain, Normal o ~ Brain volume (including cerebellum) with t age • Relative t CSF spaces • Selective atrophy of WM (not gray matter) predominates o "Successfully aging brain": Thin periventricular high signal rim without white matter hyperintensities o May find focal/confluent periventricular white matter hyperintensities • Encephalomalacia, NOS o All etiologies appear as CSF replacing destroyed parenchyma due to • Post-ischemic loss of tissue following parenchymal hypoxic cell death • Post-traumatic loss from parenchymal irreversible traumatic insult • Post-inflammatory loss by irreversibly injured tissue

• Progressive Non-Familial Adult Onset Cerebellar Degeneration o Chronic Vertebrobasilar Insufficiency • Vertebral artery stenosis, posterior circulation ischem ia • Posterior circulation ischemia of hemodynamic or embolic etiology • Atrophy w/sulcal enlargement; DWI dark o Alcoholic Encephalopathy • Primary (direct) effects of EtOH = neurotoxicity - cortical/cerebellar degeneration & atrophy • Best clue: Disproportionate superior vermian atrophy • F-18 FDG PET:Significant decrease in whole-brain metabolism o Phenytoin (Dilantin) Use, Chronic • Dilantin vs. seizures as cause of atrophy debated • Dilantin induces organic cerebellar damage & may interfere w/intestinal absorption of folate causing folate deficiency - cerebellar atrophy • Seizures can cause cerebellar atrophy as cerebellum is very sensitive to hypoxia cerebellar atrophy • Normal orientation & anisotropy of middle cerebellar peduncle & transverse pontine fibers o Paraneoplastic Syndromes • Remote neurological effect(s) of cancer, associated with extra-CNS tumors • Most common tumor: Small cell lung carcinoma • Manifestation of paraneoplastic encephalomyelitis associated w/cerebellar degeneration o Lithium Intoxication • Lithium is a neurotoxin with a particular affinity for the cerebellum • Atrophy of internal granule and Purkinje cell layers with dentate gliosis neuronal loss and spongiosis • Preceded by neuroleptic malignant syndrome o Radiation and Chemotherapy • Injury may be divided into acute, early delayed injury, late delayed injury • Diffuse white matter injury or necrosis • Radiation - induces cryptic vascular malformations; blood products

CEREBElLAR ATROPHY o

Hypothyroidism • Best diagnostic clue: Symmetrical pituitary enlargement reversible with thyroid hormone replacement therapy • May see generalized atrophy; alternatively focal cerebellar vermis or olivo pontocerebellar atrophy • • Cerebral perfusion & metabolism

Helpful Clues for Less Common Diagnoses • Cerebellitis, NOS o Rare inflammatory syndrome typically occurring as primary infectious, post-infectious, post-vaccination, or idiopathic disorder o Bilateral diffuse hemispheric abnormalities are most common (73%) o Often results in moderate to severe atrophy Helpful Clues for Rare Diagnoses • Multiple System Atrophy o Sporadic progressive neurodegenerative disorder of adult onset, unknown etiology o "Hot cross bun" sign: Cruciform pontine hyperintensity on T2WI o Impaired orientation/anisotropy of middle peduncle transverse pontine fibers • Ataxia, Hereditary, NOS o Example: Friedreich ataxia - cerebellar, spinal atrophy o Can be divided into autosomal dominant, autosomal recessive, X-linked, mitochondrial

Some etiologies (e.g., cerebrotendinous xanthomatosis) may have diffuse white matter T2 hyperintense lesions • Ataxia Telangiectasia o Progressive neurodegenerative disorder; onset in early childhood; 1 in 40,000 o Multisystem disease - cerebellar ataxia, oculomucocutaneous telangiectasias, & susceptibility to certain infections and neoplastic processes o Purkinje cell loss, atrophy of dentate nuclei, diffuse spongy degeneration, multiple foci of coagulative necrosis w/calcification in white matter • Cerebellar Atrophy, Hereditary, NOS o Middle-aged patients; severe superior vermian atrophy o Lesser involvement of cerebellar cortex o Severity of cerebellar atrophy correlates well with degree of ataxia • Congenital Vermian Hypoplasia (Mimic) o Prototype = Joubert syndrome o Inherited hypoplasia or aplasia of vermis characterized by transient episodic hyperpnea, oculomotor abnormalities, ataxia, variable mental retardation o "Molar tooth" brainstem; "bat wing" or "umbrella" shaped 4th ventricle; vermian remnant variable size o

Encephalomalacia,

Axial T2WI MR 3T MR obtained at age 76 if/ustrates generalized alfophy changes of prominent folial =:I and subarachnoid spaces 81. Also note slfiking ectasia of the basilar artery~

III

~

Co

..,III OJ

~

NOS

Axial NEeT demonslfates a typical case of right cerebellar chronic cerebral infarction as focal low

attenuation in the right PICA vascular distribution

=.

I 7 19

ro

CEREBELLAR

E

ATROPHY

>.r: u

c

~ Q)

ro

IL

c

ro ~

ro .~ .2 c Q)

-

ro~ C

Encephalomalacia,

NOS

(Lefl) Axial T1 WI MR reveals focal left cerebellar atrophy as a residua of closed head injury. (RighI) Sagittal T1 WI MR shows the classic finding of significant cerebellar atrophy with supratentorial parenchyma that appear normal.

=

=

::::l

-"1Il

Phenytoin (Dilantin) (Lefl) Coronal T2WI MR demonstrates

significant

Use, Chronic

=

diffuse cerebellar atrophy in this 4 I year old man with chronic Oilantin use. (RighI) Axial FlAIR MR demonstrates bilateral hyperintensities of

=

paraneoplaslic

cerebellili5,

which will likely result in cerebellar degeneration.

Radiation and Chemotherapy (Left) Axial FlAIR MR shows T2 hyperintense

toxic

=

in a 46 year old woman undergoing chemotherapy for breast cancer, which will likely result in atrophy. (RighI) Axial FlAIR MR shows T2 confluent hyperintensity of leukoencephalopathy of cerebellar peduncles & temporal lobes E!i:I in a hypothyroid patient with Hashimoto encephalopathy. demyelination

=

I 7 20

Paraneoplastic

Syndromes

CEREBELLAR ATROPHY

(/)

" c Dl

:J C-

OO .,

Cerebellitis, NOS

Dl

(Left) Axial GCT demonstrates a typical CT case with enhancement of cerebella, hemispheres bilaterally =:I. (Right) Sagittal TI WI MR of spontaneous olivopontocerebellar atrophy shows striking atrophy of the pons =:I,medulla 8l and cerebellar vermis Note the normal appearance of cerebral hemispheres .

=.

:J ::J ...•• OJ CD ::J

0::::!. III

OJ ., III

::J 'U III

.,

CD

::J n

::T

'< 3 III

(Left) Sagittal T7 WI MR of hereditary olivopontocerebellar atrophy reveals striking vermian atrophy =:I as well as severe pontine atrophy with flattening 81. (Right) Axial T2WI MR reveals severe diffuse atrophy and gliosis =:I of cerebellar hemispheres in a patient with spinocerebellar ataxia.

(Left) Axial T7 WI MR demonstrates diffuse cerebellar =:I atrophy. Not shown are the normal cerebral hemispheres. (Right) Axial T2WI MR reveals hypoplasia of the

vermis, which could be mistaken for cerebellar atrophy =:I. Note the typical "molar tooth" shape g>J of the mesencephalon.

I 7 21

CEREBELLAR

CIl

E

MASS

>.J:: U C Q)

~

DIFFERENTIAL DIAGNOSIS

CIl (L

C

CIl

~

IJ) CIl

'C

.9 c Q)

co~ .•... C

C

Common • Cerebral Ischemia-Infarction, Acute • Hypertensive Intracranial Hemorrhage • Neoplasms o Medulloblastoma (P ET-MB) o Pilocytic Astrocytoma o Hemangioblastoma o Metastases, Parenchymal

III

~

a:l

"0

c III

Less Common • Enlarged Perivascular Spaces • "Tumefactive" Demyelinating Disease o Multiple Sclerosis o ADEM • Abscess • Cerebellitis, NOS • Vascular Malformation, with/without Hemorrhage o Cavernous Malformation o Arteriovenous Malformation o Dural A-V Fistula Rare but Important • Tuberculosis • Glioblastoma Multiforme • Dysplastic Cerebellar Gangliocytoma • Oligodendroglioma • Ganglioglioma • Remote Cerebellar Hemorrhage

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Child vs. adult o Child: Neoplasm> infection, demyelinating disease o Adult: Ischemia, hypertensive hemorrhage > neoplasm

I 7 22

Helpful Clues for Common Diagnoses • Cerebral Ischemia-Infarction, Acute o PICA distribution most common • DWI restriction w/correlating ADC map • Early cortical swelling • "Hemorrhagic transformation" in 15-45% • Hypertensive Intracranial Hemorrhage o Round/elliptical high density mass o 10% occur in pons, cerebellum • Medulloblastoma (PNET-MB) o 4th ventricle> cerebellum o Desmoplastic variant

• Pilocytic Astrocytoma o Best clue: Cystic mass + enhancing mural nodule o Childhood (not adult) tumor • Hemangioblastoma o Adult with intra-axial posterior fossa mass with cyst, enhancing mural nodule abutting pia o May be associated with von Hippel-Lindau syndrome • Metastases, Parenchymal o Intra-axial posterior fossa mass in middle-aged/older adult? Think metastasis! o Can be solitary but look for other lesions Helpful Clues for Less Common Diagnoses • Enlarged Perivascular Spaces o Fluid-filled spaces that look like CSF, surround/accompany penetrating arteries o No diffusion; may have FLAIR hyperintense parenchymal rim • Multiple Sclerosis o Fulminant acute plaque or conglomeration of acute plaques forming mass lesion(s) o May display ring enhancement simulating tumor or abscess o Most common disabling CNS disease of young adults; 1:1000 in developed countries • ADEM o Lesions 10-14 days following infection/vaccina tion o Large flocculent FLAIRhyperintensity but with less mass effect than that expected o Punctate, ring, incomplete ring, peripheral enhancement • Abscess o Especially in children o Ring-enhancing lesion • High signal on DWl, low ADC • T2 hypointense rim with surrounding edema o Central necrotic area may show presence of acetate, lactate, alanine, succinate, pyruvate, amino acids on MRS • Cere belli tis, NOS o Typically occurs as a primary infectious, post-infectious, post-vaccination, or idiopathic disorder o Variable enhancement - none to intense;

meningeal enhancement can be seen o

Abnormal T2 hyperintensity

&

swelling

CEREBEllAR

,.. en

MASS

C

Bilateral diffuse hemispheric abnormalities are most common (73%) • Cavernous Malformation o "Popcorn ball" appearance with complete hypointense hemosiderin rim on T2WI MR o ECT: 40-60% Ca++ • Arteriovenous Malformation o "Bag of black worms" (flow voids) on MR with minimal/no mass effect o Flow-related aneurysm on feeding artery 10-15%; intranidal "aneurysm" > 50% • Dural A-V Fistula o Best imaging tool: DSA with superselective catheterization of feeders o Dural AVFinvolving the region of the foramen magnum, tentorium, torcula Herophili, or posterior fossa veins (e.g., inferior vermian vein) may affect cerebellum o Most often presents with hemorrhage Helpful Clues for Rare Diagnoses • Tuberculosis o CECT: "Target sign" -+ central Ca++ or enhancement surrounded by enhancing rim o T1 C+: Solid homogeneous to rim enhancement; ± central necrosis o MRS: Prominent lipid, lactate but no amino acid resonances • Glioblastoma Multiforme o Thick irregular enhancing rind of neoplastic tissue surrounding necrotic core

Cerebral

Ischemia-Infarction,

Acute

Axial T2WI MR demons!rales a lypical case of PICA acute infarction as hyperintensity associated with swelling in lhe righl cerebellar hemisphere SI and laleral medulla =:I_

Characterized by necrosis and neovascularity o Viable tumor extends far beyond signal abnormali ties Dysplastic Cerebellar Gangliocytoma o Widened cerebellar folia with a striated appearance on MR o Thinning of skull may be apparent o a.k.a., Lhermitte-Duclos disease, associated with Cowden syndrome Oligodendroglioma o Partially Ca++ subcortical/cortical mass in middle-aged adult o Majority calcify -+ nodular or clumped Ca++ (70-90%) o May expand, remodel, erode calvarium Ganglioglioma o Partially cystic, enhancing, cortically based mass in child or young adult o Ca++ common -+ 35-50% o Cortical dysplasia is commonly associated Remote Cerebellar Hemorrhage o Occurs after supratentorial craniotomy o Superior cerebellar folia • Bilateral (33%) • Contralateral to side of surgery (29%) • Ipsilateral (22%); isolated vermian (9%) o

o

•

•

•

•

Hypertensive

Intracranial

Cii :J

0" ~ Qi-

ro ~

Q)

:J II

Q)

~ CD

:J ::T '< n

3 Q)

Hemorrhage

Axial NEeT shows a large high densily mass in !he lefl cerebellar hemisphere =:I wilh some adjacenl areas of s/ighdy lesser increased auenualion indica ling aclive

hemorrhage.

:J

Q)

=

I 7 23

ro

CEREBElLAR

E

MASS

>-

.r: u

c

~ (!)

ro

CL

c ro ~

co

ro o C

.;:: (!)

-

ro~ c

c

•... '"

CO

"tl C

'"

Medulloblastoma

(PNET-MB)

(Left) Axial T7 C+ MR shows a poorly defined mass with components in vermis, right cerebellar hemisphere with irregular pattern of enhancemenl Note temporal horn enlargement from obstructive hydrocephalus 81. (Right) Axial T7 C+ MR shows classic cystic cerebellar pilocylic astrocytoma with

=.

nonenhancing

rim

robustly enhancing mural nodule 81.

Hemangioblastoma

Metastases,

Parenchymal

(Left) Axial T7 C+ FS MR demonstrates a typical MR appearance of cerebellar hemangioblastoma with both an avidly enhancing solid nodule and cystic component 81. (Right) Axial T7 C+ MR demonstrates left cerebellar, temporal tip intensely enhancing masses T7 and T2 shortening (not shown) demonstrated hemorrhage. Pathology confirmed metastases from renal cell carcinoma.

=

=.

Metastases, Parenchymal (Left) Axial T7 C+ MR shows solitary metastasis with thin rim enhancement no

=.

edema.

Numerous

supralentoriallesions

were

also found (not shown). Resection revealed

adenocarcinoma metastases of unknown origin. (Right) Axial T7 C+ MR demonstrates a variably sized cluster of non enhancing CSF-like cysts in left dentate nucleus, cerebellum P.>J Note mild mass effect on 4th ventricle

I 7 24

Enlarged Perivascular Spaces

CEREBEllAR

,...

MASS

CJl

c:

III

::::l

a.

.. .-. .. .. ..

01 III

(Left) Axial T2WI MR shows variant case of MS with large demyelinating plaques in pons ~ and the right cerebellar hemisphere A mild mass effect is present. fRight) Axial FLAIR MR demonstrates hyperintense flocculent ADEM lesions of the cerebellum.

=.

=

::::l ::::l

III

CD ::::l 8"

Qi.

01 III

::::l

""1l III Ctl

::::l (") ::::l"

'
> CT

• Bilateral hemispheric involvement (75%) • T2 hyperintensity • Variable enhancement (none to intense) • Atypical Teratoid-Rhabdoid Tumor o Infant/young child o 50% infra tentorial o Off-midline> vermis o Mass often large, heterogeneous o Can mimic PNET-MB

Axial NECT shows a rounded hyperdense mass ~ within expanded 4th ventricfe 81, Note enlarged temporal horns indicative of obstructive hydrocephalus,

=

CIl

""c:

• Dermoid Cyst o Rare: < 0.5% of 1 intracranial tumors o Fat appearance: Use fat-suppressed sequence to confirm o With rupture find fat droplets in cisterns, sulci, ventricles w/extensive enhancement possible from chemical meningitis • Glioblastoma MuItiforme o Rapidly enlarging tumor with necrosis, neovascularity o Peak 45-70 years but may occur at any age o Cerebellum uncommon primary site o 95% have thick, irregular enhancing rind of neoplastic tissue surrounding necrotic core • Ganglioglioma o Well-differentiated, slowly growing neuroepithelial tumor composed of neoplastic ganglion cells & glial cells o Partially cystic, enhancing, cortically based mass in child or young adult o Hemispheres> > cerebellum o Ca++ common (35-50%) • Dysplastic Cerebellar Gangliocytoma o Also known as Lhermitte-Duclos disease o Thick cerebellar folia with "striated" appearance on MR o Mass effect may be striking o Associated with Cowden syndrome • Rhombencephalosynapsis (Mimic) o Single lobed cerebellum w/transverse folia o Dentate nuclei, superior cerebellar peduncles fused o Vermis absent 0

Sagiual T1 C+ MR shows a midline cystic mass ~ with solid enhancing nodule E2 in vermis. Note compression, anterior displacement of 4th ventricle

and tonsillar herniation

=

III

::l

Co

OJ .., III

::l

..•. ..,

:J

III

CD :J

8" .., iii' OJ .., III :J

-u III .., CD

:J

()

::r

'
,

.r:.

U

c

~ Q)

co

a.. c co ~

Metastasis

co

(Left) Sagiltal T1 C+ MR in an adult with headache, papilledema demonstrates

o

inferior

Q)

with strong but

OJ

'C

C

-ro

~

c

c ro ~

OJ "C

c ro

vermian

Hemangioblastoma

metastasis

heterogeneous enhancement

=.

Pathology confirmed adenocarcinoma of unknown primary. (Right) Sagittal T1 C+ MR in an adult with headache, papilledema demonstrates cystic mass involving vermis, with a strongly enhancing mural nodule SlI. Note compression, anterior displacement of 4th ventricle

!:J.

Dural A-V Fistula

Arteriovenous

Malformation

(Left) Sagiltal T2WI MR shows prominent flow voids within the posterior fossa m

that impact the inferior vermis as well as mulliple serpentine {Jow voids

adjacent to the cervical cord Also note extensive cord

=.

hyperintensity and mild fusiform cord expansion from C1 to C4 !:J. (Right) Axial CECT show an enlarged feeding artery in the CPA cistern

E'l a

round

=-

focus

of

acute hemorrhage and a large posterior draining vein

adjacent to the vermis !t].

Cavernous (Leh) Axial T2WI FS MR demonstrates a mixed signal intensity lesion or the vermis It] with a "popcorn"

appearance and classic peripheral hemosiderin staining. (Right) Axial CECT shows diffuse enhancement of the cerebellum ~ in a young patient with cerebellitis.

I 7 30

Malformation

Cerebellitis

en

VERMIS MASS

" c:

Dermoid Cyst (Left) Sagittal T1 C+ MR in lhis 2 year old shows a

heterogeneously enhancing

~ OJ

mass in the 4th ventricle

CD

Appearance

:J

mimics

medulloblaslOma. (Right) Axial NECT shows a bi/obed,

=

o ::::!. OJ

fat density, extra·axial mass

OJ

lhal involves bOlh lhe lefl middle cranial fossa & cerebellopontine angle. This

OJ

lesion extends into the ambient

quadrigeminal,

&

superior vermian cisterns. Low densily foci are scattered in the subarachnoid space, indicative of rupture ~.

Glioblastoma

:J

:J

II

OJ

~ C1l

:J n :,'
,

.r:

(J

c

Cl) C1l (L

~ c C1l

~

CD

C1l ·C

o

C Cl)

a

Common • Tonsillar Ectopia • Chiari 1 • Herniation Syndromes,

Intracranial

-

less Common • Intracranial Hypotension • Basilar Invagination (Mimic)

"C

Rare but Important • Brain Death

ro~ C

c ra In"-

• Sagittal phase contrast MR best Low torcular, effaced posterior fossa cisterns o Folia orientation runs more vertically o Look for syrinx, CVJ/skull base anomalies • Herniation Syndromes, Intracranial a Tonsils impacted inferiorly into FM a Posterior fossa CSF cisterns effaced a Clinically associated with decreased mental status or obtundation

DIFFERENTIAL DIAGNOSIS

c: ra

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Cerebellar tonsils may normally lie up to 5 mm below foramen magnum (FM) • Normal rounded tonsillar shape/configuration more important than precise measurement • Normal folia course horizontally, not vertically • Chiari 2 is not in differential diagnosis (herniated tissue is nodulus of vermis, not tonsils!) Helpful Clues for Common Diagnoses • Tonsillar Ectopia a Zero to 4.8 mm below foramen magnum a Avoid terms "Chiari A" or "Chiari 1/2" • Chiari 1 a Pointed "peg-like" cerebellar tonsils> 5 mm below foramen magnum o Absent CSF space/flow behind tonsil

Helpful Clues for less Common Diagnoses • Intracranial Hypotension a Can be spontaneous or acquired o "Slumping" midbrain, flattened pons, optic chiasm draped over dorsum sellae a Diffusely enhancing thickened dura ± SOH • Basilar Invagination (Mimic) a A mimic -+ tonsils are normal a Primary often associated with bony malformations such as occipitalization of the atlas or Klippel-Feil; often familial a Secondary from acquired bone diseases that cause "softening" & skull base flattening, such as osteogenesis imperfecta, osteomalacia, Paget Helpful Clues for Rare Diagnoses • Brain Death a Gyral swelling with complete central brain herniation -+ tonsils pushed downward a No intracranial vascular flow a Clinical diagnosis, legal criteria varies

Tonsillar Ectopia

I 7

Parasagiltal T2Wf MR demonslrales lOnsillar eclopia

measured at

4.7

mm.

Note

morphology and configura lion.

32

=

normal rounded

=

Sagiaal nWI MR shows poinled cerebellar tonsils protruding through foramen magnum, effacing normal poslerior CSF spaces ~ _ Note relroflexed dens.

Foreshortened clivus, norma/4th ventricle.

lOW CEREBEllAR TONSilS III

:l a.

..,

[D III

(Left) Sagittal CINE phase contrast MR demonstrates CSF flow as black on this diastolic image Lack of posterior CSF flow E!:J is

=.

confirmed,

secondary

to

tonsillar impaction. (Right) Sagittal T1WI MR shows tonsillar herniation ~ as a result of a large left posterior fossa mass (not seen).

Note

associated compression of the fourth ventricle E!:J and enlarged ventricles from obstructive hydrocephalus

=.

Intracranial Hypotension

:l

-

:l

OJ CD ::J

o.., 0;' CD

OJ ::J II III .., (1)

::J n ::r

'< 3

III

Basilar Invagination (Mimic) (Left) Sagittal T1 WI MR shows tonsillar descent obliteration of suprasellar cistern as well as a sagging and fat midbrain. (Right) Sagittal T1 WI MR

=-

a.

shows severe basilar invagination

secondary

to

osteogenesis imperfecta with the clivus and odontoid nearly at right angles to each other; margins of the foramen

magnum

=.

indicated

are

(Left) Sagittal T2WI MR shows extensive bony malformation aboullhe foramen

magnum

associated

with severe type 1 Klippel-Feil syndrome, which can mimic

=.

low cerebellar

tonsils (Right) Axial T2WI MR reveals tonsillar herniation with bilateral tonsils completely impacted into the foramen

=.

magnum

I 7 33

ro

E

"CYSTIC-APPEARING"

POSTERIOR

FOSSA lESION

>.r: u

c

~ Q)

ro

a.. c

ro ~

(]:J

ro o C

·C

2 ro ~

c

DIFFERENTIAL DIAGNOSIS Common • Mega Cisterna Magna • Arachnoid Cyst • Dandy-Walker Continuum • Pilocytic Astrocytoma • Encephaloceles • Obstructive Hydrocephalus less Common • Epidermoid Cyst • Dermoid Cyst • Neuroglial Cyst • Ependymal Cyst • Hemangioblastoma • Schwannoma (Cystic) • Abscess • Enlarged Perivascular Spaces Rare but Important • Syringobulbia • Neurenteric Cyst • Atypical Teratoid-Rhabdoid Tumor • Metastases, Intracranial, Other • Neurocysticercosis • Chordoma • Congenital Muscular Dystrophy

ESSENTIAL INFORMATION

I 7 34

Key Differential Diagnosis Issues • Cystic-appearing lesion exactly like CSF on all sequences? o Mega cisterna magna (MCM), arachnoid cyst (AC), Dandy-Walker Continuum (DW) o Trapped 4th ventricle, enlarged perivascular spaces (t PVSs), neuroglial or ependymal cyst • Cystic-appearing lesion not exactly like CSF? o Congenital inclusion cyst (dermoid, epidermoid, neurenteric cysts) o Infection such as abscess, neurocysticercosis (NCC) o eoplasm (pilocytic astrocytoma, hemangioblastoma, metastasis, chordoma) • Is cyst intra- or extra-axial? • Intra-axial o Trapped fourth ventricle (4th V), t PVSs o Neoplasm (e.g., pilocytic astrocytoma), infection (abscess, NCC) o Inclusion cyst in 4th V (epidermoid)

• Extra-axial o MCM, AC, DW, neurenteric cyst, NCC, neoplasm (schwannoma) • DWI, Tl C+ scans helpful additions Helpful Clues for Common Diagnoses • Mega Cisterna Magna o Communicates freely with all CSF spaces o Normal tegmento-vermian angle « 5-10°) • Arachnoid Cyst o Mass effect on vermis o ± Hydrocephalus o Use FLAIR,DWI to exclude epidermoid • Dandy-Walker Continuum o "Classic" Dandy-Walker malformation • Cystic dilatation 4th V ~ t posterior fossa (PF), torcular-lambdoid inversion • Hypoplastic vermis • Vermian remnant rotated anterosuperiorly over cyst o Blake pouch cyst (BPC) • Embryonic BPC doesn't regress • Enlarged PF, 4th V open inferiorly • Vermis anatomically complete • Pilocytic Astrocytoma o Cystic cerebellar mass o Enhancing mural nodule • Encephaloceles o Isolated encephalocele: Lacks Chiari 2 o Chiari 3 = Chiari 2 PLUS • Occipital or cervical encephalocele containing cerebellum o Syndromic occipital encephalocele • Klippel-Feil, Meckel-Gruber, etc. • Obstructive Hydrocephalus o Outlets obstructed4th ventricle t t o Maintains "kidney bean" configuration o 3rd V, shunted lateral ventricles small Helpful Clues for less Common Diagnoses • Epidermoid Cyst o Cerebellopontine angle> 4th V > diploic o Frond-like, cystic (CSF-like) o Doesn't suppress completely on FLAIR o Restricts on DWI • Dermoid Cyst o Midline "fatty" mass • "Droplets" in CSF if ruptured • Look for dermal sinus, midline vertebral/skull base anomalies • Neuroglial Cyst o

CSF-like parenchymal cyst

o

No enhancement,

DWI restriction

"CYSTIC-APPEARING"

POSTERIOR

,..

FOSSA LESION

CJl

l:

• Ependymal Cyst o CSF-like o Intra- > para ventricular • Hemangioblastoma o Posterior fossa mass with cyst, enhancing mural nodule that abuts pia o ± Arterial feeders, flow-voids o Look for markers of von Hippel-Lindau (VHL) • Visceral cysts, renal clear cell carcinoma o Adult> > older teen (unless VHL) • Check family history! • Schwannoma (Cystic) o Vestibular schwannoma (VS) looks like "ice cream on cone" o Cysts can be intratumoral or VS-associated (arachnoid) o Solid component enhances • Abscess o T2 hypointense rim with surrounding edema o Ring-enhancing o DWI hyperintense, ADC hypointense • Enlarged Perivascular Spaces o CSF-like, nonenhancing, non restricting o Most common PF site = dentate nuclei o Less common = cerebellum, pons Helpful Clues for Rare Diagnoses • Syringobulbia o May occur with either Chiari 1 or 2 o Cervicaljholocord syrinx common o May extend further into brain (syringocephaly)

• Neurenteric Cyst o Slightly hyperintense extra-axial cystic mass, nonenhancing o Anterior pontomedullary, CPA cisterns • Atypical Teratoid-Rhabdoid Tumor o 50% infratentorial (usually off-midline) o Intratumoral cysts, hemorrhage common o Gross macrocysts less common • Metastases, Intracranial, Other o Myriad of non enhancing interfoliate cysts • Low or high grade brain or spine primary • Also reported with breast primary o Choroid plexus papilloma cysts can be entirely extra-axial, nonenhancing • Neurocysticercosis o Cyst with "dot" (scolex) inside o Subarachnoid spaces, sulcal depths most common o Intraventricular cysts often isolated • 4th ventricle most common • Chordoma o High signal T2 o Moderate to marked enhancement unless necrotic, mucinous o High attenuation foci (CT) may be occult onMR • Congenital Muscular Dystrophy o Best diagnostic clues • Severely "floppy" infant • Z-shaped or cleft pons • Multiple small CSF-like cerebellar cysts (may be PVSsor trapped CSF from overmigration of neurons)

Arachnoid

D>

:J Co

..,

OJ D>

:J

:::J

.OJ.,

CO :::J ..,8"

Qi.

..,OJ

OJ :::J II

..,

OJ

(1)

:::J () ::T

'< 3 OJ

Cyst

I Sagittal T1WI MR shows a mega cisterna magna 81. The tentorium is normally located, and the posterior fossa is mildly prominent. There is no mass effect upon the vermis.

Sagittal T1WI MR shows a reuocerebellar arachnoid cyst. There is enlargement of the posterior fossa, elevation of the lent, and mild compression of Ule

7

vermis.

35

ro

"CYSTIC-APPEARING"

E

POSTERIOR FOSSA LESION

>-

.r:::: t.l

c

~ Q)

ro

ll.

c ro ~ III

ro o C Q)

'C

-

ro~ c

Dandy-Walker

Continuum

Dandy-Walker

Continuum

(Left) Sagittal T1 WI MR shows typical enlarged posterior rotation

fossa, upward of the small vermian

remnant,

elevation

tentorium,

of the

and mass effect

upon the brainslem

in

"classic" Dandy-Walker malformation. (Right) Sagillal T2WI MR shows enlargement

4th ventricle communicates enlarged

of the inferior

which with an

cisterna magna

in

this infant with a Blake pouch cyst.

(Left) Sagillal T1 C+ MR shows a large cystic neoplasm of the vermis. There is compression of the brainstem and 4th ventricle PJ::l by the rim-enhancing mass. Nodular thickening E!:I is present in the caudal aspect of this cerebellar "juvenile" pifocylic astrocytoma UPA). (Right) Axial T2WI MR shows very high signal of the cystic component

The solid rim of

the JPA is thick Ii8 and brighter than gray mailer.

Encephaloceles (Left) Sagillal PO FSf MR shows a classic Chiar; 3 malformation

with extension

of infratenloriallissue and also the venous system 0::>] into the large occipital encephalocele. (Right) Axial T2WI MR shows cerebellar tissue ~ protruding into the encephalocele sac.

I 7 36

Encephaloceles

"CYSTIC-APPEARING"

POSTERIOR

CIl

FOSSA LESION

:>..c u c:

~ Q)

co

0...

c:

co ~

CD

CO 'C

a C Q)

ro

..=c: c: infant presentation most common; rare adult presentation

Pineal Cyst

I Axial FlAIR pineal cyst

=

hyperintense.

MR shows the classic finding

of a presumed

that does not suppress and is moderately

Axial CrCT shows

1:11 splaying inferolaterally

intact.

a CSF collection

the internal

Ell.

Note

cerebral

between

the fornices

veins & choroid

the septum

pellucidum

plexus ~

8

is

3

c

PINEAL REGION

.Q

MASS, GENERAL

Ol Q)

0:: Cll Q)

c

a:: (Left) Sagillal T2WI FS MR

shows an isoinlense mass

=

wilh flow voids ~. Visualization of a normal pineal gland ~ & elevation of midbrain lectum ~ helps exclude pineal tumors from lhe differential diagnosis. (Right) Axial CECT shows a lypical CT case of a pineocytoma with "exploded" pre-existing calcificalion Also note the typical lack of significant mass effect.

=.2.

Arachnoid (Left) Sagillal T1 WI MR

shows an arachnoid cyst extending posteroinferiorly from the quadrigeminal

cistern, compressing the superior vermis inferiorly -7. (Right) Sagittal T2WI MR demonstrales a typical tectal plate low grade astrocytoma as a predominantly homogeneous, slightly hyperintense mass involving the lectal plale proper EB

(Left) Axial T2WI FS MR shows multiple cysticercosis cysts in the quadrigeminal cistern atrium right lateral ventricle ~ (Courtesy E. Bravo, MO). (Right) Axial T1WI MR reveals a fat-intenSity lesion =.2 within the quadrigeminal cistern exerting mass effect

upon the quadrigeminal plate (R> L). Fat suppression (not shown) confirmed lipoma.

I 8 4

Cyst

Tecta I Plate Glioma

en

PINEAL REGION MASS, GENERAL

" c:

Intracranial Hypotension

Medial Atrial Diverticulae (Obstructive Hydrocephalus) (Left) Sagittal T1 C+ MR shows cisternal effacement by splenium impacting internal cerebral veins ~ & quadrigeminal plate BI. Note 1055 of suprasellar cistern & dural enhancement . (Right) sagillal T1 WI MR shows an atrial diverticulum ~ that has protruded through the lateral ventricle medial waif

=

under the Fornix

Note

the severely compressed displaced 4th ventricfe BI.

-u ::l C1> OJ

;0 C1> > SAH • Thalassemia • Hemochromatosis

Rathke Cleft Cyst

Pituitary Microadenoma

I 8 20

=.

Coronal T2WI MR shows a hyperintense intrasellar mass Pre-operative diagnosis was Rathke cleft cyst. An almost entirely cystic m;croadenoma was found at

surgery.

=

Coronal T2WI MR shows hyperintense cystic intJasellar mass found incidentally on MR. This is probably a Rathke cleft cyst or pars intermedia cyst.

INTRASEllAR

lESION

(fl

"

c: III

:J

C-

...

O:!

Neurosarcoid

III

(Lefl) Sagittal T1 WI MR

shows a hyperintense inlra~/suprase/Jar mass

=

that displaces the pituitary gland I!::ll. Totally intra sellar craniopharyngioma

without

suprasellar extension is rare. (RighI) Coronal T1 C+ MR shows a slightly enlarged pituitary gland with a thickened infundibulum above ~ in a patient with

=

proven neurosarcoidosis.

:J (fJ

~ ~

'c: x 1ii (j)

~

m .'"

-u ::J m

(1)

;:0 (1)

co

o ::J

lymphocytic

Hypophysitis (Lefl) Sagittal T1 C+ MR shows an enlarged, uniformly

enhancing

=

pituitary gland

with slight

suprasellar extension. This was proven to be lymphocytic hypophysitis. (Rig"') Coronal T2WI FS MR

shows

II

kissing"

(paramedian)

=

cavernous

ICAs projecting medially into the selJa turcica. Cavernous ICAs normally lie laterally within carotid sulcus of sphenoid bone.

eNS Siderosis (Left) Coronal T1 C+ MR shows a mass lesion diffusely infiltrating/expanding pituitary gland Note

=.

extension

into cavernous

sinus

suggesting more

aggressive pathology. (Rig"') Coronal T2WI MR in 9 year old with long-standing thalassemia major shows profoundly hypoimense pituitary gland caused by iron overload syndrome.

=

I 8 21

c Q

CYSTIC INTRASELlAR MASS

OJ OJ

cr: Iii OJ c 0..

DIFFERENTIAL DIAGNOSIS Common • Empty Sella (ES) • Intracranial Hypertension,

Idiopathic

less Common • Obstructive Hydrocephalus • Rathke Cleft Cyst • Craniopharyngioma • Arachnoid Cyst (AC) • Epidermoid Cyst • Neurocysticercosis Cyst Rare but Important • Pituitary Apoplexy • Saccular Aneurysm (Thrombosed)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Cystic mass originating WITHIN sella vs. intra sellar extension from suprasellar lesion • Intrasellar extension of suprasellar lesion> cystic intrasellar mass Helpful Clues for Common Diagnoses • Empty Sella (ES) o Small crescent of compressed pituitary gland lines bottom of sella turcica o "Primary" ES considered normal variant o "Secondary" = surgery, pituitary infarction • Intracranial Hypertension, Idiopathic o "Pseudotumor cerebri" F> > M o Empty sella ± dilated optic nerve sheaths, small ventricles

Helpful Clues for less Common Diagnoses • Obstructive Hydrocephalus o Anterior recesses of 3rd ventricle enlarge • Herniate inferiorly into sella • If chronic may expand, erode bony sella • Rathke Cleft Cyst o Usually < 1 em; can be giant, erode sella o 45% have "intra cystic nodule" o ± "Claw sign" (enhancing rim of pituitary around nonenhancing cyst) • Craniopharyngioma o Truly intrasellar craniopharyngioma rare o If no Ca++ difficult to distinguish from Rathke cleft cyst • Arachnoid Cyst (AC) o Truly intra sellar AC rare o Usually extension from suprasellar AC • Epidermoid Cyst o Suprasellar location < off-midline • Neurocysticercosis Cyst o Suprasellar cysts - intrasellar Helpful Clues for Rare Diagnoses • Pituitary Apoplexy o Can be life-threatening (secondary to pituitary insufficiency) o Acutely may present as necrotic, rim-enhancing mass • Saccular Aneurysm (Thrombosed) o Medially projecting from cavernous ICA o If thrombosed may appear low signal intensity on Tl C+ scans

Intracranial

I 8 22

Sagittal T1WI MR shows empty sella with herniation of CSF through the diaphragma sellae =.lI flattening the pituitary gland inferiorly against the sellar floorE:l.

Hypertension,

Idiopathic

Axial T2WI MR shows idiopathic intracranial hypertension (pseudolumor cerebri) with "empty sella" =.lI and dilated opUc nerve sheaths 1!:i2.

CYSTIC INTRASEllAR

MASS III

:;, Co

III ., III

(Left) Sagiltal T2WI MR shows aqueduclaf stenosis with severe obstructive hydrocephalus. NOle marked enlargement of bony sella 1:1

m

and intrasellar inferior

herniation

of

3rd ventricle ~

(Right) Coronal T1 WI MR shows an intrasellar Ralhke clefl cyst seen here as a CSF-like mass that displaces Ihe piWitary gland inferiorly and laterally around it.

=.

Arachnoid

:;, (f)

~

iii

'c )(

iii f/l

~

iii 0"

Cyst (AC) (Left) Coronal T2WI MR shows a CSF-like intrasellar mass ~ Surgery disclosed inlrasellar craniopharyngioma

with

only a small suprasellar component. (Right) Sagiltal T1WI MR shows an intra· and suprasellar arachnoid cyst 1:1. The lesion did not restrict on OWl, differentiating

epidermoid

it from

cyst.

(Left) Axial T2WI MR shows a large epidermoid cysl extending into the sella and suprasellar subarachnoid

'-=

space from the quadrigeminal and ambient cisterns 1:1. (Right) Sagiltal T7 C+ MR shows suprasellar

'-=

racemose NCC CYSlS extending into sella turcica E!ll (fattening pituitary gland against sellar (foor ffi

I 8 23

SUPRASEllAR MASS, GENERAL ro 75% of all suprasellar masses • Pituitary Macroadenoma o Most common of all suprasellar masses = suprasellar extension of macroadenoma o Gland, mass can't be separated o Cystic, hemorrhagic changes common o Mass is the pituitary gland • Meningioma o Arises from diaphragma sellae

Thin black line (diaphragma sellae) separates mass from pituitary o "Dural tail sign" • Not pathognomonic but highly suggestive • Signal intensity following contrast usually> tumor itself • Saccular Aneurysm o Most arise from circle of Willis o Are usually slightly eccentric, not midline o Signal intensity may be mixed • Partial/complete thrombosis common • Complex/disturbed flow may cause spin dephasing • Look for phase artifact o Occasionally fusiform aneurysm/ectasia of basilar artery may project into suprasellar cistern • Craniopharyngioma o Most common suprasellar mass in child o Adamantinomatous subtype o Imaging • 90% Ca++, 90% cystic • 90% enhance (rim ± nodule) o Second peak in middle-aged adults • Papillary subtype • Solid> cystic; Ca++ uncommon • Pilocytic Astrocytoma o Second most common suprasellar mass in children (rare in adults) o Hypothalamus/optic pathways o Pilocytic > > pilomyxoid type (see below) o

Helpful Clues for less Common Diagnoses • Dilated Third Ventricle o Most common "cystic" suprasellar mass o Third ventricle enlarged secondary to obstructive hydrocephalus • Arachnoid Cyst o Elevates, displaces third ventricle • Neurocysticercosis o Suprasellar cistern, sylvian fissures common sites o Variable size cysts, enhancement o Reactive meningeal changes may be striking (e.g., stalk thickening, vascular encasement) • Rathke Cleft Cyst o Look for intracystic nodule o Pituitary displaced by mass

• Neurosarcoid o

Thickened stalk may be only sign

SUPRASELLAR

MASS, GENERAL

C/l

~ c:

• •

• •

o Look for dural-based masses Langerhans Cell Histiocytosis o Thickened stalk, child with Dl Germinoma o Stalk ± gland o Can be only site but look for pineal mass Dermoid Cyst o Fat-like ± droplets (ruptured) Lipoma o Fatty mass stuck on hypothalamus o Use fat-saturated Tl WI

•

•

•

Helpful Clues for Rare Diagnoses

• Lymphocytic Hypophysitis o Thick, nontapering stalk ± pituitary mass o Diabetes insipidus common o Often occurs in peripartum females • Tuber Cinereum Hamartoma o Clinical presentation helpful (gelastic seizures; male with precocious puberty) o Can be "collar button" or "sessile" o Between infundibulum (anteriorly), mammillary bodies (posteriorly) o Signal intensity like cortex o Does not enhance • Pituicytoma o Low grade (WHO I) glial neoplasm of infundibulum or neurohypophysis oM> F, most patients 40-60 years o Hypopituitarism, visual disturbances o Well-demarcated, homogeneously enhancing infundibular mass • Diffuse Astrocytoma, Low Grade

• •

•

•

o Infiltrating mass difficult to distinguish from pilocytic astrocytoma (PA) Pilomyxoid Astrocytoma o Rare, more aggressive PA variant o Infant/young child with bulky H-shaped suprasellar mass o Often hemorrhages (PA, low grade do not) Metastasis o Gland ± stalk mass in patient with known primary Lymphoma, Metastatic o Destructive, infiltrative mass engulfs gland, stalk Leukemia o Gland/stalk + sinus mass clues Cavernous Malformation o "Popcorn ball" mass o Third ventricle, optic chiasm rare sites Tuberculoma o TB meningitis> > frank tuberculoma in suprasellar cistern o Focal mass wiring enhancement common o If caseating, mass is hypointense on T2WI o If non caseating, mass generally hyperintense on T2WI Pituitary Abscess o Very rare but potentially life-threatening o May resemble pituitary apoplexy at imaging • Cystic-appearing intrasellar mass with suprasellar extension • Hypodense on NECT • Hyperintense on T2WI • Rim-enhancing

III

::J a.

...

OJ

!!!. ::J (f)

~

1il

c::: c

x iii (f) C1>

..• 0>

Pituitary Macroadenoma

=.

Sagittal T 1 C+ FS MR shows a pituitary macroadenoma The pituitary gland cannot be seen separate from U,e mass. The mass is the gland, which is diffusely enlarged by the tumor.

Sagittal T7 C+ MR shows a classic suprasellar meningioma arising from the diaphragma sellae Idl which clearly separates the mass from the normal pituitary below Ell. Note dural "tails"

=.

I 8 25

c

SUPRASELLAR

Q

MASS,

GENERAL

Ol Q)

a:: co Q)

c 0...

..: co Q)

rn

co X

--, OJ

ro

Q) (f)

C III

"-

ell "'C C III

:s .>t:.

en

Saccular Aneurysm (Left) Sagittal T7 WI MR shows a farge, mixed signal intensity, suprasellar mass Laminated clot of different ages gives mass an

=.

"onion skin" appearance.

Note residual patent lumen 81. (Right) Sagillal T7WI MR shows a craniopharyngioma 81 with variable T7 shortening within the multilocu/aled

cystic

components. The pituitary gland PJ:J:l is clearly distinct from the mass .

