Imaging and Urodynamics of the Lower Urinary Tract Second Edition
Uday Patel
Imaging and Urodynamics of the Lower Urinary Tract Second Edition
Uday Patel Department of Diagnostic Radiology St. George’s Hospital Blackshaw Road London SW17 0QT UK
[email protected] ISBN: 978-1-84882-835-3 e-ISBN: 978-1-84882-836-0 DOI: 10.1007/978-1-84882-836-0 Springer Dordrecht Heidelberg London New York Library of Congress Control Number: 2009938951 © Springer-Verlag London Limited 2010 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Product liability: The publishers cannot guarantee the accuracy of any information about dosage and application contained in this book. In every individual case the user must check such information by consulting the relevant literature. Cover design: eStudio Calamar, Figueres/Berlin Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)
Preface
Lower urinary tract symptoms may be the result of a structural or functional abnormality. To consider either in isolation would be an incomplete assessment, but combined anatomical and functional imaging provides a more powerful and complete tool for investigation of lower urinary tract malfunction. Yet many of the currently available radiological texts concerning lower urinary tract imaging fail to discuss these two aspects in a holistic manner. We hope that this book will fill this gap. Although it is written to be as comprehensive as possible such that it covers the vast majority of lower urinary tract disorders that will be encountered in adult urological practice, it is not meant to replace conventional textbooks of uroradiology. Rather, it is meant to be practical and user friendly. It is intended for everyday clinical use; it should allow the trainee and trained radiologist or urologist to plan a logical, yet complete radiological and dynamic investigation of the lower urinary tract. It should also be useful for nurse practitioners, medical students, and all other medical staff who commonly manage lower urinary tract disorders.
London, UK
Uday Patel
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Contents
Part I The Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
1
The Normal Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Embryology of the Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Anatomy of the Bladder (and Prostate) . . . . . . . . . . . . . . . . . . . . . . 1.2.1 The Urinary Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.2 Relations of the Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.3 Blood Supply to the Bladder . . . . . . . . . . . . . . . . . . . . . . . . 1.2.4 Nerve Supply to the Bladder . . . . . . . . . . . . . . . . . . . . . . . . 1.2.5 The Prostate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.6 Gross Anatomy of the Prostate . . . . . . . . . . . . . . . . . . . . . . 1.2.7 Physiology of the Bladder and Control of Micturition . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 3 3 3 4 5 5 5 5 5 6
2
Imaging Modalities Used for Assessment of the Bladder . . . . . . . . . . . 2.1 Plain Abdominal Radiograph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Intravenous Urogram (IVU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Cystography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Ultrasound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.1 Ultrasound of the Bladder: Technique . . . . . . . . . . . . . . . . . 2.5 Sonographic Appearances of the Normal Bladder . . . . . . . . . . . . . . 2.6 Color Doppler Ultrasound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 Computed Tomography (CT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.8 Magnetic Resonance Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.9 Lower Tract Urodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.10 Simple Flowmetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.11 Ultrasound Cystodynamogram (USCD) . . . . . . . . . . . . . . . . . . . . . . 2.12 Urodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.13 Normal Videourodynamics Study . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9 9 9 11 12 12 12 12 13 14 15 17 18 19 20 21
3
Congenital Anomalies of the Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Absent or Congenitally Small/Large Bladder or Duplication Anomalies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Cloacogenic Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3 Exstrophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4 Congenital Bladder Diverticulum . . . . . . . . . . . . . . . . . . . . . . . . . . .
23 23 23 23 23 vii
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3.5 Prune Belly Syndrome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6 Urachal Abnormalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25 25 27
4
Intraluminal Abnormalities of the Bladder . . . . . . . . . . . . . . . . . . . . . . 4.1 Stones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Blood Clot or Hemorrhage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Gas in the Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4 Foreign Bodies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
29 29 30 31 33 33
5
Abnormalities of the Bladder Wall or Mural Abnormalities . . . . . . . . 5.1 Diffuse Bladder Wall Thickening . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Bladder Wall Calcification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 Infection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 Chronic Inflammation or Infiltration . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 Bladder Tumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5.1 Benign Tumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5.2 Malignant Tumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
35 35 35 36 38 41 41 42 46
6
Staging of Bladder Cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1 Clinical Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 Methods of Staging of Bladder Cancer . . . . . . . . . . . . . . . . . . . . . . . 6.3 TNM Staging Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4 Radiological Staging Modalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4.1 Ultrasound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4.2 Computed Tomography and Magnetic Resolution Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4.3 Computed Tomographic Findings . . . . . . . . . . . . . . . . . . . . 6.4.4 Magnetic Resonance Findings . . . . . . . . . . . . . . . . . . . . . . . 6.5 Additional Radiologic Staging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
49 49 49 50 50 51
7
Abnormal Bladder Contour or Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 Normal Bladder Shape and Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2 Abnormal Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.1 Small Volume Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.2 Large Volume Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.3 Abnormal Bladder Shape . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.4 The Pear-Shaped Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.5 Displaced Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 Postoperative Bladder Appearances . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
57 57 57 57 57 57 58 58 59 60
8
Functional Abnormalities of the Bladder . . . . . . . . . . . . . . . . . . . . . . . . 8.1 Reduced Functional Bladder Capacity . . . . . . . . . . . . . . . . . . . . . . . 8.2 Small Volume Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3 Bladder Overactivity (or the Unstable Bladder or Detrusor Overactivity) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
61 63 65
51 52 53 55 55
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8.4 Stress and Urge Incontinence and Sphincter Incompetence . . . . . . . 8.5 Abnormal Bladder Emptying: Bladder Outflow Obstruction . . . . . . 8.6 Abnormal Bladder Emptying: Poor Sphincter Relaxation . . . . . . . . 8.7 Detrusor Weakness (or Detrusor Inactivity or Failure) . . . . . . . . . . . 8.8 Postprostate Surgery Dysfunction . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.9 The Neuropathic Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
66 69 71 73 74 74 78
Part II The Urethra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
79
9
The Normal Urethra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.1 Anatomy of the Urethra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.1.1 The Male Urethra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2 The Female Urethra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.3 Radiological Investigation of the Urethra . . . . . . . . . . . . . . . . . . . . . 9.3.1 Contrast Urethrography in the Male . . . . . . . . . . . . . . . . . . 9.4 Contrast Urethrography in the Female . . . . . . . . . . . . . . . . . . . . . . . 9.5 Ultrasound of the Urethra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.6 Ultrasound Urethrography in the Male . . . . . . . . . . . . . . . . . . . . . . . 9.7 Ultrasound Urethrography in the Female . . . . . . . . . . . . . . . . . . . . . 9.8 Other Imaging Modalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
81 81 81 82 82 82 83 84 84 85 86 86
10 Congenital Anomalies of the Urethra . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1 Posterior Urethral Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2 Urethral Duplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.3 Congenital Meatal or Urethral Stenosis . . . . . . . . . . . . . . . . . . . . . . 10.4 Hypospadias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.5 Megalourethra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.6 Urethral Diverticulum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7 Cowper’s Duct Cyst or Diverticulum, or A Syringocele . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
87 87 87 88 88 89 89 89 91
11 Intraluminal Abnormalities and Filling Defects of the Urethra . . . . . . 11.1 Calculi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Foreign Bodies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3 Hair Balls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4 Polyps of the Male Urethra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
93 93 93 93 94 95
12 Intrinsic Abnormalities of the Urethral Wall . . . . . . . . . . . . . . . . . . . . . 97 12.1 Urethritis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 12.2 Urethral Strictures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 12.3 Female Urethral Diverticulum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 12.4 Male Urethral Diverticulum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 13 Lower Urinary Tract Trauma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 13.1 Bladder Trauma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 13.2 Injury of the Male Urethra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
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13.3 Investigation of Suspected Urethral Trauma . . . . . . . . . . . . . . . . . . . 105 13.4 Injury of the Female Urethra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 14 Neoplasms of the Urethra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.1 Benign Tumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.2 Urethral Carcinoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
109 109 109 112
Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Part Detection and TheAnalysis Bladder
I
1
The Normal Bladder
1.1 Embryology of the Bladder Development of the bladder commences between the 5th and 7th week of embryonic life, with the formation of the cloaca, which is the early common chamber that comprises both the urinary and alimentary tracts. A thin membrane, called the claocal membrane, overlies the cloaca. In time, the cloaca is further subdivided by the urorectal septum, with the anterior section becoming the bladder and the posterior portion forming the rectum. Complete separation of these two compartments into separate chambers underneath the anterior bladder wall occurs before the cloacal membrane regresses; if not, the result is exstrophy (definition: eversion of a hollow organ at birth), either bladder exstrophy or cloacal exstrophy. The mesonephric ducts join the bladder inferiorly, and this develops into the bladder trigone and also the ureteric orifices. The upper part of the primitive bladder is continuous with the allantois (embryonic diverticulum from the hindgut) and urachus (connecting the umbilicus to the apex of the bladder), which degenerates into a cord-like structure called the median umbilical ligament. This structure may persist to a variable degree after birth. At birth, the bladder is more superior in location within the true pelvis than its final position in the adult. Development is completed by the 12th week of fetal life.