Pilocytic Astrocytoma

Dilated Third Ventricle

(Left) Sagiltal T7 C+ MR shows a large pi/ocytic astrocytoma, seen here as a lobulated inhomogeneously enhandng suprasellar mass Pituitary 81 is clearly separate from the mass. (Right) Sagittal T7 C+ MR

=.

shows obstructive hydrocephalus with a dilated 3rd ventricle 81. The large anterior recesses compress and displace the infundibular stalk and hypothalamus inferiorly.

=

Arachnoid (Left) Sagittal T7 WI MR

shows a class;c suprasellar arachnoid cyst. Note that the CSF-Iike suprasellar mass

=

elevates the 3rd ventricle and displaces the infundibular stalk anteriorly 81. (Right) Sagiltal T7 WI MR in a patient with known neurocysticercosis shows a markedly thickened inFundibulum e.'I as well as multiple supra- and intrasellar cysts 8asal cistern lesions are common in NCe.

=.

I 8 26

Cyst

Neurocysticercosis

SUPRASELLAR

Rathke Cleft Cyst

MASS, GENERAL

Neurosarcoid (Lefl) Sagittal TI WI MR shows a typical Rathke cle(t cyst. Note that the well-delineated hype,intense sup,asellar mass I:] is clearly distinct from the pituitary gland below PJ:ll. (RighI) Sagillal T1 C+ MR in a patient with known systemic sarcoidosis and diabetes insipidus shows a thickened, enhancing

infundibulum

=.

This was the only intracranial finding.

(Leh) Sagillal T1 C+ MR in a child with known histiocytosis and diabetes insipidus shows a strongly enhancing mass involving the infundibular stalk and hypothalamus 1:]. (RighI) Sagillal T1 C+ MR shows a germinoma with sellar 81 and suprasellar involvement. The infundibular stalk is markedly thickened, while the pineal gland is normal.

=

(Lefl) Sagillal T1 C+ MR shows a ruptured dermoid cyst 81 with a large

supra/parase/Jar component. Note multiple high signal intensity droplets I:] scallered throughout the subarachnoid space. (RighI) Sagillal T1WI MR shows a hypothalamic lipoma seen here as a lobulated hyperintense mass above and behind the sella. This

=-

was an incidental

finding in

an asymptomatic

patient.

I 8 27

c

SUPRASELLAR

.Q

MASS,

GENERAL

Ol Q)

cr:

ro Q)

c

0::

..: ro Q)

(fl

ro X

--,:J

ro

Qi (fJ

..

C

I1l

m "t:l

c I1l

Tuber Cinereum

Hamartoma

(Left) Sagittal T1 C+ FS MR in a 19 year old pregnant woman shows a uniformly enhancing sellar/suprasellar mass m. Note reactive dural thickening 81. Lymphocytic hypophysitis was found at surgery. (Rig!Jt) Sagittal T 1 WI MR shows a classic luber cinereum hamartoma The hamartoma looks like a "collar button" of gray

m.

matter interposed between the infundibulum and mammillary bodies.

(Left) Axial T1 WI MR shows an epidermoid cyst The lobulated CSF-like mass extends into the suprasellar !:ill and quadrigeminal 81 cisterns. (Right) Sagitlal T1 C+ MR shows a pituicytoma,

=.

seen here as a large solid infundibular mass !:ill with mild mass effect on the optic chiasm and anterior 3rd ventricle.

Diffuse Astrocytoma, (Left) Coronal T1 C+ MR shows a rounded enhancing mass separate from pituitary gland below Ell displaced optic chiasm above !:ill. Grade 11fibrillary

=

astrocytoma

=.

I 8 28

of

hypothalamus (possibly infundibular stalk) was found at surgery. (Right) Coronal T2WI MR in a 21 year old man with sudden headache and visual problems shows a hemorrhagic suprasellar mass Initial diagnosis was pi/oeytie astrocytoma. Final diagnosis was PMA.

Low Grade

Pilomyxoid

Astrocytoma

SUPRASELLAR

en ,.-

MASS, GENERAL

r:: Ql

::l Co

.,

[Jl

Metastasis

Ql

(Left) Sagittal T7WI MR shows posterior pituitary ectopia, seen here as a hyperintense focus !:>J along the upper infundibulum. Note a small pituitary gland Ell with an absent "bright spot". (Right) Sagittal T7 C+ MR shows a metastasis enlarging the infundibulum, extending into the pituitary gland ~ This was the only intracranial manifestation of metastatic lung carcinoma.

=

lymphoma,

Metastatic

::l

en !E.

!iI c.... r::

x iii en

CD Q)

-.,

leukemia (Left) Sagillal T7 WI MR shows a destructive, diffusely infiltrating mass with signiHcant infra-, 5upra- and

relrose/Jar extension

=.

Lesion enhanced strongly. quite uniformly on T7 C+ scans (not shown) and demonstrated "dural tail sign" Ell. (Right) Coronal CECT shows opacification of sphenoid sinus Other images

(not shown)

disclosed lobulated

mucosal-based

masses in the

maxillary/ethmoid sinuses. Note rounded, thickened infundibular stalk

=.

Tuberculoma (Left) Sagillal T7WI MR

shows suprasellar "popcorn ball" of mixed signal intensity ~

appearing

to arise within

3rd ventricle. Type 2 cavernous

malformation

was

diagnosed. (Right) Axial CECT shows a tuberculoma in the suprasellar cistern, seen here as a ring-enhancing mass. Note accompanying findings of TB meningitis Ell. (Courtesy S. Candy, MO).

=

I 8 29

c .Q

SUPRASEllAR MASSES, PEDIATRIC

Ol Q)

0:: co Q)

c CL

..:

.!!1 Q)

en co

X

:J ....,

.!!1 (jj

CI) C 95% hypodense (similar to CSF) • FLAIR,DWI best to distinguish epidermoid from AC, enlarged 3rd ventricle • Epidermoid doesn't suppress completely, restricts on DWI • Enlarged Perivascular Spaces (PVSs) o Usually variable-sized "clusters" o Off-midline (basal ganglia) o Round or ovoid (basal ganglia), linear (white matter) o Like CSF on all sequences (contain interstitial fluid) • Suppresses completely on FLAIR • Does not restrict on DWI Helpful Clues for Rare Diagnoses • Pituitary Macroadenoma o Solid ± intra- or extra tumoral cysts • Extratumoral cysts may be trapped/enlarged PVSs or arachnoid cysts • Cysts often hyperdense/intense compared to CSF o Solid> rim enhancement • Pituitary Apoplexy o Rare; may be life-threatening (severe panhypopituitarism) o Necrotic pituitary with little/no enhancement (may show rim) o Hemorrhage may bloom on T2* (GRE, SWI)

=-

Sagillal T2WI MR shows EVOH wilh markedly enlarged laleral 3rd El and 4lh I!:1\'l ventricles. A CSF suprasellar mass caused by an enlarged 3rd venlficle was diagnosed.

Compression/edema of hypothalamus, optic chiasm/tracts may cause hyperintensity on T2WI o Restricts on DWI o Markedly hypointense on ADC • Astrocytoma o Pilocytic > > pilomyxoid astrocytoma o Most suprasellar astrocytomas are solid, not grossly cystic • Ependymal Cyst o Rare; 3rd ventricle least common site o Round/ovoid; CSF-like • Saccular Aneurysm o Aneurysms may be associated with true perianeurysmal cysts • Obstructed perivascular spaces posited as etiology o Partly or completely thrombosed may have "cystic"-appearing foci within clot • Rare • Acute thrombosis can present with panhypopituitarism, SAH o Imaging can mimic necrotic adenoma • Hypodense center, iso-/hyperintense rim on TlWI • Look for mixed age laminated clot • "Blooms" on GRE • Rim may enhance o

Sagillal T2WI MR shows massively enlarged 3rd SlI and laleral ventricles, an enlarged "funnel-shaped" aqueducl and a medial atrial diverticulum R> compressing the 4th ventricle

=-

=.

Ql

:l

Q.

III "" Ql

:l (JJ

~

-

Q)

'xc

Oi en

~ OJ 0""

I 8 37

c

SUPRASEllAR

o

CYSTIC MASS

Ol Q)

0:: CIl Q)

c 0..

~.!l1 Q) (f)

CIl

X

-,:J

co Qi (f)

c

'..."

llJ

"0

c

'"

Arachnoid Cyst (Left) Sagiltal T2WI FS MR shows a lobulated, sharply marginated, CSF-like, suprasellar cyst =:I extending into the sella 8l elevating the 3rd ventricle ICR and causing obstruclive hydrocephalus. (Right) Coronal T2WI FS MR in an 8 year old child with delayed growth shows a hyperintense suprasellar mass =:I that slightly compresses and displaces the pituitary gland SI toward the lelt.

Rathke Cleft Cyst (Left) Coronal T2WI MR shows a suprasellar cystic mass and a moderate

=

compensated hydrocephalus. Another cyst is present in the right Meckel cave 81 in this patient with racemose NCe. (Right) Sagittal T1 C+ MR shows an intra- and suprasellar cyst that does not enhance. Note the displaced pituitary gland and infundibular stalk =:I form a "claw" around the lesion.

Dermoid Cyst (Left) Axial NECT shows a large, mixed density suprasellar and subfrontal mass =:I. Low density "droplets" that resemble fat are seen in the adjacent sylvian fissure E1 in this patient with a ruptured dermoid. (Right) Axial T2WI MR shows an epidermoid cyst in the suprasellar cistern, widening the interpeduncular fossa and extending into the ambient and quadrigeminal

.:=

cisterns.

I 8 38

SUPRASELLAR

en

CYSTIC MASS

c: "

Ql

:l

Co

..• lJl Ql

(Left) Sagillal TI WI MR in a 1S year old with headaches shows multiple CSF-like cysts in the hypothalamus, thalamus, and midbrain ~ that bulge into the suprasellar subarachnoid space [;8 (Right) Axial TI C+ MR shows 2 neoplasm-associated cysts: A large trapped perivascular space 81 caused by a pituitary

(f)

CD Q)

c:: c: x

OJ Ul ~ Q)

-~

-u :l CD Q)

;0

macroadenoma

and a small imrawmoraJ cyst

~

:l

within the adenoma.

CD

--, ell OJ

(/)

C ltI

~

co

'0

c

ltI

DIFFERENTIAL DIAGNOSIS Common • Atherosclerosis, Intracranial • Craniopharyngioma • Meningioma • Aneurysm o Saccular Aneurysm o Fusiform Aneurysm, ASVD Less Common • Neurocysticercosis • Pilocytic Astrocytoma • Dermoid Cyst Rare but Important • Pituitary Macroadenoma • Tuberculosis • Chondroid Tumor

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Is Ca++ curvilinear, punctate, globular, etc.? • Does lesion enhance? Helpful Clues for Common Diagnoses • Atherosclerosis, Intracranial o Curvilinear Ca++ o Usually bilateral o Often multifocal o Older patients • Craniopharyngioma o Globular, punctate, &/or ring Ca++ o Younger patients (older adult tumors more often solid, Ca++ less frequent)

Atherosclerosis,

I 8 40

=

• Meningioma o Psammomatous (sand-like) Ca++ o Solid> rim enhancement o Middle-aged, older patients (unless NF2) • Aneurysm o Saccular Aneurysm • Calcification less common than with fusiform aneurysm, ASVD • Curvilinear (peripheral arcs, rings) pattern o Fusiform Aneurysm, ASVD • Linear ± rim Ca++ • Ca++ often present in other vessels Helpful Clues for Less Common Diagnoses • Neurocysticercosis o Nodular calcified stage o Usually parenchymal> > cisternal Ca++ • Pilocytic Astrocytoma o Common in children, young adults o Ca++ uncommon in hypothalamic PA • Dermoid Cyst o 20% have capsular Ca++ o Contain lipid o Look for evidence of rupture (fatty droplets in subarachnoid spaces, cisterns) o No enhancement unless chemical meningitis Helpful Clues for Rare Diagnoses • Only 1-2% of macroadenomas calcify • TB, healing/healed granulomatous infections cause parenchymal> > cisternal Ca++ • Chondromas, enchondromas arise from central base of skull

Intracranial

Axial NEeT shows a fusiform, parUally calcified mass in the suprasellar cistern that represents an ectaUc~ supraclinoid, internal carotid artery with calcified

Axial NEeT shows a cystic suprasellar mass with globular and rim calcificaUons Note fluid-fluid level within one of the cysts m. This is an example of classic

atherosclerotic plaque.

craniopharyngioma.

=.

CALCIFIED SUPRASELLAR MASS

,...

VI C Ql

:J

Co

...

OJ Ql

(Left) Axial NECT shows a hyperdense suprasellar mass with Focal calciFications m in this patient with cfassic meningioma arising from the central skull base. (Right) Axial NECT shows a huge, well-delineated hyperdense suprasellar mass with rim calciFications The diagnosis: Giant mostly thrombosed, saccular aneurysm.

=

=.

:J

en CD Q)

c:: c X

1ii (f)

~ Q)

-""'

-0

:J CD

Ql

;0 CD CO

o· :J

Fusiform Aneurysm, ASVD

Neurocysticercosis (Left) Axial NECT shows a hype,dense FusiFormbasi/ar artery aneurysm 81 and calcified fusiform aneurysmal ectasias of both internal carotid arteries (Right) Axial NECT shows a suprasellar, ambient cistern Ca++ in this patient with racemose Nee, multiple cysts. (Courtesy E. Bravo, MO).

=.

=

Dermoid Cyst (Left) Axial NECT shows a low density suprasellar mass with rim and globular calciFication 81. Biopsy disclosed pilomyxoid variant of pi/oeytie astrocytoma. (Right) Axial NECT shows a large hypodense calciFied suprasellar mass aD. Note fat density droplets 81 in subarachnoid space. This is a ruptured dermoid cyst.

=

I 8 41

c

ENHANCING SUPRASElLAR MASS

o

Ol Q)

tr ro Q)

C

c::

.. C III

1IJ

"tl

c

III

DIFFERENTIAL DIAGNOSIS Common • Pituitary Macroadenoma • Meningioma • Saccular Aneurysm • Craniopharyngioma • Pilocytic Astrocytoma Less Common • Diffuse Astrocytoma, Low Grade • Neurosarcoid • Langerhans Cell Histiocytosis • Germinoma • Lymphocytic Hypophysitis Rare but Important • Metastasis • Lymphoma • Leukemia

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Effect of age on differential diagnosis important • Common lesions ("big five") account for > 75% of all suprasellar masses • Most other lesions < 1-2% each • Differential diagnosis narrows if mass confined to infundibulum Helpful Clues for Common Diagnoses • Macroadenoma vs. Meningioma o Macroadenoma: Gland can't be identified separate from mass

Meningioma: Mass distinct from gland (hypointense diaphragma sellae separates mass above from pituitary gland below) • Saccular Aneurysm o Coronal plane helpful in distinguishing aneurysm from normal pituitary o Look for phase artifact, "flow void" on MR • Craniopharyngioma o 90% Ca++, 90% cystic, 90% enhance o Papillary variant (more common in adults) may be solid, noncalcified, enhances strongly • Pilocytic Astrocytoma o More common in children o Expands hypothalamus, optic chiasm, may extend into optic nerves/tracts o Variable enhancement o Pilomyxoid variant • Infant> child • Aggressive behavior • Large, bulky tumor with lateral extension to temporal lobe common • Hemorrhage in 20-25% o

Helpful Clues for Less Common Diagnoses • Histiocytosis, germinoma in children/young adults • eurosarcoid in older patients Helpful Clues for Rare Diagnoses • Solitary metastasis to gland/stalk rare • Lymphoma, leukemia usually with systemic disease

Pituitary Macroadenoma

I 8

Coronal T1 C + M R shows inhomogeneously enhancing

intra- and suprasellar mass

=. Pituitary gland can't be

found separate from and indeed IS the mass.

42

Coronal TI c+ FS MR shows suprasellar enhancing mass 81 separated from normal pituitary gland below P:!.':l by thin black line of diaphragma sellae

=.

ENHANCING

SUPRASEllAR

,..

en

MASS

c: III

::::l

c..

..•

OJ III

(Left) Axial T1 C+ MR shows suprasellar enhandng mass

=

with prominent phase artifact E!llI caused by large basilar lip aneurysm with

slow intralumcnal

flow.

(Right) Coronal T1 C+ MR in a child shows

intra·/supraseJlar mass. Apical

nonenhancing

::::l (f) C1l

Q)

'c >
WHO grade II fibrillary) o Age < 5 years o Endocrine dysfunction in 20% o Look for evidence for NFl • 20-50% of patients with pilocytic astrocytoma Helpful Clues for Less Common Diagnoses • Craniopharyngioma o Second-most common suprasellar mass in children o Occurs anywhere from intrasellar to stalk to anteroinferior 3rd ventricle o 90% calcify, 90% have multiple cysts (mixed signal intensity), 90% calcify • Germinoma o Can be primary in hypothalamus/stalk • M = F (vs. male predominance in pineal gland) o 10% "double" midline lesions (pineal & hypothalamus) o DI, diencephalic syndrome, precocious puberty common o Thick enhancing stalk, 3rd floor, absent posterior pituitary "bright spot" • Neurosarcoid o Adult with stalk, meningeal lesions o Other infectious/inflammatory lesions that can mimic sarcoid • Wegener granulomatosis • TB, syphilis • Langerhans Cell Histiocytosis o Stalk/hypothalamus lesion in a child • Lipoma o Lipoma: Sessile T1 hyperintense lesion on subpial surface of hypothalamus o Osteolipoma: Rare; fat density/signal intensity & calcification • Lymphocytic Hypophysitis o Peripartum female most common o Can mimic macroadenoma • Metastases o Hypothalamic/Pituitary Axis Metastases • 1-25% of systemic cancers at autopsy • Less common at imaging • Breast, lung most common primary tumors

HYPOTHALAMUS

en ;1r:

lESION

c:

Lymphoma • Pituitary/stalk/hypothalamus uncommon site • Can be primary or metastatic a Leukemia • Often involves dura, paranasal sinuses • Tuber Cinereum Hamartoma a Children with gelastic seizures, males with isosexual precocious puberty a Can be pedunculated or sessile a Density/signal intensity typically isointense with cortex a No Ca++, enhancement a Sessile lesion may be difficult to distinguish from hypothalamic astrocytoma (no change on follow-up) a

Helpful Clues for Rare Diagnoses • Other Gliomas a Chordoid Glioma • Floor of 3rd ventricle • Hyperintense with strong, uniform enhancement a Pilomyxoid Astrocytoma • Infant/young child • "H"-shaped tumor of hypothalamus; extension into medial temporal lobes common • Often large, bulky, ± hemorrhage (rare in pilocytic astrocytoma) • ± Hemorrhage (25% of PMAs; rare in pilocytic astrocytoma) a Pituicytoma • Stalk, posterior pituitary lobe

Sagittal T2WI MR shows classic pilocytic astrocytoma =:I originating from hypothalamus and optic chiasm. (Courtesy P.Rodriguez, MO).

• Low grade astrocytoma • Enhances strongly, uniformly a Ganglioglioma • Very rare in hypothalamus/chiasm • Young adult (mean age = 20 years) • Demyelinating Disease a Optic chiasm involvement> > hypothalamus a Enhancing, slightly enlarged optic nerves/chiasm seen with both MS, ADEM • Wernicke Encephalopathy a Acute: Abnormal hyperintensity/enhancement of mamillary bodies, inferolateral walls of 3rd ventricle, periaqueductal gray matter a Chronic: Mamillary atrophy a Note: Occurs in both alcoholics, nonalcoholics (e.g., long-standing parenteral nutrition) • Cavernous Malformation a Hypothalamus/3rd ventricle rare location a Looks like CM elsewhere

::9:J Ctl

OJ

;0 Ctl non-ASVD (e.g., inherited vasculopathy, AIDS-related, etc.) o ASVD often Ca++ • Meningioma o 10% in sellar/suprasellar region o Pituitary gland separate from mass Helpful Clues for Less Common Diagnoses • Craniopharyngioma o Children: Adamantinomatous type • Usually cystic, Ca++ • Rarely hyperdense o Adults: Papillary type more common • Iso/slightly hyperdense • Solid, rarely calcified • Rathke Cleft Cyst o Only 10% purely suprasellar, hyperdense • Germinoma o Mildly hyperdense to brain o Look for pineal mass (but can be primary infundibulum/3rd ventricle lesion) Alternative Differential Approaches • Hyperdense suprasellar mass with Ca++ o Children: Craniopharyngioma o Adults: Aneurysm, meningioma

Pituitary Macroadenoma

I 8 52

Axial NECT in a 60 year old woman presenting in the emergency department with severe headache shows a hyperdense mass in the suprasellar cistern !:ill. Scout view (not shown) demonstrated an expanded sella.

Axial NECT in a patient with headache and bitemporal hemianopsia shows a somewhat lobulated hyperdense suprasellar mass !:ill. CTA demonstrated partially thrombosed lCA aneurysm.

HYPERDENSE

SUPRASEllAR

MASS III

::l Cl.

to ., III

(Left) Axial NECT in elderfy woman with "altered mental staWs /I shows very large, hyperdense, partially calcified frontal/suprasellar mass =:I. NOle acute obstructive hydrocephalus SlI. (Rig"') Axial NECT shows a hyperdense suprasellar mass SlI that contains punctate calcifications DJ. Craniopharyngioma was found at surgery.

::l (fJ

~

m c:::

c

x

fii (J)

~ OJ ., "U

:::J (1)

OJ

;0 (1)

co

o :::J

Germinoma (Left) Axial NECT in a patient with headaches and normal neurologic examination shows a hyperdense sellar/intrasellar mass =:I. MR showed Rathke cleft cyst with classic inlracystic nodule. (Right) Axial NECT in a 22 year old man with headaches, lethargy, and diabetes insipidus shows a hyperdense suprasellar mass MR showed a 2nd lesion in the pineal gland.

Tuberculosis (Left) Axial NECT shows hyperdense suprasellar mass Extension into cavernous sinus helps distinguish this from many other entities

in this location. (Right) Axial N[CT in a patient with known tuberculosis shows an inhomogeneously hyperdense suprasellar mass DJ. Rim enhancement was seen following contrast in this patient with caseating tuberculoma.

I 8 53

c

T1 ISOINTENSE SUPRASELLARMASS

.Q OJ Cl)

0::: cu Cl) c

a::

..: cu

Qj

'"cu

X

-,:J

co Cl)

(fJ

c ns •...

!Xl

'tl C

ns

DIFFERENTIAL DIAGNOSIS Common • Pituitary Macroadenoma • Pituitary Hyperplasia • Meningioma • Pilocytic Astrocytoma • Diffuse Astrocytoma, Low Grade Less Common • Rathke Cleft Cyst • Germinoma • Neurosarcoid • Langerhans Cell Histiocytosis • Tuber Cinereum Hamartoma • Lymphocytic Hypophysitis Rare but Important • Metastasis (Pituitary &/or Stalk) • Pituicytoma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Where does lesion arise from? o Pituitary gland/sella turcica (macroadenoma, hyperplasia, hypophysitis, metastasis) o Infundibulum (germinoma, histiocytosis, pituicytoma) o Brain (astrocytoma), meninges (meningioma) • Does it enhance? o Yes: Macroadenoma, meningioma, aneurysm, neoplasm

No: Tuber cinereum hamartoma, RCC • Few lesions remain isointense with cortex on all MR sequences o Pituitary macroadenoma or hyperplasia o Meningioma, tuber cinereum hamartoma o Histiocytosis, sarcoidosis o

Helpful Clues for Common Diagnoses • Pituitary Macroadenoma, Hyperplasia o Both isointense to gray matter (GM) • Meningioma o Usually isointense on all sequences o ± Ca++, enhances • Astrocytomas (pilocytic > diffusely infiltrating) o Usually iso-/hypo- on Tl, hyperintense on T2WI o Variable enhancement (none to striking) Helpful Clues for Less Common Diagnoses • Rathke Cleft Cyst (depends on cyst content) o Most are hypointense o 25% iso-, 10% hyperdense o Rim may enhance ("claw sign") • Germinoma o Isointense on Tl-, iso/hypo on T2WI o Enhances strongly, uniformly • Neurosarcoid, Langerhans Cell Histiocytosis o LCH (child), sarcoid (adult) - thick, enhancing stalk • Tuber Cinereum Hamartoma o > 90% isointense on Tl WI, non enhancing o May be slightly hyperintense on PD, FLAIR

Pituitary Macroadenoma

I 8 54

Coronal TJWI MR shows a large intra- and suprasellar mass elevating and compressing the optic chiasm m. The mass cannot be distinguished from the pituitary

m that is isoinlense

gland.

gland below

=

Sagittal T7WI MR shows an intra- and suprasellar mass with gray maHer. The diaphragma

sellae ~

clearly separates the mass from the pituitary

T1 ISOINTENSE SUPRASEllAR

MASS

(J)

c: " III

:J Co

OJ "'"

III

(Left) Axial T1WI MR shows an enlarged optic chiasm c;. and nerves in this patient with neurofibromatosis type

1. (Right) Axial T1WI MR shows a slightly inhomogeneous suprasellar mass I:] that is largely isoinlense with adjacent brain.

:J (f)

ell Q)

L

c: >
elevating and compressing the optic chiasm. (Rigl1t)Sagittal T IWI MR in a patient with visual

problems and diabetes insipidus shows an ;so;ntens€ suprasellar mass arising from

the inlundibular stalk 1:]. The lesion enhanced strongly and uniformly. (Courtesy A Hasso, MO).

I 8 55

c

11 HYPERINTENSE SUPRASELLAR MASS

.Q Ol Ql

0::: co Ql

C

a.. ..:

~ Ql

en

co

X

-,::J

co Qj (/)

C 01

•....

en

"0

c:

01

DIFFERENTIAL DIAGNOSIS Common • Pituitary Macroadenoma • Craniopharyngioma Less Common • Saccular Aneurysm (Thrombosed) • Rathke Cleft Cyst • Ectopic Neurohypophysis • Lipoma • Dermoid Cyst Rare but Important • Pituitary Apoplexy • Pilomyxoid Astrocytoma • Cavernous Malformation • Meningioma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Most common cause for t Tl is subacute hemorrhage o T2* (GRE or SWI) useful • Age helpful in common diagnoses o Children = craniopharyngioma o Adults = pituitary macroadenoma, thrombosed aneurysm Helpful Clues for Common Diagnoses • Pituitary Macroadenoma o Hemorrhage, sometimes cystic change • Craniopharyngioma o 90% Ca++, 90% cystic, 90% enhance

o

"Crankcase" oily content hyperintensity

..• Tl

Helpful Clues for Less Common Diagnoses • Saccular Aneurysm (Thrombosed) o Usually eccentrically located, not directly suprasellar o Subacute/chronic mural thrombus • Rathke Cleft Cyst o May have very short Tl if high protein content or hemorrhage from cyst apoplexy o Look for intracystic nodule o Look for "claw" of enhancing pituitary gland wrapped around cyst • Ectopic Neurohypophysis o Pituitary stalk tiny or nonexistent o "Bright spot" on hypothalamus o Does not saturate with fat suppression • Lipoma o Suppresses with fat saturation • Dermoid Cyst o Fat droplets in sulci, cisterns (ruptured) Helpful Clues for Rare Diagnoses • Pituitary Apoplexy o Subacute hemorrhage has short Tl o Rim enhancement typical • Pilomyxoid Astrocytoma o May hemorrhage • Cavernous Malformation o "Popcorn" appearance • Meningioma o • Tl (psammomatous Ca++; hemorrhage, lipomatous transformation rare)

Pituitary Macroadenoma

Craniopharyngioma

I 8 56

Sagittal TI WI MR shows a hemorrhagic intra- and suprasellar mass in a patient who presented with pituitary apoplexy. The diagnosis was macroadenoma with subacute hemorrhage.

=

Coronal

TlWI

MR

shows

hyperintense suprasellar mass ffi inCJasellarcomponent is seen

BI.

a

homogeneously

A

smalle" isoinlense

Craniopharyngioma

with ;ntra and suprasellar components. 4

11 HYPERINTENSE

SUPRASELLAR

MASS Q)

::::l 0tll

Saccular Aneurysm (Thrombosed)

-. Q)

Rathke Cleft Cyst (Left) Sagittal T1 WI MR shows a mixed signal, mostly hyperintense, suprasellar mass Note a "flow void" from the anterior cerebral artery SI supplying this largely thrombosed giant aneurysm. (Right) Sagittal T1WI MR shows a presumed Rathke cleft cyst, seen here as a well-delineated hyperintense suprasellar mass ~ clearly separable from pituitary gland. This was found incidentally on a standard MR scan.

=.

Dermoid

::::l (J)

~

III

'c:

x

III

en

~ III

.-'

II ::::l CD III

;0 CD (Q

c;::::l

Cyst (Left) Sagittal T1 WI MR shows a hyperintense hypothalamic mass with absent infundibulum. Anterior pituitary ~ is normal to slightly small in size. Note the lack of a "bright" neurohypophysis. (Right) Axial T1WI MR shows a mixed signaf~ primarily hyperintense mass SI in the suprasellar and quadrigeminal cisterns. Note fat droplets in subarachnoid spaces in this

=

=

patient

with ruplUred

dermoid cyst.

Cavernous Malformation

Meningioma (Left) Sagittal T1 WI MR shows a mixed iso-, hyperintense suprasellar mass E±I with hypointense rim [;8 characteristic of Zabramski type 2 cavernous malformation. (Right) Axial T1WI MR shows mostly isointense suprasellar mass with

some

Tl shortening

ED.,

possibly caused by psammomatous calcification, not hemorrhage.

I 8 57

11 HYPOINTENSE SUPRASELLAR LESION

c Q

OJ

OJ

0:: ro OJ c

a.. ..: ro Qi

en ro

X

-,:J

ro OJ (/)

c ro

"III "C

r::

DIFFERENTIAL DIAGNOSIS

o

Rim/ring (NCC, craniopharyngioma,

RCC)

Helpful Clues for Common Diagnoses • Dilated Third Ventricle o Enlarged 3rd ventricle recesses protrude into suprasellar cistern, sella turcica o Behaves exactly like CSF on FLAIR, OWl • Arachnoid Cyst (AC) o Bows 3rd ventricle up, over cyst o Suppresses on FLAIR, no restriction on OWl • Neurocysticercosis (NCC) o Cysts often show rim enhancement

Common • Dilated Third Ventricle • Arachnoid Cyst (AC) • Neurocysticercosis (NCC) Less Common • Pilocytic Astrocytoma (PA) • Craniopharyngioma • Epidermoid Cyst • Rathke Cleft Cyst • Enlarged Perivascular Spaces

III

:J

-"(/)

Rare but Important • Pituitary Macroadenoma • Saccular Aneurysm (Acutely Thrombosed) • Pituitary Apoplexy • Pilomyxoid Astrocytoma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Tl hypointense lesion = hypointense compared to brain, not necessarily - CSF • Lesions CSF-like on all sequences o Enlarged 3rd ventricle, arachnoid cyst, perivascular spaces o Epidermoid cyst • Lesions hypointense to brain but hyperintense to CSF on Tl WI o Neoplasms o Congenital or infectious cysts • Enhancing hypointense lesions o Solid (astrocytoma, adenoma)

Helpful Clues for Less Common Diagnoses • Pilocytic Astrocytoma (PA) o Hyperintense to CSF on Tl WI o Enhancement typical • Craniopharyngioma 090% cystic, 90% Ca++, 90% enhance o Cyst signal variable (hyper> hypointense) • Epidermoid Cyst o No suppression on FLAIR, restricts on OWl • Rathke Cleft Cyst o Cyst fluid more often hyperintense o Look for "claw sign" of enhancing pituitary around cyst Helpful Clues for Rare Diagnoses • Pituitary Macroadenoma o Small intratumoral cysts common o Extratumoral cysts (trapped perivascular spaces) less common o Necrosis/apoplexy may appear cystic, show rim enhancement

Dilated Third Ventricle

I 8

Sagittal T7 WI MR shows aqueductal stenosis 81 causing marked enlargement or the third ventricle with herniation

58

cistern I!!f].

of anterior

recesses into

the suprasellar

=-

Sagittal T7 C+ MR shows a CSF-like suprasellar mass compressing/elevaUng the 3rd ventricle deviating lhe inFundibulum anteriorly E1 and causing severe obstrucUve hydrocephalus.

T1 HYPOINTENSE

SUPRASELLAR

en

LESION

"

c: Ql

:J

a.

ro ., Ql

(Left) Sagittal T1 C+ MR shows multiple hypoimense basal cYS15with peripheral enhancemenl~in the supra· and intrasellar ~ cisterns. (Right) Axial T1 WI MR in child with known NFl shows a lobulated hypointense mass filling the suprasellar cistern. The mass enhanced strongly but heterogeneously following contrast administration.

::l (f)

CD

-'iil c X

tii

Ul

CD OJ

." "U

:::J

CD OJ

:;0 CD (Q

o· :J

(Left) Coronal T1WI MR shows a mixed ;50- EI and hypointense suprasellar mass in a child with chiasm compression ~ causing bitemporal hemianopsia. Hypoinleflsily in this case is caused by dense calcification. (Right) Axial T1 C+ FS MR shows a lobulated, CSF-Iike, non enhancing mass infiltrating the quadrigeminal, ambient 1:1 and suprasellar cisterns

=

a

Enlarged Perivascular Spaces

Saccular Aneurysm (Acutely Thrombosed) (Left) Axial T1 WI MR shows variable-sized CSF-like cYS15 E±J in hypothalamic region. Prominent PV5s are common in basal ganglia, less common in midline basal brain structures. (Right) Axial T1 C+ MR shows nonenhancing, hypoinlense, intra- & suprasellar mass I::] in a female with headache & sudden onset left CN6 palsy. Pituitary apoplexy was pre-operative diagnosis. An

rs

acutely thrombosed internal carotid artery aneurysm was found at surgery.

I 8 59

SECTION 9 Arteries Anatomically Based Differentials Abnormalities of Arterial Shape/Configuration Fusiform Arterial Enlargement

Modality-Specific

1-9-2 1-9-6

Imaging Findings

Hyperattenuating ("Dense") Artery Vascular Calcification(s)

1-9-8

1-9-10

ABNORMALITIES OF ARTERIAL SHAPE/CONFIGURATION

IJl QJ 'C QJ

t

« c:

... III

lXl

"0

c:

III

DIFFERENTIAL DIAGNOSIS Common • Atherosclerosis, Intracranial • Dolichoectasia • MR Artifacts, Flow-Related • Saccular Aneurysm • Fusiform Aneurysm, ASVD Less Common • Vasospasm • Fusiform Aneurysm/Vasculopathy, Non-ASVD • Dissection • Pseudoaneurysm Rare but Important • Blood Blister-like Aneurysm • Vasculitis • Moyamoya

ESSENTIAL INFORMATION

I 9 2

Key Differential Diagnosis Issues • Effect of patient age on diagnosis o Middle-aged or elderly • Atherosclerosis (ASVD) • Dolichoectasia • Saccular aneurysm • Fusiform aneurysm o Child or young adult • Consider inherited vasculopathy (e.g., collagen-vascular disease like Ehlers-Danlos) • Child with fusiform vasculopathy: Check HIV status • Moyamoya • Is there evidence for hemorrhage? o Subarachnoid • Saccular aneurysm ± vasospasm • Blood blister-like aneurysm • Dissection or dissecting aneurysm (especially vertebrobasilar) o Parenchymal • Moyamoya (adult) • Vasculitis (especially drug-related) • Pseudoaneurysm (especially with trauma history) • Does lesion involve short or long segment of vessel, bifurcation vs. nonbranching point? o Short, bifurcation -+ saccular aneurysm,

ASVD

o o

Short nonbranching -+ pseudoaneurysm, blood blister-like aneurysm Long, nonbranching -+ ASVD, dolichoectasia, fusiform aneurysm (ASVD, non-ASVD), vasculitis, vasospasm

Helpful Clues for Common Diagnoses • Atherosclerosis, Intracranial o Distal basilar artery (BA), cavernous/supra clinoid internal carotid artery (lCA) > cortical branches o Findings • ormal aging: Arterial Ca++, wall thickening • Most common: Focal stenosis, luminal irregularities • Less common: Elongation/ectasia • Uncommon: Thrombosis, occlusion o Remember: Most common cause of "vasculitis" appearance is ASVD, not vasculitis! • Dolichoectasia o Elongation, dilatation, tortuosity without focal aneurysmal dilatation o BA > ICA > MCA o Slow flow may cause signal inhomogeneity, phase artifact • MR Artifacts, Flow-Related o Pulsation may cause spin dephasing, signal loss in adjacent CSF (especially around distal basilar artery) o Phase artifact propagation may distort vessel contours, propagate across imaged slice o Slow flow & fully relaxed spins in entry slice(s) -+ Tl shortening may mimic thrombus • Saccular Aneurysm o Round or ovoid outpouching ± "tit" or lobulations o Arises from major vessel bifurcation o Variable neck (narrow, wide, broad-based) o Aneurysmal SAH common • Fusiform Aneurysm, ASVD o Long segment irregular fusiform/ovoid arterial dilatation o Vertebral arteries, BA > ICA, MCA o Hematoma with variable aged clot common o Residual lumen enhances strongly o Variant = "giant serpentine aneurysm" • Large, partially thrombosed mass

ABNORMALITIES OF ARTERIAL SHAPE/CONFIGURATION • Clot of varying age • No definable neck Helpful Clues for Less Common Diagnoses • Vasospasm o Etiology • Most common: Ruptured aneurysm ~ aSAH ~ vasospasm 5-7 days later • Less common: Trauma o Imaging • Long- or short-segment stenosis • Often multifocal • ± Cerebral ischemia/infarction • Fusiform Aneurysm/Vasculopathy, Non-ASVD o Fusiform or ovoid dilatation in absence of ASVD o Long, affects nonbranching vessel segments o Can be solitary or multifocal o Vertebral/BA > carotid o Younger patients o Inherited (e.g., Ehlers-Danlos) or acquired (viral or collagen-vascular) • Dissection o Can be traumatic or spontaneous o May cause SAH o Vertebral> > internal carotid artery o Look for Tl hyperintense clot around residual lumen o Focal dilatation ~ dissecting aneurysm • Pseudoaneurysm o Cavitated clot lacks normal arterial wall o Trauma, infection = common causes

Atherosclerosis,

Peripheral location (distal to circle of Willis) o Often adjacent to skull base or dura (tentorial incisura, falx) o

Helpful Clues for Rare Diagnoses • Blood Blister-like Aneurysm o Broad-based hemispheric bulge o No definable neck o Contained only by adventitia/fibrous cap so easily ruptures o Look carefully for BBA in "angiogram-negative" SAH o Most common location = supraclinoid ICA • Vasculitis o Primary arteritis of the CNS o Secondary vasculitis • Infectious • Autoimmune • Substance abuse • Radiation-induced o Multifocal alternating stenoses, dilatations o Remember: Most common cause of "vasculitic" pattern in older patient is ASVD! Other Essential Information • Mimics of arterial abnormalities o Anything with short Tl can mimic aneurysm on MRA • Lipoma • Pituitary gland on Tl C+ • ROI that includes part of adjacent vessel o Pulsation artifact

Dolichoectasia

Intracranial

I Anteroposterior angiography shows mulUfocal stenoses characteristic for atherosclerosis (ASVD). ASVD is most common cause of this vasculitis-like pattern of alternating stenoses and dilatations.

Axial T1WI generalized €CtaUcMCA the pulsating

MR in normal 79 year old man with arterial dolichoeclasia shows elongated. =.2 with substanUal phase arUfact SI from vessel.

9 3

en

ABNORMALITIES

Q)

OF ARTERIAL SHAPE/CONFIGURATION

·C Q)

t::

J and narrowed cortical vessels ~

indicating a

vasospasm caused by an aneurysmal subarachnoid hemorrhage (aSAI I). (Right) Lateral angiography in 47 year old man with spontaneous intracranial hemorrhage (not shown) shows fusiform elongation of an MCA branch ~ Patient later admitted to using street drugs.

I 9 4

Fusiform Aneurysm/Vasculopathy, Non-ASVD

ABNORMALITIES

en ,.-

OF ARTERIAL SHAPE/CONFIGURATION

c: Ql

:> Q.

..•

Fusiform Aneurysm/Vasculopathy, Non-A5VD

OJ Ql

(Left) Axial T2WI MR in a 13 yea, old child with II/VIAIOS shows enlarged, bizarre-appearing middle cerebral arteries 3-. (Right) Axial T7 C+ FS MR in a

patient

with

:>

posterior

circulation ischemic symptoms several days after a severe deceleration injury shows that both vertebral

arteries are markedly enlarged by subacute clot

=. Right VA appears

completely thrombosed, while small residual lumen is seen on left 81.

Pseudoaneurysm

Blood Blister-like Aneurysm (Left) Axial MRA shows traumatic pseudoaneurysm arising from P2 segment of posterior cerebral artery Impaction against tentorium during CJ 1/ probably injured PCA, creating this gradually enlarging pseudoaneurysm. (Right) Lateral angiography shows classic blood blister-like aneurysm c7 along greater curvature of supra clinoid internal carotid artery. Hemispherical bulge with broad orifice is typical for BBAs. (Courtesy D. Phillips, MO).

Vasculitis

Moyamoya (Left) Sagittal oblique angiography shows classic changes of vasculitis, with alternating areas of stenosis and dilatation ffi Note pseudoaneurysm ~ a rare complication of vasculitis. (Right) Lateral angiography shows tapered occlusion ~ of supra clinoid internal carotid artery, with tangle of

"puff of smoke lenticulostriate collaterals.

II

:t>-

I 9 5

rn

FUSIFORM ARTERIAL ENLARGEMENT

Q)

·C Q)

t

l:

•..'"

CO l::J

l:

'"

DIFFERENTIAL DIAGNOSIS Common • Arachnoid Granulations, Dural Sinuses • Dural Sinus Hypoplasia-Aplasia • Thrombosis, Dural Sinus • Dural A-V Fistula Less Common • Meningioma • Metastasis • Lymphoma • Depressed Skull Fracture • Intracranial Hypotension Rare but Important • Dural Venous Sinus Stenosis • Thrombophlebitis • Polycythemia • Hemangioma • Leukemia • Rosai-Dorfman Disease • Extramedullary Hematopoiesis • Lipoma • Masson Vegetant Intravascular Hemangioendothelioma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Includes generic lesions affecting ALLdural venous sinuses o Cavernous sinus (CS) unique because of contents, proximity to skull base o Has diagnoses (e.g., perineural metastasis, aneurysm, schwannoma) that do not affect other sinuses • Imaging challenge: Differentiate dural sinus thrombosis (DST) from stenosis, anatomic variants o CTV best o MRV shows anatomical narrowing/occlusion o T2* (GRE/SWI) shows thrombus

I 10 2

• Transverse sinus (TS) most common site "Flow gaps" on MRV can mimic DST • Confirm "flow gaps" on source data • No "blooming" thrombus on T2* • If MRV is unclear, CTV helpful • Thrombosis, Dural Sinus o Symptoms vary with extent of thrombus, collaterals, cortical vein involvement o NECT • Hyperdense clot in sinus • Cortical/subcortical hemorrhages (bilateral parasagittal if superior sagittal sinus or temporal lobe if vein of Labbe) • ± Edema (vasogenic > cytotoxic) o CECT shows "empty delta sign" o

Helpful Clues for Common Diagnoses • Arachnoid Granulations, Dural Sinuses o Can be large (> 1 cm), remodel calvarium • May narrow but not occlude sinus o Round/ovoid, well-circumscribed o CSF density/signal intensity • Dural Sinus Hypoplasia-Aplasia o Seen in up to 1/3 of normal scans

o

MR

• Loss of normal "flow void" • Clot elongated, fills sinus, shows susceptibility on T2* • Confirm with MRV o Chronic thrombosis difficult diagnosis • Progressive recanalization &/or granulation tissue forms • Chronic thrombus enhances, mimicking patent dural sinus • Dura also thickens, enhances; bizarre-appearing collaterals may mimic vascular malformation • May have clinical, imaging findings of intracranial hypertension (pseudotumor cerebri) • Dural A-V Fistula o Most acquired; clinical manifestations vary • Pulsatile tinnitus, exophthalmos • Less common = progressive encephalopathy (dementia), diffuse white matter hyperintensity from chronic venous hypertension o Imaging • Flow voids within wall of thrombosed dural sinus common • High grade lesions prone to intracranial (usually parenchymal) hemorrhage • Small web of vessels on collapsed MRA images may suggest diagnosis • DSA gold standard for diagnosis Helpful Clues for Less Common Diagnoses • Meningioma o Enhancing dural-based mass ± "tail" o May invade, occlude, or compress dural sinuses

DURAL SINUS

LESION,

GENERAL

CIl

"

c:

Bony hyperostosis variable Metastasis o Systemic primaries may compress or invade dural sinuses o Usually arise from calvarium with secondary dural involvement Lymphoma o Dural-based mass(es) common in metastatic lymphoma Depressed Skull Fracture o May lacerate/compress/occlude dural sinus o ± Venous epidural hematoma (EDH) o Venous EDH develops slowly, presents late! Intracranial Hypotension o Dural venous engorgement, enhancement o Slumping midbrain, tonsillar descent, SDHs

•

•

•

•

Helpful Clues for Rare Diagnoses • Dural Venous Sinus Stenosis o Focal short segmental narrowing on CTV, MRV, or DSA (venous phase) o May cause intractable headaches (intracranial hypertension) o Patients with suspected symptomatic venous outflow restriction, pressure gradient at venography may improve after stent • Thrombophlebitis o Complication of infection (meningitis, rhinosinusitis, or mastoiditis) o Infection spreads easily due to valveless nature of intracranial venous system

Arachnoid

Granulations,

May cause septic venous thrombosis Polycythemia o High hematocrit - "dense" dural sinus Hemangioma o Capillary/cavernous vasoformative neoplasm o Convexity dura or venous sinus (CS most common) o May present with mass effect or intracranial hypertension Leukemia o Dural-based enhancing masses o May compress/invade dural sinuses Rosai-Dorfman Disease o Younger patients o Lymphadenopathy> para nasal sinus disease o Lymphadenopathy usually coexists if C S disease is present o Solitary/multiple dural-based enhancing masses Extramedullary Hematopoiesis o Dural-based enhancing masses o Dural sinus compression/invasion rare Lipoma o Fat in dural sinus rare; CS most common Masson Vegetant Intravascular Hemangioendothelioma o Rare benign tumor of young patients o Papillary endothelial hyperplasia o Can cause stenosis, hypertension o Can mimic meningioma o

o

• •

•

•

•

• •

III

::l

Co

OJ ., III

::l

< C1> ::l CJ>

< C1> ::J

o

c: CJ>

0::l c: CJ> C1> CJ>

Dural Sinuses

I Axial T2WI FS

= ~

MR

shows

in the righllranSVerse probably

represenUng

a

large ovoid

CSF-signal mass

sinus with internal "flow vein.

void"

Axial

T1 C+ FS MR in the same patient

shows that the

lesion E:II does not enhance and is the same signal as CSF. Vein ~

enhances.

in an asymptomatic

This was an incidental

patient.

10

finding

3

rn

DURAL SINUS LESION, GENERAL

Q)

rn OJ

c

i:Ii rn OJ

o

c Q)

> rn

c Q)

> c: ltl

"ell "C

c:

ltl

Arachnoid Granulations,

Dural Sinuses

(Left) Axial erCT shows hypodense CST-like lobulated filling defect in the

right transverse sinus

=.

Note adjacent calvarial scalloping ~ (Right) Axial bone CT in the same patient shows smooth, well-delineated erosion of the calvarium caused by arachnoid granulation.

Arachnoid Granulations,

Dural Sinuses

Arachnoid Granulations,

Dural Sinuses

Arachnoid Granulations,

Dural Sinuses

Arachnoid Granulations,

Dural Sinuses

(Left) Sagittal T1 WI MR shows a round fluid signal cystic lesion within the

superior sagittal sinus

= that

followed CSF on all sequences. This is a variant case because of the atypical size and location of the lesion. (Right) Coronal oblique angiography shows a large filling defect =:I in the superior sagittal sinus caused by giant arachnoid granulation.

(Left) Axial T2WI MR with video inversion shows a cluster of sharply marginated CSF-like cysts I2J remodeling the inner calvarium. (Right) Axial T2WI MR shows an arachnoid granulation that appears to communicate directly with the adjacent subarachnoid space via ~1 defect in its inner margin

I 10 4

along the inner table of the calvarium ~. It also contains a hypoinlense "knuckle" of tissue E:lthat forms an intraosseous meningoencephalocele.

DURAL SINUS

lESION,

en

GENERAL

c: "" III

:J

Co OJ .., III

(Left) Coronal MRV shows no flow-relaled signal wilhin the left transverse or sigmoid sinuses on lhe MRV MIP projection. Compare to normal dominant right transverse and sigmoid ~ sinuses. (Right) Coronal MRV shows flow-related signal within an asymmetrically smaller lefl transverse sinus it is

=

=.

:J


1Il "tl

c: ns

Dural A-V Fistula

(Left) Lateral angiography shows thrombosis at the of the transverse,

dural sinuses. Several enlarged lransosseous perforating branches from occipital artery supply dAVF ffi (Right) Axial T2WI MR shows normal right "flow void'l liB Left side is hyperintense and contains numerous

tiny" (Jow voids"

=.:I.

Dural AVF developed in chronically occluded left transverse sinus.

Meningioma (Left) Axial NECT shows a densely calcified meningioma that originated within and mildly expands superior sagittal sinus (Right) Coronal T1 C+ MR

=.

shows dural-based metastasis

=.:I on

both sides of superior sagittal sinus, which is invaded and thrombosed by the tumor E!1I.

(Leh) Sagittal T1 C+ MR shows an enhancing dural-based mass =.:I in the region of cisterna magna that is encroaching into the region of the torcular

herophili E!1I in a patient with systemic lymphoma. (Right) Axial NECT shows a large acute epidural hematoma due to a depressed skull fracture through the torcular and transverse sinus (not shown), resulting in dural sinus laceration and bleeding.

=

I 10 6

Metastasis

DURAL SINUS

lESION,

GENERAL III

:J

C.

III ., III

(Left) Coronal T7 C+ MR in this patient with intracranial hYPolensions shows engorged dural venous sinuses ~ thickened enhancing dura ~ Pituitary gland (not shown) also appeared enlarged. (Right) Axial MRV shows small caliber of both

transverse-sigmoid junctions,

sinus

< (1)

:J

U>




(j)

:J C U> (1)

with focal stenosis

in the left transverse sinus

:J

=

U>

in a patienl with papilledema and headaches.

Thrombophlebitis (Left) Axial CECT shows bilateral proptosis. The

cavernous sinuses are enlarged with a lack of contrast

opacification

due to

thrombosis PJ:ll. Mucosal disease and fluid levels consistent with acute rhinosinusitis can be seen in multiple sinuses. (Right) Axial NECT shows hyperdense superior sagillal sinus ~ & cortical veins ~ and mimics CrCT in this 22 year old patient

with chronic

right-to-left cardiac shunt, hematocrit of 67.

(Left) Coronal T7 C+ MR in this /] year old shows a strongly enhancing left

=

cavernous sinus lesion encasing

the left internal

carotid artery

a",

extending

into sella and middle

cranial

fossa. (Right) Sagittal T7 C+ MR in another 73 year old with frontal 50ft tissue swelling shows dural, calvaria/ enhancing mass that occludes anterior

superior sagillal sinus PlB. Acute lymphoblastic leukemia was found.

I 10 7

en OJ en :J c

US en :J

o C

OJ

> en c

.Qj

> c ns •..

[JJ

"C C

ns :J

-"Vl

ENLARGED CORTICAL VEINS

DIFFERENTIAL DIAGNOSIS Common • Normal • Developmental Venous Anomaly • Arteriovenous Malformation • Dural A-V Fistula Less Common • Thrombosis, Dural Sinus • Thrombosis, Cortical Venous Rare but Important • Venous Varix • Vein of Galen Malformation • Sinus Pericranii

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Is there one enlarged vein or several? • Are they definitely veins? Could some be arteries? • Is there evidence of thrombosis? Helpful Clues for Common Diagnoses • Normal o Major anastomotic cortical veins (Trolard, Labbe, SMCV) can be very prominent • Developmental Venous Anomaly o Central vein of DVA can drain cortically o "Medusa head" configuration • Arteriovenous Malformation o Prominent cortical veins tend to be regional, geographically related to nidus o Look for varices, stenoses, stagnant flow

Normal

Caution: Prominent veins may persist even if no residual AV shunting present • Dural A-V Fistula o Chronic dural sinus thrombosis (vascularized thrombus) common precursor o Cognard type ITB shows reflux into cortical veins; types III-IV have direct cortical drainage • Hemorrhage risk t o

Helpful Clues for Less Common Diagnoses • Thrombosis, Dural Sinus o Thrombosis/stenosis causes increased back pressure o T2* (clot "blooms"), CECT or Tl C+ MR ("empty delta" sign) helpful • Thrombosis, Cortical Venous o Can occur without dural sinus occlusion o Hyperdense on NECT ("cord sign") o T2* most useful ("blooms") Helpful Clues for Rare Diagnoses • Venous Varix o Usually with AVM or dAVF o Isolated venous varices are rare • Vein of Galen Malformation o Deep veins but cortical may t if large • Sinus Pericranii o Transcalvarial communication between dural venous sinus, extracranial (scalp) veins o Sometimes associated with DVA

Developmental

Venous Anomaly

I 10 8

Axial Tl C+ MR shows symmetric prominenl enhancing comcal veins, right SlI larger than lelt 1:ll1. These are much larger than the other cortical veins PJ::I.

Lateral

digital

subtraction

angiography

with

3D

rendering shows classic DVA with "hair-like" difated medullary veins I:ll1 and large transcortical draining vein SlI. (Courtesy P.Lasjaunias, MOJ.

en ,...

ENLARGED CORTICAL VEINS

c: Ql

::l 0-

[Jl .,

Arteriovenous

Malformation

Dural A-V Fistula

Ql

(Lefl) Axial T2WI MR shows ma,kedly enlarged cortical veins (/I varices") in a patient with right frontal lobe

=

arteriovenous

malformation

(not shown). (RighI) Axial TI C+ FS MR in a patient with righllransverse sinus dAVF shows reflux into very enlarged

cortical

vein

Note very prominent artifact=.

Thrombosis,

Dural Sinus

Thrombosis,

Cortical

::l







en

B.

::J

phase

U>

C

CD

U>

Venous (Lefl) Anteroposterior angiography shows thrombosed left transverse sinus [~J with prominent filling of regional cortical veins, including

vein of

Labbe EB (RighI) Axial T2* GRE MR shows thrombosed superior sagittal sinus ED with blooming clot extending into multiple enlarged cortical veins ~.

Vein of Galen Malformation

Sinus Pericranii (Lefl) Sagillal TI WI MR shows variant type of vein of Galen

malformation

with

enlarged vein of Galen ~ straight sinus Idl and innumerable dilated cortical veins (RighI) Lateral angiography shows paramedian venous anomaly from the sagittal sinus involves the sagittal sinus, calvarium, and scalp E!iilI in a patient with sinus pericranii.

I 10 9

rJl Q)

ENLARGED DEEP (MEDULLARY/EPENDYMAL)VEINS

rJl

:::>

c

us

rJl

:::>

o c Q)

> rJl C

.Qi

> C ltl

•...

l:ll "0

c

ltl

DIFFERENTIAL DIAGNOSIS Common • Developmental Venous Anomaly • Arteriovenous Malformation Less Common • Sturge-Weber Syndrome • Thrombosis, Deep Cerebral Venous • Thrombosis, Dural Sinus • Dural A-V Fistula • Glioblastoma Multiforme • Intracranial Hypotension Rare but Important • Capillary Telangiectasia • Blue Rubber Bleb Nevus Syndrome • Dural Venous Sinus Stenosis • Vein of Galen Malformation • Demyelinating Disease, NOS • Lymphoma, Intravascular (Angiocentric) • Encephalitis (Miscellaneous) • Granulomatous Angiitis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Urgent: Look for deep (i.e., internal cerebral) vein or dural sinus occlusion! • If not venous occlusion, consider o Could the lesion be a DVA? o Are there prominent cortical vessels as well? o Is there associated cortical abnormality?

I 10 10

Helpful Clues for Common Diagnoses • Developmental Venous Anomaly o Enlarged medullary veins o Drains into single dominant transcortical vein o Empties into dural sinus or deep ependymal vein o Solitary unless blue rubber bleb nevus syndrome o Hemorrhage rare unless associated with cavernous malformation • Arteriovenous Malformation o Parenchymal nidus, prominent cortical vessels o Enlarged medullary veins less common o Deep (subependymal) drainage associated with t hemorrhage risk

o

On Tl C+ small AVMs may appear as focal "blush" & draining vein

Helpful Clues for Less Common Diagnoses • Sturge- Weber Syndrome o Facial hemangioma ipsilateral to leptomeningeal (pial) angiomatosis o Paucity of normal cortical venous drainage causes chronic venous ischemia o NECT: Cortical Ca++, atrophy o CECTITl C+ MR • Enhancing pial angioma • Enlarged medullary veins • Enlarged choroid plexus ipsilateral to malformation common o FLAIRMR: "Ivy sign" of t sulcal signal • Thrombosis, Deep Cerebral Venous o Usually affects both internal cerebral veins (ICVs) ± vein of Galen (VaG), straight sinus (SS) o Initial findings may be subtle! o NECT • Hyperdense ICVs ± VaG, SS • Hypodense thalami, basal ganglia, ± deep white matter • ± Petechial hemorrhages o CECT • "Empty delta sign" if clotted SS, venous confluence • May see irregular "shaggy" enhancement around ventricles from engorged medullary veins oMR

• Tl: Deep veins iso- to hyperintense • T2: Hypointense clot may mimic "flow voids" • T2/FLAIR: Bilateral basal ganglia, thalami hyperintensities • T2* (GRE/SWI): Best sequence; clots "bloom" • Tl C+: Deep medullary veins may enlarge, enhance o DSA • Absent ICVs ± nonfilling of VaG, SS • Thrombosis, Dural Sinus o Chronic superior sagittal sinus occlusion medullary, ependymal veins enlarge as collateral venous drainage o Can mimic blue rubber bleb nevus syndrome • Dural A-V Fistula o Higher Cognard grades (IlB and above)

ENLARGED

DEEP (MEDULLARY/EPENDYMAL)

VEINS

CIl

c: ""

• Enlarged cortical> > medullary veins • Increased flow voids near or in dural venous sinus • Glioblastoma Multiforme a GBM, other malignant gliomas may develop necrosis, prominent neovascularity a Draining deep white matter (medullary, ependymal) veins may become very prominent • Intracranial Hypotension a Orthostatic headaches a Look for "sagging" floor of 3rd on sagittal, tonsillar herniation a Passive dural venous congestion common; medullary/deep ependymal vein enlargement less common Helpful Clues for Rare Diagnoses • Capillary Telangiectasia a Large capillary telangiectasia (typically> 1 cm) may have prominent central draining vein a Best seen on Tl C+ scan a Becomes hypointense on T2* (GRE/SWI) images • Blue Rubber Bleb Nevus Syndrome a Multiple cutaneous (bluish venous "blebs"), GI hemangiomas a Diverse CNS vascular malformations, venous variants common • Multiple DVAsclassic • Variant: Sinus pericranii & multiple DVAs

• Dural Venous Sinus Stenosis a Patients often have undiagnosed source of severe chronic recurrent headaches a Increased collateral flow, venous prominence, variable t ICP • Vein of Galen Malformation a Infant/child with dilated VOG a Enlarged ICVs, ependymal veins> > medullary veins • Demyelinating Disease, NOS a Fulminant demyelinating disease • Causes acute perivenular inflammation • Increased blood flow, loss of normal BBB a MS, ADEM, acute necrotizing/hemorrhagic leukoencephalopathy variants a Enhancement of deep medullary veins may be very prominent • Lymphoma, Intravascular (Angiocentric) a Clinical presentation • Stroke-like symptoms • Less common: Dementia, progressive mental status decline a Intravascular tumor plugs ± extension into perivascular spaces a Punctate, linear enhancing foci • Encephalitis (Miscellaneous) a Parenchymal T2/FLAIR abnormality ± mild-moderate enhancement • Granulomatous Angiitis a Enhancing foci ± mass effect a May have striking deep perivenular enhancement

Developmental

ll>

::::l Co

., OJ

!!!. ::::l


c:: ltl •...

m "'C

c::

ltl

Lymphoma, Metastatic,

Intracranial

(Left) Axial T7 C+ FS MR shows a classic case of nasopharyngeal carcinoma extending superiorly into the sphenoid sinus, clivus, and cavernous sinuses The left Meckel cave is involved while the right BI is spared. (Right) Axial T7 C+ MR shows an extensive, destructive central skull base mass that infiltrates the sphenoid sinus and both cavernous sinuses The

=.

=.

mass encases both cavernous

carotid arteries

~"

Neurofibromatosis (Leh) Coronal T 1 C+ FS MR shows schwannomas in both Meckel caves Bilateral vagal schwannomas are also present~. (Right) Axial T2WI MR shows numerous abnormal II (Jow voids II, predominately in the left ~ but also the right cavernous sinuses, in this patient with red eye, proptosis 2 weeks following head trauma.

=.

=

(Left) Axial T7 C+ MR shows bilateral cavernous sinus thrombosis, resulting as a complication of acute sinusitis. Note nonenhancing areas within the cavernous sinus thickened enhancing dura of tentorium and sphenoid wings BI. (Right) Coronal T2WI MR shows a large dival chordoma with bilateral

=

=-

cavernous

I 10 20

sinus invasion

S.

Type 2

Carotid-Cavernous

Fistula

BILATERAL CAVERNOUS

SINUS

LESIONS

CIl

~ c:

III

::l

Co

CD ., III

Neurosarcoid (Left) Axial T2WI FS MR shows isointense central skull base mass that extends superiorly into the sella turcica and both cavernous sinuses (Right) Coronal T1 + FS MR shows both Meckel caves Iilled with

strongly enhancing tissue

m.

Note that the infundibular stalk 81 and pituitary gland appear normal.

langerhans

Histiocytosis,

Skull Base

Pseudotumor,

::l

< (1)

::l (f>

< (1)

::J

o C (f>

CIl ::J C (f> (1)

(f>

Intracranial ILeft) Coronal CECT shows a central skull base lytic lesion with sharply defined margins. A large 50ft tissue component invading skull

base, both cavernous sinuses, and nasopharynx P.:I enhances strongly and uniformly. (Right) Axial T1 C+ MR shows bilateral cavernous sinus enhancement left more striking than right, in a patient with left-sided cranial neuropathies. Symptoms resolved with the administration of steroids.

leukemia

Germ Cell Neoplasms (Left) Axial T2WI MR shows a leukemic mass in the right orbit !::l infiltrating the lacrimal gland and the superior reclus muscle ~ Note isoinlenS€ tissue in

both cavernous sinuses ~ suggesUng extension of leukemic infiltrate. (Right) Coronal CECT shows an enhancing mass infiltrating the pituitary gland 81 and both cavernous sinuses

=.

I 10 21

en Q) en :::J c

MECKEl CAVE lESION

(f)

en

---

C Q)

Common

o

> en c Q)

> C ltI

•..

1IJ "'C C

ltI

• Schwannoma, Trigeminal, Intracranial • Meningioma • Metastasis, Skull Base less Common

• • • • • • •

Metastasis, CSF/Meningeal Metastasis, Perineural CNV3 Meningitis Neurosarcoid Neurofibroma Pseudotumor, Intracranial Pituitary Macroadenoma

Rare but Important

• • • • • • •

Metastasis, Perineural CNV2 Trigeminal Herpetic Neuritis Lipoma Epidermoid Cyst Dermoid Cyst Neurocysticercosis Chronic Thrombosis, Dural Sinus

---

ESSENTIAL INFORMATION

Key Differential

I 10 22

• Acute muscles • Chronic muscles

DIFFERENTIAL DIAGNOSIS

:::J

Diagnosis Issues

• Normal Meckel cave (Me) o Anatomy • CSF-filled, dura-arachnoid lined invagination into cavernous sinus (CS) • Contains CNS fascicles, semilunar ganglion • Communicates directly, freely with prepontine/cerebellopontine cisterns o Normal imaging • Ovoid, smooth CSF-filled cisterns on axial, coronal scans resemble "open eyes" • Bilaterally symmetric hypointensity on TlWI • Bilaterally symmetric hyperintensity on T2WI • Abnormal Meckel cave o "Winking" Meckel cave sign • One MC filled with soft tissue, not CSF • One MC therefore NOT = CSF density /intensity • Asymmetric appearance = "Winking" Meckel cave (one "eye" appears closed) o Look for CNS motor denervation secondary to MC mass • May be only sign of subtle lesion

hyperintensity, enhancement of of mastication - atrophy, fatty infiltration of of mastication

Helpful Clues for Common

Diagnoses

• Schwannoma, Trigeminal, Intracranial o Variable configuration • "Dumbbell" tumor with CPA component, constriction of tumor at entrance to Meckel cave, Meckel cave mass • May involve MC only • ± Extracranial extension along VI, V2, &/or V3

Unilateral unless NF2 o Hyperintense on T2WI, strong enhancement on TI C+ o May result in atrophy of muscles of mastication • Meningioma o Uni- > bilateral involvement o Dural thickening along cavernous sinus, tentorium (dural "tail sign") o ± Ipsilateral denervation, atrophy of muscles of mastication • Metastasis, Skull Base o Metastases to Meckel cave can be hematogenous, direct geographic extension, perineural, or CSF spread • Hematogenous spread to central skull base (BaS) with secondary involvement of cavernous sinus • Direct extension from extracranial primary (e.g., nasopharyngeal squamous cell carcinoma) into central BaS • Uni- > bilateral involvement o Sagittal Tl WI helpful • Look for replacement of normal fatty clival marrow ± cortical destruction o

Helpful Clues for less Common

Diagnoses

• Metastasis, CSF/Meningeal o Pia-arachnoid tumor spread may extend into MCs o ± Enhancement along cisternal CNS • Metastasis, Perineural CNV3 o Retrograde tumor spread along mandibular nerve o Look for mass in retromolar trigone, masticator space o Adenoid cystic carcinoma, squamous cell carcinoma most common

CJl

MECKEL CAVE LESION

'"

c:

CNV3 appears thick, enhancing ± erosion of foramen ovale • Meningitis o Any etiology (e.g., pyogenic, TB) o Dura-arachnoid disease can extend into o

MC o Look for basal cistern enhancement • Neurosarcoid o Pituitary gland, infundibular stalk, dural masses common o Can be uni- or bilateral • Neurofibroma o Orbit/scalp/lid plexiform in NFl o May extend posteriorly through SOF, infiltrate VI branches - MC • Pseudotumor, Intracranial o Typically originates in/around orbit o Extends through SOF into CS, MC o Variable dura-arachnoid thickening, enhancement o Idiopathic invasive subtype • May erode bone, mimic aggressive infection, neoplasm • Pituitary Macroadenoma o Can extend into one or both CSs, MCs o Pituitary gland generally cannot be distinguished from mass o Gland IS mass o Aggressive invasive type may destroy central skull base, clivus • Pituitary adenoma> > > > carcinoma • Can mimic malignant disease, so do endocrine workup

ll>

Helpful Clues for Rare Diagnoses • Metastasis, Perineural CNV2 o Often skin carcinomas (basal, squamous cell) o Infiltrates along inferior orbital canal o May enlarge/erode foramen rotund urn o Thickened, enhancing maxillary nerve • Trigeminal Herpetic Neuritis .. o Herpes zoster oticus > trigeminal neuntls o Edematous, enhancing CNS • Ophthalmic division most commonly involved • Lipoma o MC is rare site o Uni- > bilateral • Epidermoid Cyst o May originate in MC or as extension from CPA epidermoid o Does not suppress on FLAIR;restricts on DWI • Dermoid Cyst o Looks like fat in MC, not CSF o May occur with or without rupture, CSF fatty droplets • Neurocysticercosis o Cysts in basal cisterns may extend into one or both MCs • Chronic Thrombosis, Dural Sinus o Chronically occluded dural sinus(es) o Dural thickening, enhancement secondary to collateral venous drainage o May involve one or both MCs

::] Q.

..,

OJ ll>

::]


(J)

c Q)

> C III

"-

II) "t:J C III

(Left) Coronal T1 C+ MR shows a meningioma in the right Meckel cave =:I. The left Meckel cave is filled with CSF E!:II as is normal. (Right) Axial T1 C+ MR shows a metastasis 10 the left petrous apex that extends in10 the clivus and the left Meckel cave =:I. The right Meckel cave B is normal and CSF-filled.

Metastasis, CSF/Meningeal (Left) Axial T I C+ FS MR in patient with diffuse CSF spread of glioblastoma multiforme shows pial

metastases covering the cerebellum~. The tumor has spread into the left Meckel cave =:I. Note the normal in the right Meckel cave E!:II. (Right) Coronal T I C+ FS MR shows perineurallumor extension of squamous cell carcinoma from the masticator space E!:IIthrough an enlarged foramen ovate ~ into the left cavernous sinus and Meckel cave =:I.

csr

Neurosarcoid (Left) Coronal T1 C+ MR shows basilar and cisternal meningitis with thickened, enhancing meninges and extension into the right Meckel cave ~. (Right) Coronal T1 C+ FS MR shows a sarcoid infiltrating the pituitary gland E!:II as well as both Meckel

=

caves

I 10 24

=.

,..c:

Ul

MECKEl CAVE LESION

Ql

:J C.

...

tll Ql

Metastasis, Perineural CNV2 (Left) Axial TI C+ MR shows an enhancing lesion in left cavernous sinus & Meckel cave l:ll. Thickened dura, enhancing pituitary gland, & infundibulum (not shown)

were also present. Symptoms, findings resolved after steroids. (Right) Axial C[CT w!curved reformatted image shows cheek melanoma l:ll spreading along left CNV2 from infraorbital foramen through inferior orbital canal !J::l & foramen {alundum ~ into Meckel cave B1. (Courtesy 5. van der Westhuizen, MO).

:J


en c:: OJ

> c::

•.. t1l

lD

"0

c:: t1l

::J

-'"

(f)

HYPERDENSE

DIFFERENTIAL DIAGNOSIS Common • Physiologic Hyperdensity • Thrombosis, Dural Sinus • Polycythemia • Subdural Hematoma, Acute (Mimic) less Common • Lymphoma, Metastatic, Intracranial • Metastases, Skull and Meningeal • Meningioma Rare but Important • Hemangioma • Leukemia • Extramedullary Hematopoiesis (Mimic) • Masson Hemangioma

ESSENTIAL INFORMATION

I 10 26

Key Differential Diagnosis Issues • Evaluate density, configuration of dural sinuses o ALLdural sinuses appear slightly hyperdense compared to adjacent brain, CSF on NECT o Margins of dural sinuses typically flat or slightly concave • Density: Is "dense dural sinus" TOO dense? o Measure dural sinus density o Compare to internal carotid artery (as internal standard) o If too dense, is it thrombosis or polycythemia? • Dural sinus thrombosis (DST) > > polycythemia • Check hematocrit! • If any question, do CECT + CTV or MR + MRV (include GRE or SWI sequence!) • Look for nonenhancing thrombus • Configuration: Disrupted dural sinus, bulging dural sinus, irregular/lobulated dural sinus o Some neoplasms invade dural sinuses o Usually meningioma or metastasis o May appear hyperattenuating if densely cellular o May also cause dural sinus thrombosis (e.g., meningioma in superior sagittal sinus)

DURAL SINUS Helpful Clues for Common Diagnoses • Physiologic Hyperdensity o At hematocrit of 43 (normal) • Intravascular blood in arteries, veins, dural sinuses appears slightly hyperdense compared to normal brain • At hematocrit of 70, circulating biood 63% denser o Dural sinuses appear especially dense in newborns because of • Physiologic polycythemia at birth • Unmyelinated/low density brain • Thrombosis, Dural Sinus o Many causes of DST o Trauma • May tear sinus • ± Thrombosis • Thin subdural hematoma can layer along falx, tentorium, mimic "empty delta sign" (latter seen on CECT, not NECT!) o Meningitis o Dehydration, hypovolemia • Shock, cardiac failure, other "low flow" states o Hypercoagulable states • Antiphospholipid antibody syndrome • Von Willebrand disease • Post-anticoagulation "rebound" phenomenon • Postpartum o Hormonal • Pregnancy, postpartum • Oral contraceptives o Hemoglobinopathies (e.g., sickle cell disease, thalassemia) o Vasculitis • Some vasculitides (e.g., Behc;:et)have propensity to cause DST • Polycythemia o Can be physiologic • Newborn • High altitude o Pathologic • Cyanotic congenital heart disease • COPD o ALLvessels (arteries, veins, dural sinuses) become hyperdense in polycythemia • t Hemoglobin protein - t dural sinus density • NECT in patient with polycythemia "looks like" a CECT

HYPERDENSE DURAL SINUS • Do not mistake for DST (MR + MRV clarifies) • Subdural Hematoma, Acute (Mimic) o May layer along tentorium, superior sagittal sinus ..• mimic dural thrombosis Helpful Clues for less Common Diagnoses • Lymphoma, Metastatic, Intracranial o Central skull base lymphoma may extend diffusely • Destroys bone • Infiltrates adjacent structures • May extend into one or both cavernous sinuses o Hyperdense, strongly enhancing • Metastases, Skull and Meningeal o Skull metastases commonly invade underlying dura o If adjacent to dural venous sinus, may extend into and compromise sinus • Meningioma o Expands into (or, less commonly, originates from) dural venous sinus o Grows slowly, so collateral blood flow develops o Sellar/parasellar/clival meningiomas commonly involve one or both cavernous sinuses Helpful Clues for Rare Diagnoses • Hemangioma o Capillary &/or cavernous hemangiomas may arise within dura o Cavernous sinus common site o May mimic meningioma

• Leukemia o Dural-based mass(es) along falx can mimic DST o Adjacent to, usually not within, venous sinus • Extramedullary Hematopoiesis (Mimic) o Dural-based mass(es) typical adjacent to, not within, venous sinus • Masson Hemangioma o Synonyms • Vegetant intravascular hemangioendothelioma • Intravascular papillary endothelial hyperplasia (IPEH) o Found in head, neck, fingers, trunk, occasionally viscera (liver) o Exuberant endothelial proliferation within veins, including dural venous sinus o Benign; can be mistaken for angiosarcoma

< ~. '" < CD o 'c" CJ)

CJ)

en c '" CJ)

CD

CJ)

Other Essential Information • Foreign body can mimic DST o Retained medical devices, catheters, bone cement, AVM glue, bullets, etc.

SELECTED REFERENCES 1.

2.

Teksam Met al: Frequency and Topographic Distribution of Brain Lesions in Pediatric Cerebral Venous Thrombosis. AJNR Am J Neuroradiol, 2008 Healy JF et al: Polycythemia mimicking venous sinus thrombosis. AJNR Am J Neuroradioi. 23(8):1402-3, 2002

I

=-

Coronal NECT in an asymptomaUc adult shows normal, slighdy hyperdense superior sagittal sinus falx

cerebri=.

-=

Axial NECT shows relaUvely hyperdense internal carotid arteries in a neonate. Note that the dural venous sinuses 81 also appear hyperdense. Low density of unmyelinated brain accentuates this appearance.

10 27

HYPERDENSE

(j) Q) (j)

DURAL SINUS

:::J C

C/) (j)

:::J

o C

Thrombosis, Dural Sinus

Q)

> (j)

c

'Qi

> c C'Cl

"ell "'C

c

C'Cl

(Left) Axial NECT in a premature

infant shows

striking hyperdensity of transverse sinuses II] caused by physiologic polycythemia of newborns and Jow density of adjacent, almost completely unmyelinated brain. (Right) Axial NECT shows a moderately hyperdense superior sagittal sinus 1m (contrast with normal mild hyperdensity). Note subtle effacement of the left frontal sulci E!l:I subarachnoid hemorrhage (later identified on FLAIR MR).

Thrombosis, Dural Sinus (Left) Axial NECT shows hyperdense, expanded straight sinus with convex margins The clot extends into the vein or Galen B torcular Herophili PJ::I. (Right) Axial NECT in the

=.

same patient shows hyperdense, expanded, somewhat lobulated-appearing superior sagillal sinus ICB clot in cortical

vein ~

("cord

sign").

(Left) Axial NECT looks like it is a contrast-enhanced scan. It isn't! The patient has a markedly elevated hematocri( which makes dura intracranial arteries, veins, venous sinuses I;] all appear hyperdense. (Right) Axial NEeT in the same patient shows striking hyperdensity of superior sagittal sinus caused by polycythemia (hematocrit = 70).

=

=

I 10 28

Thrombosis, Dural Sinus

HYPERDENSE

Ul

DURAL SINUS

'"c: III

::::l

a. OJ ....• III

(Left) Axial NECT in a patienl with subdural hematoma shows mimic of thrombosed dural sinus. High densily blood is layered along the straighl sinus and falx ~ It also mimics lhe "empty delia sign" seen with OS!. which is idemified on CECT as enhancing dura

surrounding nonenhancing clol. (Right) Axial NEeT shows an acute right-sided subdural hematoma that has spread inlo interhemispheric fissure along lhe falx 81 and

=

tentorium

lymphoma,

Metastatic,

Intracranial

::::l

< ctl OJ

en


4 adjacent levels affected o May see smaller foci of ossification due to trauma, aging, or seronegative arthropathy o Look for other signs of trauma to help make distinction o Small foci of ossification ALLdistinguished from trauma by normal configuration of underlying vertebra • Posterior element injuries not uncommonly missed acutely o Malalignment, focal degenerative disease signs suggest prior injury • Fracture nonunion sometimes difficult to determine o Prolonged failure of bridging callus • Time to healing depends on age, health, and fracture location o Sclerosis of apposing fracture margins • Craniocervical instability due to multiple causes o Trauma o Arthritis: Rheumatoid arthritis, seronegative, calcium pyrophosphate deposition disease o Congenital: Achondroplasia, trisomy 21 o Infection • Kyphosis, scoliosis due to many causes o Short curve deformities suggest trauma, infection, congenital, or tumor

Os Odontoideum

Sagittal oblique T2WI MR shows 2S year old man with

Sagittal NEeT shows nonunited dens fracture ~

fXJsHraumatic disc degeneration arthritis. Chronic facet subluxation

odontoideum) and posHraumatic PLL ossification Ea. Pseudarthrosis in DISH -7 is a common finding and

= and uncovertebraJ

unless oblique views are obtained.

~

is easily missed

does not necessarily indicate trauma.

(os

CERVICAL, CHRONIC

POST-TRAUMATIC

en

ABNORMALITY

"tl

:J CD

-I

~

Ossification,

OJ

Anterior longitudinal ligament

:J

,

CI>

(Left) Sagittal STIR MR shows post-traumatic kyphosis and acce/eraled degeneralive disease. (Right) Laleral radiograph shows mature-appearing ossicle fell/O be degenerative in

en

"~ OJ

=-

origin, in anterior

longitudinal ligament of a 55 year old. Underlying vertebral contour is normal, excluding leardrop-Iype fracture.

Post-Operative Change, Normal

Rheumatoid Arthritis, Adult (Left) Sagillal NrcT shows normal post-operative appearance afler C2 corpec/Omy =:I and slrul graft E!lI placement posleriorly. (Right) Sagillal bone CT shows anterior occipul-C7 subluxation !:Jl and extensive bony erosions ~ Allhough C7-2 subluxation is more common in rheumatoid

arthrilis,

subluxation also occurs at this level and in lower cervical spine.

Juvenile Idiopathic Arthritis

OPll (Left) Lateral radiograph shows facet fusion at C2-3 =:I. Congenital fusion anomalies may have same appearance as }IA. fusions may involve

vertebral

bodies, posterior elements, or bOlh. (Right) Sagillal bone CT shows bulky ossification PLL >=:> as well as ALL =:I. Post-traumatic heterotopic ossificalion is usually limited to 1-2 levels in cervical spine.

II 1 3

CERVICAL, LOWER, POST-TRAUMATIC BONY ABNORMALITY

ro ro

:.::; II (f)

,

'"cro

~

I I

DIFFERENTIAL DIAGNOSIS

ESSENTIAL INFORMATION

f0-

Common

Key Differential

al

• Subaxial Cervical Spine Fractures o Hyperflexion Injury, Cervical o Posterior Column Injury, Cervical o Burst Fracture, Cervical o Hyperflexion-Rotation Injury, Cervical o Lateral Flexion Injury, Cervical o Hyperextension Injury, Cervical o Hyperextension-Rotation, Cervical o Pathologic Vertebral Fracture o Shear Injury • Post-Traumatic Deformity o Accelerated Degeneration o Facet Arthropathy, Cervical o Kyphosis o Scoliosis • Nontraumatic Entities that Mimic Trauma o Ossification of Anterior Longitudinal Ligament o Metastases, Lytic Osseous o Rheumatoid Arthritis, Adult o Juvenile Idiopathic Arthritis o Klippel-Feil Spectrum o Post-Operative Change, Normal o Facet Arthropathy, Cervical o Incomplete Fusion, Posterior Element o Osteomyelitis, Pyogenic

• Evaluate for post-traumatic instability with flexion/extension views o Not accurate in 1st week after injury

c: '0. rn

Less Common

• Spondyloarthropathy,

Seronegative

Diagnosis Issues

Helpful Clues for Common

Diagnoses

• Signs of acute injury o Malalignment, focal kyphosis, or lordosis o Soft tissue swelling (not always present) o Fracture line • Signs of remote trauma o Cervical deformity o Single level facet osteoarthritis • MR very helpful in questions of acuity of injury, and distinguishing trauma from trauma mimics o Look for bone marrow edema on fluid sensitive sequences • Trauma mimics o Ossification of anterior longitudinal ligament: No bone donor site visible o Growth disturbance in congenital and childhood disorders o Infection: Vertebral end plates eroded o Metastatic disease • May see round or oval bone lesion, or involvement of entire vertebral body • Cortex destroyed not just disrupted as in trauma o Incomplete fusion shows smoothly contoured margins, unlike trauma

II 1 4

Lateral radiograph

shows

flexion

teardrop

fracture

=

due to anterior compression, and widened interspinous distance [;8 due to posterior distraction.

Coronal bone CT shows isolated articular pillar fracture I:llI of C7 due to lateral flexion injury. Although posterior column fractures may be isolated, search should be made for associated

fractures.

CERVICAL, LOWER, POST-TRAUMATIC

BONY ABNORMALITY

Hyperflexion-Rotation Injury, Cervical (Leh) Sagiltal bone CT shows loss of height of C7 verlebral body and relropulsed fragment ~ into canal indicating axial load (burst) injury. (Right) Laleral radiograph shows focal kyphosis indica ling flexion injury. Grade 1 anlerofislhesis and unilateral facel dislocation P al C5-6

=

indicate

rotational

component

of injury. C6

articular pillars are superimposed, but pillars of C5 and above levels are rotated; this is a key sign of rOlation

injury.

Pathologic Vertebral Fracture (Lefl) Sagittal bone CT shows hyperextension injury with small bony avulsion 81. I'yperextension teardrop fractures such as this are usually smaller than Ihose seen in hyperflexion injuries. Note fused levels above fracture (RighI) Lateral radiograph shows severe compression fracture of C5 81 due to multiple myeloma. All visualized vertebrae are oSleopenic, but no focal lesions are visible, a

=.

common

appearance

on

radiographs of diffuse spine myeloma.

Ossification of Anterior longitudinal ligament (Lefl) Lateral radiograph shows discontinuous ligamentous ossification 1m. Ossification is adjacent to vertebral bodies with normal contour, and no donor sites are visible. (Right) Axial N[CT shows enlarged spinal canal and dysplastic posterior elements. Clues lO nonlraumatic

etiology

are

smooth, corticated edges of bone defecls 81 and normal SOfllissues.

II 1 5

THORACIC BONY TRAUMA

ro

~

a.

(f)

U, c

~

Ial

c: Co II)

DIFFERENTIAL DIAGNOSIS Common • Fractures o Anterior Compression Fracture o Pathologic Vertebral Fracture o Lateral Compression Fracture o Chance Fracture o Burst Fracture o Facet-Lamina Fracture • Nontraumatic Fracture Mimics o Schmorl Node o DISH o Physiologic Wedging, Vertebral Body o Kyphosis, Idiopathic o Scheuermann Disease o Limbus Vertebra/Ring Apophysis o Sickle Cell o Osteomyelitis, Pyogenic Less Common • Trauma and Post-Traumatic Abnormalities o Fracture-Dislocation, Thoracolumbar Junction o Distraction Fx, Low Thoracic o Kilmmell Disease • Nontraumatic Fracture Mimics o Langerhans Cell Histiocytosis o Scoliosis and Kyphosis, Congenital o Renal Osteodystrophy o Achondroplasia o Osteomyelitis, Granulomatous o Cushing Disease

Anterior

Compression

Fracture

I I

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues • Important to distinguish between types of vertebral body fractures since treatment differs by type • Fractures most common at thoracolumbar junction • When one spine fracture is seen, always look for others Helpful Clues for Common Diagnoses • Anterior Compression Fracture o Never involves posterior vertebral body cortex or neural arch o Easily missed in upper T-spine on radiographs • Chance Fracture o Usually extends through posterior vertebral body cortex, but no retropulsed fragment o Horizontal fracture of posterior elements OR rupture of interspinous ligaments and facet joints • Burst Fracture o Always extends through posterior vertebral body cortex, may have retropulsed fragment o Vertical fracture of posterior elements also present • Scheuermann Disease o 4 or more levels involved; undulating end plates; normal anterior cortex

Burst Fracture

II 1 6

Sagillal NECT shows T4 compression fracture ~ and TS Chance fracture The degree of anlerior heighl loss and presence of horizontal posterior element fracture E!2 disunguish Chance fracture.

=.

Sagillal bone CT shows T3 bUN fracture wilh ret.ropulsed fragment Compression fractures are present at T4 and T5 r.:D. Patient is skeletally immature (nole ring apophyses ffi.

=.

THORACIC

BONY TRAUMA

(Left) Axial bone CT shows right T1 0 laminar fracture PJ::l associated with vertebral body fracture Chance injury. Facet (ractures may be isolated, but laminar fractures rarely are. (Right) Lateral radiograph shows mild anterior wedging T12 and L 1 81. Physiologic wedging may occur at T11-L7 and involves both endplates, while the anterior vertebral body cortex is

=-

normal,

(Left) Lateral radiograph shows thoracic kyphosis ~ without focal bony deformity. Idiopathic kyphosis probably originates as a postural problem but often becomes rigid. (Right) Sagiltal bone CT shows 4 adjacent vertebral bodies 81 affected

with anterior

wedging, undulating endplates, and Schmor/ nodes. These findings, especially combined with normal anterior vertebral

body cortices, are pathognomonic.

Fracture-Dislocation, Thoracolumbar Junction

Scoliosis and Kyphosis, Congenital (Left) Sagiltal bone CT shows ]-column fracture-dislocation.

=

Anterior

~ and posterior longitudinal ligament avulsions result in anterolisthesis of T6-7. Posterior column disruption is shown by spinous process fraclure

at T5

fractures

ffi

laminar

were also present

(not shown). (Right) Lateral radiograph shows focal kyphosis 81 at T10-11 due to vertebral body fusion. Diagnosis is readily made by CT or MR if radiographs are

II

equivocal.

1 7

ro ~ Cl. (/) , C/)

c

ro ~

Iell C

a.