1.2 Anatomy of the Bladder (and Prostate) 1.2.1 The Urinary Bladder The urinary bladder has to serve as a storage organ with a periodic expulsive function, and its unique
neurology and anatomy make it ideally suited for this role. It lies centrally in the pelvis and although extraperitoneal, the peritoneum reflects over its superior surface (Fig. 1.1). It is spherical in shape when fully distended, but when partly full it approximates to a more cuboid outline. The bladder base or trigone lies inferiorly and is indistinguishable from the rest of the bladder, except that it may be slightly raised, particularly in the male because of the prostate gland. The trigone is also smoother in outline compared to the more irregular outline of the rest of the bladder. The ureters enter the trigone approximately 2 cm either side of the midline, and are identifiable as a slight corrugation on ultrasound imaging as they traverse diagonally through the bladder wall. With full distension, the normal bladder neck may be seen as a slightly open funnel at the base of the bladder. These – the trigone, ureters, and bladder neck – are the only fixed landmarks seen on imaging. The walls of the bladder have been described as having three major components – outer adventitia, intervening detrusor (smooth) muscle, and inner transitional cell-lined (urothelium) mucous membrane. The detrusor muscles have been described in the past as subdivided into three parts – the outer longitudinal muscle layer, the middle circular muscle, and an inner longi tudinal layer. However, it has now been proposed that rather than composed of discrete layers (as described earlier), the detrusor muscle is in fact a composite of interlacing muscle fibers following no particular direction. Some of the muscle fibers at the base of the bladder merge with the prostate capsule or the anterior vaginal wall. The urothelium (transitional cell epithelium) lines the inner part of the muscle layer, and is continuous with the urothelium of the ureters and urethra.
U. Patel, Imaging and Urodynamics of the Lower Urinary Tract, DOI: 10.1007/978-1-84882-836-0_1, © Springer-Verlag London Limited 2010
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4
1 The Normal Bladder
a
b Ureter Parietal peritoneum Detrusor muscle Ureteric openings Trigone
Prostate gland Prostatic urethra Membranous urethra
Bulbourethral gland and duct
Bladder neck Internal urethral sphincter External urethral sphincter Urogenital diaphragm Urethra
Crus of penis Bulb of penis Spongy (penile) urethra Erectile tissue of penis
External urethral orifice
Fig. 1.1 Line drawing of the anatomy of the bladder (and also the urethra). (a) Illustrates the anatomy in the male, and (b) in the female
The interior surface is smooth on full distension, but corrugated when not, except around the trigone, which is always smooth as it is a fixed structure. The muscles around the bladder neck fuse to form the internal urethral sphincter, which encircles the upper prostatic urethra (Fig. 1.1). In the female, the external urethral sphincter lies just below the bladder neck, with the uterus lying posteriorly. In the male, the prostate gland lies between the bladder neck and the external urethral sphincter, with the seminal vesicles and rectum as the posterior structures (the rectovesical pouch lies in-between).
1.2.2 Relations of the Bladder Superiorly, the peritoneum separates the bladder from the small and large bowel loops. The anterior surface is extraperitoneal; when empty, the retropubic space,
with its fat and veins, lies in front. As the bladder expands, the peritoneum is peeled off the anterior abdominal wall and lifted superiorly by the elevation of the bladder dome, and the rectus sheath, with its contents, becomes the anterior relation. Thus, surgically, extraperitoneal access is possible through a low abdominal/pelvic incision, as long as the organ is well distended. The space of Retzius (described by Anders Retzius, anatomist at the University of Lund in the nineteenth century) lies between the anterior bladder wall and the posterior aspect of the pubis symphysis. It is also known as the anterior perivesical space, and is another landmark during pelvic surgery. Posterior and inferior relations are gender-dependent. In the male, the seminal vesicles and the vas deferens separate the bladder from the rectum. A cone of peritoneum, the rectovesical pouch, lies between the two. In the female, the uterus, the uterine cervix, and the vagina lie posteriorly, from superior to inferior respectively,
1.2 Anatomy of the Bladder (and Prostate)
separated by the rectouterine pouch (the female equivalent of the rectovesical pouch). The most inferior relation in both sexes is the bladder neck, which leads to the urethra – within the external sphincter and perineal body in the female, and within the prostate in the male. The infero-lateral relations are the obturator nerve and superior vesical vessels, the obturator internus, and the levator ani muscles.
1.2.3 Blood Supply to the Bladder Blood supply originates from branches of the anterior division of the internal iliac artery. The superior vesical arteries are the dominant suppliers, but there are further variable and smaller branches arising from the obturator and inferior gluteal arteries, or from the uterine and vaginal arteries in the female. Venous drainage is also variable. The vesical venous plexus drains into the internal iliac vein, but there are further direct pathways draining into the inferior vena cava, via the ovarian and sacral veins.
1.2.4 Nerve Supply to the Bladder Autonomic fibers (sympathetic from the T11-L2 nerves and parasympathetic from the S2–4 nerves) from the pelvic plexuses travel with the vessels to the bladder wall. These aspects, as well as further details of the neural control of micturition, are given below.
5
size and shape of a walnut). For unknown reasons, though presumably hormones play a role, the gland increases in size and changes shape with age. Like the bladder, the prostate is a retroperitoneal structure, lying anterior to the rectum and inferior to the bladder. Between the gland and the rectum lies the Denonvillier’s fascia – an obliterated peritoneal plane (described by Charles-Pierre Denonvilliers, a French surgeon). The shape of the prostate gland conforms to the anatomical limitations of the deep pelvic boundaries, and looks like an inverted cone or pyramid. On the sides lie the levator ani and obturator internus muscles. The superior margin, or the base of the gland, lies immediately below the bladder. The most inferior part of the gland is the apex (Fig. 1.1), lying just above the urogenital diaphragm, which is a fibrous supporting ring that also contains the urethra and the external urethral sphincter. The deep pelvis is a restricted space, and insufficient to accommodate significant gland enlargement. Beyond a certain size, the gland will preferentially enlarge superiorly, protruding into the bladder base – the so-called median lobe enlargement. Enlargement may be substantial and asymmetric, and there may be marked distortion of the bladder base and trigone. In the past, the gland was considered a lobar structure, with a right lobe, a left lobe, and a midline median lobe. Lobar anatomy is no longer thought to be an accurate representation in the adult, and the gland is now split into three glandular zones – the central, transition, and peripheral zones. The neurovascular bundles lie posterolaterally, and contain the branch arteries, veins, and nerves (Fig. 1.2).
1.2.5 The Prostate Some brief details of prostate anatomy are included here as in the male the bladder, particularly functionally, is closely related to this gland. Embryologically, the prostate gland develops from outgrowths of the urogenital sinus and the embryological prostatic urethra.
1.2.6 Gross Anatomy of the Prostate Post puberty, the gland has a volume of up to 25 mL – its size being approximately 3.5 cm long or high, 4.0 cm wide, and 2.5 cm anterior to posterior depth (the
1.2.7 Physiology of the Bladder and Control of Micturition The bladder has a dual physiological role of storage and expulsion, which requires complex interaction between the bladder (or the detrusor muscle), the various continence-maintaining muscular sphincters, and the urethra. All these actions are under the control of finely harmonized and linked neural connections. These are illustrated in Fig. 1.3. Filling of the bladder is facilitated by relaxation of the detrusor muscle. Bladder enlargement excites low-frequency stimulation of the afferent nerve fibers.
6
1 The Normal Bladder
Fig. 1.2 An axial ultrasound view of the bladder and surrounding anatomical structures. The wall of the bladder is indicated by the long arrows. This view was taken with a 3.5-MHz curved array probe. Views of the anterior bladder wall (long vertical arrow) can be improved and internal artefactual shadows (short arrows) reduced by the use of harmonic or pulse inversion techniques. The open arrow indicates the right iliac vessels
Filling
Micturition
Pontine storage centre (Sympathetic/somatic)
Active
Inactive
Pontine micturition centre (Parasympathetic)
Inactive
Active
Volume
±
+++
Detrusor muscle tone (Sympathetic/parasympathetic)
±
–
–
Bibliography
++ + +
+++
–
–
+++
Urethral sphincter tone (Sympathetic/somatic)
+++
+++
_
Pelvic floor tone (Somatic)
+++
+++
_
+
++
–
Urge
This stimulus is transmitted via the spinal cord to the pontine storage center. In turn, the pontine storage center activates the sympathetic and somatic bladder innervation, which relaxes the detrusor muscle, but also contracts the smooth muscle of the bladder neck, urethral muscles, and the pelvic floor. Increasing bladder expansion further reinforces these neural stimuli, and sizable volumes can be stored without urinary leakage. The inherently high bladder compliance means that storage occurs without much increase in intrabladder pressure until distension reaches a critical limit (which varies with age and sex), and the afferent nerve fibers fire at a higher frequency. This is conveyed to the higher centers, and a desire to micturate reaches the higher consciousness. When appropriate (e.g., when in the toilet), the pontine micturition center takes over from the pontine storage center. Sympathetic and somatic signals diminish and the parasympathetic system takes control, inducing detrusor contraction and relaxation of the bladder neck and the pelvic floor, and – most importantly – the active relaxation of the striated muscle of the external sphincter. The bladder empties promptly, unless there is obs truction to the outflow. Thus, it can be seen that although filling and maintenance of continence is an unconscious reflex action, and the urge to empty is also an unconscious action, emptying (and continence) can, to an extent, be consciously controlled through increased contraction of the striated muscled external urethral sphincter.
Fig. 1.3 Illustration of the neural control of bladder filling and micturition
Caldamone AA (2001) Clinical embryology of the urinary tract. In: Weiss RM, George NJR, O’Reilly PH (eds) Compre hensive urology, 1st edn. Mosby International, London, pp 15–30 De Groat WC (1993) Anatomy and physiology of the lower urinary tract. Urol Clin North Am 20:383–401 George NJR (2001) Bladder and urethra: function and dysfunction. In: Weiss RM, George NJR, O’Reilly PH (eds) Comprehensive urology, 1st edn. Mosby International, London, pp 67–80 Gosling JA, Dixon JS (2001) Applied anatomy of the urinary tract. In: Weiss RM, George NJR, O’Reilly PH (eds) Comprehensive urology, 1st edn. Mosby International, London, pp 31–46 Hayes WS (1994) The urinary bladder. In: Davidson AS, Hartman DS (eds) Radiology of the kidney and urinary tract. WB Saunders, Philadelphia, pp 607–610
Bibliography McNeal JE (1968) Regional morphology and pathology of the prostate. Am J Clin Pathol 49:347–357 McNeal JE (1981) The zonal anatomy of the prostate. Prostate 2:35–49. Patel U, Rickards D (2002) Handbook of transrectal ultrasound and biopsy of the prostate. Martin Dunitz, London
7 Waugh A, Grant A (2001) Ross and Wilson anatomy and physiology in health and illness, 9th edn. Churchill Livingstone, London, pp 349–351
2
Imaging Modalities Used for Assessment of the Bladder
2.1 Plain Abdominal Radiograph Prior to the introduction of ultrasound, the plain abdominal radiograph or the radiograph of the kidney, ureter, and bladder (KUB), followed by an intravenous urogram (IVU) or excretory urogram (EU), was the “workhorse” imaging modality of the urinary tract. The KUB also has a long history; one of the very first radiographic diagnoses made was a renal stone. Indeed, a book devoted to the contribution of radiography in the diagnosis and management of urinary tract calculi was published in 1908 by Harry Fenwick, a London-based surgeon. However, the value of the KUB is now increasingly challenged by the explosion in the technical ability of the cross-sectional and computerized modalities such as ultrasound, computerized tomography, and magnetic resonance imaging, although it still maintains a role in certain situations. Its particular value is still in demonstrating the presence or absence of calcification or calculi related to the urogenital tract (Fig. 2.1). For confident imaging, it is important to ensure the entire tract is imaged adequately from the upper poles of kidneys to the bladder base, and further supplementary views may be necessary. Oblique views, views in another phase of respiration, or in plain tomography can all contribute to improved visualization of the renal areas and increase diagnostic confidence. However, additional views, such as oblique views, do not contribute any further to the evaluation of suspected bladder calcification unless they are taken as part of a contrast-enhanced series. On lateral views, the bladder is overlain by the pubic bones. The bones should be scrutinized for congenital vertebral anomalies; for example, widened pubis symphysis seen with bladder exstrophy and destructive bony lesions in adults of appropriate age group indicates malignant or infective bony disease, and a neural cause
Fig. 2.1 A plain radiograph showing layers of calcification within the bladder (short arrows). This proved to be calcified bladder carcinoma. The plain radiograph has the highest sensitivity (after computerized tomography) for identification of calcification within the urinary tract. However, calcification should be differentiated from other causes of pelvic calcification, such as phleboliths (hatched arrow), ovarian or uterine calcification, and calcium in arteries or lymph nodes (open arrow)
for bladder dysfunction (Fig. 2.2). The bladder outline itself is poorly seen, as there is often insufficient surrounding fat around the bladder to confer visibility by virtue of a density gradient, unlike the kidneys and their abundant surrounding retroperitoneal fat.
2.2 Intravenous Urogram (IVU) Intravenous (sometimes also called excretory) urography was first introduced into radiological practice in the early 1900s, although a retrograde pyelogram
U. Patel, Imaging and Urodynamics of the Lower Urinary Tract, DOI: 10.1007/978-1-84882-836-0_2, © Springer-Verlag London Limited 2010
9
10
2 Imaging Modalities Used for Assessment of the Bladder
a
Fig. 2.2 A plain radiograph showing an artificial urethral sphincter (arrowed ). Also note the contrast-filled balloon reservoir of the sphincter (arrowhead ) located at the right of the pelvis
was first performed as early as 1906, very soon after Röentgen’s discovery of the X-ray. The technique of intravenous urography has changed very little over the intervening years. Although it is principally a method for imaging upper tract anatomy, it also gives some indication of bladder anatomy and abnormality. The early images are dedicated to the study of the upper urinary tract, but later views will show gradual opacification of the bladder. Unfortunately, full distension of the bladder takes time, and views are not as informative as those obtained by retrograde cystography. Nevertheless, there are many conditions that can potentially be seen on these “bladder” views, but the study suffers from having large “blind” areas. The anterior and posterior bladder walls are not seen; consequently, the false negative rate is appreciable. Comparative studies in patients presenting with macroscopic hematuria have shown accuracy rates of 26–80% for the diagnosis of bladder cancer, (Fig. 2.3a, b). Consequently, the use of the IVU for imaging of the lower urinary tract is now very limited. It is not indicated for routine bladder imaging.