(/)

LUMBAR

DIFFERENTIAL DIAGNOSIS Common • Fractures o Anterior Compression Fracture o Burst Fracture o Chance Fracture o Pathologic Vertebral Fracture o Facet-Posterior Fracture o Transverse Process Fracture • Fracture Mimics, Vertebral Body o Schmori Node o Physiologic Wedging o Limbus Vertebra o Scheuermann Disease o Scoliosis and Kyphosis, Congenital o Neurogenic (Charcot) Arthropathy o Sickle Cell o Osteomyelitis, Pyogenic o Post-Operative Spinal Complications • Fracture Mimics, Posterior Elements o Incomplete Fusion, Posterior Element o Spondylolysis o Post-Operative Change, ormal Less Common • Fracture and Post-Traumatic Abnormalities o Lateral Compression Fracture o Fracture-Dislocation o Ktimmell Disease o Insufficiency Fracture, Pedicle o Apophyseal Ring Fracture • Fracture Mimics o Renal Osteodystrophy o Achondroplasia Anterior

II 1

Compression

o

Osteomyelitis,

Sagittal bone CT shows fracture BI involving anterior and superior cortices of vertebral body; while sparing

Granulomatous

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Anterior Compression Fracture o Never involves posterior vertebral body cortex or neural arch o Unless osteoporosis, > 40% loss of height suggests Chance fracture, not compression • Burst Fracture o Extends through posterior vertebral body cortex o Usually but not always have retropulsion of fragment into spinal canal o Fractures of posterior elements vertically oriented • Chance Fracture o Often extends through posterior cortex o Always either horizontally oriented posterior element fracture OR widened interspinous distance due to interspinous ligament rupture • Transverse Process Fracture o Associated with retroperitoneal soft tissue injury, bony and ligamentous injury in pelvis • Physiologic Wedging o May be seen at Tll-Ll levels o Usually affects both superior and inferior endplates equally o No angular deformity of endplates or anterior cortex

Fracture

posterior cortex. Posterior elements are also intact

8

BONY TRAUMA

Burst Fracture

=

Sagittal bone CT shows involvement of posterior cortex which distinguishes this injury from compression

fracture.

LUMBAR BONY TRAUMA

Pathologic Vertebral

Fracture (Left) Sagittal NEeT shows anterior vertebral compression and horizontal fracture through posterior elements. In contrast, a burst fracture

has vertically

oriented posterior element fracture. (Right) Lateral radiograph shows L3 compression fracture Lytic bone lesion is not well

=.

seen, but anterior

displacement of aorta E2 due to sort tissue rnass points to pathologic fracture.

Schmorl Node

Limbus Vertebra (Left) Lateral radiograph shows multiple Schmorl nodes.' Shallow, smooth, bowl-shaped vertebral endplate depressions [;>J. Fractures are more angular in appearance. (Right) Lateral radiograph shows nonunited ring apophysis Sclerotic margins of apophysis and subjacent vertebral body are helpful signs to distinguish from chip fracture.

=.

Neurogenic

(Charcot)

Arthropathy

Sickle Cell (Left) Lateral radiograph shows chronic fractures with 1055 of height of L3 vertebral body I!:iJ and absence of anleroinferior

corner of L2

E2. There is clear instability, with widened facet joints. Sclerosis and extensive bone

=

debris are clues to diagnosis, as is patient history. (Right) Sagittal T2WI MR shows central depressions in vertebral endplates at multiple levels, the classic Lincoln log appearance reflecting bone II

infarcts.

/I

II 1 9

SCOLIOSIS

co

~ Cl. CIJ, (/)

c

co ~

IQl

c Q.

CIJ

DIFFERENTIAL DIAGNOSIS Common • Scoliosis, Idiopathic • Scoliosis, Degenerative • Trauma o Lateral Compression Fracture, Lumbar o Lateral Compression Fracture, Thoracic o Lateral Flexion Injury, Cervical • Scoliosis, Neuromuscular o Cerebral Palsy o Muscular Dystrophy o Friedrich Ataxia o Poliomyelitis o Hemiparesis/Hemiplegia o Paraparesis/Paraplegia • Scoliosis and Kyphosis, Congenital o Partial Vertebral Duplication o Failure of Vertebral Formation o Klippel-Feil Spectrum o VACTERLAssociation • Infection o Abscess, Paraspinal o Osteomyelitis, Pyogenic o Osteomyelitis, Granulomatous • Failed Back Surgery Syndrome • Neurogenic (Charcot) Arthropathy • Limb Length Inequality • Chest Wall Abnormality o Rib Anomaly o Sprengel Deformity Less Common • Pleural or Pulmonary o Empyema

Pneumonectomy o Fibrothorax • Tumor o Pathologic Vertebral Fracture o Osteoblastoma o Osteoid Osteoma • Congenital Syndromes with Normal Segmentation o Connective Tissue Disorders o Neurofibromatosis Type 1 o Osteogenesis Imperfecta o Mucopolysaccharidoses o Fibrous Dysplasia o Fetal Alcohol Syndrome o Proteus Syndrome o Tethered Spinal Cord • Radiation Therapy in Childhood o

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Painful scoliosis: Trauma, tumor, infection • Short-curve scoliosis: Congenital anomaly, tumor, infection, trauma, degenerative, post-operative • Balanced S-curve scoliosis: Idiopathic, connective tissue disorders • C-curve scoliosis: Neuromuscular, osteogenesis imperfecta

Abnormality

Scoliosis, Idiopathic

II 1 10

Anteroposterior radiograph shows classic, balanced, S-shaped curve, convex to right in thoracic spine. There is often minimal wedging of vertebrae on concave side of scoliosis.

Coronal T2WI MR shows asymmetric degeneraUve disc disease, with narrowing and discogenic sclerosis E!:t on left at U-4.

SCOLIOSIS

Trauma

Scoliosis, Neuromuscular (Left) Anteroposterior radiograph shows lateral compression fracture of L 7 resulting in short-curve scoliosis. (Right) Anteroposterior radiograph shows C-shaped curve SI characteristic of neuromuscular scoliosis. Failure of Fusion of the

=

posterior elements I:] is seen in the lumbar spine.

Rib Anomaly (Left) Anteroposterior radiograph shows leFt T7 7 hemivertebra IJ::]:l Fused to T72, and right T7 I hemivertebra Fused to T70. (Right) Anteroposterior radiograph shows dextroscoliosis related to the rib anomaly SI which has

caused separation

or right

4th and 5th ribs.

Osteoid Osteoma (Left) Anteroposterior radiograph shows short-curve scoliosis and pleural thickening in patient with focal pain. Because of these Findings, CT

=

scan was performed

and

showed osteoid osteoma. (Right) Anteroposterior

radiograph shows extreme scoliosis leading to shortening of trunk in osteogenesis imperfecta. Multiple

rib fractures are a/so

present.

II 1 11

KYPHOSIS

C1l

~ C>(/) , en

c

DIFFERENTIAL DIAGNOSIS

t= Ql

c: '0.

en

Osteogenesis Imperfecta Neurofibromatosis Type 1 o Achondroplasia o Mucopolysaccharidoses • Osteomyelitis, Granulomatous o o

C1l

Common • Postural Kyphosis • Idiopathic Kyphosis • Degenerative Disc Disease • Fracture o Anterior Compression Fracture, Thoracic o Anterior Compression Fracture, Lumbar o Burst Fracture, Lumbar o Hyperflexion Injury, Cervical o Chance Fracture, Thoracic o Chance Fracture, Lumbar o Hangman's C2 Fracture o Pathologic Vertebral Fracture • Multiple Myeloma • Metastases, Lytic Osseous • Metastases, Blastic Osseous • Scheuermann Disease • Failed Back Surgery Syndrome • Hardware Failure Less Common • Osteomyelitis, Pyogenic • Seronegative Spondyloarthropathy • Juvenile Idiopathic Arthritis • Post-Operative Infection • Neurogenic (Charcot) Arthropathy • Scoliosis, Neuromuscular • Paraparesis/Paraplegia • Scoliosis and Kyphosis, Congenital o Failure of Vertebral Formation o Klippel-Feil Spectrum o Vertebral Segmentation Failure • Congenital Syndromes

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Flexible Kyphosis: Postural, sometimes degenerative, failed fusion • Short-Curve Kyphosis: Infection, trauma, Charcot arthropathy and congenital fusion anomalies, degenerative (sometimes adjacent to surgical fusion) • Undulating Endplate: Scheuermann kyphosis • Cortical Break or Angular Deformity: Trauma • Destruction Vertebral Endplate: Infectious or post-infectious, neuropathic arthropathy, severe instability • Fused Vertebrae: Congenital, juvenile idiopathic arthritis, infection, seronegative spondyloarthropathy, post-traumatic, post-surgical • Multiple Wedged Vertebrae: Osteoporosis, pathologic fracture due to myeloma or metastasis, Scheuermann kyphosis, osteogenesis imperfecta, achondroplasia, mu copo Iysaccha rid osis

Degenerative

Postural Kyphosis

Disc Disease

II 1 12

Lateral radiograph shows diffuse kyphosis without bony abnormality. This is a common finding due to poor posture and may become fixed over time.

l.iJteral radiograph

shows

loss of normal

lordosis and

I:] due to degenerative disc disease. Degenerative kyphosis is

slight

kyphosis

common

at

C4-5

and

C5·6

in both cervical and lumbar spine.

KYPHOSIS

Anterior

Compression

Fracture, Thoracic

Burst Fracture, Lumbar (Left) Lateral radiograph shows multiple compression fraclUres due to senile osteoporosis in 80 year old patient. Always consider multiple myeloma in differential of this appearance. (Right) Lateral radiograph shows dynamic kyphosis at acute burst fraclure when patient stands upright in a brace 81.

=

=

Measure

deformity

from

1

level above fracture to I level below.

Chance Fracture, Lumbar

Failed Back Surgery Syndrome (Left) Sagitlal bone CT shows kyphosis due to combination of anterior compression and posterior distraction with horizontal spinous process fraclure 81 and widened interspinous distance ~. (Right) Lateral radiograph shows kyphosis al 13-4. Deformity developed post-surgery. Lucency around pedicle screw -7 is sign of failed fusion.

=

=

Achondroplasia

Osteomyelitis,

Granulomatous (Leh) Lateral radiograph shows anteriorly wedged vertebral bodies, scalloped posterior vertebral body cortices and short pedicles characteristic of achondroplasia. (RighI) Sagitlal bone CT shows

=-

characteristic hairpin-turn kyphosis called gibbus deformity and extensive spinal fusion seen in POll disease (spinal tuberculosis).

=

II 1 13

ro ~ DC/), C/)

c

co ~

IC1l

c '0.

en

KYPHOSCOLIOSIS,

DIFFERENTIAL DIAGNOSIS Common • Traumatic o Burst Thoracolumbar Fracture o Lateral Compression Fracture, Lumbar o Lateral Compression Fracture, Thoracic o Lateral Flexion Injury, Cervical o Chance Fracture, Thoracic • Congenital o Scoliosis and Kyphosis, Congenital o Failure of Vertebral Formation o Klippel-Feil Spectrum o Partial Vertebral Duplication o Tethered Spinal Cord o Caudal Regression Syndrome • Scoliosis, Idiopathic • Scheuermann Disease • Scoliosis, Neuromuscular • Juvenile Idiopathic Arthritis • Kyphosis, Idiopathic • Kyphosis ormal in Infants Less Common • Infection o Osteomyelitis, Pyogenic o Osteomyelitis, Granulomatous o Prevertebral Abscess o Post-Operative Infection • Tumor o Osteoid Osteoma o Osteoblastoma o Aneurysmal Bone Cyst o Ewing Sarcoma o Langerhans Cell Histiocytosis

• • • • •

CHILD

Syringomyelia Neurofibromatosis Type 1 Connective Tissue Disorders Post-Operative Spinal Complications Diastematomyelia

Rare but Important • Post-Radiation

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • MR may be useful in certain cases o Painful scoliosis: Tumor, infection o Atypical curve: Often have underlying bony or neural abnormalities o Congenital scoliosis: Assess full extent of bony abnormalities • CT useful to characterize congenital scoliosis Helpful Clues for Common Diagnoses • Congenital curve may progress rapidly, especially if it includes unfused hemivertebrae • Scheuermann kyphosis presents in adolescence, may be misdiagnosed as fracture o Involves multiple levels, see Schmorl nodes or undulation of end plates without angular deformity • Lumbar kyphosis normal in infants o Lumbar lordosis develops after infant begins to sit upright

Traumatic

II 1 14

Sagillal bone CT shows kyphoUc deformity !l:lI in flexion-distraction type injury. Kyphosis also seen due to burst or compression fracture.

Anteroposterior bone CT 3D reformation shows left T II hemivertebra Short-curve, unbalanced kyphoscoliosis is typical of congenital kyphoscoliosis.

=.

KYPHOSCOLIOSIS,

CHILD

Scheuermann

Disease (Left) COlOnaIbone CT shows Klippe/-Feil spectrum, with extensive fusion anomalies of cervical spine, with dexlroscoliosis. Kyphosis was also present. (Right) Sagittal bone CT shows kyphosis due to vertebral wedging~. Note undulating endplates and Schmor/ nodes at 4 contiguous levels. 7S% of Scheuermann cases show

scoliosis.

Juvenile Idiopathic

Arthritis (Left) Anteroposterior radiograph shows C-shaped scoliosis typical of

neuromuscular scoliosis. There is a/so often

persistence of infantile kyphosis in neuromuscular disease. (Right) Lateral radiograph shows mild kyphosis due to cervical fusions~. Kyphosis due to juvenile chronic (idiopathic) arthritis is usually not severe.

Infection (Left) Sagittal T2WI MR shows infantile

tuberculosis

causing kyphotic deformity, epidural abscess =:I, and pre vertebral abscess ~. Spinal TB can be present without pulmonary abnormalities. (Right) Lateral radiograph shows large expansile mass =:I, aneurysmal bone cyst in this case, involving posterior

elements and causing kyphotic deformity at C2- J level.

II 1 15

PlATYSPONDYlY,

Cll

DIFFUSE

~

CL (/J

U, C Cll ~

IQl C

a. (/)

DIFFERENTIAL DIAGNOSIS Common

• • • •

Multiple Myeloma Osteoporosis Sickle Cell Scheuermann Disease

less Common

• Metastases, Lytic Osseous • Osteogenesis Imperfecta • Mucopolysaccharidoses Rare but Important

• • • • • •

Spondyloepiphyseal Dysplasia Ehlers-Danlos Syndrome Achondroplasia Cushing Disease Thanatophoric Dwarfism Gaucher Disease

ESSENTIAL INFORMATION Key Differential

Diagnosis Issues

• Uncommon condition irrespective of cause • In adults, usually due to severe osteoporosis or myeloma o Compression fractures may be so extensive that they cause uniform flattening at all levels o More commonly, amount of vertebral height loss varies from level to level o Metastases uncommonly show uniform platyspondyly • Dwarfisms show limb abnormalities also

Multiple Myeloma

II 1 16

Lateral radiograph shows 1055 of vertebral body height at almost all visualized levels, due to multiple pathologic fractures. Height los5 is greater anteriorly than posteriorly.

• Connective tissue disorders show scalloping of posterior vertebral body margin o Due to dural ectasia Alternative

Differential

Approaches

• Uniform flattening o Spondyloepiphyseal dysplasia o Osteogenesis imperfecta • Anterior height loss> posterior o Osteoporosis o Multiple myeloma o Scheuermann disease o Metastases, lytic osseous o Osteogenesis imperfecta • Vertebral "beak" o Mucopolysaccharidoses o Achondroplasia (at thoracolumbar junction) • Limited to lumbar region o Ehlers-Danlos syndrome • Central loss of vertebral body height o Sickle cell ("Lincoln Log" vertebrae) o Cushing disease ("fish mouth" vertebrae) o Osteogenesis imperfecta ("fish mouth" vertebrae) o Gaucher disease • Also seen in multiple rare dwarfism syndromes o Enchondromatosis has been reported to involve spine (spond yloenchondrod ysplasia) o Dysosteosclerosis o Kniest dysplasia

Sickle Cell

Sagittal T1WI MR shows abnormal low T1 marrow signal and characteristic 1055 of vertebral body height at all levels due to bone infarcts.

PLATYSPONDYLY,

Scheuermann

Disease

DIFFUSE

Osteogenesis

Imperfecta (Left) Laleral radiograph shows flattened vertebral bodies and undulating endplates at every visualized level. Vertebral

flattening

;5

characteristically more severe anteriorly than posteriorly. (Right) Anteroposterior radiograph shows flattening of all included vertebral bodies, central endplate depression,

and severe osteoporosis.

Achondroplasia fLeft) Sagittal T2WI MR shows lIattened vertebral bodies throughout visualized spine and undulating endplates. Appearance differs from Scheuermann disease in lack of vertebral wedging (Righi) Sagittal TI WI MR shows diffuse vertebraillattening. At thoracolumbar junction there is additional,

characteristic

anterior hypoplasia in kyphosis.

Thanatophoric

Dwarfism

Gaucher

resulting

Disease (Left) Anteroposterior radiograph

shows diffuse

=

platyspondyly and characteristic limb shortening and deformity~. (Right) Lateral radiograph shows extensive bony infarcts and" Lincoln Log" appearance ~ that can mimic sickle celf disease.

=

II 1 17

SACRAL MASS, ADULT

CIl

.~ 0(fJ

,

Vi C

~ CI>

c Q.

III

Common • Lytic Osseous Metastases • Sacral Stress Fracture • Occult Intrasacral Meningocele • Chordoma • Lymphoma • Giant Cell Tumor • Multiple Myeloma • Paget Disease

•

Less Common • Anterior Sacral Meningocele • Aneurysmal Bone Cyst • Chondrosarcoma Rare but Important • Secondary Osteosarcoma • Ewing Sarcoma

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Multiplicity suggests metastases or multiple myeloma • Soft tissue component with character of internal matrix (e.g., chondroid matrix) can provide diagnostic clues

II 1 18

Helpful Clues for Common Diagnoses • Lytic Osseous Metastases o Most often with breast, lung, kidney, thyroid, oro- & nasopharyngeal, GI tract, bladder, uterine, ovarian, melanoma, chordoma, & paraganglioma primaries • ExpansiJe, osteolytic lesions observed with kidney & thyroid mets o Hypointense on Tl WI, hyperintense on T2WI & STIR; diffusely enhance • T1 hypointensity after therapy may be residual tumor or fibrosis o Cortex, particularly posteriorly, & pedicles are often destroyed, while intra vertebral discs are usually spared • Sacral Stress Fracture o T1 hypointensity & T2 hyperintensity reflects marrow edema • Occult Intrasacral Meningocele o CSF pulsation remodels sacral canal, which shows smooth enlargement o Follows CSF signal intensity; no neural elements are seen within cyst

Tarlov cyst is similar in etiology: Congenital dilatation of nerve root meningeal sleeve • Tarlov cysts frequently multiple & eccentrically centered over neural foramen Chordoma o Arise in midline o Most common locations: Sacrococcygeal> spheno-occipital> vertebral body o Hyperintense to discs on T2WI; internal septations, variable enhancement, often amorphous intra tumoral calcium o Can have large soft tissue component o Involvement of adjacent vertebral bodies via transdiscal extension; may be epidural, perivertebral, & perineural extension Lymphoma o May involve epidural space with vertebral body extension & bone erosion o May be primarily osseous with bone destruction or "ivory vertebra" appearance o Appears slightly hyperdense on NECT & demonstrates homogeneous enhancement Giant Cell Tumor o Lytic expansile lesion in sacrum or a vertebral body with narrow zone of transition & usually non-sclerotic margins o Although internal matrix is absent, there may be residual bone trabeculae o Can coexist with an ABC o Radiologically & histologically identical to brown tumors, which occur in setting of hyperparathyroidism o Majority occur in 3rd to 5th decades Multiple Myeloma o Bone scintigraphy detects only 10%; PET imaging is sensitive for monitoring treatment response, as MM lesions are metabolically active o Clinically, monoclonal gammopathy and Bence Jones proteinuria are present Paget Disease o Hypointense cortex & thickened trabeculae o Active phase: Fibrovascular marrow (Tl hypointense/T2 hyperintense) o Mixed phase: Fatty marrow (hyperintense on T1 WI and T2WI) o

DIFFERENTIAL DIAGNOSIS

CIl

•

•

•

Helpful Clues for Less Common • Anterior Sacral Meningocele

Diagnoses

SACRAL MASS, ADULT Presacral cyst that is contiguous with thecal sac, protruding through an anterior osseous defect; widened sacral canal & neural foramina o No soft tissue mass, enhancement, or calcification, which are seen with sacrococcygeal teratomas o Neurenteric cyst is within spinal canal; may be associated with dysraphism & vertebral formation anomalies • Aneurysmal Bone Cyst o Arise in neural arch & majority (75-90%) extend into vertebral body o Cortical thinning & focal cortical destruction are common • More permeative bone destruction, wider zone of transition and infiltration into surrounding soft tissues with sarcomas • Expansile remodeling of bone can result is loss of pedicle contour on AP radiograph o Fluid-fluid levels can be seen with telangiectatic osteogenic sarcoma as well as o

ABC

Majority of patients younger than 20 years o Renal cell carcinoma can also have a "soap bubble" expansile appearance • Chondrosarcoma o May be isolated or secondary to osteochond rom a/ en ch on drom a degeneration o 50% of these lytic destructive lesions demonstrate a chondroid matrix with "rings and arcs" o

o

Cortical disruption tissues

& extension

into soft

Helpful Clues for Rare Diagnoses • Secondary Osteosarcoma o Often has an osteolytic, expansile appearance without periosteal reaction • Cortical disruption may not be present • Permeative appearance with a wide zone of transition • 80% have a bone matrix and 20% have a lytic appearance o Secondary osteosarcomas can occur after radiation treatment or may be sarcomatous transformation of Paget disease or other benign bone lesion • Most secondary osteosarcomas patients are older than 50 years • Insidious onset of pain, greatest at night o Calcified pulmonary metastases can be seen • Ewing Sarcoma o Permeative destructive lesions of sacrum or vertebral body; cortical perforations rather than extensive cortical bone loss o Majority before 20 years old; however, second smaller peak at age 50 years, which present with spine & sacral lesions o Central areas of necrosis are common

lytic Osseous Metastases

Axial NEeT shows multiple blas/ic BI and somewhat permeative lytic lesions throughout the sacrum and visualized pelvi.t;. There is no SOfllissue mass.

=

Axial T1 WI M R shows an il/-defined T1 hypoinlense area involving the right sacral ala ~ with haziness of the adjacent fat & obscuration of cortical margins. Discrete fracture line is not identified.

II 1 19

SACRAL MASS, ADULT

co

~ Cl. (fJ, (/)

c

co ~

IQ)

c Cl.

(fJ

Occult Inlrasacral Meningocele (Left) Axial T2WI MR demonstrates an extradural cyst IJ:ll of fluid signal in caudal spinal canal. Cyst remodels and enlarges the spinal canal. (Right) Sagittal TI C+ MR shows a flonenhancing extradural cyst in caudal spinal canal. These are sacral meningeal cysts, while dorsal meningoceles arc true meningoceles protruding through dysraphism.

=

(Left) Sagittal TI WI MR shows a destructive sacral mass that demonstrates T I hypointensily. Mass may

=

extend along nerve roots and enlarge neural foramina. (Right) Sagittal T2WI MR shows a destructive sacral mass with marked T2 hyperintensityand septalioflS, which is characteristic of a chordoma.

=

Locaf recurrence

is common

(90%), and there may be seeding along the operative

tract

(Left) Axial NECT shows epidural lymphoma that fills the left sacral neural foramina ~ and erodes into adjacent bone 1J:ll. (Right) Sagittal NECT shows massive sacral giant cell tumor with pelvic extension~. There is erosion of the inFerior sacrum Pathologic fractures occur in 30%, and these lesions are locally aggressive with 12·50% recurrence.

=.

II 1 20

Occult Intrasacral Meningocele

SACRAL MASS, ADULT

(Left) Axial T2WI MR shows innumerable small marrow

lesions

= in sacrum and

iliac wings. (Right) Axial T1WI MR shows typical heterogeneous fatty signal and thickened dark trabeculae of Paget disease involving the sacrum.

=

Anterior

Sacral Meningocele

Secondary Osteosarcoma (Left) Sagittal T1 WI MR

reveals a cystic presacral

=.

mass Sacrum has a scimitar shape. There is a

sma/J unrelated Tarlav cyst 81. (Right) Axial NEeT with sofe tissue windows confirms an aggressive, expansile process & with multiple areas of cortical breakthrough. No definite bone production by tumor is

present.

Ewing Sarcoma

Ewing Sarcoma (Left) Axial bone CT shows i/f·defincd sclerosis in right parasacral ilium with

a

unilaminar periosteal reaction. Sofllissue mass ~ is appredable on both sides of ilium. (Right) Coronal STIR MR demonstrates heterogeneous high signal on STIR and involvement of right sacrum ~ and adjacent portions of right ilium. It extends along sacral

nerves a a common pattern in sacral Ewing sarcoma.

II 1 21

SACROCOCCYGEAL

ro

~ Q. CfJ, rJl C

ro

.=

Ql

c Q.

CIl

DIFFERENTIAL DIAGNOSIS Common • Sacrococcygeal Teratoma • Presacral Abscess Less Common • Chordoma • Neuroblastic Tumor • Plexiform Neurofibroma • Lymphoma • Chondrosarcoma • Ewing Sarcoma Rare but Important • Rhabdomyosarcoma • Osteosarcoma • Dermoid and Epidermoid Tumors • Myxopapillary Ependymoma • Anterior Sacral Meningocele • Terminal Myelocystocele • Enteric Cyst

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Myriad pathologies produce sacrococcygeal masses; clinical data directs differential list • Fever, elevated inflammatory markers prompt search for infection source • Identification of tumor matrix narrows differential considerations • Location and relationship of mass to important regional structures impacts tumor resecta bility • Look for osseous invasion or epidural extension, which may alter surgical planning

II 1 22

Helpful Clues for Common Diagnoses • Sacrococcygeal Teratoma o Very heterogeneous density/signal intensity, enhancement of solid tumor portions o AAP grade based on proportion of external and internal tumor • Male sex, large proportion internal tumor, older age at diagnosis portend worse outcome o Often detected on routine obstetrical ultrasound => elective cesarean section • Fetal MR valuable for confirmation of diagnosis, AAP grading

MASS, PEDIATRIC Sacrum and coccyx usually spared, even when tumor spreads into spinal canal via sacral hiatus o Coccyx must be resected or recurrence risk high • Presacral Abscess o Fever, serum inflammatory markers usually elevated, prompting clinical consideration of diagnosis o Regional soft tissue inflammation, discitis, epidural abscess, or vertebral osteomyelitis o Rim enhancement and diffusion restriction on DWI MR characteristic o

Helpful Clues for Less Common Diagnoses • Chordoma o Strong predilection for sacrum (50%) • Other common locations include clivus (35%) and vertebra (15%) o Characteristic very high T2 signal intensity limits differential considerations o No tumor matrix (in distinction to chondrosarcoma) • Osseous debris within tumor may mimic matrix on CT • Neuroblastic Tumor o Paraspinal location along sympathetic chain (neural crest derivatives) o Benign (ganglioneuroma) -+ intermediate grade (gangJioneuroblastoma) highly malignant (neuroblastoma) o Frequently calcified, encircles vessels and regional structures o Important upstaging findings affecting surgical management include bilaterality and epidural extension • MR best imaging modality for detecting tumor extension into spinal canal through neural foramen • Plexiform Neurofibroma o Neurofibromatosis type 1 o Grape-like or botryform morphology with characteristic distribution along nerves (major or minor peripheral nerves/plexi) o Hyperintense on STIR MR, T2Wl MR • Lymphoma o Protean imaging appearances o Often large at diagnosis; may be focal or diffuse o Relatively low signal intensity on T2WI MR ± mild diffusion restriction reflects high tumor cellularity -+

SACROCOCCYGEAL MASS, PEDIATRIC • Chondrosarcoma a Very high T2 signal intensity; may be difficult to distinguish from chordoma on imaging a Chondroid matrix (when present, 50%) diagnostic • Ewing Sarcoma a Usually older child/adolescent presentation age a Aggressive or permeative bone destruction a Cellular signal intensity (relatively low signal intensity on T2WI MR) Helpful Clues for Rare Diagnoses • Rhabdomyosarcoma a Aggressive soft tissue mass with frequent bone invasion a Rarely arises primarily in sacrum; usually regional extension from prostate or uterus primary tumor a Signal characteristics variable; frequently shows cellular characteristics with lower signal intensity on T2WI MR • Osteosarcoma a Destructive lesion with frank bone destruction and large soft tissue mass a May arise in pre-existing lesion (aneurysmal bone cyst, fibrous dysplasia) a Osteoid matrix makes diagnosis • Dermoid and Epidermoid Tumors a Consider previous lumbar puncture with nonstyletted needle, congenital dermal sinus tract a Contains fat &/or squamous debris

Sacrococcygeal Teratoma

Epidermoid component ~ diffusion restriction Myxopapillary Ependymoma a Very uncommon sacral and presacral ependymomas have been described a Most myxopapillary ependymomas arise near conus or filum (may be confined entirely to filum terminale) a CSF-disseminated intradural metastases common Anterior Sacral Meningocele a Cyst contiguity with thecal sac through enlarged neural foramen is diagnostic a Most ASM are simple CSF signal cysts; may also have lipomatous component (complex ASM) Terminal Myelocystocele a Spinal cord termination always low a Cystic dilatation of distal spinal cord central canal (myelocystocele) extending through a dilated subarachnoid fluid collection (meningocele) Enteric Cyst a Fortuitous adjacent location to sacrum in isolated mesenteric or intestinal duplication cyst a Split notochord malformations (neurenteric cysts) a

•

•

•

•

Other Essential Information • Patient age and signal characteristics on MR imaging are most helpful criteria to narrow pertinent differential diagnosis list

Presacral Abscess

Sagittal T2WI MR shows typical case of large MP type 2 SeT with mixed cystic and solid mass. The internal

Sagillal STIR MR shows intervertebral disc space infection at L5~57 level with extensive prevertebral T2

portion is predominately solid portion E1 is more cystic.

hyperinlensily representing presacral abscess.

=

and the external

II 1 23

SACROCOCCYGEAL

co

MASS, PEDIATRIC

~ 0.. CIJ, Cf)

c co

t=

Chordoma

Q)

c 'Q. CJ)

(Left) Sagittal STIR MR shows a well-defined, markedly hyperintense mass at the S2 level involving the central aspect o( the sacrum extending into presacral space and dorsally into sacral canal. (Right) Sagittal T2WI MR demonstrates a large presacral soft tissue mass with sacral vertebral bone involvement as well as epidural extension ~ through the neural foramina.

=

Plexiform

Neurofibroma

lymphoma

(Left) Coronal STIR MR in a patient with NF / reveals multilevel bilateral T2 hyperintense plexiform neurofibromas involving the spinal and pelvic nerves and relevant plexuses. (RighI) Axial TI C+ MR shows a large destructive sacral mass with avid enhancement spreading into the dorsal soft

rs

tissues.

Ewing Sarcoma (Left) Axial T2WI FS MR shows a large sacral Ewing sarcoma with bone destruction and extension into the dorsa/lumbosacral soft tissues. (Right) Sagittal T2WI MR demonstrates a large exophytic sacral mass engulfing lower sacral verlebra and extending into central spinal canal It] through the sacral hiatus EB

II 1 24

Rhabdomyosarcoma

SACROCOCCYGEAL

MASS, PEDIATRIC

(J)

"0

::::l

11l

-l

~ tll ::::l

en,

Osteosarcoma (Left) Axial T1 C+ FS MR demonstrates a destructive pelvic mass with multiple enhancing areas of solid tumor ~ as well as fluid-filled, nonenhancing necrotic regions =:I. (Right) Sagittal T1 WI MR depicts a mixed signal intensity

(j) -0

~ tll

expansile extradural sacral mass =:I. Additional findings include low-lying spinal cord and fatty filum infiltration.

Myxopapillary

Ependymoma

Anterior

Sacral Meningocele

rs MR

(Left) Sagittal T1 C+ reveals a heterogeneous

presacral mass with osseous destruction and spinal extension. Conus ;5 low lying. Exact pathological diagnosis of this rare lesion has been debated but shows many features of sacral ependymoma. (Right) Sagittal T2WI MR demonstrates a large CSF signal intensity presacral cyst that is contiguous with the thecal sac through an enlarged sacral foramen =:I.

Anterior

Sacral Meningocele

Terminal Myelocystocele (Left) Sagittal T1WI MR in a patient with caudal regression depicts a variant complex ASM with both cyst and lipoma components extending through the sacral foramina to produce sacral mass. (Right) Sagittal T1WI MR shows classic

=

appearance

of terminal

myelocystocele, with a low-lying tethered spinal cord, distal hydromyelia =:I traversing a meningocele EJ.

II 1 25

SACRAL DEFORMITY

ro

~

n.

(f)

enc

ro ~

t-

a>

c

'Q.

en

Common • Sacral Foraminal Mass o Dural Dysplasia o Neurofibroma • Insufficiency Fracture, Sacral • Sacral Traumatic Fracture • Metastatic Disease • Ependymoma, Myxopapillary,

•

Spinal Cord

less Common • Dorsal Dysraphism o Myelomeningocele/Myelocele o Lipomyelomeningocele/Lipomyelocele o Terminal Myelocystocele • Meningocele, Occult Intra sacral • Meningocele, Anterior Sacral • Chordoma • Teratoma, Sacrococcygeal • Caudal Regression Syndrome

•

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Bone-algorithm CT and MR are complementary modalities • CT superior to assess bone cortex o Bony remodeling: Dural dysplasia, neurofibroma, ependymoma o Bone destruction: Metastases, chordoma • MR superior to assess soft tissue contents of the sacral canal and foramina Helpful Clues for Common Diagnoses • Dural Dysplasia o Intrinsic weakness in dura o Transmission of chronic CSF pressures leads to bony remodeling and expansion of lumbosacral canal and neuroforamina o Contents follow CSF signal on MR and show no appreciable enhancement o Can be seen with neurofibromatosis type 1, Marfan disease, homocystinuria, Ehlers-Danlos, and ankylosing spondylitis • Neurofibroma o Fusiform enlargement of nerve root(s) o Heterogeneous enhancement o Multiple lesions typical of type 1 neurofibromatosis

II 1 26

Bony remodeling caused by intraspinal or transforaminallesions can cause scalloping or the posterior lumbar vertebra and sacrum, neuroforaminal widening Insufficiency Fracture, Sacral o Unilateral or bilateral vertical component through the sacral alae, possibly with a horizontal component through the body o Subtle fracture may be hard to identify even with high-quality CT o Associated marrow edema signal most conspicuous on fat-saturated T2WI (e.g., STIR) o Increased tracer uptake on bone scan Sacral Traumatic Fracture 095% occur in conjunction with other pelvic fractures o Denis classification • Zone 1: Lateral to neuroforamina • Zone 2: Through neuroforamina • Zone 3: Through spinal canal o Higher Denis zones associated with increasing probability of significant neurologic deficit Metastatic Disease o Renal, lung, breast, and prostate carcinomas are common primaries to develop osseous metastases o Sacral fracture can develop within bone weakened by tumor or by pelvic radiation therapy Ependymoma, Myxopapillary, Spinal Cord o Most common neoplasm of the conus and distal spinal canal o Marked enhancement typical o Can show signs of necrosis (heterogeneity, cyst formation) and hemorrhage: Subarachnoid hemorrhage, superficial siderosis o Bony remodeling when large: Scalloping of the margins of the spinal canal, foraminal enlargement o

DIFFERENTIAL DIAGNOSIS

•

•

Helpful Clues for less Common Diagnoses • Dorsal Dysraphism o Common features: Everted elements of dorsal neural arch; tethered, dysraphic cord o LipomyelomeningoceJe, lipomyelocele: Placode adherent to fatty mass contiguous with subcutaneous fat; intact skin

SACRAL DEFORMITY

Myelomeningocele, myelocele: Placode exposed; no overlying skin o Lipomyelocele, myelocele: Placode lies within spinal canal o Lipomyelomeningocele, myelomeningocele: Placode and meninges protrude through spinal defect o Terminal myelocystocele: Meningeal sac containing tethered, hydromyelic cord extends through sacral defect; intact skin • Meningocele, Occult Intrasacral o CSF-containing meningeal cyst within the sacral canal; thin or imperceptible wall; no appreciable enhancement o Does not contain neural elements o Chronic CSFpulsation pressure leads to expansion and bony remodeling o Often asymptomatic, may be associated with low back pain, radicular symptoms, and bladder dysfunction • Meningocele, Anterior Sacral o CSF-containing meningeal sac protruding into the pelvis through an enlarged sacral foramen or a defect in a dysplastic sacrum o Important to determine if nerve roots traverse the neck of the sac for surgical planning • Chordoma o Malignant tumor arising from notochord remnants; 50% sacrococcygeal in location o Hyperintense on T2WI; usually containing multiple septae; calcification common in sacral chordoma o

Peak incidence in 5th and 6th decades, rare in children • Teratoma, Sacrococcygeal o Rare, congenital tumors arising from totipotential cells in the caudal cell mass o Most are large, encapsulated with mixed solid and cystic components o Sacral canal involved in 2% o Classified by location • Type I: Caudal, external tumor mass without a significant presacral component • Type II: Caudal tumor with significant pelvic component • Type III: Mainly intrapelvic, with minimal external mass • Type IV: Completely intrapelvic (presacral) • Caudal Regression Syndrome o Spectrum of congenital anomalies arising from maldevelopment of lower vertebral column, cord, and pelvic viscera o Hypoplastic distal cord with truncated or "blunted" terminus o Hypoplasia or variable agenesis of the lumbosacral spine o Non-spine anomalies, variably present • Anal atresia • Bladder exstrophy, abnormalities of external genitalia • Renal aplasia or ectopia o

Dural Dysplasia

Axial

NEeT

and foramina

shows widened, remodeled sacral canal

1m due

to enlarged thecal sac and nerve

root sleeves in this patient with dural dysplasia.

=

Sagittal T2WI MR shows marked seal/oping of the posterior sacrum and L5 vertebral body

with an

II 1

enlarged thecal sac in this patient with dural dysplasia and neurofibromatosis

type

,.

27

SACRAL DEFORMITY

.~

ro

D-

,

C/) (/)

enhancing epidural phlegmon ± peripherally enhancing fluid collection • May also see isolated epidural abscess without discitis • Lower thoracic, lumbar> cervical, upper thoracic a Abscess, Subdural • Purulent pus collection developing in "potential" space between dura and arachnoid • Post-Operative Complication a Hematoma, Epidural • Blood extravasation into the epidural spinal compartment • Long segmental extra-axial mass encasing or displacing spinal cord or cauda equina • Typically multisegmental, but Illay be focal when associated with focal fracture or disc extrusion o Hematonla, Subdural • Accumulation of blood between dura and arachnoid

ACUTE BACKPAIN/RADICULOPATHY, POST-OPERATIVE

o

o

o

• Signal characteristics variable depending on age of blood products Hardware Failure • Mechanical breakdown, malfunction, or malposition of metallic implant • May present either with chronic pain or calamitously with acute pain Vertebroplasty Complications • Cement extravasation into spinal canal, foramen, or vertebral venous plexus • Pulmonary artery cement embolization • Vertebral osteomyelitis • "Bounce back" vertebral fracture Bone Graft Complications • Graft migration, graft displacement, or graft extrusion • Abnormal alignment, position, or placement of graft ± associated neurologic deficit, instability, infection • Cervical> thoracic> lumbar

Helpful Clues for Rare Diagnoses • Post-Operative Complication o Brachial Plexus Traction Injury • Stretch injury or avulsion of ~ 1 cervical roots, brachial plexus • Stretch injury: Enlargement or attenuation of stretched (but contiguous) plexus elements

Intervertebral Disc Herniation, Recurrent

• Avulsion injury: Attenuated or disrupted proximal roots/rami within or immediately distal to lateral CSF-containing dural sac diverticulum devoid of neural elements ± retracted distal nerve roots, nerve "retraction ball" o Infarction, Spinal Cord • Thoracic spinal cord infarction 2° arterial occlusion (radicular artery) • Artery of Adamkiewicz frequently implicated • Usually extends to involve more than one vertebral body segment • Central hyperintensity on T2WI more common than wedge-shaped involvement of anterior 2/3 of spinal cord • Post-Operative Infection o Abscess/Myelitis, Spinal Cord • Spinal cord infection with necrosis • Spinal cord neoplasm mimic; ring-enhancing mass within cord with appropriate clinical history of inflammation/infection is highly suggestive • Pyogenic infection most common but granulomatous infections have been described • May show positive diffusion (reduced ADC) restriction similar to brain abscess, but lack of diffusion restriction does not exclude abscess

Intervertebral Disc Herniation, Recurrent

II Sagittal T1 C+ MR in a posl-operalive

=

recurrel1l

back pain demonstrates

that ventrally

compresses

a

paUent with

recurrent

the thecal sac.

L4-5 IINP

Axial Tl C+ FS MR in a post-operative

recurrent back pain reveals a large recurrent disc herniation ~~L

patient

with

post-operalive

1 31

ACUTE BACK PAIN/RADICULOPATHY,

Cll

POST-OPERATIVE

~ a. (/) , en c

~ Cll

fell

c a.

(/)

Intervertebral

Disc Herniation,

Cervical

Intervertebral

Disc Herniation,

Intervertebral

Disc Herniation,

Lumbar

Intervertebral

Disc Extrusion, Foraminal

Thoracic

(Left) Axial T2* eRE MR reveals a large left cervical disc herniation

producing

spinal cord deformation

and

narrowing of the lefllateral spinal canal. (RighI) Axial T2WI MR depic15 a left paracentral thoracic disc herniation that produces mild spinal cord deformation but no significanl narrowing of the central spinal canal.

(Lefl) Axial T2WI MR in a patient with left leg pain demonstrates a huge left lateral recess disc extrusion =:I that obliterates lhe left lateral recess and deforms the thecal sac. (RighI) Axial T2WI MR reveals a huge right Foraminal and far lateral

=

disc extrusion in a symptomatic patient with acute right leg pain.

Peridural Fibrosis (Lefl) Axial T1 C+ MR shows diffuse enhancement of right lateral epidural space and surrounding exWng root t;econdary to peridural fibrosis. There is extensive enhancement of the disc curette site =:I. (RighI) Axial T1 C+ MR depic15 extensive enhancing epidural fibrosis circumferentially

surrounding

the thecal sac =:I. Note mewl susceptibility artifact from fusion cage ~.

II 1 32

Peridural Fibrosis

ACUTE BACK PAIN/RADICUlOPATHY,

Abscess, Paraspinal

POST-OPERATIVE

Abscess, Paraspinal (LeFt) Sagiltal STIR MR aFter L4-S posterior lumbar interbody fusion (PUF) shows abnormal fluid signal intensity in L4-5 disc

interspace and posterior

50ft

tissue abscess with fluid-debris level ffi (Right) Axial T2WI MR following L4-S PUF shows increased signal intensity in dorsal soft tissues &, abscess collection surrounding posterior spinal fusion hardware (metallic susceptibility E!lI! & edema

in paraspinal muscles.

Abscess, Epidural

Abscess, Epidural (Left) Sagi!!al T7 C+ MR in a patient with back pain and fever demonstrates a well-delineated,

post-operative

rim-enhancing,

post-operative epidural abscess at the SI level (Right) Axial T7 C+ FS MR delineates a well-circumscribed,

=.

=

rim-enhancing

epidural

abscess producing mass effect and displacement of the thecal sac to the right

(LeFt) Sagi!!al T2WI MR shows two level fusion from

CJ to C5 with metal artifact from screws. Screw artifact at C5 level extends to the ventral epidural space adjacent to the spinal cord

E1.

Note congenital

fusion at

C6-7. (Right) Axial T7 C+ MR following interbody Fusion and posterior pedicle screw fixation shows

extensive enhancement

of

paraspina/ musculature involving dorsal muscles as we/J as psoas and multifidus muscles=.

II 1 33

ACUTE BACK PAIN/RADICULOPATHY,

co

POST-OPERATIVE

~ Q. (f) , (/)

c

co ~

IQ)

C

e-

rn

Hematoma,

Epidural

Hematoma,

Epidural

Hematoma,

Subdural

Hematoma,

Subdural

(Left) Sagillal T7 WI MR shows wide cervical laminectomy defect with intermediate signal intensity filling the laminectomy defect, representing epidural hematoma; which compresses posterior thecal sac and spinal cord~. Note surgical drain 81. (Right) Sagittal TlWI MR following L]-L5 laminectomy shows intermediate signal mass (not /racking CSF) filling the laminectomy site and extending into dorsal epidural space, compressing

=

the thecal sac.

(Left) Sagillal T7 WI MR reveals a mildly hyperintense subacute subdural hematoma I:ll following spinal surgery that dorsally

compresses the thecal sac and spinal cord. (Right) Sagittal T2WI MR following vertebroplasty in a patient with severe multilevel

degenerative disc disease shows severe compression deformities at T72, L1, and moderate deformity at L2. Note subdural I:ll and subarachnoid blood layer PJ::l in distal thecal sac.

Hardware (Left) Axial bone CT following myelography with bilateral pedicle screws in place shows lucency surrounding the left pedicle screw indicating loosening

with superimposed stress fracture through the left pedicle and posterior vertebral body I:ll. (Right) Lateral radiograph in an NF I patient with operated

scoliosis shows dramatic presentation with acute back pain and spinal hardware protruding through skin.

II 1 34

Failure

ACUTE BACK PAIN/RADICULOPATHY,

POST-OPERATIVE

Bone Graft Complications (Lefl) Axial TI WI MR shows injected low signal intensity methacrylate within the anterior vertebral body as intended, as well as extending into the left

paravertebral soft tissues adjacent 10 the aorta E!:I.

=

(RighI) Sagillal TI WI MR depicts disccctomy and bone graft placement at C3-4 through CS-6. There is posterior displacement of graft components

into

ventral epidural space, producing spinal cord

compression

Brachial Plexus Traction Injury

=.

Brachial Plexus Traction Injury (Lefl) Coronal STIR MR in an infant with right arm

paralysis following difficult obstetrical delivery demonstrates right C6 and C7 nerve raal avulsion

pseudorncningoceles

m.

(RighI) Axial T2' eRE MR shows right CB and TI nerve

rool/ventral primary ramus stretch injuries resulting in marked nerve root enlargement and abnormal T2 hyperintensity.

Infarction,

Spinal Cord

Abscess/Myelitis,

Spinal Cord (Left) SagiHal T2WI MR in a patient manifesting post-operative paraplegia following thoracoabdominal aneurysm repair shows abnormal T2 hyperintensity extending from mid La distal thoracic spinal cord (RighI) SagiHal TI C+ MR shows intramedullary rim-enhancing spinal cord abscess with adjacent Jow signal intensity edema.

=.

II 1 35

:gco

CHRONIC BACK PAIN/RADICULOPATHY, POST-OPERATIVE

Q. (/)

,

rJ)

c

co

~ Q)

c Q. (/)

DIFFERENTIAL DIAGNOSIS Common • Failed Back Surgery Syndrome • Peridural Fibrosis • Intervertebral Disc Herniation, Recurrent • Degenerative Disc Disease • Instability • Post-Laminectomy Spondylolisthesis • Accelerated Degeneration Less Common • Hardware Failure • Bone Graft Complications • Vertebroplasty Com pJications • Post-Operative Infection • Scoliosis, Degenerative Rare but Important • Arachnoiditis, Lumbar • Arachnoiditis Ossificans, Lumbar

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Careful clinical exam will often distinguish radiculopathy from mechanical back pain, enabling a tailored differential list • Carefully consider hardware failure or indolent infection in post-operative implant patients presenting with chronic back pain

II 1 36

Helpful Clues for Common Diagnoses • Failed Back Surgery Syndrome o Continued low back pain ± radicular pain following lumber spinal surgery o Myriad etiologies manifest clinically as failed back surgery syndrome (FBSS) o Look for specific abnormal imaging findings that may be addressed clinically • Peridural Fibrosis o Scar formation within epidural space following lumbar spinal surgery o Subset of FBSS o Tl C+ FS MR imaging increases sensitivity for detecting peridural fibrosis and permits differentiation of fibrosis from disc herniation • Intervertebral Disc Herniation, Recurrent o Focal extension of disc material beyond endplate margins at previously operated intervertebral disc level o Subset of FBSS

T1 C+ FSMR imaging increases sensitivity for detecting peridural fibrosis and permits differentiation of fibrosis from disc herniation • Degenerative Disc Disease o Generalized and multifactorial process affecting discovertebral unit leading to biomechanical/morphologic alterations o Imaging diagnosis of degenerative disc disease does not distinguish symptomatic from asymptomatic levels • May be asymptomatic or associated with back/neck pain ± radiculopathy • Instability o Loss of spine motion segment stiffness, where applied force produces greater displacement than normal, producing pain/deformity o Deformity increases with motion and increases over time o Any spinal motion segment (comprised of two adjacent vertebrae, disc and connecting spinal ligaments) may be involved • Most common at post-operative levels, particularly if posterior elements removed by laminectomy o AP translation at unstable level may vary from few mm to entire width of vertebral body • Post-Laminectomy Spondylolisthesis o Loss of spine motion segment stiffness, where applied force produces greater displacement than normal, producing pain/deformity o AP canal diameter narrows at subluxation level, distinguishing from spondylolysis where the AP canal diameter is increased • Accelerated Degeneration o Synonyms include spinal "transitional degenerative syndrome" and "accelerated segmental degeneration" o Degeneration of disc space/facets at level(s) adjacent to spinal fusion 2° to altered biomechanical forces - degenerative disc changes, disc herniation, and/or subluxation o Identical changes occur at motion segments above or below congenital segmentation anomaly levels o

CHRONIC BACK PAIN/RADICUlOPATHY, Helpful Clues for less Common Diagnoses • Hardware Failure o Mechanical breakdown or malfunction of spinal fusion hardware o Malposition of spinal fusion hardware without mechanical failure of implant o Presentation symptoms range from indolent with chronic pain to calamitously with acute pain • Bone Graft Complications o Abnormal alignment, position, or placement of graft or hardware ± associated neurologic deficit, instability, infection • Graft migration, graft displacement, or graft extrusion o Cervical> thoracic> lumbar • Vertebroplasty Complications o Complication types include • Extravasation of cement into spinal canal, neural foramen, or vertebral venous plexus • Pulmonary embolization of cement • Vertebral osteomyelitis • "Bounce back" fracture adjacent to vertebroplasty level • Post-Operative Infection o Infectious sequelae following operative procedures o Most frequently begins in intervertebral disc space ~ disci tis, epidural abscess, subdural abscess, &/or paraspinal abscess

POST-OPERATIVE

Look for unexpected abnormal MR enhancement post-spinal surgery imaging • Scoliosis, Degenerative o "De novo" scoliosis o Lateral spinal curvature due to degenerative disc and facet disease o Radiculopathy secondary to foraminal narrowing and nerve root compression o Usually seen in older patients o

Helpful Clues for Rare Diagnoses • Arachnoiditis, Lumbar o Post-inflammatory adhesion and clumping of cauda equina nerve roots in thecal sac o Imaging shows either absence of discrete nerve roots ("empty sac") or peripheral displacement of nerve roots in thecal sac • Arachnoiditis Ossificans, Lumbar o Intradural ossification associated with post-inflammatory adhesion and clumping of lumbar nerve roots o Look for focal calcific density on CT or hyperintensity on TlWI and T2WI within lumbar nerve root aggregate

II Sagittal T7 C+ MR shows

large recurrent

L4-S disc

T7WI MR shows large osteophyte at U-4 compressing thecal sac and prior multilevel laminectomies. High signal within thecal sac is

herniation compressing thecal sac E2 with thin peripheral enhancement. Note linear enhancement

residual from prior

within disc due £0 disc degeneration

Sagittal

=

Panlopaque

myelography.

=.

1 37

CHRONIC

co

BACK PAIN/RADICUlOPATHY,

POST-OPERATIVE

~ a. CfJ, en c co ~

I-

al C

a. m

Peridural Fibrosis

Peridural Fibrosis

Intervertebral Disc Herniation, Recurrent

Intervertebral Disc Herniation, Recurrent

Intervertebral Disc Herniation, Recurrent

Intervertebral Disc Herniation, Recurrent

(Left) Axial TI C+ MR shows a large amount of homogeneously enhancing left lateral epidural fibrosis surrounding thecal sac and exiting root =:I. (Right) Axial TI C+ MR demonSlrates exuberant

enhancing

epidural fibro.;is circumferenlially surrounding the thecal sac =:I. Note metal artifact

(rom

intervertebral fusion cages

Sli

(Left) Sagittal TI C+ MR demonstrates post-operative changes following L4 & L5 laminectomies. Absence of enhancement helps distinguish

recurrent

L4-5

disc herniation lID from epidural scar tissue. (Right) Axial TI C+ FS MR demonstrates post-operative laminectomy changes with recurrent left L4-5 paracentral disc extrusion =:I. Note absence of disc fragment

enhancement.

(Left) Sagittal TI C+ MR shows a recurrent intervertebral disc herniation =:I following decompressive laminectomy. so(t tissue enhancement

of paraspinal

muscles is common in subacute period. (Right) Axial TI C+ FS MR after L5 left hemilaminectomy shows large recurrent L5-S 1 disc extrusion/free

Fragment with

variant peripheral enhancement lID.

II 1 38

CHRONIC

Bone Graft Complications

BACK PAIN/RADICULOPATHY,

Post-Operative

POST-OPERATIVE

Infection (Left) Axial NECT in a patient with right back and flank pain and palpable mass demonstrates protrusion of colon and mesenteric Fat through the large right iliac wing bone graft harvest site (Right) SagiILal T 1 C+ MR following upper lumbar

=.

decompressive laminectomy shows extensive mufti/evel degenerative disc changes and large dorsal epidural abscess at lumbosacral junction.

=

Post-Operative

Infection

Scoliosis, Degenerative (Left) Axial T1 C+ MR in a patient with chronic back pain SlaWS post explantation of spinal fusion hardware shows enhancing muscle changes of pyomyositis as well as pus and inflammawry phlegmon in operative bed and pedicle screw track 7,. (Right) Anteroposterior radiograph shows multilevel degenerative disc and facet disease producing degenerative scoliosis.

=

Arachnoiditis,

lumbar

Arachnoiditis Ossificans,

lumbar (Left) Sagittal bone CT after myelography shows a large soft tissue intradural filling defect that engulfs the distal cauda equina =>

=

chronic

inflammatory

pseudomass of arachnoiditis. (Right) Axial NECT shows irregular calcification involving the distal thecal sac at the sacral level indicating end-stage calcific

=.

arachnoiditis

(similar to

bone, less dense than Panwpaque).

II 1 41

ro

ACUTE UPPER EXTREMITY

PAIN/WEAKNESS

~

Cl. (fJ

enc

ro ~

IQ.)

c c.

(fJ

DIFFERENTIAL DIAGNOSIS Common • Intervertebral Disc Herniation o Intervertebral Disc Herniation, Cervical o Intervertebral Disc Herniation, Traumatic • Cervical Fracture with Nerve Compression o Burst Fracture, Cervical o Hyperflexion Injury, Cervical o Lateral Flexion Injury, Cervical o Hyperflexion-Rotation Injury, Cervical o Pathologic Vertebral Fracture Less Common • Syringomyelia • Traumatic Dural AVFistula • Peripheral Neuropathy o Brachial Plexus Traction Injury o Radial Neuropathy o Ulnar Neuropathy o Median Nerve Entrapment o Suprascapular erve Entrapment • Infection o Abscess, Paras pinal o Abscess, Epidural o Osteomyelitis, Granulomatous o Osteomyelitis, Pyogenic Rare but Important • Idiopathic Brachial Plexus Neuritis • Acute Transverse Myelitis, Idiopathic • Secondary Acute Transverse Myelitis • ADEM, Spinal Cord

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Careful clinical exam distinguishes radiculopathy from mechanical back pain or myelopathy, limiting pertinent differential diagnosis list

II 1 42

Helpful Clues for Common Diagnoses • Intervertebral Disc Herniation o Intervertebral Disc Herniation, Cervical • Localized « 50% of disc circumference) displacement of disc material beyond edges of vertebral ring apophyses • Clinical symptoms affected by level, location, herniation size o Intervertebral Disc Herniation, Traumatic • Disc herniation following trauma

• Muscle, ligamentous injuries suggest etiology • Cervical Fracture with Nerve Compression o Burst Fracture, Cervical • Typically mid- or lower cervical spine • Axial compression - comminuted fracture extending through both end plates o Hyperflexion Injury, Cervical • Typically mid or lower cervical spine • Flexion force disrupts capsular & posterior ligaments - anterior vertebral displacement/angulation, focal kyphosis, t space between spinous processes o Lateral Flexion Injury, Cervical • Typically mid or lower cervical spine • Articular mass fracture ± fractures of transverse and uncinate processes, vertebral body o Hyperflexion-Rotation Injury, Cervical • Typically mid or lower cervical spine • Traumatic disruption of cervical spine (ligaments ± bony elements) - facet subluxation, focal vertebral angulation, rotation o Pathologic Vertebral Fracture • Fracture through abnormal bone weakened by tumor or infection • Search for trabecular and cortical bone destruction, spinal cord &/or nerve root compression Helpful Clues for Less Common Diagnoses • Syringomyelia o Expanded spinal cord with central dilated, beaded, or sacculated cystic cavity • Traumatic Dural AV Fistula o AVFnidus with enlarged draining veins o Radiculopathy 2° to nerve compression by enlarged epidural veins • Peripheral Neuropathy o Brachial Plexus Traction Injury • Stretch injury or avulsion of ~ 1 cervical roots, brachial plexus elements • Denervation changes in dorsal paras pinal muscles, arm and forearm muscles innervated by terminal peripheral nerve branches o Radial Neuropathy • Focal radial nerve enlargement, abnormal T2 hyperintensity

ACUTE UPPER EXTREMITY • Characteristic entrapment locations include mid humeral shaft or fibrous arch of Frohse o Ulnar Neuropathy • Focal ulnar nerve enlargement, abnormal T2 hyperintensity • Most common in cubital tunnel (elbow); uncommon in Guyon tunnel (wrist) or brachial plexus o Median Nerve Entrapment • Focal median nerve enlargement, abnormal T2 hyperintensity • Entrapment most common at carpal tunnel or pronator teres muscle o Suprascapular Nerve Entrapment • Mass impinges nerve at spinoglenoid or suprascapular notch • Abnormal T2 hyperintensity in denervated muscles • Infection o Abscess, Paraspinal • Paravertebral enhancing phlegmon or peripherally enhancing liquified pus collection o Abscess, Epidural • Spondylodiscitis with adjacent enhancing epidural phlegmon ± peripherally enhancing fluid collection • May extend over many vertebral segments o Osteomyelitis, Granulomatous • Tuberculosis or brucellosis most common

PAIN/WEAKNESS

o

• May produce spinal cord, nerve compression Osteomyelitis, Pyogenic • Ill-defined abnormal vertebral marrow signal centered at disc with loss of adjacent end plate definition • May produce spinal cord, nerve compression

Helpful Clues for Rare Diagnoses

• Idiopathic Brachial Plexus Neuritis o Parsonage-Turner syndrome o Immune-mediated neuropathy of brachial plexus o Smooth enlargement of brachial plexus elements, mild diffuse nerve and muscle enhancement • Acute Transverse Myelitis, Idiopathic o Inflammatory lesion involving both spinal hemicords - bilateral motor, sensory, and autonomic dysfunction o Lesion extent> 2 vertebral segments + eccentric enhancement • Secondary Acute Transverse Myelitis o Inflammatory disorder of spinal cord associated with many etiologies o T2 hyperintense lesion with mild cord expansion, minimal to no enhancement • ADEM, Spinal Cord o Para/postinfectious immune-mediated inflammatory disorder of spinal cord white matter o Multiple sclerosis mimic

II T2WI MR demonslIates a C4-5 cervical disc herniation with spinal cord deformation. location corresponds with left arm pain. Sagittal

Axial T2* eRE MR shows a large left C6-7 cervical

herniation

with

deformation of

concordant

with clinical

localization

disc

the spinal cord

1

of leh arm pain.

43

ACUTE UPPER EXTREMITY PAIN/WEAKNESS

o c CIl

~

U Q)

C 0-

en

DIFFERENTIAL DIAGNOSIS Common • Trauma o Odontoid C2 Fracture o Burst Fracture, C2 o Hangman's C2 Fracture o Jefferson C1 Fracture o Occipital Condyle Fracture o Dissection, Vertebral Artery o Traumatic Disc Herniation o Os Odontoideum o Spinal Cord Injury Without Radiographic Abnormality (SCIWORA) • Nontraumatic Mimics o Pathologic Vertebral Fracture o Cran iovertebral Junction Variants o Incomplete Fusion, Posterior Element o Pseudosubluxation C2-3 o Torticollis less Common • Atlanto-Occipital Dislocation • Atlanto-Axial Rotary Subluxation

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • MR very useful to evaluate for ligament injuries o Coronal STIRrarely performed but useful in this region • Coronal, sagittal reformations essential on CT for full evaluation of injury

Odontoid

C2 Fracture

• CT arteriogram equally accurate and faster than MR arthrogram for vertebral dissection o Time is often of the essence in these patients, who tend to have multiple injuries Helpful Clues for Common Diagnoses • Odontoid C2 Fracture o Usually low-velocity injury in elderly • Jefferson CI Fracture o If combined displacement of lateral masses > 6.9 mm, unstable o High likelihood of other fractures: Spine, skull, pelvis, lower extremity • Os Odontoideum o Chronic, nonunited odontoid fracture • Spinal Cord Injury Without Radiographic Abnormality (SCIWORA) o Occurs primarily in children o MR: Injuries to cord, ligaments, intervertebral discs, cartilaginous endplates 02/3 severe cervical injuries in children < 8 years are SCIWORA • Pseudosubluxation C2-3 o Children < 10 years old, anterolisthesis may measure up to 4 mm Helpful Clues for less Common Diagnoses • Atlanto-Occipital Dislocation o High incidence cord injury o Formerly usually fatal; now often survive to hospital

Burst Fracture,

C2

II 2 2

Sagittal NCCT shows type 2 dens fracture 1::1 in an osteoporotic patient. Soft tissue swelling is mild. These fractures are commonly subtle on radiographs and best seen on lateral (not odontoid) vie\oV.

Sagittal bone CT shows comminuted C2 body fracture with characteristic retropulsion of posterior cortex

=.

Additional burst fractures are commonly elsewhere in the spine.

present

CRANia-CERVICAL

Hangman's

C2 Fracture

JUNCTION

ACUTE INJURY

Jefferson Cl Fracture (Left) Sagittal oblique 3D CT shows bilateral C2 pedicle (ractures

=

without

fracture

of vertebral body. Effendi classification uses presence of disruption of C2- 3 disc and facet joints as a measure of the severity of injury. (Right) Axial bone CT shows multiple fractures of C 1 ring 1:':1. Lateral displacement in this patient indicates rupture of transverse ligament of dens and resultant instability.

Occipital

Condyle Fracture

Os Odontoideum (Left) Coronal NECT shows nondisplaced occipital condyle fracture 1:':1 as well as C4 articular pillar fracture reflecting lateral flexion injury. (Rig"') Sagittal bone CT shows chronic, nonuniled dens fracture so-called as odonloideum. This may be unstable, and flexion-extension views should be performed.

a

=-

Craniovertebral

Junction Variants

Craniovertebral

Junction Variants (Left) Axial bone CT shows anterior

and posterior

cfefts

SII of C 7. Smooth, corticated margins are signs distinguishing this from trauma. (Rig"') Sagittal bone CT shows anterior arch of C I fused 10 clivus 1:':1 and posterior arch fused 10 C2 SII.

II 2 3

c

CVJ ABNORMALITY,

o

GENERAL

U C

--,:J

.Q

c

Pannus from Rheumatoid

o

Arthritis


ro ~

.0 Q)

t Q)

>

.Q

c

~

U Ql

c .0. tJ)

DIFFERENTIAL DIAGNOSIS Common • Rheumatoid Arthritis • Retro-Odontoid Pseudotumor • Osteomyelitis, CI-C2 • Extramedullary Tumor o Metastases o Lymphoma o Plasmacytoma o Nasopharyngeal Carcinoma o Neurofibromatosis Type 1 o Schwannoma o Paraganglioma o Chordoma o Chondrosarcoma o Meningioma • Intramedullary Mass o Syringomyelia o Chiari 1 Malformation o Chiari 2 Malformation o Glioma, Brainstem o Hemangioblastoma, Spinal Cord Less Common • Carotid Pseudoaneurysm/Dissection • Synovial Cyst Rare but Important • Neurenteric Cyst

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Do intralesion calcifications represent arc-whorl intralesional calcifications (chondrosarcoma) or fragmented destroyed bone (chordoma, metastasis)? • Does patient have known primary neoplasm (metastasis), myeloma (plasmacytoma), or a nasopharyngeal mass (nasopharyngeal carcinoma)?

II 2 8

Helpful Clues for Common Diagnoses • Rheumatoid Arthritis o Thickened & inflamed synovium called pannus o ever involves spine without hands &/or feet involvement o Odontoid erosions, ligamentous laxity o CI-C2 instability in 33% of all RA patients o Neutral, flexion, and extension lateral radiographs performed for evaluation

• High correlation to neurologic symptoms with distance 9 mm or more between Cl-2 • Retro-Odontoid Pseudotumor o Increased soft tissue dorsal to odontoid secondary to Cl-2 osteoarthritis • Low signal mass on T1 & T2 (fibrotic) • May cause cervicomedullary junction compression o Usually seen with altered biomechanics of lower cervical spine •• surgical/congenital fusion o Mimics appearance of RA o Multiple other levels of degenerative disc disease • Osteomyelitis, CI-C2 o Infection starts as septic arthritis of Cl-2 o Risk factors include diabetes, drug abuse, endocarditis, immunocompromise o Soft tissue mass and bone destruction at Cl-2 level • Staph aureus most common organism in USA • Mycobacterium tuberculosis most common worldwide o MR shows low Tl signal mass centered at Cl-2 with variable involvement of odontoid and lateral masses at C2 o May show enlarged atlanto-dental interval o Epidural mass with thecal sac/cord corn pression o Grisel syndrome: Inflammatory, nontraumatic subluxation of CI-C2 following peripharyngeal infection • Extramedullary Tumor o Metastases • Multiple lesions, bone destruction, systemic primary o Lymphoma • Large pharyngeal mucosal space mass with associated cervical adenopathy> 50% of time • NHL 5x as common as Hodgkin disease in head & neck o Nasopharyngeal Carcinoma • Mass centered in lateral pharyngeal recess of NP with deep extension & cervical adenopathy • Nodal metastases present in 90% of cases at presentation

CVJ SOFT TISSUE ABNORMALITY • Multi-planar images show invasion of clivus, sphenoid bone & sinus, Cl & C2 bodies o Neurofibromatosis Type 1 • Plexiform neurofibroma => diffuse enlargement of major nerve trunks/branches - bulky rope-like ("bag of worms") nerve expansion with adjacent tissue distortion • Look for kyphoscoliosis ± multiple nerve root tumors, plexiform neurofibroma, dural ectasia/lateral meningocele o Schwannoma • Hypoglossal or upper cervical roots as site of origin • Hypoglossal neuropathy results in tongue denervation • Dumbbell with uniform enhancement • Larger lesions may show central cystic formation o Paraganglioma • Multiple black dots ("pepper") in tumor substance indicating high velocity flow voids from feeding arterial branches • Jugular foramen or vagal varieties may present with upper cervical/skull base level mass o Chordoma • Mass is hyperintense to discs on T2WI, with multiple septa • Destructive, lytic lesion • May extend into disc, involve 2 or more ad jacen t vertebrae o Chondrosarcoma

Rheumatoid Arthritis

• Lytic mass with or without chondroid matrix, cortical disruption, and extension into soft tissues • Chondroid matrix mineralization of "rings and arcs" (characteristic) o Meningioma • Foramen magnum, jugular foramen OF), upper cervical dura locations • Carotid space => connection to JF above with JF margins showing permeative-sclerotic or hyperostotic changes on bone CT • Absence of high-velocity flow voids on T1 MR • Tl C+ MR shows enhancing, JF mass Helpful Clues for Less Common Diagnoses • Aneurysm/Vertebral Dissection o Multiple etiologies => dissection, post-traumatic, atherosclerotic, iatrogenic, congenital • Synovial Cyst o Round, central T2 hyperintense mass with low signal margin o Associated with dorsal Cl-2 articulation or degenerated facets Helpful Clues for Rare Diagnoses • Neurenteric Cyst o Intraspinal cyst + vertebral abnormalities (persistent canal of Kovalevsky, segmentation and fusion anomalies)

Retro-Odontoid Pseudotumor

II Sagittal T1WI MR shows rheumatoid arthritis involving

C1·C2 articulation with dens erosion and extensive

=.

pannus (ormation There is mild compression of medulla by pannus and obscuraUon of fat planes.

Sagittal T1WI MR shows CI-C2 degenerative pseudopannus in patient with DISH. The odontoid is not eroded, but tile ADI is t. Cord compression occurs between degenerative pannus & posterior C 1.

=

2 9

c

CVJ SOFT TISSUE ABNORMALITY

o

nc -,::J t1l .0

~ Ql

Osteomyelitis,

t

Ql

> .Q c t1l

~

U Ql

C

a.

r/)

Cl-C2

Metastases

(Left) Sagiltal T2WI MR show large pre vertebral abscess spanning Cl to C4 lID and extension posteriorfy involving interspinous region 81. Findings are typical for T8. (Right) Axial Tl C+ FS MR shows melaslatic lung cancer with extensive extracapsular nodal spread.

Post-contrast image shows Ihe mass has ill-defined borders with invasion of the longus capitis muscle !'::1l and invasion to the pharyngeal mucosal space 81.

Metastases

Lymphoma

(Left) Axial CTA shows Ihe classic appearance of thyroid metastasis with thin

expansiJe bony margin with the predominalely

lytic

lesion within left

facel/lamina of C3 ~. (Right) Axial CECT shows homogeneous mass in the relropharyngeal space, displacing Ihe parapharyngeal fal anterolaterally 81 and encircling the right internal carotid artery

Plasmacytoma (Left) Sagiltal Tl C+ MR shows variant MR case an unusually large skull base plasmacytoma engulfing the clivus and extending into the nasopharynx and abutting Cl-C2. (Right) Sagiltal TlWI MR shows a typical case of an aggressive nasopharyngeal squamous cell carcinoma with invasion of Ihe skull base by direct extension H2.

or

=

II 2 10

Nasopharyngeal

Carcinoma

en "2.

CVJ SOFT TISSUE ABNORMALITY

::::l CD

o ~ III

::::l

Neurofibromatosis

Chordoma

Type 1

(Left) Axial TI C+ MR shows multiple

large neurofibromas

within dorsal 50ft tissues and

paravertebral regions. Symmetrical

=

farge intradural

lesions compress the cervical cord at the C2 level. (Right) Sagillal TI C+ MR demonstrates an isointens€ expansile mass arising from the cfivus~. Notice the posterior indentation or "thumbing"

0· < CD ::I. CD

r:::r

~ III L. C

::::l

$:l0· ::::l

of the pons.

Chordoma (Left) Sagillal T 1 C+ MR shows large heterogeneous signal mass in the cervical epidural space, involving rhe dorsal aspect of C2- 3 junction and extending larerally, with diffuse enhancement. (Rig"') Coronal TI WI MR shows typical MR case of petro·occipital

fissure skull

base chondrosarcoma

Carotid

=.

Pseudoaneurysm/Dissection (Left) Sagillal T1 C+ MR shows well-defined and

homogeneously

enhancing

mass with a broad dural margin

Ea at

the foramen

magnum, typical for meningioma.

There is

compression of the medulla. (Right) Axial CTA shows the CT features of a pseudoaneurysm of rhe internal carotid artery locared below the skull base.

=

II 2 11

c

Cl-C2

o

nc

-,:J CO

~

.c Q) t Q)

> .Q c CO

~

U OJ

c:

'Q. CJ)

INSTABILITY

Common • Trauma o Jefferson Cl Fracture o Odontoid C2 Fracture o Hyperflexion Injury, Cervical o Rotary Subluxation, Atlantoaxial o Os Odontoideum o Pathologic Vertebral Fracture • Non-Traumatic o Rheumatoid Arthritis, Adult o Spondyloarthropathy, Seronegative Less Common • Non-Traumatic o CPPD o Osteomyelitis, CI-C2 o Grisel Syndrome o Achondroplasia o Trisomy 21 (10-20%, 1-2% Symptomatic) o Spondyloepiphyseal Dysplasia o Mucopolysaccharidoses (MPS) • Mimics of Instability o Normal Variant o Incomplete Fusion, Posterior Element o CraniovertebraJ Junction Variants o Calcific Tendinitis, Longus Coli o Pseudosubluxation (Childhood)

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Imaging Evaluation of Instability

Transverse ligament of dens critical to anteroposterior stability o Normal distance from inferior margin Cl arch to dens < 2 mm in adults o Increased distance indicates rupture transverse ligament • Flexion-extension views useful • May be false negative in 1st week after injury o Jefferson fracture unstable if combined lateral displacement of Cllateral masses relative to articular pillars of C2 " 7 mm Incomplete fusion of posterior elements does not cause instability because ligaments intact Grisel syndrome in association with retropharyngeal infection, primarily seen in children Rheumatoid arthritis often also involves atlanto-axial articulations, lower cervical uncovertebral and facet joints o Will not be present in C-spine unless peripheral involvement also present o RA pannus does not calcify Calcified inflammatory tissue around dens usually due to CPPD o

DIFFERENTIAL DIAGNOSIS

•

•

•

•

Other Essential Information • Craniocervical junction injuries often multilevel • Os odontoideum felt to represent nonunited dens fracture

Jefferson C1 Fracture

Odontoid C2 Fracture

II 2

=

Axial bone CT shows lateral dislocation of C1

relative

lateral displacement

12

instability.

to C2 arUcular pillars

of lateral masses>

of lateral masses . Combined

7 mm confirms

Sagittal

NECT shows

type

/I odontoid

fracture

=.

unstable injury seen primarily in elderly paUents, after a trivial injury such as a ground level fall.

an

often

Cl-C2

en

INSTABILITY

-C ::::s (1)

Os

Odontoideum

Rheumatoid

Arthritis,

Adult (Lefl) Sagillal bone CT shows nonuniled

dens fracture

=..

called as odontoideum. These are commonly unstable and should be evaluated with flexion/extension views. (RighI) Sagillal NECT shows widening of CI-2 interval SI due to rupture of transverse ligament of dens caused by

pannus. Note bony erosion ofdens=.

CPPD fLeft) Sagillal bone CT shows calciFications around dens ~ in this patient presenting with instability. CPPO crystals were seen on biopsy at time of surgical fusion. (RighI) Sagillal T2WI MR shows MRSA infection involving

occiput

=

to C2.

Prevertebral abscess

and

abscess surrounding dens =:7& narrowing evident.

Craniovertebral

spinal canal are

Junction Variants (Left) Sagillal N[CT shows C2-] pseudosubluxation = in a child. Posterior laminar line from C1 to C] is normal. C2-] anterolisthesis of < 4 mm is seen as a normal variant in up to 40% of children. fRighl) Anteroposterior radiograph shows failure of fusion of posterior arch C 7 8l mimicking fracture. Unlike (racture, rnargins of defect are smooth

and corlicaled.

II 2

c

ODONTOID

o

DEFORMITY

13 c

--,::J

co ~

.0

OJ

t

OJ

> .Q

c co ~

U Q)

c a.

en

DIFFERENTIAL DIAGNOSIS

CPPD Rarely, gout • Hypoplasia: Odontoid short and body of C2 dysmorphic o o

Common • Trauma o Odontoid C2 Fracture o Os Odontoideum • Arthritis o Rheumatoid Arthritis, Adult o CPPD o Seronegative Spondyloarthropathy o Juvenile Idiopathic Arthritis • Tumor o Metastases, Lytic Osseous o Multiple Myeloma • Craniovertebral Junction Variants Less Common • Congenital o Spondyloepiphyseal Dysplasia o Hypoplastic Odontoid Process o Klippel-Feil Spectrum o Down Syndrome o Mucopolysaccharidoses • Tumor o Osteochondroma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Erosion vs. hypoplasia vs. trauma • Erosion of odontoid: Odontoid may have pencil tip or erosion at base • Soft tissue mass around odontoid o Infection o Rheumatoid arthritis Odontoid

Helpful Clues for Common Diagnoses • Acute Trauma: Odontoid may be displaced or angled posteriorly on lateral view o Often difficult to see fracture on odontoid view, especially in osteopenic patients • Chronic Post-Traumatic Deformity o Os Odontoideum: Rounded ossicle o Angular Deformity: Tip of odontoid points posteriorly • Bone Tumor: Marrow abnormality visible on CT or MR; lytic lesions difficult to see on radiographs due to overlying structures • Rheumatoid Arthritis (RA): Pannus never calcifies; arthritis always present in hands or feet if seen in neck • Seronegative Spondyloarthropathy o Syndesmophytes fuse multiple vertebrae; erosions of odontoid may look same as RA • CPPD: Soft tissue mass contains calcification • Infection: Usually unifocal; often epidural extension • Congenital Deformity: Odontoid abnormal in shape but cortex intact; other anomalies often present

C2 Fracture

II 2 14

=

I.2teral radiograph shows posterior displacement of the odontoid relative to the body of C2, indicating an odontoid fracture.

Sagittal STIR MR shows a sofl tissue mass around U,e dens and bony erosion of the dens 81.

=

ODONTOID

DEFORMITY

o ~ OJ

:J

Juvenile Idiopathic

a

Arthritis


QJ t

QJ

> CI>

c '0.

en

DIFFERENTIAL DIAGNOSIS Common • Pathologic Vertebral Fracture o Osteoporosis o Metastases, Lytic Osseous o Metastases, Blastic Osseous o Plasmacytoma o Multiple Myeloma o Steroids o Langerhans Cell Histiocytosis o Giant Cell Tumor o Ewing Sarcoma o Leukemia o Lymphoma o Osteomyelitis, Pyogenic o Hemangioma • Burst Fracture • Chance Fracture • Failure of Vertebral Formation less Common • Ki.immell Disease

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Single vertebra plana should always raise suspicion for underlying lytic lesion Helpful Clues for Common Diagnoses • Radiographic findings suggesting that a vertebra plana is due to tumor o Normal bone density in remainder of spine

II 3 6

Cortical destruction: Vertebral body or neural arch o "Absent pedicle" sign o Lytic or blastic lesion seen in other vertebrae • MR appearance often allows differentiation between vertebra plana due to osteoporosis and tumor a Osteoporosis: Band-like or stellate abnormal signal, focal cortical break but no widespread cortical destruction o Tumor: Cortical destruction, round or ovoid marrow replacement, marrow replacing entire vertebral body or involving neural arch • Langerhans cell histiocytosis most likely cause in young patients • Congenital vertebral anomalies cause well-demarcated hypoplasia o

Helpful Clues for less Common Diagnoses • Ki.immell Disease a Gas in flattened vertebral body Other Essential Information • Paraspinous soft tissue mass not a helpful differen tial diagnostic finding o May be due to hematoma in non pathologic fracture, to paraspinous tumor, or to paraspinous abscess

Osteoporosis

Osteoporosis

Sagittal bone CT shows flattened, sclerotic T6 \'ertebra with callus formation, in elderly paUent. Mild T7 compression fracture is a/50 present

Sagittal Tl WI MR shows fracture line at LJ surrounded by band of low signal intensity, characteristic of acute fracture edema/hemorrhage. allow-up confirmed osteoporotic burst fracture.

81 due to subacute burst fracture,

=

=

r

flATTENED

VERTEBRAL BODY, SOLITARY

< ,

-0

o

[l)

ro ~

.0 Q)

t Q)

> Q)

c:

enC-

DIFFERENTIAL DIAGNOSIS Common • Traumatic Fractures • Pathologic Vertebral Fracture o Osteoporosis o Metastases, Lytic Osseous o Multiple Myeloma o Metastases, Blastic Osseous o Leukemia o Lymphoma • Sickle Cell • Scheuermann Kyphosis less Common • Osteogenesis Tmperfecta • Achondroplasia • Cushing Disease • Spondyloepiphyseal Dysplasia • Caudal Regression Syndrome Rare but Important • Radiation Therapy to Spine in Childhood

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Traumatic spine fractures often occur at multiple contiguous or noncontiguous levels even in young patients • MR useful to look for marrow replacement disorder in patients with multiple fractures • Metastases o Radiographs: Cortical breakthrough, loss of pedicle

Traumatic

II 3 8

Fractures

Sagittal STIR MR shows mulliple compression

~ due patient.

10

oCT: Destruction of trabeculae o MR: Rounded lesions underlying fractures, often elsewhere in spine as well • Myeloma, lymphoma, leukemia o Similar to metastases, but loss of pedicle uncommonly seen on radiographs o MR, CT show posterior element involvement is common o Lytic lesions in spine often difficult to see on radiographs • Most common appearance is diffuse osteopenia, fractures o Focal, round areas of marrow replacement or diffuse marrow replacement may be seen • Sickle cell: Vertebral height lost centrally only ("Lincoln Log vertebrae") • Scheuermann kyphosis o 5° wedging of at least 4 contiguous vertebrae o Schmorl nodes & undulating vertebral endplates o Usually involves thoracic spine Helpful Clues for less Common Diagnoses • Osteogenesis Imperfecta o Severe osteopenia, thin bone cortices o Multiple fractures varying in severity, including pancake vertebrae o Scoliosis often present • Cushing Disease o Pronounced concavity of end plate ("fish mouth vertebrae")

Osteoporosis

fraclUres

molar vehicle accident in a 30 year old

LLlteraJ radiograph shows multiple compression fractures ~ due 10 osteoporosis. CT or MR is useful in these patients to exclude marrow replacement by tumor.

flATTENED

en

VERTEBRAL BODY, MULTIPLE

"0

::;, (l)

< C1l ;::l. C1l

Metastases,

.,

CJ

Blastic Osseous (Left) Sagittal bone CT shows mulliple flallened verlebrae There is a moth-eaten appearance lhroughoullhe verlebral bodies due 10 myeloma and a single large lytic lesion E2. (Right) Coronal bone CT shows 1055 of heighl of mulliple verlebral bodies E2 due 10 blaslic metastases. Allhough the bone is increased in density, it is not structurally sound, and patients are at increased fracture risk.

=.

Q)

OJ

o Cl. '< \J

o (fl

ro.,

o· ., m

ro 3 C1l

::;,

Ui

(Left) Coronal NECT shows diffuse bony sclerosis and vertebrae with variable degrees of flallening. Cenlral verlebral flaltening with preserved margins

=

resembles

lOy

"Lincoln

Logs". (Right) Sagiltal T2WI MR shows flaltening and wedge deformities of 5 adjacent vertebrae

=.

Involvement

of at

least 4

vertebrae with at least 50 wedging of each verlebra, undulating appearance of endplales, and definable Schmor! nodes indicate Scheuermann kyphosis.

Osteogenesis

Imperfecta (Left) Anleroposterior radiograph shows severe osteoporosis. Variable degrees of vertebral flaltening refleCl fraclure, of varying severity. (Right) Coronal bone CT shows mild verlebral flaltening and undulating vertebral endplates.

II 3 9

en

DYSMORPHIC VERTEBRAL BODY

C Q)

E

~ w ~ o ·C Q)

eno

D...

>-

"0

o

CO

ro ~

.0 Q)

t Q)

> Q)

c: Co

C/)

DIFFERENTIAL DIAGNOSIS Common • Single Vertebral Body o Post-Traumatic Deformity o Schmorl ode o Limbus Vertebra o Metastases, Lytic Osseous • Multiple but not all Vertebral Bodies o Abnormal Segmentation • Partial Vertebral Duplication • Vertebral Segmentation Failure • Klippel-Feil Spectrum o Scheuermann Disease o Scoliosis o Metastases, Lytic Osseous o Juvenile Idiopathic Arthritis o Neurogenic (Charcot) Arthropathy o Post-Radiation Changes • Diffusely Abnormal Vertebral Bodies o Sickle Cell o Osteogenesis Imperfecta o Achondroplasia less Common • Single Vertebral Body o Klimmell Disease o Osteochondroma o Ewing Sarcoma o Langerhans Cell Histiocytosis • Multiple Vertebral Bodies o Osteomyelitis, Pyogenic o Osteomyelitis, Granulomatous • Diffusely Abnormal Vertebral Bodies o Thanatophoric Dwarfism Schmorl Node

II 3

Lateral fluoroscopy shows extending into Schmorl node

discographic contrast Schmorl nodes are

=:I.

caused by disc intravasation into vertebrallxx1y.

10

o

Mucopolysaccharidoses

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Single vertebrae with abnormal appearance usually post-traumatic • 2 or more adjacent vertebrae with abnormal appearance usually segmentation anomaly Helpful Clues for Common Diagnoses • Scheuermann disease causes undulating appearance of vertebral endplates • Cushing disease causes cupping deformity of vertebral endplates • Infection and neurogenic arthropathy are centered on intervertebral disc and show endplate erosions • Juvenile idiopathic arthritis results in vertebral bodies that are tall relative to anteroposterior diameter • Klimmell disease distinguished by gas in vertebral body • Sickle cell causes "Lincoln Log" deformity • Mucopolysaccharidoses and achondroplasia cause "bullet vertebrae" with anterior portion of body small • Vertebral bodies near apex of a scoliosis often mildly misshapen • Tumors involving only part of vertebral body may cause a dysmorphic appearance due to partial collapse

Limbus Vertebra

Sagittal bone CT shows well-marginated ossicle

=:I at

anterior corner of vertebral body. Limbus vertebra is due to disc herniating between vertebral body & ring apophysis, preventing normal fusion.

DYSMORPHIC

Vertebral

Segmentation

Failure

VERTEBRAL BODY

Scheuermann

Disease (Left) Lateral radiograph shows congenital fusion of occiput and C1 Ell with resultant abnormal motion causing a dysmorphic appearance of C2 ~. C4 and CS are flatter than normal,

without

definite

fusion anomaly. (RighI) Sagiual bone CT shows mild anterior wedging and irregular vertebral endplales due to multiple Schmorf nodes characteristic of Scheuermann kyphosis.

a

Sickle Cell

m C1l

3 C1l

::J

en

=

(Left) Laleral radiograph shows fused vertebrae with narrow

AP diameter

due to growlh failure. Erosion of dens ~ is a clue to Ihe diagnosis. (Right) Sagiual T2WI MR shows /I Lincoln Log'I appearance 81 of almosl alf the included vertebrae, with preserved peripheral body height and central flattening reflecting bone infarcts.

Osteochondroma

Osteomyelitis,

Granulomatous (Left) Coronal bone CT shows an osteochondroma of C2 causing deformity of both the C2 and C 1. Osteochondromas of the

=

spine are very rare, even in

patienls with multiple hereditary exostoses. (Right) Sagittal bone CT shows multiple, fused, misshapen verlebrae and kyphosis due to tuberculosis.