b
Fig. 2.3 (a) An intravenous urogram (IVU) taken in a patient with hematuria originating from the left kidney. A clot can be seen in the bladder (arrow), and also in the left ureter and renal pelvis (hatched arrow). A clot in the bladder is typically large and smooth in outline, and usually fills the bladder, but the appearances are otherwise nonspecific. (b) An IVU image of the bladder showing a right-sided filling defect (arrow), which proved to be a bladder tumor
2.3 Cystography
11
2.3 Cystography In comparison to the IVU, this equally ancient contrast-based study still retains a central role for evaluation of the lower urinary tract. Cystography is the fluoroscopic study of the well-distended bladder (Fig. 2.4a, b). It is an invasive study that requires instrumentation or catheterization of the urethra or bladder, using an aseptic technique. During this study, the bladder can be evaluated for any areas of thickening (such as trabeculation) or any structural abnormalities (such as a diverticulum). Intravesical or mural abnormalities are seen as filling defects within the pool
a
b
Fig. 2.4 A plain radiograph (a) and accompanying cystogram (b) in a patient with thin mural calcification (arrow) in a patient with schistosomiasis
Fig. 2.5 A bladder view showing the poor resolution for the posterior wall. In this case, there are two posteriorly placed bladder diverticula (starred ). Note that detailed analysis of the internal characteristics of these diverticula is impossible. Ultrasound, CT, or MRI do not have this limitation
of contrast, and stones (or foreign bodies) are recognized by their mobility. Reflux up the ureters, the consequence of either abnormal ureteral insertion, as seen with reflux nephropathy, or the result of widened, incompetent ureteral tunnels as a consequence of longstanding high pressure voiding or after ureteric reimplantation, can be recognized. The study has similar limitations to the IVU in its inability to visualize the whole bladder, particularly the posterior wall (Fig. 2.5). Oblique views are easily carried out with an interactive study such as cystography, but views are still limited, and this limits its value when compared to the cross-sectional modalities such as ultrasound or CT. Lateral views of the bladder are often non-diagnostic, as the pelvic bones degrade the image. Furthermore, there is no information about the surrounding structures, particularly tumors that may have invaded through the wall or any abnormality of the colon, such as diverticular disease and abscess that may have spread to involve the bladder. In practice, there are two areas where contrast cystography is of continuing clinical value: the exclusion of bladder leak, either postoperative or traumatic (though CT is more accurate in this respect, although difficult to interpret at times) and the study of ureteral reflux (although this can also be studied with alternative, nonirradiating/less-irradiating modalities, such as ultrasound or nuclear medicine). A further advantage of the cystogram is that it can be combined with a micturating study to perform cystourethrography. This enhances the ability to identify
12
ureteral reflux, as, in some cases, reflux is only seen during the higher intravesical pressures induced by the voiding reflex. Furthermore, evaluation during voiding provides a “global” view/analysis of the lower urinary tract; for example, the status of the bladder neck can be ascertained.
2.4 Ultrasound 2.4.1 Ultrasound of the Bladder: Technique This is the commonest imaging technique used for the bladder, being simple to use, safe, and very patient-acceptable. A full bladder is essential, but the bladder should not be distended to the extent that the patient has pain. Only in a well-distended bladder can true wall abnormalities be recognized, otherwise apparent focal wall masses or diverticula can be simulated by invaginations of the deflated bladder wall, and conversely true bladder lesions, such as calculi, may be obscured by the non-distended bladder folds. The supine position is adequate, but lateral scanning can help differentiate mobile intravesical abnormalities (such as stones or foreign bodies) from fixed lesions (such as tumors). A 3.5–5-MHz curved array probe is ideal, but the anterior bladder wall is sometimes better seen with higher frequency linear probes. During scanning, a systematic method should be used. First, the organ is scanned axially and note made of any asymmetry of the wall. The normal bladder wall is smooth and thin (the normal wall thickness is quoted as 3–5 mm, and measuring 400 mL Position: Supine (oblique/decubitus in some) Probes: 3.5–5 MHz curved array probe. 7.5–10 MHz may be useful for the anterior wall (±Harmonic/Pulse Inversion imaging) Method: Scan systematically in both axial and longitudinal planes Images: Axial and longitudinal positions Assess: Bladder wall Thickness – normally 1 g/1 h or >8 g/24 h is considered to confirm leakage Simple flowmetry Ultrasound cystodynamogram (USCD) Urodynamics (simple cystometry/pressure – flow studies or videourodynamics)
18 Fig. 2.10 A line drawing of a normal flow curve
2 Imaging Modalities Used for Assessment of the Bladder After scanning the bladder is emptied into a flowmeter, and the following information calculated: • Voided volume (should be > 150 ml) • Maximum flow rate (should be > 15 ml/s) • Average flow rate (should be > 10 ml/s) • Flow pattern • Post-void bladder residue (an empty bladder has < 25 ml) (Note: Voiding parameters are affected by sex, age and the voided volume)
Artefacts: A
B
15ml/s
15ml/s
30s
30s D
C 15ml/s
15ml/s
30s
30s
Notes: A = Initial artefactual spike due to a jet of urine hitting the spinning disc. True maximal flow rate will be lower than calculated by the flowmeter B = Later artefactual spikes due to squeezing of the prepuce resulting in a ‘jet’ hitting the disc C = Wavy profile due to abdominal straining D = Prolonged flow inspite of normal flow rates. This is due to an overfull bladder and is often accompanied by further smaller voids
The age and sex of the patient will influence flow rates, but there are some recognized sources of measurement error. Of these, the amount of voided volume is most important, and a volume of >150 mL should be ensured. In practical terms this means that the patient should be asked to void when they feel their “normal” urge to void. Other sources of error are listed in Fig. 2.10 . In clinical practice it is often necessary to acquire a number of flow recordings on different days to account for artifacts due to straining and the like. Doing so helps to develop a unique reference range for a given patient.
2.11 Ultrasound Cystodynamogram (USCD) This test is an extension of flowmetry, and further enhances the clinical value of flow rates for every day clinical management. By combining flowmetry with bladder ultrasound, additional information is obtained about bladder status and the completeness (or otherwise) of bladder emptying. Information about completeness of bladder emptying is important management information for patients with symptoms such as urinary frequency, pis-en-deux (feeling of
2.12 Urodynamics
19
Table 2.6 The ultrasound cystodynamogram Bladder ultrasound for anatomical information Good bladder distension is important (>200 mL at least) Bladder wall thickness. The normal wall thickness is quoted as 3–5 mm, and it measures 10-15 cmH2O
Normal desire (ND) Strong desire (SD) Urgency (U)
< 250 ml < 250 ml < 250 ml
> 15 cmH2O > 15 cmH2O > 15 cmH2O
Voiding
Flow rate > 15 ml/s
b
Pressure 40-60 to 100 cmH2O
Observations These flow rates apply to primary detrusor instability, when they are often high; but detrusor instability associated with bladder outflow obstruction will result in an obstructive voiding pattern (hatched line). Long-standing detrusor instability may result in detrusor weakness (Figure 8.8). Fluoroscopy may show bladder thickness and trabeculation. Strong contractions may overwhelm the detrusor tone and result in urinary leakage.
8.5 Abnormal Bladder Emptying: Bladder Outflow Obstruction Table 8.4 Incontinence: causes and predisposing factors Loss of pelvic floor support
SUI
Urethral hypermobility (associated with poor pelvic support)
SUI
Intrinsic sphincter deficiency
SUI
Postoperative sphincter damage
SUI
Detrusor instability
UUI
Poor compliance
UUI
Small bladder volume
UUI
Fistula
Continuous leakage
Ectopic ureter
Continuous leakage
Overflow incontinence
Continuous leakage and SUI Note that there is an overlap in symptomatology; and many women with SUI will also complain of “urge” because of the fear of leakage during activity with a full bladder
intra-abdominal pressure. It is believed that those with a strong sphincter, but weakened pelvic floor musculature (sometimes also called urethral hypermobility, but this term is less often used now as it is difficult to define) are able to resist changes up to 100 cm H2O, while women with intrinsic sphincter deficiency will leak at pressures 250 ml > 350 ml Nil Flow rate
Pressure < 15 cmH2O < 15 cmH2O < 15 cmH2O
> 15 ml/s
< 40 cmH2O
Pressure
Observations Volumes (and functional bladder capacity) are reduced because of the fear of leakage. Similarly 'urgency' may be a result of fear of leakage. Abdominal leak pressure < 60 cmH2O seen with intrinsic sphincter deficiency (but this is an area of dispute). Pelvic floor weakness may be seen on fluoroscopy.
c
Fig. 8.5 Stress incontinence. (a) Functional bladder abnormalities seen with genuine stress incontinence (GSI). Filling and voiding pressures are normal, but functional capacity may be apparently reduced because of fear of leakage. Fluoroscopy may be normal, and show pelvic floor descent (see text) or urethral hypermobility. (b) Is an example of GSI with a well-supported pelvic floor, and leakage
d
(arrow) is due to sphincter weakness. (c and d) Are examples of stress incontinence associated with pelvic floor weakness/descent (hatched line is the level of the floor and the arrow points to the leak) and urethral hypermobility (arrow points to the mobile urethra). The last example may be associated with outflow obstruction due to “kinking” of the urethra. ALPP abdominal leak pressure
8.6 Abnormal Bladder Emptying: Poor Sphincter Relaxation Table 8.7 Causes of bladder outflow obstruction Anatomical obstruction Prostatic hypertrophy Prostatic cysts Urethral stricture Bladder or urethral calculi Bladder, prostate or urethral tumor Bladder or urethral compression by pelvic mass Post prostate/bladder surgery Sphincter over-activity Detrusor-sphincter dyssynergia Bladder neck dyssynergia
cancer, or urethral stricture. Beyond the age of 40 years, the prostate hypertrophies, and more than 50% of men above the age of 50 years will have some degree of BPH. By the age of 85 years, over 90% will have BPH. It is estimated that approximately half of all men with histological evidence of BPH will demonstrate some prostate or bladder-specific symptoms. Both the glandular and stromal elements enlarge, particularly in the transition zone and the periurethral glands, but it can uncommonly also affect the peripheral zone. The exact cause is not known, but hormones (testosterone and 5 alpha dihydrotestorone) play a part. Hypertrophy may be diffuse or as distinct adenomas, and there is also hypertrophy of the periurethral muscle spiral. However, simple hypertrophy is not the only pathophysiological mechanism that leads to symptoms. Increased alpha-adrenergic-mediated smooth muscle tone of the prostate and bladder neck are also factors, especially in voiding dysfunction. There is no clear relation between the degree of hypertrophy and outflow obstruction. Some men may present with urinary frequency or nocturia rather than significantly reduced flow rates. Others may present with urgency and incontinence due to secondary detrusor instability. Thus, the entire symptom complex secondary to prostate gland enlargement is now simply referred to as lower urinary tract symptoms or LUTS. As explained above, it is most useful to consider bladder dysfunction in terms of the dominant abnormality, i.e., either abnormal bladder storage or abnormal voiding, or, alternatively, as the dominant symptom or symptoms. Such a functional classification results in a more clinically meaningful approach. For the evaluation of the patient with BPH, the simplest investigation after the IPSS scoring is uroflowmetry or the ultrasound cystodynamogram (USCD). The addition of bladder ultrasound can detect diverticula, any
71
obstructing intravesical mass (e.g., tumor or calculus), bladder wall thickness may be measured, and other signs of high pressure voiding (e.g., wall trabeculation, diverticula, dilated lower ureters) may be detected. Upper tract ultrasound should be especially carried out in those with biochemical evidence of renal dysfunction. Transrectal ultrasound (TRUS) of the prostate has not been proven to add any extra information in the evaluation of the patient presenting with reduced flow rates or LUTS. However, the current EAU guidelines state that prostate size evaluation should be an optional investigation, carried out (preferably by the transrectal route) to determine the prostate size and shape, and should be done for the selection of surgery, prior to minimal-invasive or medical therapy with 5α-reductase inhibitors. Rarely, an obstructing cyst may be seen near the bladder neck on TRUS, acting as a “ball-valve.” The value of TRUS for evaluation of recurrent outflow obstruction after transurethral resection of the prostate has also not been proven. On scanning, regrowth (Fig. 7.4) and restriction of the bladder neck may be seen, but does not directly influence management as much as urinary flowmetry and postvoid residues. Equally, TRUS is not of proven value in the follow-up of the patient on conservative or pharmacological management of known BPH and LUTS. 5α reductase agents can decrease the gland size by approximately 25%, but this information (i.e., the amount of reduction in the volume of the gland) does not directly influence management, though this situation may change in future with more directed chemotherapy for BPH and BPH-associated LUTS. Thus, in most cases presenting with LUTS due to suspected BPH, simple flowmetry with USCD (as shown in Table 2.7) is all that is necessary. However, in patients with indeterminate results or in those thought to have secondary poor or overactive detrusor function, formal urodynamics are of value (Table 8.8). The EAU guidelines recommend it as an optional investigation in some groups of patients. Figure 8.6 summarizes the findings seen on flowmetry and urodynamics in a patient with uncomplicated bladder outflow obstruction.
8.6 Abnormal Bladder Emptying: Poor Sphincter Relaxation A normally functioning micturition arc should ensure relaxation of both the bladder neck and the external urethral sphincter on voluntary initiation of micturition.
72
8 Functional Abnormalities of the Bladder
Relaxation, however, may fail at either of these two levels, resulting in symptoms of outflow obstruction. Detrusor bladder neck dyssynergia may be due to a spinal cord lesion above T5, while detrusor sphincter dyssynergia may be associated with neurological disorders such as Parkinson’s disease or multiple sclerosis. A separate group comprises men 20–40 years of age who present with a long history of poor stream and, on investigation, are found to have features identical with detrusor bladder neck dyssynergia. A congenital abnormality is felt to be the cause. Either of these may be associated with detrusor overactivity or underactivity. Somewhat similar clinical and urodynamic features may be seen in over-anxious men or women with
Table 8.8 Pressure-flow study in those with bladder outflow obstruction Voided volume 15 mL/s LUTS in men >80 years Postvoid residual urine >300 mL Suspicion of neurogenic bladder dysfunction After radical pelvic surgery After unsuccessful invasive BPH treatment It is the only test that can distinguish between bladder outlet obstruction and detrusor hypocontractility and should be done prior to surgery in these cases FLOWMETRY Reduced flows and curves
15 ml/s
30 s URODYNAMICS Normal filling High pressure voiding
FLUOROSCOPY Obstructed urethra Enlarged prostate
100
FILLING Bladder pressure (cmH2O)
100
Abdominal pressure (cmH2O)
100
VOIDING
Detrusor pressure (cmH2O)
60 15 450
Fig. 8.6 Bladder outflow obstruction. Functional abnormalities seen with uncomplicated bladder outflow obstruction (e.g., due to prostate enlargement or urethral stricture; this is an example of prostate enlargement). The diagnostic abnormality is high voiding pressures, reduced flow rates, and abnormal fluoroscopy
250 150
Filling (ml)
Flow (ml/s) ND
SD
15 ml/s
FS SUMMARY
Filling First sensation (FS) Normal desire (ND) Strong desire (SD) Urgency (U) Voiding
Volume > 150 ml > 350 ml > 450 ml Nil Flow rate < 10 ml/s
Pressure < 15 cmH2O < 15 cmH2O < 15 cmH2O Pressure > 60 cmH2O
Observations Bladder residue may be substantial with retention. On fluoroscopy, bladder wall thickess and trabeculation may be seen. On voiding the prostatic urethra is seen to be narrowed. There may be associated bladder overactivity or detrusor weakness, and filling/voiding values will reflect this.
8.7 Detrusor Weakness (or Detrusor Inactivity or Failure)
73
8.7 Detrusor Weakness (or Detrusor Inactivity or Failure)
a nxiety-related failure to completely relax their sphincters. Undoubtedly, the embarrassment of voiding in public during the urodynamics test will contribute, but such patients will characteristically relate that their symptoms are episodic, and are much better when they are removed from their particular anxiety-generating scenario (e.g., symptoms clear while on holiday and away from their job or normal, stressful lifestyle). The functional abnormalities encountered with dyssynergia are illustrated in Fig. 8.7.
Proper voiding requires an active detrusor muscle, such that it can mount a sufficient and sustained detrusor contraction to overcome the urethral resistance to allow prompt and complete voiding. Detrusor weakness, as the name implies, is a poorly active detrusor muscle. This occurs usually after prolonged high detrusor pressures, such as untreated bladder outflow obstruction or bladder overactivity, or with a neuropathic bladder.
FLOWMETRY Reduced flows and curves
15 ml/s
30 s URODYNAMICS Normal filling High pressure voiding
100
100
100
FLUOROSCOPY Narrow bladder neck (top), sphincter (bottom) or urethra
VOIDING
FILLING Bladder pressure (cmH2O)
Abdominal pressure (cmH2O)
Detrusor pressure (cmH2O)
60 15 450
Fig. 8.7 Bladder neck or external sphincter dyssynergia. Functional bladder abnormalities seen with bladder neck or sphincter dyssynergia. On fluoroscopy, either the bladder neck or the external sphincter is seen to be contracted during voiding, which is at high detrusor pressure and low flow rates
250 150
Filling (ml)
Flow (ml/s) ND
SD
15 ml/s
FS SUMMARY
Filling First sensation (FS) Normal desire (ND) Strong desire (SD) Urgency (U) Voiding Vo
Volume > 150 ml > 350 ml > 450 ml Nil Flow rate < 10 ml/s
Pressure < 15 cmH2O < 15 cmH2O < 15 cmH2O Pressure > 60 cmH2O
Observations Appearances are similar to those seen with bladder outflow obstruction caused by prostate enlargement. Fluoroscopy demonstrates obstruction at the level of the bladder neck or the external sphincter. Instability, detrusor weakness or bladder retention may be associated.