II 3 11

!!l

c:

ENLARGED VERTEBRAL BODY/POSTERIOR

ElEMENT

Q)

E Q)

w ~ o 'C Q)

Ul o

a.. >o

"0

CO ctl ~ .0 Q)

1:: Q)

> CIl

c:

'0.

en

DIFFERENTIAL DIAGNOSIS Common • Facet Arthropathy o Facet Arthropathy, Cervical o Facet Arthropathy, Lumbar o Baastrup Sign • Paget Disease • Aggressive Hemangioma • Compensatory Enlargement o Scoliosis o Spondylolysis • Congenital Fusion Less Common • Metastases, Lytic Osseous • Aneurysmal Bone Cyst • Osteoblastoma • Chordoma Rare but Important • Fibrous Dysplasia • Chondrosarcoma • Osteochondroma

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Osteoblastoma should always be considered in the differential diagnosis of painful scoliosis • Center of the lesion in the vertebral body vs. posterior element may help with the differential diagnosis

II 3 12

Helpful Clues for Common Diagnoses • Facet Arthropathy, Cervical o Capsular laxity and joint space narrowing may lead to degenerative spondylolisthesis o Osteoarthritis of synovial-lined zygapophyseal joints o Hypertrophic changes with osteophytes, normal bone mineralization, & joint space narrowing • Facet Arthropathy, Lumbar o Osseous hypertrophy with articular joint space narrowing and encroachment upon neural foramen o Irritation of synovium produces synovial hyperplasia with paradoxical joint space widening o Facet arthrosis syndrome with low back, hip, and buttock pain aggravated by rest

• Baastrup Sign o Close approx. & contact of adjacent spinous process with reactive sclerosis, enlargement & flattening of apposing interspinous surfaces o "Kissing" spinous processes o Cystic degeneration of interspinous ligaments and posterocentral epidural cyst • Paget Disease o Enlarged vertebra and neural arch with diffusely coarsened & haphazard bony trabecular pattern • Most commonly L3 & L4 • Cortex is thickened • Anterior concavity of the vertebral body is lost o Can cause spinal stenosis & neural forami nal narrowing o 0 epidural soft tissue component unless sarcomatous degeneration • Aggressive Hemangioma o Expanded & indistinct cortex, irregular honeycombing pattern, & soft tissue mass • Trabecular condensation thinner in comparison to Paget disease o Lesions commonly involve entire vertebral body with extension into neural arch o Typically occur between T3 & T9 o Epidural extension may cause cord compression o Can become symptomatic with growth, which often occurs during pregnancy • Compensatory Enlargement o Scoliosis • Minimal structural vertebral deformities & advanced degenerative changes • Facet osseous overgrowth, asymmetric disc space, & discogenic sclerosis at the concave aspect of the scoliosis • Unilateral radicular symptoms on the side of the concavity of the deformity o Spondylolysis • Defects in pars interarticularis (PI) may be due to repetitive stress injury • Spinal canal is elongated at the level of the pars defect on axial imaging • Most common at LS • Sclerosis of PI, volume averaging of superior facet spur, partial facetectomy, blastic metastases may mimic spondylolysis

ENLARGED

VERTEBRAL BODY/POSTERIOR

• Congenital Fusion a Vertebral bodies smaller than normal with tapered contour at fused disc space a Rudimentary disc space with reduced height & diameter, "wasp waist" a Degenerative changes at adjacent levels a ± Fusion of posterior elements Helpful Clues for less Common Diagnoses • Metastases, Lytic Osseous a 50-70% bone destruction required for detection on radiography a Lesion involves posterior cortex & pedicle a Diffuse involvement of marrow gives the appearance of brighter disc than bone on TlWI a Fat suppression on enhanced Tl WI helpful to unmask lesions • Aneurysmal Bone Cyst a Arise in the neural arch with the majority (75-90%) extending into the vertebral body a Expansile remodeling of bone with cortical thinning a Fluid-fluid levels with hemorrhage a No tumor matrix • Osteoblastoma a Originate in the neural arch, often extend into the vertebral body 0> 1.5 cm (osteoid osteoma < 1.5 cm) a Narrow zone of transition with sclerotic rim a Bone matrix on CT or radiograph

ElEMENT

May be associated with an aneurysmal bone cyst (10-15%) a Painful scoliosis (50-60%) • Chordoma a Rare involvement of the vertebral body a Purely lytic a T2 hyperintense with multiple septations a Variable enhancement a Amorphous intratumoral Ca++ in 30% of vertebral lesions a

< ct> :4ct> 0-

~ III CD

o a. '
vertebral body a Spine involvement in polyostotic disease a Mildly expansile lesion with characteristic ground-glass matrix a Heterogeneous Tl & T2 signal and enhancement • Chondrosarcoma a Lytic, destructive lesion with cortical destruction and extension into the soft tissues a ± Chondroid matrix (50%) of "rings & arcs" • Osteochondroma a Sessile or pedunculated osseous lesion contiguous with the parent vertebra a Cartilaginous cap> 1.5 cm in adults concerning for malignant transformation

Facet Arthropathy

Axial

bone

overgrowth stenosis.

CT shows severe left unilateral

ffi

facet

causing moderately severe central

=

Sagittal T7WI MR shows degeneration changes of lhe interspinous ligament and ligamentous flavum WiU1 a poslerior epidural cySI!:;].

II 3

ENLARGED VERTEBRAL BODY/POSTERIOR

VJ

C

ELEMENT

QJ

E QJ

W

~ o

'C QJ

U; o

0..

>-

"0

o

CO

ro ~

.0 QJ

t

QJ

> Q)

c: '0. (/)

Paget Disease (Left) Sagittal STIR MR shows a mildly enlarged L2 vertebral body in the AP dimension with relatively low signal. Enlargement & brighter signal in the spinous process 81 reflect more fibrovascular tissue. (Right) Sagittal T2WI MR shows a T2 hyperintense mass involving a thoracic vertebral body & posterior elements, with a large amount of epidural extension & cord compression A typical hyperintense hemangioma is seen the level above 81.

=

=

=.

=

Scoliosis

Spondylolysis

fLeft) Axial T2WI MR shows (acet osteoarthritis asymmetric disc space narrowing, &. discogenic sclerosis E2 at the concave aspect of the scoliosis. Disc bulges can be far lateral & are better seen on the axial views. (Right) IIxial CECT shows myelogram of chronic isthmic spondylolysis 1:1 resulting in the "wide canal" sign. There is increased AP diameler of bony canal at L5 relative to more the cephalad levels.

Congenital Fusion (Left) Sagittal bone CT shows fusion of L I, L2, & L3 vertebral bodies. Smaller fused vertebrae are characteristic of congenital

=

fusion. Advanced

degenerative disc disease below the kyphoscoliosis results in spinal & neural foraminal stenosis ~. (Rig"') Sagittal STIR MR shows an enlarged hyperintense upper thoracic vertebral body lesion and a smaller lesion in the body below A heterogeneous enlarged thyroid mass is also

=.

II 3 14

seen

81.

Metastases,

Lytic Osseous

ENLARGED VERTEBRAL BODY/POSTERIOR

ElEMENT


;l. C1>

CJ"

~

Schwannoma (Left) Sagiltal Tl C+ MR shows a large lobulated enhancing mass tilling the distal thecal sac and expanding & remodeling the lumbosacral canal (Right) Sagittal Tl C+ MR shows unusually extensive,

llJ

OJ

o Q. '


::::l

Ui

Achondroplasia (Left) Sagittal T2WI MR shows a large lobulated extradural mass, tollowing CSF signal, widening the spinal canal by remodeling the dorsal elements and compressing the spinal cord. (Right) Lateral radiograph

=

shows shortened pedicles and posterior scalloping

Diastematomyelia

Juvenile Idiopathic

vertebral

Arthritis (Left) Axial T2' GRE MR shows dysmorphic vertebral body with enlarged cervical canal and a split spinal cord ~> (Right) Lateral radiograph shows tusion at multiple abnormally slender cervical vertebral bodies with a widened

=

cervical

canal

=.

II 3 19

SPONDYlOLISTHESIS

c'" Q)

E Q)

w

~ o "C Q)

eno

0..

>.

"0

o

CD

ro~ .0 Q)

t

Q)

> Q)

c: Co

en

DIFFERENTIAL DIAGNOSIS Common • Pediatric Pseudosubluxation • Dysplastic • Degenerative Disc Disease • Spondylolysis • Post-Treatment Instability • Posterior Column Injury, Cervical Less Common • Osteomyelitis, Pyogenic • Tuberculous Infection • Tumor o Metastasis o Lymphoma o Multiple Myeloma o Primary Bone Tumor • Osteosarcoma • Osteoblastoma • Chondrosarcoma • Rheumatoid Arthritis, Adult

ESSENTIAL INFORMATION

II 3 20

Key Differential Diagnosis Issues • Spondylolisthesis ~ displacement of one vertebral body relative to another o Dysplastic (congenital abnormality of arch) o Isthmic (fatigue or stress fractures of pars) o Degenerative (osteoarthritic segmental instability of facets) o Traumatic o Pathologic (local bone disease) • Most common is isthmic and degenerative • Spondylolisthesis can occur with or without spondylolysis • Spondylolisthesis graded by amount of anterior displacement of superior body by 25% stages o < 25% ~ grade 1, < 50 ~ grade 2, < 75% grade 3, < 100% ~ grade 4, > 100% ~ spondyloptosis • Anterior displacement of vertebral body ~ "uncovering" of the posterior disc margin with pseudobulge deformity • Look for focal herniations in addition to the pseudobulge at the level of spondylolisthesis and at adjacent levels where stress is increased

• Spondylolysis ~ break in pars interarticularis of vertebrae leaving two parts o Anterior component of vertebral body, pedicle, superior facet o Posterior component of inferior facet, lamina, spinous process Helpful Clues for Common Diagnoses • Pediatric Pseudosubluxation o Normal mobility C2 on C3 in flexion o Seen in 40% of children at C2-3, 14% of children at C3-4 level o Only seen with flexion o May be mistaken for ligamentous injury, since 70% of cervical spine fractures in children occur from Cl to C3 o C2 displaced up to 3-4 mm o Age < 14 years o Swischuk line: Drawn from anterior aspect of CI-C3 spinous processes ~ normal within 1 mm of anterior C2 spinous process o If in doubt on plain film or CT, then MR to exclude ligamentous injury • Degenerative Disc Disease o Most common at L4-5 o Wide canal sign not present since no defects in pars o Usually grade 1 without lysis o Look for severely degenerated facets + disc degeneration o Lose of height of neural foramen with stenosis as superior body slips forward o Posterior retrolisthesis ~ disc degeneration with disc height loss, rostrocaudal subluxation of facets • Spondylolysis 090% at L5-S1, bulk of remainder at L4-5 • L3 and above unusual ~ question gymnastics o 20% may have unilateral defect in pars o May show contralateral compensatory bone hypertrophy and sclerosis • Not to be mistaken for osteoid osteoma! o Wide canal sign present (increase in AP diameter of bony canal at lysis level relative to normal levels) with bilateral lysis • Post-Treatment Instability o Deformity that increases with motion and increases over time o Dynamic slip> 3 mm in flexion/extension

SPON DYLOLISTH ESIS Static slip of 4.5 mm or greater Angulation> 10-15° suggests need for surgical intervention o Stabilizing anatomic structures • Anterior longitudinal ligament (resists hyperextension) • Posterior longitudinal ligament • Intertransverse ligaments (connect neighboring transverse processes) • Interspinous ligaments (resists hyperflexion) • Facet capsule • Ligamentum flavum • Intervertebral disc: Main stabilizer of lumbar and thoracic spine • Muscular attachments • Posterior Column Injury, Cervical o Fractures of laminae, facets, or spinous processes o Disruption of ligaments bridging spinous processes + laminae o If capsular ligaments torn, facets, &/or laminae both fractured, rotational instability may exist o Flexion extension films or fluoroscopy to assess degree of instability o o

Helpful Clues for Less Common Diagnoses • Tuberculous Infection o Endplate irregularity and bone destruction o T2 hyperintense disc, vertebral bodies o Look for associated epidural phlegmon/ abscess

Pediatric

Fat-suppressed post-contrast Tl images useful for epidural disease and paravertebral/psoas extension • Tumor o Destruction of posterior elements + vertebral body leads to secondary instability • Rheumatoid Arthritis, Adult o Subaxial anterior + posterior subluxations common o Atlantoaxial subluxation in 5% of patients with cervical rheumatoid arthritis o Instability may also be present at lower levels of cervical spine o Spine radiographs in flexion/extension to assess for instability o Look for Cl-2 involvement with retrodental pannus + subaxial spondylolisthesis o


.

o " CO

~

Gl

c:

'0. en

DIFFERENTIAL DIAGNOSIS Common • Vertebral Body Only a Anterior Compression Fracture, Thoracic a Anterior Compression Fracture, Lumbar a Lateral Compression Fracture, Lumbar a Lateral Compression Fracture, Thoracic a Burst Fracture (Mild) a Pathologic Vertebral Fracture a Hyperflexion Injury, Cervical a Hyperextension Injury, Cervical • Vertebral Body Plus Posterior Elements a Burst Thoracolumbar Fracture a Burst Fracture, Lumbar a Burst Fracture, Cervical a Pathologic Vertebral Fracture a Burst Fracture, C2 a Hyperflexion Injury, Cervical a Hyperextension Injury, Cervical a Chance Fracture, Thoracic a Distraction Fx, Low Thoracic • Fracture Mimics a Schmorl Node a Limbus Vertebra a Kyphosis, Idiopathic a Scheuermann Disease a Sickle Cell a Scoliosis and Kyphosis, Congenital a Neurogenic (Charcot) Arthropathy a Osteomyelitis, Pyogenic Less Common • Lymphoma • Cushing Disease • Ki.immell Disease • Osteomyelitis, Granulomatous • Congenital Syndromes a Failure of Vertebral Formation a Osteogenesis Imperfecta a Diastematomyelia a Achondroplasia, Mucopolysaccharidoses a Mucopolysaccharidoses Rare but Important • Ewing Sarcoma • Apophyseal Ring Fracture

ESSENTIAL INFORMATION

II 3 28

Key Differential Diagnosis Issues • Mechanism of injury a Compression, burst: Axial load injuries

Chance: Anterior compression, posterior distraction a Fracture/dislocation: Shear forces • Treatment of different types of fractures is different, so imaging distinction is important • Imaging may overestimate or underestimate mechanical instability of spine • Fracture vs. fracture mimic a History of trauma may not be available or reliable a Fractures may be single or multiple levels a May have different kinds of fractures at different levels • e.g., burst and compression at 2 different levels a Multiple, uniformly involved levels of deformity usually not traumatic a

Helpful Clues for Common Diagnoses • Compression Fracture a Does not involve posterior vertebral body cortex or posterior elements a Common throughout thoracic and lumbar spine a May involve anterior or lateral portion of vertebral body a Often occur at multiple levels in normal or osteoporotic bone a Most common type of pathologic fracture • Burst Fracture a Burst fracture extends through posterior cortex of vertebral body a More severe burst fractures show vertically oriented fractures of neural arch a Most common at thoracolumbar junction • Chance Fracture a Anterior compression vertebral body a In conjunction with horizontally oriented fracture of posterior elements OR ligamentous injury resulting in separation of adjacent spinous processes a Most common at thoracolumbar junction • Hybrid Fractures a Some fractures have elements of both burst- and chance-type injury • Retropulsion of posterior vertebral body cortex + separation of posterior elements • Best to categorize as Chance and add description of burst elements • Compression or Burst Fracture due to Trauma or Osteoporosis

FRACTURE, VERTEBRAL BODY

MR: Band-like configuration of abnormal signal a CT: Trabeculae compressed but not destroyed • Compression or Burst Fracture due to Tumor a Radiographic findings • Focal osteopenia or osteosclerosis • Cortical destruction • Nonvisualization of pedicle contour on AP radiograph a helpful sign a MR findings • Rounded configuration of abnormal signal, or diffuse abnormal signal adjacent to fracture • Cortical breakthrough beyond fracture line is often seen • Additional areas of abnormal signal without fracture helpful signs when present a CT findings • Destruction of trabeculae adjacent to fracture • Cortical break beyond fracture line is often seen • Additional areas of bony destruction without fracture helpful signs when present • Limbus Vertebra a Ossicle anterior corner of vertebral body, smoothly contoured & corticated a Failure of fusion of ring apophysis • Kyphosis, Idiopathic a

Anterior Compression Fracture, Lumbar

Smooth vertebral endplate contour, multiple vertebrae a Diagnosis of exclusion • Scheuermann Disease a Undulating contour of endplates a Discrete Schmorl nodes variably present a 4 or more contiguous vertebral bodies with at least S° wedging each • Sickle Cell a H-shaped or "Lincoln Log" vertebrae with central depression and preserved margins • Infection or Neuropathic Arthropathy a Endplate destroyed, irregular a

3 (1)

::J

en

Helpful Clues for Less Common Diagnoses • Kiimmell Disease a Gas in vertebral body cleft; flattened vertebral body • Osteomyelitis, Granulomatous a Multiple vertebral fusions, kyphosis • Congenital Vertebral Anomalies a Smoothly marginated, usually involve multiple vertebral bodies • Osteogenesis Imperfecta a Severe osteopenia, scoliosis, multiple fractures of varying severity • Achondroplasia, Mucopolysaccharidoses a Bullet-shaped vertebrae

Burst Thoracolumbar Fracture

SI in this young palient with normal bone density

Lateral radiograph shows burst fracture in a young patient, with retropulsion of posterior vertebral body

Palient has chronic spondylolysis of L4.

cortex~.

Lateral radiograph shows anterior compression fracture

m (1)

II 3 29

FRACTURE, VERTEBRAL BODY

(J)

c Q)

E Q)

w ~ a ·C Pathologic Vertebral

Q)

tl a

Cl..

>a

"0

co ro ~ .0 Q)

t Q)

> C1l

c: a.

en

Fracture

(Left) Sagiltal T2WI MR shows vertically oriented compression fracture of L3 due to metastases from

=

breast cancer.

Marrow

is

diffusely abnormal signal intensity. (Rigl1t) Lateral radiograph shows wedge deformity and "flexion teardrop" fragment at CS. Widened interspinous distance ~ and laminar

1::1

fracture m are evidence of posterior distraction Force.

(Left) Sagittal NECT shows characteristic pattern of cervical injury in DISH. Hyperextension fracture ~ extends through ossified ALL and vertebral body. In ankylosing spondylitis, fracture usually extends through disc and spares vertebral body. (Right) Sagiltal STIR MR shows

anterior vertebral

=

compression and tear of interspinous ligaments E2 indicating

flexion-distraction

(Chance) fracture.

Chance Fracture, Thoracic (Left) Sagiltal bone CT shows flexion-distraction

injury,

with anterior compression E1 and posterior distraction fractures. There is also retropulsion r=::l of the posterior cortex of the vertebral body (Lypical of

=

burst fracture);

howeve"

the

preponderant patlern is that of a Chance fracture. (Right) Sagiltal NECT shows fracture-dislocation at T4-S Ell. Cord was lransected.

II 3 30

FRACTURE, VERTEBRAL BODY

Schmorl Node

Kyphosis, Idiopathic (Left) Sagittal bone CT shows a typical Schmorf node a bowl-shaped depression in the vertebral endplate due to disc material herniating through endplate. (Right) Lateral radiograph shows marked kyphosis of the upper thoracic spine and multilevel degenerative disc disease m. There are no congenital abnormalities, fractures, Scheuermann

a

OJ

o Q. '
Gl

c: Co

rtl

DIFFERENTIAL DIAGNOSIS Common • Normal Variant o Facet Tropism • Facet Arthropathy o Facet Synovial Cyst • Tumor Destruction o Metastases, Lytic Osseous o Lymphoma o Multiple Myeloma Less Common • Rheumatoid Arthritis, Adult • Congenital Fusion • Septic Facet Joint Arthritis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Assess vertebral abnormalities, multiplicity (i.e., metastases), & soft tissue component (i.e., RA pannus, epidural abscess) Helpful Clues for Common Diagnoses • Normal Variant o Facet Tropism • Asymmetry in orientation of zygapophyseal joint surfaces up to 35% • L5-S1 > L4-5 • Stress hypertrophy of pedicle on the more coronally oriented side • Facet Arthropathy o Osseous facet overgrowth with encroachment upon neural foramina

II 3 32

Cartilage erosion & joint space narrowing o Facet Synovial Cyst • Extradural cystic mass extending from degenerative facet joint • Internal high Tl/low T2 signal due to hemorrhage or proteinaceous content & low T2 rim 2° wall calcification • Tumor Destruction o Lytic mets: Irregular preservation of trabeculae & buttressing, isolated fronts of cortical bone resorption coalescing to confluence o Multiple myeloma: Sharply defined, spheroid lesions with smooth borders & effaced/erased trabeculae, absence of remodeling o

Helpful Clues for Less Common Diagnoses • Rheumatoid Arthritis, Adult o Inflammatory arthritis involve synovial joints (facet & uncovertebral) w/erosions o Cervical spine involvement in 60% • C1-C2 instability in 33%; atlantoaxial subluxation in 5% • Congenital Fusion o Segmen tation failure of 2 or more cervical vertebra o Vertebral body narrowing at fused rudimentary disc space o ± Fusion of facets & spinous processes • Septic Facet Joint Arthritis o T2 hyperintensity and enhancement extends into adjacent soft tissues o ± Epidural abscess/phlegmon

Facet Tropism

Facet Synovial Cyst

Axial T2WI MR shows asymmetry of the face15 and lamina 8

Axial T2WI MRshows an extradural lesion SI extending anleromedially into the spinal canal from a hypertrophic facet joint !:D. Internal mixed to proteinaceous material.

hypoinlensily

may be due

FACET ABNORMALITY,

en

NON-TRAUMATIC

"S!. :::l Cll

< Cll ;::I. Cll

Metastases, lytic Osseous

0-

Metastases, lytic Osseous (Left) Sagillal TI WI MR shows expansile hypoinlense lesion involving the body, pedicle, and articular pillars of a mid-thoracic vertebral body The soft tissue component extends into the epidural space. (Right) Axial CTA shows a thyroid metastasis giving thin expansile bony margin with the predominantly lytic lesion involving the vertebral body and left facet/lamina of C3 There is epidural extension with cord compression E1.

=.

~ Q) CD

o

a. '< II

o en CD ~ o ~

m

en 3

,

""0

o

CO

CIl

~

.n OJ

t

OJ

> ell

c: Co

en

I I

DIFFERENTIAL DIAGNOSIS Common • Cervical o Hyperextension Injury, Cervical o Burst Fracture, Cervical o Hangman's C2 Fracture o Lateral Flexion Injury, Cervical o Jefferson Cl Fracture o Burst Fracture, C2 o Clay Shoveler's Fracture o Hyperflexion-Rotation Injury, Cervical o Hyperflexion Injury, Cervical • Thoracic o Chance Fracture, Thoracic o Burst Thoracolumbar Fracture o Facet-Lamina Fracture, Thoracic • Lumbar o Burst Fracture, Lumbar o Spondylolysis o Facet-Posterior Fracture, Lumbar o Transverse Process Fracture o Chance Fracture, Lumbar o Pedicle Stress Fracture • All Spinal Levels o Pathologic Vertebral Fracture Less Common • Fracture Mimics o Metastases, Lytic Osseous o Incomplete Fusion, Posterior Element o Neurogenic (Charcot) Arthropathy o Vertebral Segmentation Failure o Hypoplastic Rib, Supernumerary Rib

Hangman's

II 3 34

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues • Must distinguish between isolated posterior column injury and multicolumn injury o Isolated posterior column • Due to lateral flexion or rotation, direct blow, or hyperflexion • Clay shoveler's fracture a stable hyperflexion injury o Multiple column • Due to any injury mechanism, not necessarily unstable • Non-bony involvement of middle, anterior columns often best seen on MR Helpful Clues for Common Diagnoses • Prevertebral soft tissues of cervical spine may be normal in isolated posterior element fracture • Burst fracture: Posterior column fracture in vertical plane • Flexion-distraction fracture: Posterior column fracture in horizontal plane • Spondylolysis easily missed on axial images; use following signs o "Double facet" sign: Spondylolysis is anterior to facet joint o "Wide canal" sign: Increased AP dimension of spinal canal

C2 Fracture

Axial bone CT shows bilateral C2 pedicle fractures indicating hangman's-type fracture.

=:I

Axial bone CT shows le{l·sided (ractures of anterior It] and posterior 8lI ring of C7. This is a variant Jefferson fracture.

en

FRACTURE, POSTERIOR ELEMENT

~. :J (l)

< (l)

;:l. (1)

cr ~

Burst Fracture, Lumbar (LeFI) Axial bone CT shows L2 burst fracture.

Unlike

Chance

fracture,

posterior

element

fractures are

vertically oriented I:'] and there is retropulsion of posterior vertebral body cortex ICB (RighI) Axial bone CT shows LS spondylolysis 81 anterior 10 lacet joints I:'] (double Facet sign). AP diameter of canal is widened (wide canal sign).

OJ

OJ

o Q. '
Ql

c: .0. In

DIFFERENTIAL DIAGNOSIS Common • Metastases, Lytic Osseous o Lung Carcinoma o Thyroid Carcinoma o Renal Cell Carcinoma • Multiple Myeloma • Osteoblastoma • Giant Cell Tumor • Aneurysmal Bone Cyst Less Common • Chordoma • Chondrosarcoma Rare but Important • Fibrous Dysplasia • Telangiectatic Osteosarcoma • Enchondroma • Angiosarcoma • Cystic Angiomatosis

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Zone of transition is helpful to assess aggressiveness • Multiplicity of lesions, soft tissue component, & vascularity of lesions can be helpful in narrowing the differential diagnosis

II 3 38

Helpful Clues for Common Diagnoses • Metastases, Lytic Osseous o Lung, thyroid, renal, breast, oro-/nasopharyngeal carcinoma • Destructive lesion involving the posterior cortex & pedicle • Intervertebral discs are spared • Location proportionate to red marrow (lumbar> thoracic> cervical) • Multiple Myeloma o Multifocal malignant proliferation of monoclonal plasma cells leads to heterogeneous Tl marrow signal o May be expansile, but vertebral compression is more common o Vertebral body more frequently involved o Pedicle involvement later than with metastases • Osteoblastoma

Ovoid expansile mass originating in the neural arch, often extend into the vertebral body o 40% in spine • 40% cervical, 25% lumbar, 20% thoracic, 15-20% sacrum o Florid edema (corona effect) suggests an aggressive process, attributable to prostaglandin release by the tumor o Peri tumoral edema enhances avidly with gadolinium administration o Usually demonstrates more discrete bone matrix as compared to fibrous dysplasia o Bone scan demonstrates avid radionuclide uptake by the tumor • Giant Cell Tumor o Expansile, lytic lesion with narrow zone of transition o ± Cortical breakthrough o Centered in vertebral body o Margin usually not sclerotic o ± Residual bone trabeculae • Aneurysmal Bone Cyst o Expansile lesion may show cortical breakthrough o Shows a narrower zone of transition o Centered in posterior elements o Can be associated with fibrous dysplasia o

Helpful Clues for Less Common Diagnoses • Chordoma o Midline soft tissue mass with osseous destruction o T2 hyperintense mass with multiple septa o Can involve adjacent vertebral bodies by extension across disc space o Arise from notochord remnants • Chondrosarcoma o Lytic mass ± chondroid matrix, "rings & arcs" o Cortical disruption o Extension into soft tissues o Nonenhancing areas: Hyaline cartilage, cystic mucoid tissue, necrosis o Neural arch involved more frequently than vertebral body Helpful Clues for Rare Diagnoses • Fibrous Dysplasia o Well-defined, expansile, radiolucent lesion o Neural arch involved more frequently than the vertebral body

ENLARGED VERTEBRAL BODY, SOAP BUBBLE EXPANSION

Spine involvement typically in polyostotic disease o Fusiform bone expansion with "ground-glass" matrix o Heterogeneous T1/T2 signal & heterogeneous enhancement o Paraspinal soft tissue extension & vertebral collapse rare o Prevalence of scoliosis in patients with polyostotic fibrous dysplasia & spinal lesions is reported between 40% and 52% • Telangiectatic Osteosarcoma o Wide zone of transition with adjacent bone o Permeative appearance & cortical disruption o Multiple fluid-fluid levels o Soft tissue mass ± mineralization • Enchondroma o Expansile, homogeneous, slightly enhancing lesion with or without calcification • Arise either from migration of hyperplasitic immature spinal cartilage outside vertebral axis • Or from metaplasia of connective tissue in contact with the spine or annulus fibrosus o Common benign cartilaginous tumour involving the acral skeleton but extremely rare in the vertebral column (2% of cases) • Angiosarcoma o Lumbar region is most commonly affected o 33% in axial skeleton o

m

CO 3 ctl :::J

SELECTED 1.

REFERENCES

en

Leet AI et al: Fibrous dysplasia in the spine: prevalence of with scoliosis. J Bone Joint Surg Am. 86-A(3):531-7, 2004 Murphey MD et al: From the archives of the AFIP. Musculoskeletal angiomatous lesions: radiologic-pathologic correlation. Radiographies. 15(4):893-917, 1995 Kumar R et al: Expansile bone lesions of the vertebra. Radiographies. 8(4):749-69, 1988 lesions and association

2.

3.

Thyroid Carcinoma

lung Carcinoma

=

SagillalSTfR MR shows a hyperintense lesion expanding a thoracic verlebral body the articular facels & epidural space 1:2.

a

Coarse trabecular/honeycomb pattern is suggestive of a vascular tumor • Cystic Angiomatosis o Lytic, well-defined, round or oval lesions within the medullary cavity o Intact cortex & variable peripheral sclerosis o Endosteal scalloping & honeycombed or latticework appearance o Discrete circular or serpentine lytic areas within bone suggest vascular channels o No periosteal reaction o

=

Axial NECT shows a lytic lesion involving the C3 body & lefl facelliamina wilh thin expansile bony margin. A soft tissue component SI in the lefl lateral epidural space is beller seen on MR (not shown).

II 3 39

ENLARGED

(/)

c

VERTEBRAL

BODY, SOAP BUBBLE EXPANSION

Q)

E Q)

l1J

~

o

'C

Renal Cell Carcinoma

Q)

U5 o

a.. >.

-0

o

[IJ ctl ~

.0 Q)

t Q)

> Cl>

c: '0. l/l

Renal Cell Carcinoma

(Left) Sagittal T7WI MR shows a large expansife mass involving the ribs & right side of T7 & TB bodies with considerable epidural extension ~. (Rig"') Axial T7WI MR shows a large mass destroying the right aspect of a mid-thoracic vertebral body, the right posterior elements, and the right ribs & costovertebral joint. Epidural extension causes cord compression The ventral

=-

margin shows bony expansion with a "soap

bubble" pattern

=:l.

Multiple

Myeloma

Osteoblastoma

(Left) Sagittal T7 C+ FS MR shows [ocal tumor involvement with enhancement E:I with

replacement of the vertebral & posterior element marrow by tumor and slight spinous process expansion~. There is severe cord compression

at both levels. (Right) Axial bone CT shows a well-demarcated expansile lesion with a narrow

transition

&

matrix~.

zone of

ground-glass

Minimal

cortical

destruction with extension into the right lateral recess is present ~.

Osteoblastoma (Left) Sagittal T7 C+ FS MR shows extensive reactive edema in the adjacent

=

posterior elements, vertebral body, & sort tissues related to an asteoblastoma.

The

peritumoral edema enhances avidly with gadolinium administration. (Rig"') Axial CECT shows a lytic, heterogeneously

enhancing

vertebral body mass ~ posterior

with

cortical

breakthrough. Mass extends into the right pedicle =:l.

II 3 40

Giant Cell Tumor

ENLARGED VERTEBRAL BODY, SOAP BUBBLE EXPANSION

Aneurysmal Bone Cyst

Chordoma (Left) Axial T2WI MR shows mass

a multi/oculated containing

multiple

fluid-fluid levels of mixed signal intensity, ,eflecting blood products. Note nodular

enhancement

of

solid componenlS & seplae between di/ated, blood-filled

spaces. Severe canal compromise by the tumor. (Right) Axial NECT shows a destructive, lytic lesion with associated sofllissue expanding lhe occipilal condyles & skull base 81. The anterior margin has a scalloped appearance 1:':1.

Chordoma

-u

o en

ro-

=:!.

o ~ m

ro 3 -

"0

o

en

ro~ .0

(!)

t (!)

>

DIFFERENTIAL DIAGNOSIS Common • Post-Irradiation Vertebral Marrow • Normal Variant • Heterogeneous Fatty Marrow • Osteoporosis less Common • Hemangiomas • Paget Disease

(Multiple)

Ql

r::

'Q.

en

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Establish whether pattern is diffusely hyperintense marrow signal or multiple foci of hyperintensity within more cellular marrow Helpful Clues for Common Diagnoses • Post-Irradiation Vertebral Marrow o Diffuse hyperintense fatty marrow signal intensity within correct clinical context o Look for abrupt sharp demarcation between hyperintense fatty marrow and lower signal intensity normal marrow at peripheral margin of radiation field • Normal Variant o Normal marrow complement of fat and cellular elements o More frequently seen in older patients • Heterogeneous Fatty Marrow o Multiple patchy areas of fat signal intensity within multiple vertebral bodies

Post-Irradiation

II 3 48

Vertebral

Marrow

o More frequently seen in older patients • Osteoporosis o Decreased cellular marrow elements with proportionally greater marrow fat content o Osteopenia on CT or plain radiography may help assist diagnosis

Helpful Clues for less Common Diagnoses • Hemangiomas (Multiple) o Fatty stroma within well-delineated benign indolent vertebral body tumors o Rarely a diagnostic dilemma • Distinct fat signal intensity masses within more conventional appearing marrow distinguishes from diffuse hyperintensity of fatty marrow involving entirety of vertebral body marrow • Paget Disease o Fibrovascular marrow in active phase • Heterogeneous but predominantly hypointense on Tl WI MR, hyperintense on T2WI MR • Interspersed foci of fatty marrow • Post-gadolinium enhancement helps distinguish from diffuse fatty marrow o Fatty marrow in mixed phase • Hyperintense on TlWl and T2WI MR • Most often imaged in this phase • Involved vertebral body may be increased in size compared to normal adjacent vertebrae

Post-Irradiation

SagiNal T7 c+ MR demanslIates diffuse ve,tebral marrow hyperintensity following craniospinal irradiaUon for CSFdisseminated aligoaslIocytoma metastases

=.

Vertebral Marrow

Sagittal T7WI MR shows typical bright T7 hyperintensity in the vertebral marrow at irradiated spina/levels in this patient with breast adenocarcinoma.

VERTEBRAL BODY, 11 HYPERINTENSE

SIGNAL,

DIFFUSE

CJl

"S!. :l

ct>

< perineural, lymphatic, CSF spread • Marrow initially infiltrated, trabeculae destroyed, then subsequently bone cortex destroyed • Blastic rather than lytic presentation occurs when bone production exceeds bone destruction o Leukemia • Acute or chronic, myeloid or lymphoid white blood cell neoplasia with spinal involvement as component of systemic disease burden • Single or multiple vertebral involvement • Most common (classic) spinal presentation is diffuse osteopenia with multiple vertebral fractures ± lytic spine lesions o Lymphoma • Lymphoreticular neoplasms with wide variety of specific diseases & cellular differentiation • Variable imaging manifestations o Multiple Myeloma • Multifocal malignant proliferation of monoclonal plasma cells within bone marrow • Multifocal, diffuse, or heterogeneous Tl hypointensity; may be diffusely hypointense in high disease burden, particularly if accompanied by severe anemia Helpful Clues for Less Common Diagnoses • HIV

Marrow hypointensity reflects generalized anemia • Need high index of suspicion to specifically diagnose in absence of ancillary findings • Sickle Cell o Hereditary hemoglobin abnormality resulting in anemia, deformed (sickle) red cells that occlude blood vessels o

VERTEBRAL BODY, 11 HYPOINTENSE

SIGNAL,

DIFFUSE

(II

~. ::l



Classic imaging appearance: Marrow hypointensity with multiple H-shaped vertebral bodies o Differing disease severity depending on hemoglobin subtype(s) and whether patient is homozygous or heterozygous • Homozygous: HbSS (sickle cell anemia) • Heterozygous: HbSA (sickle cell trait, asymptomatic), HbSC (less severe form) o Sickle cell crisis: Acute episode of severe bone, abdomen, chest pain • Renal Osteodystrophy o Bony changes attributable to chronic, end-stage renal disease o Secondary hyperparathyroidism (HPTH), osteomalacia, bone sclerosis, aluminum toxicity contribute to findings o Best diagnostic imaging clue: "Rugger jersey" spine o

Helpful Clues for Rare Diagnoses • Myelofibrosis o Very low signal intensity noted in bone marrow on all MR pulse sequences o Myelodysplastic syndromes: Myeloproliferative disorders that may show myelofibrosis at some point in their evolution • "Primary" form may be a precursor to polycythemia vera and chronic myeloid leukemia • More commonly reflects a secondary phenomenon secondary to leukemia, lymphoma, or metastatic tumor

• Osteopetrosis o Heterogeneous grouping of hereditary osteoclast disorders o Diffuse increase in bone density and thickened bone cortex involving entire skeleton • Fibrous Dysplasia o Best diagnostic clue: Mildly expansile lesion with ground-glass bone matrix o Monostotic: Single bone lesion only • Monostotic disease usually an incidental finding o Polyostotic: Bone lesions in multiple bones • Usually presents in first or second decade • Often associated with growth disturbances, pathological fractures through abnormal weakened bone o McCune-Albright syndrome: Polyostotic FD, precocious puberty, cafe-au-Iait skin lesions • Extramedullary Hematopoiesis o Epidural ± paravertebral proliferation of hematopoietic tissue in response to profound chronic anemia o Minimally enhancing isointense thoracic intra- or paraspinal soft tissue masses in conjunction with diffuse marrow hypointensity o Consider when thoracic epidural/paraspinal isointense masses detected in patients with hemoglobinopathies or myeloproliferative disorders


biopsy required

Helpful Clues for Common Diagnoses • Degenerative Disc Disease/Endplate Changes o Disc hypointense on Tl WI and T2WI o Endplates may be irregular, with Schmorl nodes, but margin between disc and vertebral body preserved o Mild post-gadolinium enhancement, often linear along endplate margins in horizontal direction o No paravertebral or epidural soft tissue to suggest infection • Schmorl Node o Well-defined, smoothly marginated end plate herniation o May see variable marrow signal around it, depending upon age of insult • Acute shows t STIR, chronic shows normal or fatty marrow halo • Accelerated Degeneration o Aberrant biophysical stresses from altered normal spinal motion/fusion o Wolff law; living tissue responds to chronic changes in stresses & strains o Increased mobility in remaining mobile segments is hypothesized to cause accelerated degenerative pathologic changes • Scheuermann Disease o Kyphosis secondary to multiple Schmorl nodes --> vertebral body wedging o Three or more wedged thoracic vertebrae with irregular endplates o Thoracic spine pain and tenderness worsened by activity in teenager, young adult • Pyogenic Disc Space Infection o Severe endplate irregularity with loss of distinction of disc from end plate o t T2 signal from disc, endplate, ± vertebral body

INTERVERTEBRAL DISC/ENDPLATE IRREGULARITY Paravertebral and epidural soft tissue • Tuberculous Disc Space Infection o Endplate irregularity and osteolysis o Multiple (non)contiguous vertebrae involved, including posterior elements o Migration of phlegmon underneath all with erosion of vertebral body corners o May mimic metastatic disease • Fungal Infection (Coccidiomycosis) o Variable appearance from small focal body involvement ~ gross vertebral body/disc destruction o Multiple bodies involved, similar to TB • Rheumatoid Arthritis o C1-C2 instability in 33% of all RA patients o Facet and uncovertebral joint erosions o Multilevel subluxations, uncommon disc and adjacent vertebral body destruction o

Helpful Clues for Less Common Diagnoses • Neurogenic (Charcot) Arthropathy o 4 of classic "S Os" related to spine: ormal density bone, destruction, disorganization, debris • Ankylosing Spondylitis o Endplate irregularity with acute inflammation phase, or chronic with fusions and Schmorl node formation o Irregularity with chronic fracture and pseudoarthrosis development • Brucellosis o Granulomatous osteomyelitis pattern o May see pattern mix similar to pyogenic w/disc involvement, + skip lesions like TB

Degenerative Disc Disease

• Bone Infarcts o Sickle cell & Gaucher disease: "H-shaped" vertebral bodies o May see only vertebral collapse with Gaucher • Post-Treatment: Bone Morphogenetic Protein o Bone morphogenetic protein (rhBMP-2) bone lytic resorption defects occur at fusion sites in up to 1/3 patients o Transforming growth factor acts as signaling molecule to attract mesenchymal stem cells • Binds to receptors and causes stem cells to differentiate into osteoblasts with bone formation • Hemodialysis Spondyloarthropathy o Peridiscal destructive arthritis in patient on long-term hemodialysis

m ::>

Cl. "0

0;-

ro

Helpful Clues for Rare Diagnoses • Ochronosis o Deposition of homogentisic acid and its metabolites secondary to absence of homogentisic acid oxidase enzyme o Premature degenerative disc disease with calcified intervertebral discs o Osteopenia and spinal ankylosis Other Essential Information • SED: Group of disorders (congenita, tarda) characteristic defect in epiphyses, which appear irregular o Likely relate to collagen II (COL2A1 gene) mutations Degenerative Endplate Changes (Modic Changes)

II

=-

Sagitlal T2WI MR shows endplate irregularity T12-L1 due to disc degeneravon and irregularity at 13-4

from Schmorl node ~.

There is multilevel severe

central stenosis. Note L1 hemangioma.

Sagittal T1WI MR shows multilevel severe disc degeneration with type II endplate changes There is diffuse irregularity of the endplates at these levels.

=.

4 7

INTERVERTEBRAL DISC/ENDPlATE

Q)

ro Q.

IRREGULARITY

u c W

u (J)

o ro ~

.n Q)

t Q)

~ Q)

c Cl)

c c.

rn

Accelerated

Degeneration

Scheuermann

Disease

(Lefl) Sagiflal T2WI MR shows C4-S anterior fusion with concomitant severe disc degeneration al CS-6 =:lI with loss of disc signal, endplate irregularity, & loss of disc heigh/. (RighI) Sagiflal bone CT shows endplale irregularities and vertebral wedging SI bUI no widening of paraspinous soft tissues. The vertebral endplate depressions have an undulating

contour.

Tuberculous

Disc Space Infection

(Lefl) Sagiflal T1 C+ MR shows nonenhancing necrotic bone extending into superior LS endplale !::I & ven1ral epidural phlegmon =:lI. L3-4 disc space infeclion shows irregular endplate enhancement ~ (RighI) Sagitwl T2WI MR shows multifocal verlebral body disease SI and disc involvement

with irregularity

=:lI & subligamenlous extension.

Rheumatoid (Lefl) Sagiltal T2WI MR shows minor disc involvement at C6-7 =:lI with extensive prevertebraf

component above and below that disc level SI. Note the extensive focal body involvemenl of C7. (RighI) Sagiltal STIR MR shows erosive changes of C 1 and odontoid process with peridental pannus with effacement of thecal sac. There is subaxial endplate irregularity most pronounced al C3-4 =:lI.

II 4 8

Arthritis

INTERVERTEBRAL DISC/ENDPlATE

IRREGULARITY

(Lefl) Coronal bone CT shows typical appearance of Charcot arthropathy of the lumbar spine with proliferative

new bone

E!:I and lucent pseudoarthrosis extending transversely across all formation

columns. (RighI) Sagittal T2WI MR shows a pronounced fracture

oblique

involving

=

thoracic spine irregular fracture

m :J

a.

~ Q)

ro

chronic

the lower

with the site

functioning as a pseudoarthrosis.

Post-Treatment: Sickle Cell

Bone Morphogenetic Protein (Lefl) Sagittal T1 WI MR shows typical MR

appearance

of vertebrae in

sickle cell disease with H-shaped vertebrae Ell and marrow low signal due to hemosiderin

deposition

from

multiple transfusions. (RighI) Sagittal T2Wt MR shows multiple

small "cystic"

appearing lesions with T2

hyperintensity involving the L5 and S I bodies. Note the smooth margins, with abrupt transition marrow

to more normal signal, and lack of

adjacent

Hemodialysis

marrow

edema.

Spondyloarthropathy (Lefl) Lateral radiograph shows destructive crystal arthropathy at C4-5 simulating

infection.

There is

diffuse endplate irregularity Ell. Soft tissue calcifications indicate

crystal deposition

J:!J. (RighI) Sagittal T2WI MR shows a 50 year old with epiphyseal dysplasia with diffuse platyspondyly with rectangular-shaped vertebral bodies and endplate

irregularity.

II 4 9

(l)

ro 0.