74
The common symptoms are a long history of poor stream, with recent deterioration and incomplete emptying. After a long period, when the bladder was able to empty completely, although slowly, by generation of high voiding pressures, the detrusor muscle begins to fail. The patient is left with a large thin-walled bladder. This is the proposed theory to explain the development of detrusor weakness, but is not proven. Others believe that these patients are a subgroup with lifelong voiding dysfunction, over and above their more recent bladder outflow obstruction. This may, perhaps, be a result of developmental abnormality of the detrusor muscle or its nerve supply in earlier life. On simple investigations, the finding is poor urinary flows, with much superimposed abdominal straining and a substantial postvoid residue. Conventional therapy for outflow obstruction, whether pharmacologic or surgical, will have shown no benefit, or will have started to fail, with recurrence of symptoms. Formal urodynamic investigations are diagnostically essential and distinctive functional features are seen (Fig. 8.8), which can be summarized as low pressure, low flow, and incomplete voiding.
8.8 Postprostate Surgery Dysfunction This is considered separately, as there may be a combination of abnormalities. Post-TURP, (or any other form of procedure to relieve outflow obstruction) the man may re-present complaining of no improvement, recurrence of symptoms, or urinary leakage. Simple flowmetry and USCD may help to resolve the problem, and will demonstrate if the fault is continuing obstruction (because of inadequate resection or regrowth of the prostate), or if there is unsuspected detrusor overactivity or weakness. Unfortunately, transrectal ultrasound measurement of the TURP cavity has not been sufficiently well studied to assess the value of this investigation. Available studies do not suggest that is of any value (Table 8.9). Postprostatectomy (total prostatectomy) symptoms can be either leakage or poor stream. Most patients have a degree of leakage immediately after prostatectomy, which improves over the subsequent months. The definition of continence used in various studies naturally has a bearing on the reported postprostatectomy incidence of incontinence. If the definition is “no
8 Functional Abnormalities of the Bladder
protection necessary” (i.e., completely dry, as is commonly understood), then approximately 80% are dry. If the slightly looser definition of “one protection or pad” is used, then the rate improves to around 90%. The main defect is incompetence of the external sphincter, and this is influenced by the quality of apical dissection carried out, whether the neurovascular bundles are spared or not, and whether the puboprostatic ligaments are preserved. Others may complain of restriction of flow rates some months after surgery, and that usually indicates an anastomotic stricture. Stress leakage may also be seen after ablative therapies such as high frequency ultrasound or cryotherapy. Outflow obstruction is more common after prostate radiotherapy. Restricted flow rates will be confirmed by simple flowmetry or USCD, but this will not identify unsuspected detrusor weakness, for which urodynamics is necessary. Fluoroscopy during urodynamics will demonstrate the anastomotic stricture, and exclude an unsuspected urethral stricture. Incontinence is usually stress incontinence alone due to a poor/weak sphincter, but urodynamics may be carried out to exclude covert detrusor instability as the cause of incontinence, and to confirm that it is due to only pure stress incontinence. Videourodynamics may be used to further study leakage, and stress leakage with an abdominal leak pressure 450 ml Nil Flow rate
Pressure < 15 cmH2O < 15 cmH2O < 15 cmH2O
< 10 ml/s
< 40 cmH2O
Pressure
Observations Hardly any rise in detrusor pressure on filling. Post-void residue may be substantial. May be secondary to bladder outflow obstruction. With idiopathic weakness, fluoroscopy shows a large, thin-walled bladder and normal bladder neck/urethra. If secondary to bladder outflow obstruction, the bladder neck/urethra are narrowed.
76 Fig. 8.9 Voiding dysfunction after radical prostatectomy. (a) Functional abnormalities seen after prostatectomy. Voiding may be obstructed or not, depending on whether the anastomosis is strictured (as shown in b). If the sphincter is damaged and weak, fear of incontinence may manifest as apparently reduced functional capacity and leakage may be seen. ALPP abdominal leak pressure
8 Functional Abnormalities of the Bladder
a
FLOWMETRY Normal (or obstructed)
15 ml/s
30 s URODYNAMICS Normal filling Normal voiding, leak or obstructed
VOIDING
100
FILLING Bladder pressure (cmH2O)
100
Abdominal pressure (cmH2O)
100
FLUOROSCOPY Normal (leak or obstructed)
ALPP
Detrusor pressure (cmH2O)
60 15 450 250 150
Filling (ml)
Flow (ml/s) Leak SD ND
15 ml/s
FS SUMMARY
Filling First sensation (FS) Normal desire (ND) Strong desire (SD) Urgency (U) Voiding
b
Volume Pressure > 150 ml < 15 cmH2O < 15 cmH2O > 350 ml < 15 cmH2O > 450 ml Nil Pressure Flow rate < 5 of > 25 ml/s < or > 60 cmH2O
Observations After prostatectomy, bladder symptoms may be due to anastomotic stricture with voiding figures consistent with bladder outflow obstruction, or the sphincter may be weak and features similar to genuine stress weakness (with leak pressure < 60 cmH2O) are seen. Rarely, prostatectomy unmasks detrusor instability.
8.9 The Neuropathic Bladder Table 8.9 Post-TURP evaluation of LUTS Poor stream Continued outflow obstruction Inadequate resection Regrowth of prostate Unsuspected urethral stricture Detrusor weakness
77 Table 8.10 Common urodynamic findings with neuropathic bladder Supraspinal lesion (e.g., CVA) may result in detrusor overactivity; but Parkinson disease may also be associated with a slow relaxation of the sphincters Spinal lesions initially result in detrusor areflexia, followed 6–12 weeks later by detrusor hyperreflexia; and there may be associated bladder neck and/or sphincter dyssynergia
Urinary frequency Bladder sensitivity Bladder calculus Urinary infection
Multiple sclerosis can present with a mixed picture with overactivity, detrusor weakness, and/or dyssynergia
Urinary urgency Unsuspected bladder overactivity
Acute disc prolapse or post pelvic surgery can cause detrusor areflexia
Leakage Unsuspected bladder overactivity Damage to urinary sphincter
Complications of a neuropathic bladder Ureteric reflux and upper tract dilatation (this is more common with poor compliance, and if detrusor pressure is consistently >40 cm H2O) Urinary tract infection Urolithiasis Autonomic dysreflexiaa Lesions of the sympathetic outflow above T6. Bladder distension may result in paroxysmal hypertension, headache, sweating, and bradycardia. May require rapid treatment, as it may lead to subarachnoid hemorrhage a
78 Fig. 8.10 Neuropathic bladder. Functional bladder abnormalities seen with a neuropathic bladder (this example shows detrusor overactivity as well as sphincter dyssynergia, but other combinations are possible)
8 Functional Abnormalities of the Bladder FLOWMETRY Variable (usually low flows)
15 ml/s
30 s URODYNAMICS Variable filling (often high pressures) High or low pressure voiding Bladder may be insensitive
100
FLUOROSCOPY Variable (often narrow bladder neck and sphincter) Thick bladder with reflux VOIDING
FILLING Bladder pressure (cmH2O)
100 Abdominal pressure (cmH2O)
100
Detrusor pressure (cmH2O)
60 15 450 250 150
Filling (ml)
FS
SD
Flow (ml/s) U
15 ml/s
SUMMARY Filling Volume First sensation (FS) Nil, increased or decreased Normal desire (ND) Nil, increased or decreased Strong desire (SD) Nil, increased or decreased Urgency (U) Nil Flow rate Voiding Nil, > or < 15 ml/s
Bibliography Abrams P (1997) Urodynamics, 2nd edn. Springer, London Abrams P, Cardozo L, Fall M et al (2002) The standardization of terminology of lower urinary tract. Neurourol Urodyn 21:167–178 Chapple CR (2000), MacDiarmid urodynamics made easy, 2nd edn. Churchill Livingstone, Edinburgh Mundy AR, Stephenson TP, Wein AJ (eds) (1994) Urodynamics – principles, practice and application, 2nd edn. Churchill Livingstone, Edinburgh
Pressure Observations < or > 15 cmH2O A variety of abnormalities may be seen < or > 15 cmH2O • reduced or absent bladder sensation • detrusor acompliance < or > 15 cmH2O • bladder neck or detrusor dyssynergia
• neurogenic detrusor overactivity On fluoroscopy, bladder may be enlarged
Pressure with a large residual, or thickened and Low or increased shrunken with ureteric reflux
O’Flynn KJ (2001) The neuropathic bladder. In: Weiss RM, George NJR, O’Reilly PH (eds) Comprehensive urology, 1st edn. Mosby International, London, pp 509–520 Saxton HM (1990) Urodynamics: the appropriate modality for the investigation of frequency, urgency, incontinence and voiding difficulties. Radiology 175:307–316 Schafr W, Abrams P, Liao L et al (2002) Good urodynamic practices: uroflowmetry, filling cystometry and pressure-flow studies. Neurourol Urodyn 21:261–274
Part Detection and TheAnalysis Urethra
III
9
The Normal Urethra
9.1 Anatomy of the Urethra 9.1.1 The Male Urethra The male urethra is divided into four parts; from proximal to distal (or internal to external), these are the prostatic, membranous, bulbar, and penile urethra (Fig. 9.1). The prostatic urethra is the most proximal, commencing just below the bladder base and entirely enclosed within the prostate gland. It is also the widest, considerably distensible, and crescentic in outline. The mid portion of the prostatic urethra is also called the verumontanum, where the paired ejaculatory ducts and the prostatic utricle are also located. The utricle is a blind-ending diverticulum that is a remnant of the paramesonephric ducts or the urogenital sinus, which
in the female forms the reproductive tract – some consider the utricle the male homologue of the vagina. The membranous portion commences as the urethra emerges from the prostatic apex, and lies within the perineal membrane (also called the urogenital diaphragm or perineal body). It is the shortest portion (1–2 cm long), encircled by the external urethral sphincter. The levator ani muscles are its lateral relations, the rectum posterior, and the pubis anterior. On emergence from the perineal membrane, the anterior urethra commences. Terminologically, this is also split into the bulbar (that part in the bulb of the corpus spongiosum) and penile (within the pendulous part of the penis) urethra. The bulbourethral, Cowper’s, and paraurethral glands (of Littré) all drain into the bulbar urethra. The most distal part of the penile urethra widens in the navicular fossa, but then again narrows at the urethral meatus.