VERTEBRAL ENDPLATE

CONTOUR

ABNORMALITY

"0 C

W

• Limbus Vertebra: Small separate corner portion of endplate, well-marginated • Fracture: Angular deformity of end plate, ± visible fracture line • Scheuermann Disease: Undulating end plates 4 or more levels + kyphosis, with or without discrete Schmorl nodes • Osteomyelitis: Endplate erosion, vertebral body destruction, osteopenia or osteosclerosis • Sickle Cell: Depression central portion of endplate ("Lincoln Log")

DIFFERENTIAL DIAGNOSIS

(j

.!!1

o

co ~

.n (l) t (l)

c: (l)

c CI>

c Co

en

Common • Schmorl Node • Degenerative Endplate Changes • Limbus Vertebra • Anterior Compression Fracture • Lateral Compression Fracture • Scheuermann Disease • Osteomyelitis, Pyogenic • Sickle Cell Less Common • Neurogenic (Charcot) Arthropathy • Osteomyelitis, Granulomatous • Cushing Disease • Osteogenesis Imperfecta • Achondroplasia • Mucopolysaccharidoses • Thanatophoric Dwarfism • Spondyloepiphyseal Dysplasia

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • May be due to trauma, developmental or congenital disorders, degenerative disease or infection Helpful Clues for Common Diagnoses • Schmorl Node: Cup-shaped defect in endplate • Degenerative Changes: Osteophytes may elongate or form hook adjacent to endplate

Helpful Clues for Less Common Diagnoses • Neurogenic Arthropathy: Mimics osteomyelitis; endplate destruction and erosion, non united fracture fragments, heterotopic ossification • Osteomyelitis, Granulomatous: Vertebral endplate destruction and deformity, but disc spaces preserved until late; may involve multiple levels; bone fusion and kyphosis • Cushing Disease: C-shaped end plate ("fish mouth") • Osteogenesis Imperfecta: Variable flattening and deformity due to fractures; severe osteopenia • Achondroplasia, Mucopolysaccharidoses: Anterior beak deformity • Spondyloepiphyseal Dysplasia: Vertebrae flattened but taller in center than at sides

Degenerative

II 4 10

Sagiltal T1WI MR shows cup-shaped

deformity

endplate and normal marrow signal intensity.

=

of

Endplate Changes

Coronal bone CT shows advanced degenerative disc disease, with endplate irregularities and subchondral cysts. Endplate remodeling is partiy due to scoliosis in this p bone destruction a Destroys posterior vertebral body cortex first - pedicle a Hypointensity reflects blastic changes • Metastases, Lytic Osseous a Bone destruction> bone production a Destroys posterior vertebral body cortex first - pedicle a Lesions diffusely enhance (may mask lesions if no fat suppression used) • Neurofibroma a Variable involvement of spinal root, neural plexus, peripheral nerve, or end organs

II 5 16

Plexiform neurofibromas are pathognomonic of NFl, often affect sacral or brachial plexus • Schwannoma a Neoplasm of Schwann cell investiture of spinal and peripheral nerves a Peripheral origin pushing adjacent axons rather than infiltration within distinguishes from neurofibroma a Consider neurofibromatosis type 2 if many tumors are identified • Lymphoma a Lymphoreticular neoplasms with wide variety of specific diseases & cellular differentiation a Multiple types with protean imaging manifestations • Plasmacytoma a Solitary monoclonal plasma cell tumor of bone or soft tissue a Often without specific features to distinguish from solitary hematogenous metastasis a

Helpful Clues for Less Common Diagnoses • Venous Vascular Malformation a Congenital transpatial vascular malformation of venous channels present from birth a Mass-like, frequently enhances moderately (less than soft tissue hemangioma) a No arterial vessels within lesion a Venous channels may be large; look for phleboliths to make specific diagnosis • Neuroblastic Tumor a Neuroblastic tumors = ganglioneuroma, ganglioneuroblastoma, and neuroblastoma a Abdominal (40% adrenal, 25% paraspinal ganglia) > thoracic (15%) > pelvic (5%) > cervical (3%); miscellaneous (12%) a Identification of intraspinal spread has important treatment and prognostic implications • MR is more sensitive than CT for detecting intraspinal spread • Ewing Sarcoma a Usually adolescents, younger adults a Permeative cellular lytic lesion of vertebral body or sacrum a Involve vertebral body, ribs, ilium before neural arch • Hemangioma

EXTRADURAL lESION, SOLID ENHANCEMENT o

o

Typical "benign" (fatty stroma) hemangioma hyperintense on Tl WI and T2WI MR + contrast enhancement "Aggressive" hemangioma iso- to hypointense on Tl WI and hyperintense on T2WI MR + avid contrast enhancement • Lesion growth, bone destruction, vertebral collapse, absence of lesion fat, active vascular component • Pathologic fracture or epidural extension is common - cord compression

Helpful Clues for Rare Diagnoses • Langerhans Cell Histiocytosis o Abnormal histiocyte proliferation granulomatous skeletal lesions o Thoracic (54%) > lumbar (35%) > cervical (11%)

Most frequent imaging appearances • Vertebra plana sparing disc space • Destructive lesion with soft tissue component resembling other epidural spinal tumors o Use location and patient age to suggest diagnosis • Extramedullary Hematopoiesis o Epidural ± paravertebral proliferation of hematopoietic tissue rests in response to profound chronic anemic state o Enhancing isointense thoracic intra- or paraspinal masses with associated diffuse marrow hypointensity o Mid-thoracic> cervical, lumbar • Osteosarcoma o

Peridural

Fibrosis

T1 C+ MR demonstrates extensive enhancing epidural fibrosis circumferenlially surrounding the thecal sac Note metal artifact from intervertebral fusion cages 8:1.

Axial

=.

Wide zone of transition, permeative appearance, cortical breakthrough, and soft tissue mass o 80% have bone matrix visible on radiographs and CT • Osteoid matrix produced directly by malignant cells o Majority arise in posterior elements • Hemangiopericytoma o Hypervascular neoplasm arising from pericytes o Avidly enhancing mass with large soft tissue component expanding/eroding spinal canal • Angiolipoma o Benign tumor with adipose and vascular elements o Hyperintense mass on unenhanced Tl WI, enhancement on fat-suppressed Tl WI o Focal or infiltrating forms • Infiltrating more common in anterior epidural space, may destroy adjacent bone • Focal more common in posterior thoracic epidural space, no bone destruction o No vascular flow voids o

Metastases,

Sagiltal T1

c+

Blastic Osseous

MR shows abnormal enhancement of

multiple vertebral breast carcinoma metastases. CT

II 5

imaging (not shown) confirmed blastic appearance.

17

EXTRADURAL LESION, SOLID ENHANCEMENT

Metastases,

lytic Osseous

Neurofibroma

(Left) Sagittal T7 C+ MR demonstrates abnormal enhancement of lytic renal cell carcinoma metastasis The diagnosis was confirmed with bone CT (not shown). (Right) Axial T7 C+ MR reveals a large right lumbar epidural and paraspinal neuroFibroma in a patient with confirmed neurofibromatosis lype ,.

=.

=

Schwannoma (Left) Axial T7 C+ MR depicts a large right cervicothoracic

schwannoma with dumbbell intradural and extradural components. Note spinal

cord I:] compression. (Right) Sagittal T7 C+ MR reveals enhancing epidural tumor extension of Ilodgkin lymphoma, producing spinal cord compression.

-=

Plasmacytoma (Left) Axial T7 C+ MR shows extensive

enhancing

epidural

tumor displacing the spinal cord. There is also marrow infiltration

into the transverse

processes

and adjacent

"Drape"

configuration

ventra/wmor confirms

rib. of the

extension

epidural

localization. (Right) Axial T7 C+ FS MR demonstrates a paraspinal enhancing neuroblastoma with epidural extension through the ipsilateral

neural foramen,

displacing the dural sac.

II 5 18

Neuroblastic

Tumor

EXTRADURAL

Ewing Sarcoma

lESION,

SOLID ENHANCEMENT

Hemangioma (Left) Axial T7 C+ MR reveals a huge paraspinal Ewing sarcoma that arises from the ipsilateral posterior rib with epidural

extension,

producing spinal cord compression. (Right) Sagiltal T7 C+ MR depicts an

aggressive vertebral hemangioma associated with pathological compression fracture, producing a large epidural mass and thecal sac

compression.

Extramedullary

Hematopoiesis (Left) Sagittal T7 C+ FS MR

demonstrates

complete

collapse of the T /2 vertebral body (vertebra plana). The vertebral body and the adjacent 50ft tissues reveal

marked enhancement following gadolinium administralion. (Right) Sagittal T7 C+ MR depicts an elongated ovoid

well-circumscribed epidural soft tissue mass with diffuse

and intense enhancement compressing the distal thoracic spinal cord.

(Left) Axial T7 C+ MR shows

a large lobulated enhancing mass in left paravertebral

soft

tissues and osseous posterior elements El extending along the dural margin into the ipsilateral

neural foramen

=. (Right) Sagiltal T7

C+ FS

a farge dorsal intensely enhancing epidural mass in the upper thoracic spine, producing spinal cord compression. MR demonstrates

II 5 19

SOFT TISSUE CALCIFICATION, PARASPINAL

Common • Heterotopic Ossification o DISH o Spinal Muscle Injury, Traumatic o Post-Operative Change, Normal o Neurogenic (Charcot) Arthropathy • Calcification o Calcific Tendinitis, Longus Coli o Osteomyelitis, Granulomatous Less Common • Heterotopic Ossification o Spondyloarthropathy, Seronegative o Osteosarcoma • Calcification o Schwannoma o Polymyositis/Dermatomyositis o Spondyloarthropathy, Hemodialysis o Juvenile Idiopathic Arthritis Rare but Important • Fibrodysplasia Ossificans Progressiva (FOP)

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Heterotopic ossification: General term meaning bone forming outside normal sites o Myositis ossificans: Heterotopic ossification forming in muscles o Causes: Trauma, surgery; paraplegia Helpful Clues for Common • Heterotopic Ossification

Over time, forms cortex and internal trabeculae • In osteosarcoma, structure lacking o DISH, seronegative spondyloarthropathy: Ossification of paraspinous ligaments follows ligament contour o Charcot arthropathy: Combination of florid periosteal new bone and small bone fragments in soft tissues • Usually more exuberant and disorganized than post-traumatic heterotopic ossification • "5 Ds" of Charcot joint: Preserved or increased density, bone debris, destruction, joint distention, joint dislocation • Calcification o Calcific tendinopathy of longus coli: Linear calcification associated with longus coli muscle edema, often fluid collection o Hydroxyapatite, gout, or scleroderma: Amorphous or globular o Calcium pyrophosphate deposition disease: Linear o Granulomatous infection: Irregularly shaped, associated with abscess o Polymyositis: Fine, reticular pattern along fascial planes o

DIFFERENTIAL DIAGNOSIS

Diagnoses

Helpful Clues for Less Common Diagnoses • Juvenile Idiopathic Arthritis o Periosteal new bone or ligament ossification

DISH

Heterotopic Ossification

II 5 20

=

Coronal bone CT shows post-traumatic ossification in paraspinous fat. Mature bone architecture distinguishes it from osteosarcoma.

=.

Sagittal bone CT shows unusually bulky ossification of anterior longitudinal ligament This degree of ossification

may cause dysphagia.

SOFT TISSUE CALCIFICATION,

Calcific Tendinitis,

PARASPINAL

Longus Coli (Left) Anteroposterior radiograph shows florid, paraspinous, periosteal new bone ~ bone sclerosis, bone debris, disorganization,

and bone destruction, all hallmarks of Charcot arthropathy. (RighI) Axial CECT shows calcification in the longus coli muscle. Muscle is Jaw attenuation and enlarged.

Osteomyelitis,

Granulomatous

Spondyloarthropathy,

=

Seronegative (Lefl) Axial NECT shows vertebral body erosions and a low attenuation paraspinous 81 and spinal canal mass !:;J. Note the calcifications Itl; this combination usually indicates TB. (RighI) Anteroposterior radiograph shows slender ossification of the paraspinou5 ligaments Sacroiliac joint fusion m is key to diagnosis.

=.

Osteosarcoma

Juvenile Idiopathic

Arthritis (Left) Axial bone CT shows a mass containing

immature

ossification and involving ilium, sacrum,

sacroiliac

joint, and sort tissues. Although the density of osteosarcoma varies, its appearance is always aggressive. (RighI) Sagittal bone CT shows heterotopic ossification related to long-standing atlantoaxial subluxation in jlA. Periosteal new bone ~ is a more

=

common

finding.

II 5 21

EXTRADURAL, NORMAL MARROW SIGNAL

ell

~ ::J

""0

ell ~ X

W

Gl

l:

a. m

Common • Disc Herniation o Intervertebral Disc Herniation, Cervical o Intervertebral Disc Herniation, Thoracic o Intervertebral Disc Herniation, Lumbar o Intervertebral Disc Extrusion, Foraminal • Osseous Degenerative Disease o Intervertebral Disc Bulge o Facet Mthropathy, Cervical o Facet Arthropathy, Lumbar o Facet Joint Synovial Cyst • Infection o Abscess, Epidural o Abscess, Paraspinal • Trauma o Hematoma, Epidural-Subdural o Hematoma, Spontaneous Epidural o Hematoma, Paraspinal • Neoplasm o Neuroblastic Tumor o Lymphoma o Schwan noma o Neurofibroma • Ligamentous Ossification o OPLL o DISH o Ossification Ligamentum Flavum • Ligamentous Hypertrophy • Peridural Fibrosis • Perineural Root Sleeve Cyst Less Common • Epidural Lipomatosis • Teratoma, Sacrococcygeal

•

•

•

Rare but Important • Neurenteric Cyst

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Clinical context helps narrow differential list

II 5 22

Helpful Clues for Common Diagnoses • Disc Herniation o Intervertebral Disc Herniation, Cervical • Localized displacement of disc material beyond vertebral ring apophyses o Intervertebral Disc Herniation, Thoracic • T6 - T11 most common, rare in upper thoracic spine

Intervertebral Disc Herniation, Lumbar • Most common at L4-5, L5-S1 o Intervertebral Disc Herniation, Foraminal • Soft tissue mass contiguous with parent disc - extruded disc material in neural foramen Osseous Degenerative Disease o Intervertebral Disc Bulge • Generalized circumferential disc extension beyond vertebral ring apophyses o Facet Arthropathy, Cervical • Osteoarthritis of synovially lined apophyseal joints - facet overgrowth + joint space narrowing o Facet Arthropathy, Lumbar • Similar findings to cervical spine o Facet Joint Synovial Cyst • Extradural cystic mass communicating with facet joint + degenerative changes disc, facet joint • Lumbar (90%) > > cervical, thoracic Infection o Abscess, Epidural • Extradural spinal infection with abscess formation ± spondylodiscitis o Abscess, Paraspinal • Suppuration of paraspinal soft tissue from direct extension or hematogenous pathogen dissemination • Calcified psoas abscesses '* tuberculosis Trauma o Hematoma, Epidural-Subdural • Hypo-, iso-, or hyperintense depending on blood product age o Hematoma, Spontaneous Epidural • Accumulation of hemorrhage between dura & spine without significant trauma or iatrogenic procedure o Hematoma, Paraspinal • Frequently associated with vertebral body fracture • Signal intensity reflects blood product composition, age Neoplasm o Neuroblastic Tumor • Ganglioneuroma, ganglioneuroblastoma, and neuroblastoma • Intraspinal spread has important treatment and prognostic implications o

DIFFERENTIAL DIAGNOSIS

•

EXTRADURAL, NORMAL MARROW SIGNAL Lymphoma • Variable imaging manifestations are often nonspecific o SchwannOina • Schwann cell neoplasm of peripheral nervous system • Consider neurofibromatosis type 2 if many tumors identified o Neurofibroma • Nerve sheath tumor of spinal root, neural plexus, peripheral nerve, or end organs • Plexiform neurofibroma pathognomonic of NFl • Ligamentous Ossification o OPLL • Flowing multilevel ossification posterior to vertebral bodies • "Upside down T" or "bowtie" configuration on axial images o DISH • Bulky flowing anterior vertebral ossification • Thoracic> cervical, lumbar spine; R > > L (opposite aorta) o Ossification Ligamentum Flavum • Linear thickening and ossification of ligamentum flavum • Ligamentous Hypertrophy o Degenerative disc disease, redundancy and thickening of ligamentum flavum - spinal stenosis • Peridural Fibrosis o

Intervertebral

Disc Herniation,

Cervical

Sagiaal T2WI MR depicts a large rounded C5·6 disc extrusion (base of herniation is narrower than apex beyond the disc margin) effacing the thecal sac.

Enhancing scar formation within epidural space after lumbar surgery • Perineural Root Sleeve Cyst o Dilatation of arachnoid and dura of spinal posterior nerve root sheath o Most common in lower lumbar spine and sacrum (Tarlov cyst) o

Helpful Clues for Less Common Diagnoses • Epidural Lipomatosis o Excessive accumulation of intraspinal fat (~ 7 mm) compressing thecal sac - cord compression, neurologic deficits o Long-term exogenous steroid administration or excessive endogenous steroid production • Teratoma, Sacrococcygeal o Large heterogeneous sacral tumor ± calcification, cysts, hemorrhage o Rarely marrow invasion, even if adjacent soft tissue tumor or intraspinal spread through sacral hiatus Helpful Clues for Rare Diagnoses • Neurenteric Cyst o Intraspinal cyst lined by enteric mucosa (split notochord spectrum) o ± Vertebral abnormalities (persistent canal of Kovalevsky, segmentation and fusion anomalies)

Intervertebral

Disc Extrusion,

Foraminal

Axial T2WI MR demonstrates a large left L4-5 far lateral disc herniation BI extending into the left neural foramen

displacing

the exiling L4

nerve

root

II 5

lEI.

23

EXTRADURAL,

C1l

~ :J

NORMAL

MARROW

SIGNAL

-0 C1l

~ X

W

Ql

c: C-

oo

Facet Arthropalhy,

Cervical

Facet Arthropathy,

Lumbar

(Lefl) Axial bone CT

demonstrates severe osseous hypertrophy and facet degenerative changes that distort the articular joint surfaces. (RighI) Axial T2WI MR reveals severe bilateral facet degenerative changes, with enlargement of the facets and distortion of the articular surfaces, narrowing the lateral recesses. Ligamentous thickening also contributes to central canal stenosis.

Facet Joint Synovial Cyst

Abscess, Epidural

(Left) Axial T2WI MR shows a large left synovial cyst 1::1 associated with severe degenerative facet changes. Note significant compression of the thecal sac SI by cyst mass effect compounded by multifactorial spinal stenosis. (RighI) Sagittal T I C+ MR

demonstrates a long segment rim-enhancing

lumbar

epidural abscess without contributory discitis or marrow signal abnormality.

Abscess, Paraspinal (Lefl) Axial T I C+ FS MR shO\vs abnormal paraspinaf muscle enhancement with a {Deal abscess in a patient with septic facet joint infection. The vertebral body

=

and transverse process marrow

II 5 24

signal is normal.

(Righi) Sagittal T1 WI MR shows a typical appearance of a large subacute epidural hematoma demonstrating T 1 hyperintensity 1::1. This presentation was spontaneous and idiopathic; no underlying lesion was detected.

Hematoma,

Spontaneous

Epidural

EXTRADURAL,

Ossification

ligamentum

Flavum

NORMAL

MARROW

Peridural

SIGNAL

Fibrosis (Left) Axial T IWI MR demonstrates a small (Deus of asymptomatic ossification within the thoracic IigamenlUm flavum (Right) Axial TI C+ MR in a post-operative patient with pain shows diffuse enhancement of the right lateral epidural space and surrounding exiting foot secondary to peridural fibrosis. There is extensive enhancement of the disc curelte site

=.1.

=.

Perineural

Root Sleeve Cyst (Left) Axial TI C+ MR reveals an incidental, well-circumscribed, nonenhancing, inlraspinat CSF intensity root sleeve cyst at the L5 level. (Right) Sagittal T1WI MR shows marked epidural lipomatosis in a young cerebral palsy patient. Imaging was obtained after inability to place an epidural catheter. Note thick dorsal epidural fat proliferation that substantially narrows the central spinal canal and

=.1

compresses the thecal sac.

Teratoma,

Sacrococcygeal (Left) Sagittal T I WI MR reveals a heterogeneous sacral tumor that anteriorly displaces the reclUm and urinary bladder. Note absence of abnormal sacral marrow signal and lack

or

tumor extension into the spinal canal through the sacral hialUs. (Right) Sagittal TI WI MR shows a large ventral cystic mass in the spinal canal compressing the ventral spinal cord in contiguity with a second prevertebraf enteric cyst with similar signal characteristics.

=

a

II 5 25

EXTRADURAL, ABNORMAL MARROW SIGNAL

DIFFERENTIAL DIAGNOSIS Common • Vertebral Fracture with Epidural Hematoma • Osteomyelitis, Pyogenic • Metastases, Blastic Osseous • Metastases, Lytic Osseous • Osteomyelitis, Granulomatous • Multiple Myeloma • Plasmacytoma • Lymphoma • Hemangioma Less Common • Chondrosarcoma • Chordoma • Osteoblastoma • Aneurysmal Bone Cyst • Ewing Sarcoma Rare but Important • Extramedullary Hematopoiesis • Hemangiopericytoma • Osteosarcoma • Giant Cell Tumor • Echinococcus

ESSENTIAL INFORMATION

II 5 26

Helpful Clues for Common Diagnoses • Vertebral Fracture with Epidural Hematoma o May be seen following any cause of vertebral fracture (traumatic, compression, pathological) o Abnormal marrow signal reflects combination of edema, hemorrhage o Look for fracture line to confirm diagnosis • Osteomyelitis, Pyogenic o Bacterial suppurative infection of vertebrae, intervertebral disc o Ill-defined hypointense vertebral marrow (TIWI), destruction of vertebral endplate cortex on both sides of disc o Paraspinal ± epidural infiltrative soft tissue ± loculated fluid collection • Metastases, Blastic Osseous o Bone production> bone destruction o Lesion centered in posterior cortex initially ~ pedicle o Hematogenous dissemination (arterial or venous via Batson plexus) > perineural, lymphatic, CSF spread

• Metastases, Lytic Osseous o Bone destruction> bone production o Lesion centered in posterior cortex initially ~ pedicle o Usually enhances diffusely; may mask lesion if fat suppression not used • Osteomyelitis, Granulomatous o Granulomatous (tuberculosis, brucellosis, fungal) infection of spine + adjacent soft tissues • Tuberculosis: Gibbus vertebrae, relatively intact discs, large paraspinal abscesses • Brucellosis: Anterosu perior epi physitis with associated sacroiliitis • Multiple Myeloma o Multifocal malignant bone marrow proliferation of monoclonal plasma cells o Multifocal diffuse or heterogeneous Tl hypointensity, T2 hyperintensity, variable enhancement • Plasmacytoma o Solitary monoclonal plasma cell tumor of bone or soft tissue o Often lacks specific features to distinguish from solitary hematogenous metastasis • Lymphoma o Lymphoreticular neoplasms with wide variety of specific diseases, cellular differentiation o Protean imaging manifestations often nonspecific • Hemangioma o Typical "benign" (fatty stroma) hemangioma: Hyperintense on Tl WI and T2Wl MR + contrast enhancement o "Aggressive" hemangioma: Iso- to hypointense on Tl WI, hyperintense on T2WI + avid contrast enhancement • Lesion growth, bone destruction, vertebral collapse, absence of fat, active vascular component • May extend epidurally ~ cord compression Helpful Clues for Less Common Diagnoses • Chondrosarcoma o Primary or secondary (degeneration of osteochondroma or enchondroma) o Lytic mass ± chondroid matrix, cortical disruption, extension into soft tissues o Tumor cells produce chondroid matrix mineralization with "rings and arcs"

EXTRADURAL,

ABNORMAL

• Chordoma o Malignant tumor arising from notochord remnants o Sacrococcygeal> clivus> > vertebral body o Lesion center in posterior vertebral body, marked T2 hyperintensity help distinguish from hematogenous metastasis • Osteoblastoma o Benign, well-circumscribed, expansile lesion of neural arch with osteoid matrix o Peritumoral edema may obscure lesion, mimic malignancy or infection on MR • Aneurysmal Bone Cyst o Expansile neoplasm centered in neural arch containing thin-walled, blood-filled cavities o Fluid-fluid levels 2° hemorrhage, blood product sedimentation • Ewing Sarcoma o Usually seen in adolescents, younger adults o Permeative lytic lesion involves vertebral body, ribs before neural arch Helpful Clues for Rare Diagnoses

• Extramedullary Hematopoiesis o Epidural ± paravertebral proliferation of ectopic hematopoietic tissue in response to profound chronic anemia o Minimally enhancing isointense thoracic intra- or paraspinal masses + diffuse cellular marrow signal • Hemangiopericytoma

Vertebral

MARROW

SIGNAL

Hypervascular neoplasm arising from pericytes o Avidly enhancing lesion expanding/eroding spinal canal, with large soft tissue component • Osteosarcoma o Aggressive sarcoma containing matrix (immature, woven osteoid) produced directly by malignant cells o Wide zone of transition, permeative, cortical breakthrough, soft tissue mass o 80% have bone matrix visible on radiographs or CT • Giant Cell Tumor o Locally aggressive neoplasm composed of osteoclast-like giant cells o Lytic expansile lesion in vertebral body or sacrum with narrow zone of transition, non-sclerotic margin o Matrix absent; may have residual bone trabeculae • Echinococcus o Tapeworm infestation in endemic areas o Multiloculated, multiseptated T2 hyperintense mass with minimal enhancement o Liver, lung most common, bone involvement rare o

Fracture with Epidural Hematoma

Sagillal T1WI MR shows a C7 burst fracture =:I with canal compromise caused by bolh retropulsion of the fracture fragment and poslerior epidural hematoma 8l compressing the spinal cord.

Sagillal T1 C + M R reveals a large prevertebral rim-enhancing abscess extending from a C5-6 disc space infeclion E:I. There is a linear ventral epidural phlegmon that extends from C4 to C6 PJ:J.

=

II 5 27

EXTRADURAL,

ABNORMAL

MARROW

SIGNAL

Q)

c: a.

C/)

Osteomyelitis,

Granulomatous

(Left) sagiltal T1 C+ MR shows marrow enhancement and palhological thoracic vertebral fracture with relalive preservation of the intervertebral disc space. There is epidural extension with spinal cord compression in lhis case of lab-proven TB. (Right) sagiltal T1 C+ Fs MR depicts multiple enhancing vertebral metastases producing abnormal marrow enhancement in the cervical and thoracic spine. There is extensive epidural tumor extension at T5

=.

Plasmacytoma (Left) Axial T1 C+ Fs MR shows extensive rib & vertebral body tumor infiltration and marrow signal abnormality. The tumor produces a large enhancing epidural mass with secondary spinal cord compression. (Right) Axial T1 C+ Fs MR demonstrales extensive tumor infiltration of a lumbar vertebra extending into the right transverse process and paraspinal 50ft tissues. Characteristic appearance of the "curtain sign II confirms epidural extension.

=

Chondrosarcoma (Left) sagiltal T1 C+ MR reveals intense patchy enhancement of a destruclive vertebral mass (path-proven chondrosarcoma) with severe spinal cord compression secondary to dorsal epidural eXlension (RighI) Sagittal T7 C+ FS MR shows a destructive heterogeneously enhancing C3 vertebral tumor with large epidural mass producing spinal cord compression. T2WI MR (nOI shown) revealed diffuse T2 hyperintensity.

=.

II 5 28

Lymphoma

EXTRADURAL,

Osteoblastoma

ABNORMAL

MARROW

Aneurysmal

SIGNAL

Bone Cyst

rs

(Left) Axial T1 C+ MR demonstrates a heterogeneous mass EJ expanding the left pedicle with extensive enhancing reactive

perilumoral

edema

in the adjacent posterior elements, vertebral body, and 50ft tissues. (Right) Axial T1 C+ MR shows an expansile

mufti/oeulated

vertebral mass with multiple fluid-fluid levels. Note extensive

conical

destruction, severe canal stenosis, and enhancement of septae between dilated, blood-filled spaces.

Ewing Sarcoma (Left) Axial TI C+ MR demonstrates a large enhancing paravertebral mass that extends into the left epidural space through the ipsilateral neural foramen, displacing the spinal cord. (Rig"') Sagittal T1 C+ MR depicts a large, lobulated enhancing mass in dorsal 50ft tissues and dorsal spinal osseous elements. Note extension along dural margin,

compressing

the

thecal sac and displacing cauda

equina.

(Left) Sagittal T7 C+ MR shows L3 bone marrow

replacement by malignant tumor that permeates through the posterior cortex into the spinal canal and paraspinou5 50ft tissues. There is diffuse marrow

and

epidural enhancement associated with a pathologic fracture. (Right) Sagittal T1 C+ MR shows a large osseous expansile

mass

involving predominantly posterior

elements,

multiple fluid-fluid

the

with

levels and

diffuse mild enhancement.

II 5 29

EXTRADURAL

LESION,

DIFFERENTIAL DIAGNOSIS Common • Normal Epidural Fat • Epidural Lipomatosis • Hematoma, Epidural-Subdural Less Common • OPLL (with Fatty Marrow) • Extraosseous Hemangioma • Lipomyelomeningocele • Terminal Lipoma Rare but Important • Angiolipoma • Metastatic Melanoma

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Normal Epidural Fat o Usually most conspicuous dorsally in the thoracic region on midline sagittal slices o Key finding is lack of significant mass effect on the thecal sac • Epidural Lipomatosis o Overabundance of epidural fat, most commonly affecting thoracic and lumbar spine o Resulting compression of the thecal sac leads to a Y-shaped or trefoil cross section o May be associated with prolonged steroid administration or with hypercortisolism • Hematoma, Epidural-Subdural

II 5

Sagittal TI WI MR shows a typical case of epidural lipomatosis in a patient taking high dose corticosteroids.

11 HYPERINTENSE Actual signal characteristics depend on hematoma age; methemoglobin (subacute) hyperintense on Tl WI o Can be clearly differentiated from epidural fat with frequency-selective fat-suppressed sequence o

Helpful Clues for Less Common Diagnoses • OPLL (with Fatty Marrow) o Always ventral to thecal sac, mostly in cervical spine o OPLL will be most reliably defined on CT • LipomyeIomeningocele o Lumbosacral dysraphism • Everted elements of neural arch • Caudal fatty mass, contiguous with neural placode of a tethered, dysraphic cord; disjunction protrudes through the dysraphic defect • Skin-covered (closed spinal dysraphism) o Often discovered in infancy, but can be occult and come to attention during adolescence or adulthood • Terminal Lipoma o Lipoma of cord terminus or filum, often associated with tethered cord o Lipoma extends through caudal spondyloschisis, becomes confluent with subcutaneous fat o Not associated with myeloschisis: Represents disorder of regressive differentiation rather than of primary neurulation

Sagittal TI WI MR shows a case of subacute spontaneous epidural hematoma Compare with

=.

normal epidural fat dorsally I~~

30

EXTRADURAL

lESION,

11 HYPERINTENSE

OPLL (with Fatty Marrow) (Lell) Sagittal T1 WI MR shows a large local lumbar epidural hemorrhage, ellacing the thecal sac and

resulting in canal stenosis.

Hyperintense T1 signal is compatible with a subacute chronicity. (RighI) Sagittal T1WI MR shows compression of an atrophic

cord by an ossilied posterior longitudinal ligament with areas 01 latty marrow

=.

Extraosseous Hemangioma (Lell) Sagittal T1 WI MR shows atypical (lipid-poor) hemangioma 01 L5 with exlraosseous extension into the ventral epidural space

=. A second

lesion is

present at L 1 ~. (RighI) Sagittal T1 WI MR shows lumbosacral delect with tethered cord and caudal latty mass R>J in this inlant

=

with IipomyeJomeningoceJe.

Terminal

Lipoma (Lell) Sagittal T1WI MR shows a tethered cord terminating in a fatty mass. Overlying

neural arches are

intact. (RighI) Sagittal T I WI MR shows a large dorsal epidural T1 hyperintense mass

with heterogeneous

signal.

II 5 31

EXTRADURAL

ell L

::J

LESION, 11 HYPOINTENSE

""CJ

ell L

X

DIFFERENTIAL DIAGNOSIS

W Cl>

c:

·ii lJ)

Common • Disc Herniation • Osteophyte • Degenerated, Hypertrophic Ligamentum Flavum • Post-Operative Change, Normal o Epidural Gas o Metal Artifact o Peridural Fibrosis • Facet Joint Synovial Cyst • Epidural Fluid Collections o Pseudomeningocele o Hematoma (Acute) o Epidural Abscess • Epidural Metastatic Disease Less Common • Neurofibroma • Arachnoid Cyst • Ossification of the Posterior Longitudinal Ligament (OPLL) Rare but Important • Extramedullary Hematopoiesis • Extraosseous Component of a Hemangioma • Primary Bone Tumor o Plasmacytoma o Osteoblastoma o Aneurysmal Bone Cyst o Lymphoma/Leukemia o Giant Cell Tumor o Chordoma o Osteosarcoma o Chondrosarcoma o Ewing Sarcoma • Tumoral Calcinosis • Extradural Arteriovenous Fistula

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Vast majority of "extradural lesions" relate to degeneration of intervertebral disc and dorsal elements • Impact of epidural mass lesion on spinal cord and nerve roots is best evaluated with MR

II 5 32

• CT myelography alternative in patients who cannot undergo MR (e.g., pacemaker, spinal stimulator, etc.)

• Contrast-enhanced sequences recommended for evaluation of infection, tumor, and post-operative spine Helpful Clues for Common Diagnoses • Disc Herniation o Most common ventral epidural lesion at level of disc space o Extrusions extend away from disc space; sequestered fragments will be separated from disc level o "Vacuum disc phenomenon" (nitrogen gas) in disc herniation can manifest as epidural signal void • Peridural Fibrosis o Post-operative epidural scar/fibrosis in the surgical bed following discectomy, laminectomy o Peridural scar/fibrosis enhances, recurrent disc herniation won't enhance (distinction important as it influences decision to re-operate in cases of failed back surgery) • Facet Joint Synovial Cyst o Circumscribed cystic lesion contiguous with facet joint o Invariably associated with degenerative facet disease o If marked enhancement or severe T2 hyperintensity in adjacent marrow, consider infected facet joint • Pseudomeningocele o Epidural CSF collection at site of dural defect (post-surgical or post-traumatic) • Hematoma (Acute) o Lobulated collection, typically extending over multiple vertebral segments o Oxyhemoglobin and deoxyhemoglobin both isointense or hypointense on T1WI, becoming hyperintense in the subacute phase with the conversion to methemoglobin o No or relatively mild peripheral enhancement o May be spontaneous, due to coagulopathy, instrumentation, or trauma • Epidural Abscess o Lobulated collection, typically extending over 1-2 vertebral segments o Marked peripheral enhancement (abscess); epidural phlegmon may enhance more homogeneousl y

EXTRADURALLESION, T1 HYPOINTENSE

CJl

"'C

::::l

lD

Associated findings: Discitis/osteomyelitis, psoas abscess; patient typically has clinical signs of infection • Epidural Metastatic Disease o Epidural extension from bony vertebral metastasis (renal cell, lung, lymphoma) or transforaminal extension from paraspinal tumor (neuroblastoma) o

Helpful Clues for Less Common Diagnoses • Neurofibroma o Can be completely extradural, can also be intradural or transdural o Circumscribed margins, foraminal remodeling/ en largement a Rapid enlargement or pain: Consider malignant degeneration • Arachnoid Cyst a Typically dorsal to thecal sac, may extend laterally into neural foramina a Follows CSF on all pulse sequences a Chronic CSF pressure leads to remodeling and thinning of neural arch • Ossification of the Posterior Longitudinal Ligament (OPLL) a Longitudinal structure in ventral epidural space: When large, often develops central T1 hyperintensity (marrow space) a Cervical spine involvement more frequent than thoracic a Can cause significant canal compromise Helpful Clues for Rare Diagnoses • Extramedullary Hematopoiesis

Paravertebral and epidural lobulated masses; thoracic paraspinallocation most common o Associated with severe marrow hyperplasia due to chronic anemia • Extraosseous Component of a Hemangioma o Extraosseous extension of vertebral hemangioma, causing epidural soft tissue mass o Extraosseous component more frequently hypointense on Tl WI • Primary Bone Tumor o In general, MR superior in assessing epidural involvement, canal compromise, scope of marrow involvement, and extension into the paraspinal soft tissues o CT can be useful to assess matrix, zone of transition, etc. o

=-

Sagittal T1WI MR shows multiple disc herniations the largest herniation, at C3-4, associated with cord

compression.

n.

c

~ Ql

Alternative Differential Approaches • If lesion has very low or absent signal, shortens differential to o Metal artifact o Epidural gas (acute post-operative, traumatic) o Gas ("vacuum disc phenomenon") in a disc herniation o Ossified ligamentum flavum o OPLL o Tumoral calcinosis o Extradural arteriovenous fistula

Degenerated, Disc Herniation

m

~ ~ Ql

Hypertrophic Flavum

Ligamentum

Axial T1WI MR through L4-5 shows advanced degenerative facet arthropathy. Marked ligamentous hypertrophy is present ICB effacing the thecal sac posterolateralfy.

II 5 33

~

EXTRADURAL

LESION,

T1 HYPOINTENSE

::J

"0

~

X

w Q)

c: ~

(Left) Axial T1WI MR shows unifateral mild ossification in the ligamentum fJavum as well-defined low signal effacing the dorsal thecal sac 1:']. (Right) Axial T1WI MR shows epidural fibrosis extending from a laminotomy defect along the left of the thecal sac to the ventral epidural space. Homogeneous enhancement is typical.

Pseudomeningocele (Left) Axial T1WI MR shows a circumscribed extradural mass I:'] at the L4-5 level closely associated with the right facet joint. Cysts are better evaluated on T2 images or post-contrast. (Right) Axial T1 C+ MR shows a large CSF collection extending dorsally from a laminectomy defect I:'] into the subcutaneous tissues.

(Left) Sagittal Tl WI MR shows a large extradural collection dorsal to the thecal sac 1:']. Low Tl signal

was due to an acute chronicity and was expected

to become hyperintense as the collection aged. (Right) Sagittal Tl WI MR shows a ventral, epidural, mass-like process extending cephalad from the LJ-4 level 1:']. Key finding is that of extensive marrow changes ;n L3 and L4 vertebral bodies 81.

II 5 34

EXTRADURAL

Epidural Metastatic Disease

LESION,

11 HYPOINTENSE

Neurofibroma (Left) Axial Tl WI MR shows a chest wall mass !:1:l destroying the adjacent thoracic vertebra and extending into the epidural space EJI in this patient with non-small cell lung carcinoma. (Right) Axial TlWI MR shows a circumscribed soft tissue mass extending through a widened neural foramen to abut the thecal sac.

=

Ossification

of the Posterior longitudinal ligament (OPll)

Extramedullary Hematopoiesis (Left) Sagittal Tl WI MR

shows an extensive ossification of the posterior longitudinal ligament 1::1 resulting in canal stenosis

and cord compression. (Right) Axial TlWI MR shows an abnormally hypointense marrow signal and rounded hypointense 50ft tissue in the ventral epidural space o( the sacral canal in this patient with thalassemia.

=

Extraosseous Component Hemangioma

of a lymphoma/leukemia (Left) Sagittal Tl WI MR

shows a low signal mass involving the posterior thoracic body and dorsal elements, with an exlraosseous dorsal epidural 50ft

tissue mass

= resulting

in cord compression. (Right) Axial Tl WI MR shows an extensive abnormal marrow signal due to leukemia and a soft tissue mass in the epidural space of the sacral canal 1::1.

II 5 35

EXTRADURAL

lESION,

12 HYPERINTENSE,

Common • Intervertebral Disc Herniation • Synovial Cyst • Peridural Fibrosis • Epidural Fluid Collections o Abscess, Epidural o Hematoma, Epidural-Subdural • Epidural Metastatic Disease • Neurofibroma • Schwannoma Rare but Important • Primary Bone Tumor o Plasmacytoma o Lymphoma o Chordoma o Chondrosarcoma o Giant Cell Tumor o Ewing Sarcoma

• (Acute)

•

ESSENTIAL INFORMATION

II 5 36

Helpful Clues for Common Diagnoses • Intervertebral Disc Herniation o Most common epidural lesion in adult population o Intermediate-to-Iow T1 signal o Variable T2 signal, depending on disc hydration • Herniations of the protrusion and extrusion subtypes most frequently hypointense relative to normal disc • Sequestered disc fragments often of moderate-to-high T2 signal • Synovial Cyst o Circumscribed, fluid-filled structure o Variable iso- or hypointensity on T1 WI; centrally hyperintense on T2WI o Adjacent/contiguous with a facet joint o Cyst along ventral facet may impinge on thecal sac or nerve root o Seen with degenerative facet changes • Peridural Fibrosis o Epidural scar formation following spinal surgery o Normal post-operative finding o Infiltrative morphology, rarely mass-like o Isointense T1; variable T2 signal, usually hyperintense relative to disc material o May surround nerve root

Can only be differentiated from recurrent disc herniation on post-contrast imaging • Peridural fibrosis will homogeneously enhance, blending into extradural fat on non-FS TlWI Abscess, Epidural o May be associated with disc space infection or instrumentation/direct inoculation o Contents typically approximate fluid signal on Tl/T2WI • Increased T1 signal (isointense) may occur secondary to increased protein content o Marked peripheral enhancement typical on post-contrast imaging Hematoma, Epidural-Subdural (Acute) o May be spontaneous or associated with trauma or instrumentation o Signal varies with the age of the hemorrhage • Acute hemorrhage (oxyhemoglobin) isoor mildly hypointense on Tl WI, hyperintense on T2WI o Minimal or no enhancement on post-contrast imaging Epidural Metastatic Disease o Enhancing soft tissue mass, may be multiple o Most often associated with epidural extension from a vertebral metastasis o May also occur with transforaminal spread from a paraspinal or posterior mediastinal tumor Neurofibroma o Enhancing nodular, fusiform, or dumbbell mass associated with a nerve root o Epidural neurofibroma typically intraforaminal or transforaminal o May be associated with vertebral scalloping, thinning/remodeling of pedicles o Most (90%) solitary, nonsyndromic o May be multiple, extensive; associated with plexiform neurofibromas (neurofibromatosis type 1) Schwannoma o Enhancing nodular, fusiform, or dumbbell mass associated with a nerve root o

DIFFERENTIAL DIAGNOSIS

•

•

•

11 ISOINTENSE

EXTRADURAL

lESION,

12 HYPERINTENSE,

Most schwannoma intradural; epidural schwannoma typically intraforaminal or transforaminal o Not reliably distinguished from solitary neurofibroma

o

Helpful Clues for Rare Diagnoses • Plasmacytoma o Solitary plasma cell tumor, osteolytic tumor, ± compression fracture, ± extraosseous extension o Often indistinguishable from lytic metastases • Lymphoma o Enhancing epidural mass or epidural extension from a vertebral lesion o Often indistinguishable from metastases o Spinal lymphoma may also manifest with leptomeningeal or intramedullary lesions • Chordoma o Arises from notochord remnants: Midline, osteolytic tumor o Sacrococcygeal location most common, followed by clivus; vertebral lesion rather uncommon o May extend into epidural/paraspinal spaces o Heterogeneous iso- or hypointense on T1WI; marked hyperintensity on T2WI o Variable enhancement • Chondrosarcoma o Destructive tumor, chondroid matrix o Iso- or hypointense on Tl WI; marked hyperintensity on T2WI

Intervertebral

Disc Herniation

11 ISOINTENSE

Heterogeneous enhancement • Giant Cell Tumor o Lytic, expansile vertebral body lesion; narrow zone of transition o May extend into epidural/paraspinal spaces o Heterogeneous iso- or hypointense on Tl WI; heterogeneous hyperintensity on T2WI • Areas of low-to-intermediate T2 signal may reflect areas of high collagen content and hemosiderin deposition o Propensity to extend across sacroiliac joint & disc space is unusual for other lesions and may simulate infection • Ewing Sarcoma o Destructive tumor o Iso- or hypointense on Tl WI; moderate to hyperintense signal on T2WI o Paraspinal soft tissue mass often a feature of spinal Ewing sarcoma o

Intervertebral

Disc Herniation

II Axial T7WI MR shows sequestered disc fragment in the left anterolateral spinal canal The fragment is similar in signal to skeletal muscle on T7WI.

=.

Axial T2WI MR shows the same disc sequestration on T2WI =1 in which it is hyperintense to both skeletal

5

muscle and to normal disc material.

37

~

EXTRADURAL

lESION,

T2 HYPERINTENSE,

T1 ISOINTENSE

:J

"0

ro ~ X

W

Gl

c: ~

(Left) Axial T1WI MR shows

an abnormal rounded mass in Ihe righllateral canal

=

spinal

that is in continuity

wilh a degeneraled facel join/. The mass has intermediale signal on T I WI. (Right) Axial T2WI MR

=-

shows the same mass on T2WI in which Ihere is a sharply circumscribed margin, Ihin wall, and hyperintense signal centrally. Nole Ihe increased fluid within both facel joints and a sublfe protrusion of Ihe lefl facet's synovial capsule

Peridural Fibrosis

Peridural Fibrosis

Abscess, Epidural

Abscess, Epidural

(Left) Axial T1 WI MR shows post-operative peridural fibrosis as abnormal soft tissue Ihat replaces the normal (brighO epidural fal between the anterolateral margin of the thecal sac and the left S 7 nerve root sleeve~. (Right) Axial T2WI MR in Ihe same patient shows epidural fibrosis to be heterogeneously hyperintense on FSE T2WI, approaching Ihe intensily of epidural fa/.

=

=

(Left) Sagillal T1 WI MR shows a L]-4 disc space infection with replaced marrow signal in adjacent vertebra and a ventral epidural abscess hypoinlense on T1 WI. A second dorsal epidural collection is a/so present. (Right) Sagillal T2WI MR in the same patient shows the ventral phlegmon as moderalely hyperinlense on T2WI The full exlent of the dorsal collection is more apparenl ~ and approaches CSF in hyperintensily.

=

=

=.

II 5 38

EXTRADURAL

lESION,

12 HYPERINTENSE,

11 ISOINTENSE

CIl

~. ::l CD

m ~ ~ OJ Hematoma,

Epidural-Subdural

(Acute)

Hematoma,

Epidural-Subdural

0-

(Acute)

C

~

(Left) Sagittal T1WI MR shows an acute epidural

hematoma

=- isoin£ense

OJ to

lhe cord on T1WI, associaled wilh bursl fracture of C7 81. (Right) Sagittal STIR MR in the same patient shows a T2 hyperintense dorsal epidural

hematoma

= associated

wilh C7 burst fracture 81.

Epidural Metastatic

Disease

Epidural Metastatic

Disease (Left) Axial T1 WI MR in lhis patient with metastatic lung

carcinoma shows a large metastatic lesion to C2 with preverlebral PJ:J:l and epidural lID extension, isoinlense to cord and skelelal muscle on T IWI, effacing lhe lhecal sac

and compressing the cervical cord 81. (Right) Axial T2' eRE MR in the same palienl shows lhe epidural sofllissue =:I 10 be moderately hyperintense on T2 weighted imaging

Neurofibroma

Neurofibroma (Left) Axial T1 WI MR shows a large lransforaminal mass, hypointense on T I WI, enlarging lhe lefl Lt-2 neural foramen.

The intraspinal

componenl =:I mildly effaces lhe thecal sac. (Right) Axial T2WI MR in lhe same palient shows more clearly lhe foraminal widening and lhecal sac effacement by lhe intraspinal

component

1tJ.

Note the central hypointensity with surrounding T2 hyperintensity, demonstrating the "target sign" of a neurofibroma.

II 5 39

EXTRADURAL

LESION, 12 HYPOINTENSE,

DIFFERENTIAL DIAGNOSIS Common • Intervertebral Disc Herniation • Endplate Osteophyte • Facet Osteophyte • Ossification Ligamentum Flavum • OPLL • Epidural Gas • Metal Artifact Rare but Important • Epidural AVF

ESSENTIAL INFORMATION Helpful Clues for Common Diagnoses • Intervertebral Disc Herniation o Most common epidural lesion in adult population o Intermediate-to-Iow Tl signal o Variable T2 signal, hyperintense signal can be seen with annular fissures and sequestrations • Endplate Osteophyte o Endplate osteophyte formation commonly accompanies degenerative disc disease o May be difficult to distinguish osteophyte from a disc herniation on MR; NECT can supplement evaluation • Ossification Ligamentum Flavum o Enlargement of ligamentum flavum causing variable posterolateral encroachment on the thecal sac o Best conspicuity of calcifications on NECT

T1 HYPOINTENSE

If sufficiently ossified, may produce marrow space with hyperintensity on TlWI o Idiopathic, probably related to hydroxyapatite or calcium pyrophosphate deposition o May observe changes of DISH or OPLL elsewhere in spine • OPLL o Idiopathic condition, resulting in calcification and thickening of the posterior longitudinal ligament o Most common in the cervical spine, can involve upper thoracic o Variable encroachment on the ventral spinal canal o If sufficiently ossified, may produce a marrow space with hyperintensity on TlWI • Epidural Gas o Routinely seen in the acute post-operative period o Can occur from • "Vacuum" disc phenomenon extending into disc herniation • "Vacuum" joint phenomenon extending into facet synovial cyst • Metal Artifact o Epidural catheters o Spinal cord stimulators o Spinal fusion hardware o Displaced intervertebral devices o

Intervertebral

Disc Herniation

II 5

Sagittal T1WI MR shows a large disc extrusion at L4-5.

Extruded disc material is similar in signal to the remainder of the intervertebral disc on T I WI.

40

Sagittal T2WI MR again shows large disc exlfusion that is hypointense on T2WI.

EXTRADURAL

LESION, 12 HYPOINTENSE,

11 HYPOINTENSE

(Left) SagiLlal T IWI MR

shows severe disc space narrowing at LS-SI with small endplate osteophytes Small disc extrusion is present at L4-S~. (Right) SagiLlal T2WI MR also shows endplate osteophytes at LS-SI =.2 and the small disc extrusion at L4-S~.

=.

Ossification

Ligamentum

Flavum

Ossification

Ligamentum

Flavum (Left) Axial T1 WI MR shows hypointense signal within a thickened thoracic ligamentum f1avum with mild posterolateral effacement of the thecal sac. (Right) Axial T2WI MR also shows hypoinlense signal associated with the thickened, ossified ligamentum f1avum

=

=

Metal Artifact (Left) SagiLlal T1WI MR shows two level fusion from

C3 to C5 with metal artifact from screws Screw artifact at C5 level extends to the ventral epidural space adjacent to the cord S.

=.

Note the congenital

fusion at

C6-7. (Right) SagiLlal T2WI MR again shows metallic artifact in epidural space at C5S due to malpositioned screw from anterior

cervical

fusion.

II 5 41

~ OJ

:J

LUMBAR SOFT TISSUE MASS, PEDIATRIC

"0

~ OJ

X w Q)

c: C-

oo

DIFFERENTIAL DIAGNOSIS Common • Lipomyelomeningocele • Myelomeningocele • Lipoma, Spinal • Spinal Muscle Injury, Traumatic • Scoliosis Less Common • Plexiform Neurofibroma • Ewing Sarcoma • Lymphoma • Venous Vascular Malformation • Lymphatic Malformation • Abscess, Paraspinal Rare but Important • Metastases, Lytic Osseous • Hemangiopericytoma • Meningocele, Dorsal Spinal • Pseudomeningocele

ESSENTIAL INFORMATION Key Differential Diagnosis Issues • Appearance of overlying skin, pertinent clinical information helps limit differential list

II 5 42

Helpful Clues for Common Diagnoses • Lipomyelomeningocele a Lipomyelocele = neural placode-lipoma complex contiguous with subcutaneous fat through dysraphic defect, attaching to and tethering spinal cord a Lipomyelomeningocele = lipomyelocele + meningocele, enlargement of subarachnoid space, displacement of neural placode outside of spinal canal • Myelomeningocele a Posterior spinal defect lacking skin covering => neural tissue, CSF, and meninges exposed to air a Lumbosacral (44%) > thoracolumbar (32%) > lumbar (22%) > thoracic (2%) a Low-lying cord on post-operative MR imaging does not always = clinical tethering • Lipoma, Spinal a Arise from premature separation (dysjunction) of cutaneous ectoderm from neuroectoderm during neurulation

Profound hypodensity on CT and Tl WI hyperintensity characteristic of fat a Use chemical fat saturation or inversion recovery MR techniques to confirm fat content • Spinal Muscle Injury, Traumatic a Paraspinal muscle fiber disruption from indirect forces => abnormal muscle T2 hyperintensity and swelling a Most commonly from MVA; also athletic injuries, blow from falling objects, direct injury • Scoliosis a General term for any lateral curvature of spine • Dextroscoliosis: Curve convex to right • Levoscoliosis: Curve convex to left • Kyphoscoliosis: Scoliosis with component of kyphosis • Rotoscoliosis: Scoliosis which includes rotation of vertebrae a Short-curve scoliosis usually has underlying abnormalities; consider congenital, neoplasm, or inflammation a

Helpful Clues for Less Common Diagnoses • Plexiform Neurofibroma a Long, bulky, multinodular nerve enlargement is pathognomonic for NFl a Often affects sacral or brachial plexi • Ewing Sarcoma a S% of all Ewing tumors in spine (sacrum> rest of spine) a Usually in adolescents or younger adults a Permeative lytic lesion of vertebral body or sacrum involving vertebral body before neural arch • Contiguous spread along peripheral nerves from spine or sacral primary, but may originate in soft tissues • Lymphoma a Lymphoreticular neoplasms with wide variety of specific diseases & cellular differentiation a Multiple types demonstrate variable imaging manifestations • Venous Vascular Malformation a Congenital trans-spatial vascular malformation of venous channels present from birth

LUMBAR SOFT TISSUE MASS, PEDIATRIC May be mass-like, frequently enhances moderately (less than soft tissue hemangioma) a No arterial vessels within lesion, venous channels may be large a Look for phleboliths to make specific diagnosis • Lymphatic Malformation a Congenital trans-spatial vascular malformation of lymphatic channels present from birth a Typically minimal to no enhancement, although septations may enhance, especially if previously inflamed a Fluid-fluid levels strongly suggest diagnosis a May grow rapidly if hemorrhage or concurrent viral infection • Abscess, Paras pinal a Suppuration of paraspinal soft tissue from direct extension or hematogenous dissemination of pathogens a Identification of calcified psoas abscesses suggests tuberculous paraspinal abscess a

Helpful Clues for Rare Diagnoses • Metastases, Lytic Osseous a Osteolytic metastases of primary tumor to spine; bone destruction exceeds bone production ~ lytic rather than blastic a Lesion usually destroys posterior cortex, pedicle first • Hemangiopericytoma

Vividly enhancing hypervascular neoplasm arising from pericytes expanding/eroding spinal canal with large soft tissue component a Dural-based if primary, epicenter in bone if metastatic a Previously called angioblastic meningioma, but probably different tumors • Meningocele, Dorsal Spinal a Skin-covered dorsal dural sac containing arachnoid, CSF protruding thorough posterior osseous defect into subcutaneous tissues • Always skin-covered; skin may be dysplastic or ulcerated a Lumbosacral junction, sacrum> > cervical, thoracic • Mild cases may show only absent spinous process or localized spina bifida • More severe cases show multisegmental spina bifida, spinal canal enlargement • Pseudomeningocele a CSF-filled spinal axis cyst with supportive post-operative or post-traumatic ancillary findings a Cyst contiguous with thecal sac, not lined by meninges a Fat-saturated T2WI best sequence to demonstrate pseudomeningocele and localize dural communication a

lipomyelomeningocele

Sagillal T7WI MR demonsl,ales a low-lying spinal cord inserting into a large lipomatous malformation that is contiguous with subcutaneous fat extending through a poslerior dysraphic defect

Sagillal T7WI MR shows a large unrepaired myelomeningocele sac 1m. Neural elements are seen protruding into the sac which was not skin covered, confirming diagnosis of myelomeningocele.

II 5

a

43

LUMBAR SOFT TISSUE MASS, PEDIATRIC

a. c OJ

-
c. c OJ

-
2 vertebral segments) with> 2/3 of cross-sectional area of cord o Central T2 hyperintensity with patchy eccentric enhancement • Infarction, Spinal Cord o Focal T2 hyperintensity in slightly expanded cord • Gray matter, adjacent white matter, or cross-sectional cord may be involved • Classically, the anterior horn cells show T2 hyperintensity • Focal hemorrhage seen as Tl hyperintensity/T2 hypointensity • Adjacent anterior vertebral body infarction o Thoracic cord most frequently involved because of arterial border zone o Restricted diffusion on DWI o Acute onset of myelopathy; motor signs predominantly • Type I DAVF o Enlarged T2 hyperintense distal cord with dilated pial veins • Intradural, extramedullary flow voids at level of conus o "Flame-shaped" edema spares cord periphery • Venous hypertension from pial vessel engorgement results in reduced tissue perfusion & cord ischemia o 80% patients are men in 5th or 6th decade presenting with progressive lower extremi ty weakness • Acute myelopathy due to venous thrombosis: Foix-Alajouanine syndrome o

Helpful Clues for less Common Diagnoses • Acute Disseminated Encephalomyelitis, Spinal Cord o Multifocal white matter lesions with little mass effect or vasogenic edema o Punctate, ring-shaped, or fluffy enhancement

CORD

lESION,

12 HYPERINTENSE,

Concomitant supratentorial involvement is characteristic • Cranial nerve involvement with ADEM to help differentiate from MS o Autoimmune process producing inflammatory reaction o Delay between clinical onset and appearance of imaging findings • Viral Myelitis o Either immune-mediated or direct viral invasion • Echovirus, Coxsackie, CMV, varicella-zoster, HSV,EBV,hepatitis o Central T2 hyperintensity with variable enhancement • Enlarged edematous cord with segmental continuous involvement • Central Tl hypointensity is higher than CSF • Cavernous Malformation, Spinal Cord o Well-defined lesion with hemorrhage of various ages o Speckled signal with peripheral T2 hypointense rim (hemosiderin) o Enhancement absent/minimal o No edema, unless acute hemorrhage o 50% thoracic, 40% cervical, 10% conus • Astrocytoma, Spinal Cord o T2 hyperintense enhancing infiltrating mass, expanding cord o Usually < 4 segments, holocord with pilocytic astrocytoma • Cervical> thoracic cord o Diffuse or partial enhancement o

CENTRAL

• Central Spinal Cord Syndrome o Diffuse disruption axons, especially within lateral columns of cervical cord (corticospinal tracts); central gray matter intact o Most common mechanism may be direct compression of cord by buckling of ligamenta flava into an already narrowed spinal canal o MR & pathology indicate that intramedullary hemorrhage is not a necessary feature, probably uncommon o Predominant loss of motor function in distal muscles of the upper limbs • Radiation Myelopathy o Fusiform cord expansion with irregular, focal rind of enhancement; demyelination in lateral, dorsal tracts o Demyelination in lateral, dorsal tracts o One month to years following fractionated radiotherapy

;:!. ., OJ

3 CD

C

OJ

-
rim-enhancing extramedullary pus ± cord signal or compression • Neoplasm and Cyst o Syringomyelia => expanded spinal cord + central dilated, beaded, or sacculated cystic cavity o eoplastic syrinx => look for nodularity or enhancement • TraUlna o Central spinal cord syndrome => arms> legs + bladder dysfunction, variable sensory loss, high T2 cord signal • Degenerative o OPLL, OLF => look for ligamentous ossification with narrowing of central spinal canal • Intervertebral Disc Herniation o Use conventional diagnostic criteria Helpful Clues for Less Common Diagnoses • Congenital o Mucopolysaccharidoses => ± dens hypoplasia, CVJ stenosis, thickened dura at foramen magnum, platyspondyly, anterior beaking, thoracolumbar gibbus deformity o Congenital spinal stenosis => reduced AP canal diameter secondary to short, squat pedicles and laterally directed laminae • Infection/Inflammation

MYELOPATHY ADEM, spinal cord => multi focal lesions (MS mimic) with minimal mass effect, vasogenic edema o Viral myelitis => swollen, edematous cord with segmental contiguous T2 signal abnormality • Neoplasm and Cyst o Osteochondroma => sessile or pedunculated osseous "cauliflower" lesion, marrow contiguous with parent vertebra o Arachnoid cyst => nonenhancing extramedullary loculated CSF intensity collection displacing cord or nerve roots • Vascular o Spinal cord infarction => central T2 hyperintensity more common than wedge-shaped injury in anterior 2/3 spinal cord o

Helpful Clues for Rare Diagnoses • Congenital o Dermoid and epidermoid tumors => CSF isodense/isointense lumbosacral or cauda equina mass o Osteogenesis imperfecta => severe osteopenia & multiple fractures • Trauma o Spinal cord herniation => herniation of spinal cord through defect in dura of ventral canal with expansion of dorsal subarachnoid space • Neoplasm and Cyst

Abscess, Epidural

Sagittal TI C+ MR in a patient with meningitis shows progression to parameningeaf inflammation and epidural abscess

=.

Neurenteric cyst => intraspinal cyst lined by enteric mucosa + vertebral segmentation abnormalities o Spinal cord metastasis => focal, enhancing cord lesion(s) + extensive edema • Vascular o Cavernous malformation => locules of blood with fluid-fluid levels surrounded by T2 hypointense rim o Type II AVM => intramedullary glomus type AVM (similar to brain AVM), nidus may extend to dorsal subpial surface o Type III AVM => juvenile-type AVM (intramedullary, extramedullary), nidus may have extramedullary and extraspinal extension • Infection/Inflammation o Spinal cord abscess/myelitis => ring-enhancing mass within cord, appropriate clinical history of inflamma tion/ infection o Acute idiopathic transverse myelitis => central cord lesion extent> 2 vertebral segments + eccentric enhancement o Secondary acute transverse myelitis => T2 hyperintense lesion with mild cord expansion, minimal to no enhancement o Vitamin BI2 deficiency => mild spinal cord enlargement, abnormal T2 hyperintensity within dorsal columns ± lateral columns o

Abscess, Subdural

Sagittal TI C+ FS MR demonstrates a large low signal fluid collection with peripheral enhancement located ventral to cord.

=

II 7 49

MYElOPATHY

Multiple Sclerosis, Spinal Cord Q)

r:: Cl. l/l

(Left) Sagittal T2WI MR shows multiple areas of abnormal

T2 prolongation

in

the brainstem and spinal cord in a patient presenting with myelopathy and known MS. (Right) Sagittal T2WI MR demonstrates a large h%cord syrinx with extra-axial

CSF collection

at

the posterior C '-C2 level in a treated patient with Chiar; 2 malformation

and congenital

craniovertebral

anomalies.

Astrocytoma,

Spinal Cord

(Left) Sagittal T1 C+ MR depicts a very large spinal cord astrocytoma encompassing the entire cervical

spinal cord. No

intrinsic enhancement

is

demonstrated. (Right) Sagittal T2WI MR reveals a typical cellular ependymoma with central cord expansion and mixed signal intensity characterized by intrinsic hypointense intramedullary blood products.

Hemangioblastoma, (Left) Sagittal T1 C+ MR shows a large intramedullary hemangioblaslOma

associated

with

syrinx within the

upper thoracic

spinal cord

and a smaller hemangioblastoma at the foramen of Magendie. (Right) Sagittal T2WI MR in a child following trauma presenting clinically with SCfWORA reveals diffuse long segment intramedullary high signa! intensity. Cervical radiographs

II 7 50

were normal.

Spinal Cord

Central Spinal Cord Syndrome

CJl

MYElOPATHY

't:l

:l

CD

Hematoma,

Epidural-Subdural (Left) Sagittal T2' eRE MR demonstrates post-traumatic cervical epidural hemorrhage and intramedullary spinal cord hemorrhage, leading to

cord compression secondary to post-traumatic disc herniation (Right) SagiLtal T2WI MR confirms a large low signal intensity spontaneous epidural hematoma =:I, producing spinal cord compression.

=.

Hematoma, Subdural

Syrinx, Post-Traumatic (Left) Sagittal TI WI MR

shows a large linear, lobulated T I hyperintense blood collection that extends throughout the cervical and upper

thoracic

spine and

that crosses the skull base along the clivus. (Right) Sagittal T2WI MR demonstrates a focal

post-traumatic

syrinx

= in a

patient with delayed worsening of quadriplegia (ascending leve/) following skiing spinal cord injury.

Stenosis, Acquired Spinal, Cervical

OPLL (Left) Sagittal T2WI MR reveals severe multilevel degenerative spondylosis producing spinal cord compression characterized by abnormal il1lramedullary T2 prolongation. (Right) Sagittal T2WI MR demonstrates multilevel hypointense

ossification

within the posterior longitudinal ligament producing vel1lral spinal cord compression with abnormal T2 prolongation and cord deformation.

II 7 51

MYELOPATHY

Intervertebral CIl

c:

'0.. l/l

Disc Herniation,

Cervical

Intervertebral

Disc Herniation,

(Left) Sagittal T2WI MR shows central disc extrusion effacing the thecal sac causing cord compression. Note abnormal T2 hyperintensily (contusion/myelomalacia) within spinal cord at C3-4. (Right) Sagillal T2WI MR

reveals severa/large

disc

extrusions that compress the ventra/thoracic spinal cord at multiple levels.

Intervertebral Disc Herniation, Traumatic

Mucopolysaccharidoses

(Left) Sagillal T2WI MR shows sequelae of cervical hyperfJexion injury with traumatic herniation

cervical

disc

and ligamentous

injury with herniated C6-7 disc disruption of anterior longitudinalligamcnl @ posterior longitudinal ligament and interspinous ligaments p:jJ. (Right) Sagillal T2WI MR (Morquio, MPS IV) shows odontoid hypoplasia and thick pannus =:I producing

a

=-

cervical canal stenosis and cord compression craniovertebraf

EJ

at the

junction.

ADEM, Spinal Cord (Left) Sagillal T2WI MR shows a variant appearance of congenital cervical spinal stenosis that results from short pedicles in conjunction with congenital vertebral anomalies, producing spinal cord compression =:I and abnormal cord T2 hyperintensity. (Right) Sagillal T2WI MR demonstrates several T2 hyperintense intramedullary lesions within the cervical spinal cord in a patient with correlative clinical history.

II 7 52

Thoracic

MYElOPATHY

Viral Myelitis

Osteochondroma (Left) Sagittal T7 C+ MR demonstrates patchy

heterogeneous

spina! cord

enhancement in a patient with proven viral myelitis (Varicella-Zoster). (Right) Coronal T2WI FS MR reveals a heterogeneous extradural mass originating

from the

right posterior spinal osseous elements that laterally

compresses the thoracic spinal cord.

Infarction,

Spinal Cord (Left) Sagittal T2WI MR demonstrates abnormal expansion

and T2

hyperintensity of the cervical cord extending from C3 to C7. (Right) Sagittal T2WI MR depicts classic central cord T2 hyperintensity sparing the cord periphery. Note multiple

serpentine

intradural flow voids along the dorsal cord surface

representing

the arterialized

venous plexus.

(Left) Sagittal T2WI MR shows multiple

abnormal

flow voids involving dorsal subarachnoid space 81 and extending into dorsal cord surface. Tocal mixed signal intensity is due to high flow aneurysm. (Right) Sagittal T2WI MR confirms characteristic vertebral

=

anomalies

with severe

cranioverlebral

junction

central canal stenosis producing spinal cord

compression.

II 7 53

INDEX A Abscess brain cyst with nodule, 1(5):29, 30 multiple enhancing lesions, 1(5):2, 4 ring-enhancing lesion, solitary, 1(5):6, 8 cerebellar mass, 1(7):22, 25 cystic-appearing posterior fossa lesion, 1(7):35, 38 effaced sulci, focal, 1(4):17,19 epidural mass, 11(5):2,4. See also Epidural abscess medulla lesion, 1(7):11, 13 midbrain lesion, 1(6):100 paraspinal. See Paraspinal abscess parenchymal lesions multiple hypodense, 1(5):60, 62 T1 hypointense, T2 hyperintense, 1(5):91, 93 periventricular, 1(3):58, 60 pituitary, 1(8):25 presacral, 11(1):22,23 prevertebral, II(1):14 pyogenic, 1(7):6 restricted diffusion, 1(5):98, 100 ring-enhancing lesions, multiple, 1(5):12, 13-14 solitary cystic mass, 1(5):17, 19 spinal cord. See Spinal cord abscess subdural, 11(1):30,11(7):48,49 Accelerated degeneration chronic back pain/radiculopathy, postoperative, 11(1):36,39-40 intervertebral disc end plate irregularity, II(4):6, 8 post-traumatic, 11(1):2,4 vertebral body, 11(3):24-25,26 Accessory sutures, 1(1):2 Achondroplasia bony trauma, 1l(1):6, 8 C1-C2 instability, II(2):12 cervical abnormality, chronic post-traumatic, 1l(1):2 craniovertebral junction abnormalities, II(2):4 kyphosis, II(1):12, 13 macrocephaly, 1(1):33, 37 pedicle abnormality, II(3):36 platyspondyly, diffuse, 11(1):16, 17 vertebral anomalies, congenital, 11(3):2 vertebral body dysmorphic, 11(3):10

flattened, II(3):8 fracture, II(3):29 scalloping or widened canal, II(3):18, 19 vertebral endplate contour abnormality, 1l(4):10, 11

Acidopathies, organic, 1(6):80 Acromegaly, 1(1):9, II(3):18 Acute necrotizing encephalopathy of childhood, 1(6):93 Acute transverse myelitis idiopathic acute upper extremity pain or weakness, II(1):43, 47 intramedullary lesions, no enhancement, 1l(7):18, 19 intramedullary lesions, T2 hyperintense, T1 isointense, II(7):30, 32 intramedullary mass, II(7):2 myelopathy, II(7):49 pediatric back pain, II(1):57 subarachnoid space narrowing, II(6):6 T2 hyperintense cord lesions, central, II(7):44, 46 intramedullary lesions, diffuse/ill-defined enhancement, II(7):20, 21 secondary acute upper extremity pain or weakness, II(1):43 intramedullary lesions, T2 hyperintense, Tl isointense, II(7):30, 32 myelopathy, 11(7):49 pediatric back pain, II(1):57, 59 ADEM (acute disseminating encephalomyelitis) basal ganglia, 1(6):70, 81 cerebellar mass, 1(7):22, 25 corpus callosum holes, 1(6):52, 53 lesion without mass effect, 1(6):54 splenium lesion, 1(6):59, 61 cranial nerve enhancement, 1(4):47 hypothalamus lesion, 1(8):49 intramedullary lesions, diffuse/ill-defined enhancement, II(7):20, 22 medulla lesion, 1(7):10, 12 midbrain lesion, 1(6):100, 102 multiple brain hyperintensities (T2/FLAIR), 1(5):70, 71 multiple enhancing lesions, 1(5):2, 4

INDEX >

< cu c

-=

-

enlarged sulci, generalized, 1(4):9, 11 large ventricles, 1(3):45 "pulvinar sign," 1(6):96-97 putamen lesions, 1(6):84, 85 restricted diffusion, 1(5):99, 101 Cryptococcosis bilateral basal ganglia lesions, 1(6):81 CSF-like parenchymal lesions, 1(5):23, 26 enlarged perivascular spaces, 1(6):74, 75 intramedullary lesions, Tl hyperintense, 11(7):35, 37

Crystalline arthropathies, 11(1):2 CSF. See Cerebrospinal fluid (CSF) Cushing disease congenital vertebral anomalies, 11(3):2 flattened vertebral body, multiple, 11(3):8 platyspondyly, diffuse, 11(1):16 thoracic bony trauma, 11(1):6 vertebral body fracture, 11(3):28 vertebral end plate contour abnormality, 11(4):10 Cyanide poisoning, 1(6):86, 88 Cysticercosis conus abnormality, 11(7):7 intradural/extramedullary lesions multiple, 11(6):20, 21 ring/peripheral enhancement, 11(6):22, 25 T2 hyperintense, T1 isointense, 11(6):34, 35 T1 hypointense, 11(6):29 intramedullary lesions multiple, 11(7):12, 13 ring/peripheral enhancement, 11(7):24, 25 T1 hypointense, T2 hypointense, 11(7):26, 27 intramedullary mass, 11(7):3 Cysts arachnoid. See Arachnoid cyst bone. See Bone cyst, aneurysmal choroid plexus. See Choroid plexus cysts colloid foramen of Monro mass, 1(3):18, 20 third ventricle mass, general, 1(3):22, 24 connatal CSF-like parenchymal lesions, 1(5):23, 25 ventricles, normal variant, 1(3):3, 5 dermoid. See Dermoid cyst discal, 11(4):3, 5 enteric, 11(1):23 ependymal. See Ependymal cyst epidermal inclusion, 1(1):4 epidermoid. See Epidermoid cyst germinolytic CSF-like parenchymal lesions, 1(5):23, 27 ventricles, normal variant, 1(3):3, 5 interhemispheric fissure, 1(4):20-23 leptomeningeal extra-axial mass, CSF-like, 1(4):52 lytic skull lesion, solitary, 1(1):19, 21 neurenteric. See Neurenteric cyst xii

neuroglial CSF-like parenchymal lesions, 1(5):23, 26 cystic-appearing posterior fossa lesion, 1(7):34, 38

solitary cystic mass, 1(5):17, 20-21 perineural root sleeve. See Perineural root sleeve cysts pineal. See Pineal cyst porencephalic. See Porencephalic cyst Rathke cleft. See Rathke cleft cyst sebaceous, 1(1):4, 5 synovial. See Synovial cyst tumor-associated, 1(4):21, 23 Cytomegalovirus (CMV) infections congenital asymmetric cerebral hemispheres, 1(6):2, 5 basal ganglia calcification, 1(6):62, 64 irregular large ventricles, 1(3):55, 57 periventricular calcifications, 1(3):66, 67 polyradiculopathy, 11(6):3, 4 radiculopathy, 11(6):15, 17

o DAI. See Diffuse axonal injury (DAI) Dandy-Walker continuum cisterna magna mass, 1(4):38, 40 cystic-appearing posterior fossa lesion, 1(7):34,

36 extra-axial fluid collection, CSF-Iike, 1(4):50, 51 infratentorial midline cyst, 1(7):14, 16 macrocephaly, 1(1):32, 35 Degeneration, accelerated. See Accelerated degeneration Degenerative disc disease chronic back pain/radiculopathy, postoperative, 11(1):36, 39

endplate irregularity, 11(4):6, 7 kyphosis, 11(1):12 myelopathy, 11(7):48 spondylolisthesis, 11(3):20, 22 T2 hyperintense disc, 11(4):14-15 T1 hypointense disc, 11(4):12 Dementia Alzheimer. See Alzheimer dementia frontotemporal. See Frontotemporal dementia multi-infarct. See Multi-infarct dementia vascular, 1(4):8, 10 with Lewy bodies, 1(4):8 Demyelinating diseases brain stem, large, 1(7):2, 3 conus abnormality, 11(7):6, 8 deep veins, enlarged, 1(10):11, 13 hypothalamus lesion, 1(8):49 intramedullary mass, 11(7):2, 3 medulla lesion, 1(7):10, 12 midbrain lesion, 1(6):100, 102

INDEX parenchymal lesions, T1 hypointense, T2 hyperintense, 1(5):90 pontine lesion, 1(7):6, 8 subarachnoid space narrowing, 11(6):6 tumefactive, 1(5):6, 9, 1(7):22 Dermal sinus, dorsal, 11(5):14 Dermatomyositis, 11(5):20 Dermoid cyst cavernous sinus mass, unilateral, 1(10):15, 17 cisterna magna mass, 1(4):39,41 cystic mass, solitary, 1(5):17, 20 extra-axial masses, hypodense, 1(4):77, 79 foramen magnum mass, 1(4):43, 45 fourth ventricle mass, 1(3):33 interhemispheric fissure cysts, 1(4):21, 23 lytic skull lesion, solitary, 1(1):18-19, 21 Meckel cave lesion, 1(10):23, 25 midline cyst, infratentorial, 1(7): 15, 17 parenchyma, fat-like lesions, 1(5):32, 33 pineal region mass, 1(8):3, 5 posterior fossa lesion, cystic-appearing, 1(7):34,

37 quadrigeminal cistern mass, 1(8):8 ruptured fat in sulci/cisterns/ventricles, 1(4):58, 59 FLAIR hyperintense CSF, 1(4):65 Tl hyperintense CSF, 1(4):62, 63 Tl hyperintense parenchymal lesions, 1(5):102 scalp, 1(1):4, 5, 16 sellar/juxtasellar calcification, 1(8): 15, 17 suprasellar mass calcified, 1(8):40, 41 cystic, 1(8):36, 38 general, 1(8):25, 27 pediatric, 1(8):31 Tl hyperintense, 1(8):56, 57 vermis mass, 1(7):29, 31 Dermoid tumor intradural/extramedullary lesions, Il(6):12, 26, 27 myelopathy, Il(7):49 sacrococcygeal mass, pediatric, 11(1):23, 24 spinal cord, intramedullary lesions, 11(7):34, 37 vertebral body scalloping or widened canal, 11(3):18 Developmental venous anomaly. See also Arteriovenous malformation enlarged cortical veins, 1(10):8 enlarged deep veins, 1(10):10, 11 ependymal enhancement, 1(3):40, 41 ependymal/subependymal lesions, 1(3):8, 10 extra-axial flow voids, 1(4):60, 61 parenchymal lesions solitary hyperdense, 1(5):44-45, 47 Tl/T2 isointense, 1(5):94, 96

Devices and complications. See also Metal artifact hyperattenuating artery, 1(9):8, 9 multiple hypointense foci on GRE/SWI, 1(5):83 Diabetes mellitus cranial nerve enhancement, 1(4):47 vascular calcifications, 1(9):10, 11 Diastematomyelia congenital vertebral anomalies, 11(3):2, 3 conus abnormality, 11(7):6 extradural lesions, Il(5):14 intramedullary lesions, 11(7):26, 27 kyphoscoliosis, child, 11(1):14 vertebral body fracture, 11(3):28 vertebral body scalloping or widened canal, Il(3):18, 19 Diffuse axonal injury (DAI) cerebral aqueduct/periaqueductallesion, 1(3):28,

30 corpus callosum abnormal shape or configuration, 1(6):47, 50 holes, 1(6):52 lesion without mass effect, 1(6):54 splenium lesion, 1(6):58, 59 large ventricles, 1(3):45 midbrain lesion, 1(6):100, 101 multiple brain hyperintensities (T2/FLAIR), 1(5):65, 68 multiple hypointense foci on GRE/SWI, 1(5):82,

84 parenchymal lesions multiple hyperdense, 1(5):50, 51 multiple hypodense, 1(5):60, 62 Tl hypo intense, T2 hyperintense, 1(5):90 periventricular T2/FLAIR lesions, 1(3):72, 74 restricted diffusion, 1(5):98, 100 Dilantin, chronic use cerebellar atrophy, 1(7):18, 20 thick skull, generalized, 1(1):8, 10 Disc herniation. See Intervertebral disc herniation Discal cyst, 11(4):3, 5 Discitis, chronic, Il(3):44, 45 Discogenic sclerosis, Il(3):44 DISH. See Skeletal hyperostosis, diffuse idiopathic (DISH) Dissection, arterial. See Arterial dissection Distraction fracture, low thoracic, 11(1):6, Il(3):28,

30 DNET (dysembryoplastic neuroepithelial tumor) in children over 1 year, 1(5):112, 115 cortical hyperintensity Tl/FLAIR, 1(6):25, 27 cyst with nodule, 1(5):29, 31 effaced sulci, focal, 1(4):16, 18 epilepsy, 1(5):119, 123 focal cortical mass, 1(6):21, 23 solitary cystic mass, 1(5):17, 19 solitary parenchymal calcification, 1(5):35, 39 thick cortex, 1(6):9, 12 thin skull, localized, 1(1):16, 17 XIII

INDEX >
< aJ

C

vertebral anomalies, 11(3):2 kyphoscoliosis, child, 11(1):14 vertebral body flattened, solitary, 11(3):6,7 fracture, 11(3):28 Falx lesions, 1(2):12-13 ossified, 1(5):32, 33 Familial tumoral calcinosis, 1(2):2 Femoral neuropathy, 11(1):48 Fetal alcohol syndrome, 1(1):38, 41, 11(1):10 Fibro-osseous lesion, 1(2):4 Fibrodysplasia ossificans progressiva, 11(5):20 Fibrolipoma. See Filum terminale fibrolipoma Fibromatosis, aggressive, 1(1):19 Fibrosarcoma, soft tissue, 11(5):8,10 Fibrothorax, 11(1):10 Fibrous dysplasia bony trabeculae, thickened, 11(3):46,47 lytic skull lesion, solitary, 1(1):18, 21 macrocephaly, 1(1):33, 37 pedicle abnormality, 11(3):36 sclerotic skull lesions, 1(1):26 , 28, 30, 31 scoliosis, 11(1):10 thick skull, 1(1):8, 10, 12, 13 vertebral body diffuse Tl hypointense signal, 11(3):53, 55 enlarged, soap bubble expansion, 11(3):38-39, 41

vertebral body/posterior element, enlarged, 11(3):13 Filum terminale fibrolipoma conus abnormality, 11(7):6,7 intradural/extramedullary lesions, 11(6):12,26 Fissure cysts, interhemispheric, 1(4):20-23 Flow artifacts, CSF foramen of Monro mass, 1(3):18, 19 intradural/extramedullary lesions multiple, 11(6):20 no enhancement, II(6):12 Tl hypointense, II(6):28 Tl hypointense, T2 hypointense, 11(6):32 intradural lesion, serpentine, 11(6):18 intramedullary lesions, T1 hypointense, Il(7):28 prepontine cistern mass, 1(4):32, 33 Flow voids, extra-axial, 1(4):60-61 Fluorosis, 1(1):9, 11(3):44 Foramen magnum mass, 1(4):42-45 Foramen of Monro mass, 1(3):18-21 Foramina, asymmetric, 1(1):2, 3 Foreign bodies, scalp mass, 1(1):4 Fracture-dislocation, Il(1):8 Fracture mimics cranio-cervical junction acute injury, II(2):2 posterior elements, Il(1):4, 8

xviii

vertebral body, 11(1):8,11(3):28 Friedrich ataxia, 1(7):4, II(1):10 Frontometaphyseal dysplasia, 1(1):12 Frontotemporal dementia asymmetric cerebral hemispheres, 1(6):2, 5 enlarged sulci, generalized, 1(4):8, 10 large ventricles, 1(3):45 thin cortex, 1(6):15, 18 Fungal diseases intervertebral disc endplate irregularity, Il(4):7, 8 multiple hypointense foci on GRE/SWl, 1(5):83, 85 multiple hypointense foci on T2, 1(5):80, 81 parenchymal lesions, Tl hyperintense, 1(5):102 prepontine cistern mass, 1(4):33, 36 ring-enhancing lesions, 1(5):7, 11, 13, 15 sulcal/cisternal enhancement, 1(4):55, 57 suprasellar mass, hyperdense, 1(8):52 Fusiform aneurysm atherosclerotic arterial shape/configuration abnormalities, 1(9):2-3,4 fusiform arterial enlargement, 1(9):6, 7 vascular calcifications, 1(9):10, 11 extra-axial flow voids, 1(4):60, 61 hyperattenuating artery, 1(9):8 nonatherosclerotic arterial shape/configuration abnormalities, 1(9):3,4-5 fusiform arterial enlargement, 1(9):6, 7 prepontine cistern mass, 1(4):32, 34 suprasellar mass calcified, 1(8):40, 41 hyperdense, 1(8):52 Fusiform arterial enlargement, 1(9):6-7

G Gadolinium blood-brain barrier leakage, FLAIRhyperintense CSF,1(4):64-65, 67 focal T1 hyperintense signal, vertebral body, II(3):50, 51 Gangliocytoma, dysplastic cerebellar cerebellar mass, 1(7):23, 27 in children over 1 year, 1(5):113 cortical hyperintensity Tl/FLAIR, 1(6):25, 27 posterior fossa adult, 1(7):41,43 pediatric, 1(7):45, 49 thick cortex, 1(6):9, 13 vermis mass, 1(7):29, 31 Ganglioglioma cerebellar mass, 1(7):23, 27 in children over 1 year, 1(5):112, 115 cyst with nodule, 1(5):28, 30

INDEX cystic mass, solitary, 1(5):17, 19 desmoplastic infantile cyst with nodule, 1(5):29 focal cortical mass, 1(6):21, 23 in newborn/infant, 1(5):106-107, 109 solitary cystic mass, 1(5):17, 21 epilepsy, 1(5):119, 123 focal cortical mass, 1(6):21, 23 hypothalamus lesion, 1(8):49 infratentorial midline cyst, 1(7):15, 17 intramedullary lesion, solid enhancement, 11(7):15,17 intramedullary mass, 11(7):3,5 parenchymal calcification, solitary, 1(5):34, 37 parenchymal lesion, solitary hyperdense, 1(5):45, 48 posterior fossa, pediatric, 1(7):44, 47 thick cortex, 1(6):9, 12 thin skull, localized, 1(1):16, 17 vermis mass, 1(7):29, 31 Ganglioma effaced sulci, focal, 1(4):16, 18 ring-enhancing lesion, solitary, 1(5):7, 11 Ganglioneuroma, 11(5):8 Gaucher disease, 11(1):16,17,11(4):7 Germ cell neoplasms cavernous sinus lesions, bilateral, 1(10):19,21 pineal + suprasellar lesions, 1(8):10, 11 pineal gland mass, 1(8):6, 7 Germinal matrix hemorrhage, 1(3):67, 70 Germinolytic cysts CSF-like parenchymal lesions, 1(5):23, 27 ventricles, normal variant, 1(3):3, 5 Germinoma in children over 1 year, 1(5):112, 115 ependymal/subependymallesions, 1(3):8 foramen of Monro mass, 1(3):19, 21 hypothalamus lesion, 1(8):48, 50 parenchymal lesions, solitary hyperdense, 1(5):45, 48 periventricular enhancing lesions, 1(3):58, 60 pineal + suprasellar lesions, 1(8):10 pineal gland mass, 1(8):6, 7 pineal region mass, 1(8):3, 5 suprasellar mass enhancing, 1(8):42, 43 general, 1(8):25,27 hyperdense, 1(8):52, 53 pediatric, 1(8):30, 32 T1 isointense, 1(8):54 thalamic lesion, unilateral, 1(6):90 thick infundibular stalk, 1(8):46 thick septum pellucidum, 1(3):16,17 third ventricle mass body/posterior, 1(3):26, 27 general, 1(3):22, 24 Giant cell astrocytoma, subependymal, 1(3):8, 10

in children over 1 year, 1(5):112, 115 foramen of Monro mass, 1(3):18, 20 intraventricular calcifications, 1(3):62, 65 lateral ventricle mass, 1(3):12, 14 in newborn/infant, 1(5):106, 109 Giant cell tumor epidural mass, 11(5):2,7 extradural lesions, II(5):32, 37 extradural marrow signal, abnormal, 11(5):27,29 sacral mass, adult, II(1):18, 20 vertebral body, 11(3):6,38, 40 Giant serpentine aneurysm, 1(9):6 Glioblastoma multiforme cerebellar mass, 1(7):23, 27 in children over 1 year, 1(5):113, 116 corpus callosum, 1(6):46, 49, 56 cyst with nodule, 1(5):28, 30 cystic mass, solitary, 1(5):16, 18 enlarged deep veins, 1(10):11, 13 ependymal/subependymallesions, 1(3):8, 10 macrocephaly, 1(1):32, 35 midbrain lesion, 1(6):100 multifocal, 1(5):13, 15 multiple brain hyperintensities (T2/FLAIR), 1(5):71,74 multiple enhancing lesions, 1(5):3, 5 in newborn/infant, 1(5):107, 110 parenchymal lesions multiple hyperdense, 1(5):51, 54 multiple hypodense, 1(5):61 solitary hyperdense, 1(5):44, 46 solitary hypodense, 1(5):56, 58 T1 hypointense, T2 hyperintense, 1(5):90 perivascular space enhancing lesions, 1(6):76, 78 periventricular enhancing lesions, ](3):58, 60 pial enhancement, 1(2):16, 18 posterior fossa neoplasms, adult, 1(7):41 ring-enhancing lesion, solitary, ](5):6, 8 spinal cord, 11(7):3 thalamic lesion, unilateral, 1(6):90 thick cortex, 1(6):9, 13 vermis mass, 1(7):29, 31 white matter lesions confluent, 1(6):34, 36 solitary, 1(6):30, 32 Glioma brainstem, pediatric. See Brainstem glioma, pediatric chordoid hyperdense suprasellar mass, 1(8):52 hypothalamus lesion, ](8):49, 51 sellar/juxtasellar calcification, ](8):15, 16 third ventricle mass, genera], 1(3):23, 25 exophytic, II(6):29 exophytic cervicomedullary, 1(7):10, 12 malignant, 1(6):28 multifoca], 1(5):80, 81

::s

Q.

I'D

>