Anterior Penile { urethra bulbar
Bladder
Posterior Membranous { urethra prostatic
Prostatic urethra VM
Penoscrotal junction
Membranous urethra Symmetrical cone of bulbar urethra
Fig. 9.1 An illustration of the normal anterior urethra as seen on an ascending or anterior urethrogram (compare with Fig. 9.2) U. Patel, Imaging and Urodynamics of the Lower Urinary Tract, DOI: 10.1007/978-1-84882-836-0_9, © Springer-Verlag London Limited 2010
Bulbar urethra Penile urethra
81
82
The entire prostatic urethra is surrounded by variable amounts of circular and longitudinal smooth muscle fibers. Most proximally, they merge with those around the bladder neck. Just below the bladder neck is the preprostatic sphincter, which prevents retrograde ejaculation. Distally (within the perineal membrane), the smooth muscle is separated by connective tissue from the striated muscle of the external sphincter, which is under voluntary control, unlike the bladder neck.
9.2 The Female Urethra This is much shorter at 3–4 cm in length, and lies between the bladder neck and the external urethral meatus. It is less well supported by the pubourethral
9 The Normal Urethra
ligaments, which attach the urethra to the posterior part of the pubis symphysis, and the striated muscle of the external urethral sphincter.
9.3 Radiological Investigation of the Urethra 9.3.1 Contrast Urethrography in the Male The principal method for imaging of the male urethra is contrast urethrography. An ascending urethrogram is dedicated to the ascending urethra (i.e., the penile and bulbar urethra), while the descending urethrogram
Table 9.1 Male Ascending Urethrography (Fig. 9.2) Equipment Fluoroscopic facilities. Ideally, digital imaging with fluoroscopic capture or store facilities. Subtraction imaging is not generally of help Knutson’s clamp or Balloon Foley catheter (8–14F) for distension of the urethra Method The clamp or the balloon catheter is inserted using an aseptic technique. The use of any anesthetic gel interferes with the efficacy of the seal, and is best not used. The discomfort of the procedure can be managed by careful patient explanation and meticulous technique. In particular, the balloon of the Foley catheter (if used) should be distended only within the fossa naviculare until a seal is obtained – approximately 1–2 mL of fluid in the balloon is sufficient. Over-distension should be avoided, as this can traumatize the urethral mucosa The patient rotates his body to the left (about 45°). This movement straightens the urethra such that the full length will be visualized from the tip to the bladder neck. Further views are seldom necessary. The position of the external sphincter is better assessed on frontal views, but the urethra is seen twisted on this view Moderately dilute iodinated contrast is used (200 g of iodine/mL) and 20–50 mL is necessary Contrast is injected slowly to avoid intravasation till the full length of the anterior urethra is seen well distended in profile To inject beyond the external sphincter, maintain a constant mild pressure till the sphincter relaxes and allows flow. It may take up to a minute for the sphincter to relax, but this is preferable because forceful injection is painful, and may lead to contrast intravasation Images are taken when the urethra is well distended and contrast is seen to flow into the bladder. Further patient rotation may be necessary to visualize the true length and position of any stricture If micturition cystourethrography is necessary as well, the bladder is filled by retrograde injection or a catheter is inserted Modifications Hypospadias, meatal stricture – insert a fine feeding catheter (6F) through the narrowing. A seal can be created by tying a ribbon tape around the penis Bladder already catheterized – e.g., postprostatectomy. A 6F feeding tube can be teased adjacent to the catheter. Some gel may be helpful, and ribbon can be used to create a tight seal. The existing catheter may need to be advanced further in, so that its balloon does not obstruct the bladder neck Patient finds procedure too painful – this is rare, but intravenous sedation should be considered Side effects Urinary tract infection. Routine prophylactic antibiotics are not necessary (but see below) Urethral trauma. Avoided by careful technique and gentle injection. Antibiotics may be helpful Intravasation of contrast Contrast allergy, particularly with intravasation
9.4 Contrast Urethrography in the Female
83
Table 9.2 Micturating cystourethrography (Figs. 9.3 and 9.4) Equipment Fluoroscopic facilities. Ideally, digital imaging with fluoroscopic capture or store facilities. Rotating C-arm is helpful Bladder catheter Methods Patient is catheterized, using an aseptic technique. Routine prophylactic antibiotics are unnecessary Using a moderately dilute iodinated contrast medium, the bladder is filled gently. Either use syringes to fill or gravity filling Fill till well distended. Between 400 and 500 mL should be used, if tolerated, as patient may not be able to micturate with lesser volumes Intermittent fluoroscopy is used if bladder trauma is suspected, and filling stopped at the first sign of extravasation. The C-arm should be rotated so that the bladder is examined in multiple projections. This is also necessary to visualize the lower ureters for reflux Once the bladder is full, spot films are taken in the anterior-posterior projection and either oblique projection The table is elevated. The patient stands on the platform at 30–45° rotation to see the urethra in profile during micturition. Men use a urinary bottle and women an appropriately designed funnel, which is gripped by the thighs over the vaginal opening. Urinary flow rates can be measured at the same time (with corrections). Stress incontinence can be tested by asking patient to cough during fluoroscopy. Pelvic floor descent can also be assessed Micturition commences. Fluoroscopy is used and spot films taken. The lower ureters should also be assessed Postmicturition residue can be estimated Side effects Urinary tract infection. Over-zealous distension can lead to bacteremia Bladder trauma Hematuria. This is usually mild, but antibiotics should be considered
evaluates the posterior urethra (the prostatic and membranous urethra). The essential requisite for either study is adequate distension of the urethra. For the ascending urethrogram, the anterior urethra is distended using either a Knutson’s clamp or a Foley urethral catheter. The technique is described in Table 9.1. Once fully distended with contrast medium, oblique images will show the full length of urethra from the navicular fossa to the external urethral sphincter, and can be assessed for strictures and mucosal lesions. Contrast urethrography is currently indispensable for evaluation of trauma to the lower urinary tract. To study the descending or the posterior urethra, good distension can only be achieved by asking the man to micturate after the bladder has been well distended with contrast media (Table 9.2). A micturating or descending urethrogram combined with an anterior urethrogram will demonstrate the integrity or otherwise of the entire urethra and distended bladder. On first presentation with urethral disease, a complete baseline – i.e., both an ascending and descending (Figs. 9.2 and 9.3) study – is important, but for further follow-up only an ascending or descending study, or even ultrasound urethrography (below), are appropriate.
Fig. 9.2 A normal ascending or anterior urethra (Pe penile urethra; B bulbar urethra; M membranous urethra; Pr prostatic urethra; thin arrow Cowper’s gland duct; thick arrow persistent utricle)
9.4 Contrast Urethrography in the Female The female urethra is much less prone to disease, and there is no ideal imaging method. Ultrasound (either transvaginal or transrectal), micturating cystography, and MRI can all help. The traditional and the easiest
84
9 The Normal Urethra
catheter. With this device, both the bladder neck and the urethral orifice can be occluded by the two balloons, and contrast is injected into the short female urethra. Better distension is achieved. Others have used just the rubber bung of the Knutson’s device or a hysterosalpingogram catheter to achieve a satisfactory seal for good retrograde distension.
9.5 Ultrasound of the Urethra
Fig. 9.3 A normal descending urethrogram. (Pe penile urethra; B bulbar urethra; M membranous urethra; Pr prostatic urethra; thick arrow verumontanum)
Although, in theory, the urethra should be well seen on ultrasound, in practice the examination is not straightforward; first, because the posterior urethra in the male is partly covered by the interference from the pubic muscles, and second, because distension is required, which can be achieved in the male but, of course, not in the female. However, it does provide the opportunity to scrutinize the paraurethral soft tissues as well, unlike traditional contrast urethrography.
9.6 Ultrasound Urethrography in the Male
Fig. 9.4 A micturating cystogram in a woman, showing the normal female urethra (arrow)
method is the micturating cystourethrogram, but, as in the male, this requires catherization and exposes the gonads to ionizing radiation. The weakness of this study is that it is not sufficiently reliable to exclude a female urethral diverticulum (Fig. 9.4); in fact, no imaging modality performs well in this area. The difficulty lies in achieving good urethral distension, as inhibition on the part of the woman inevitably means that the bladder neck is not fully open and urinary flow is poor. This is made further difficult by the standing position necessary during this study. To overcome this limitation, a retrograde or ascending study would be necessary, but this is very difficult in the woman because of the short urethra. One method of retrograde female urethrography is with the use of a double-balloon female urethral
In the male, a superficial probe, such as 7.5–12 MHz linear array probe, is used. The most convenient method is to distend the urethra using either a Knutson’s clamp or a Foley catheter with the balloon distended in the navicular fossa. The urethra is distended using saline. An alternative distension agent is the use of lignocaine gel or ultrasound gel, which can be made more transonic by initial agitation with air. An alternative would be the use of ultrasound contrast media, but, unlike saline, all these other agents may obscure intraurethral bodies/calculi. In practical terms, saline is the best agent. An alternative method is self-distension. After the urethral catheter has been inserted and the balloon has been inflated, as used by some, the patient is asked to void against the balloon of the catheter, by which self-distension of the entire urethra is produced. However, some men may be unable to void because of inhibition. Another described technique for self-distension is to ask the man to pinch and occlude the urethral tip with one hand, and then to void against this occlusion. Proponents of this technique state that good distension can be achieved.
9.7 Ultrasound Urethrography in the Female
Fig. 9.5 A normal ultrasound urethrogram showing a normal smooth urethral outline (arrowheads). This study is carried out after distension of the urethra with saline, using a flat array ultrasound probe (see text). Only the anterior urethra can be well seen by this method. Thus, unlike contrast urethrography, an ultrasound urethrogram is not a global study of the urethra
Once the urethra has been distended, it is scanned in the transverse and longitudinal planes. Note is made of the smoothness of the urethral mucosal lining, and discrepancies noted and carefully examined. Both strictures and subtle wall irregularities of the anterior urethra are readily seen (Fig. 9.5). The ability to visualize the stricture as well as the corresponding surrounding wall thickness or “(presumed) inflammatory” change is an advantage of this technique over contrast urethrography. Whether this additional information is of any clear advantage and helps in the selection of appropriate stricture therapy has not been proven. In theory, the knowledge that a given stricture has significant associated abnormal but unstrictured mucosa may indicate that a longer length of urethroplasty is necessary, and that surgery rather than optical urethrotomy is needed. However, controlled data on this aspect are lacking. The superiority of ultrasound over contrast urethrography is not yet proven. The urethra can be scanned easily up to the membranous urethra, using longitudinal scanning, but the posterior urethra will be insufficiently visualized. To better visualize the posterior urethra, either transperineal scanning with a 3.5–5-MHz curved array probe or a transrectal probe (Fig. 9.6) can be used. Distension of the posterior urethra is only well achieved by asking the man to void. Overall posterior ultrasound urethrography is much less reliable than micturating or descending contrast urethrography.
85
Fig. 9.6 This view is an ultrasound study of the posterior urethra (thick arrow is the bladder neck, thin arrow is the prostatic urethra). To study the posterior urethra by ultrasound, scanning needs to be carried out via the transperineal or transrectal route
To summarize, ultrasound urethrography is a suitable technique for visualizing the male anterior urethra, being as good as ascending contrast urethrography in published series. Whether it is better remains to be proven. It, of course, has the advantage of avoiding ionizing radiation – an important consideration, as most urethral stricture disease occurs in the young, and the testes are in the direct line of the radiation beam with contrast urethrography. Its disadvantages are that it is possibly more cumbersome, particularly if the self-voiding technique is used for distension, global studies of the urethra (i.e., both the anterior and posterior urethra) are less easily obtained (and possibly the posterior urethral views less reliable), and that it is not suitable for the assessment of early urethral trauma. As yet, ultrasound urethrography cannot replace contrast urethrography, but should be seriously considered as a follow-up option in the man with known anterior urethral stricture.
9.7 Ultrasound Urethrography in the Female This is much less convenient than the comparable study, which is micturating cystourethrography, as the transrectal or transvaginal route is necessary during the
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9 The Normal Urethra
Table 9.3 Magnetic resonance imaging of the urethra Preprocedure
Pelvic surface coil is used In the male, the penis is taped in the midline to the anterior abdominal wall. Urethral distension is achieved (the balloon of the catheter is inflated in the fossa naviculare and the urethra distended with saline injection) Nondistended studies in the female
Procedure
Small field of view Thin section (3–5 mm) acquisitions Male and female patients T1 and T2 axial T1 and T2 sagittal Other sequences useful Postcontrast T1 (axial and sagittal) In the male, posterection studies are useful (using prostaglandin injection) Inversion recovery sequences
voiding phase. Nonvoiding studies can be carried out using transperineal (or labial) curved array ultrasonography, but evaluation is difficult. One area, however, where ultrasound may be of particular value is in the evaluation for a urethral diverticulum. This abnormality is notoriously difficult to exclude, but sometimes the diverticulum can be easily seen on ultrasound at rest, and any contained calculus will be seen.
9.8 Other Imaging Modalities Of the other imaging modalities, MRI has the potential to provide significant additional information compared to contrast or ultrasound urethrography, but it has not been fully exploited. This is because distension is difficult to achieve and maintain within the small bore of the MRI machine. The technical details are given in Table 9.3. Currently, it is mostly used for the staging of urethral and penile cancers, and for the evaluation of suspected female urethral diverticulum.
Bibliography Bearcroft PWP, Berman LH (1994) Sonography in the evaluation of the male anterior urethra. Clin Radiol 49:621–626 Caldamone AA (2001) Clinical embryology of the urinary tract. In: Weiss RM, George NJR, O’Reilly PH (eds) Comprehensive urology, 1st edn. Mosby International, London, pp 15–30 De Groat WC (1993) Anatomy and physiology of the lower urinary tract. Urol Clin North Am 20:383–401 Gosling JA, Dixon JS (2001) Applied anatomy of the urinary tract. In: Weiss RM, George NJR, O’Reilly PH (eds) Comprehensive urology, 1st edn. Mosby International, London, pp 31–46 McAnich JW, Laing FC, Jeffrey RB (1988) Sonourethrography in the evaluation of urethral strictures: a preliminary report. J Urol 139:294–297 McCallum RW (1979) The adult male urethra: normal anatomy, pathology and method of urethrography. Radiol Clin North Am 17:227 Neitlich JD, Foster HE, Glickman MG, Smith RC (1998) Detection of urethral diverticula in women: Comparison of a high resolution spin echo technique with double balloon urethrography. J Urol 159:408–410 Patel U, Lees WR (1995) Penile sonography. In: Solbiatti L, Rizzatto G (eds) Ultrasound of superficial structures. Churchill Livingstone, London Ryu JA, Kim B (2001) MR Imaging of the male and female urethra. Radiographics 21:1169–1185
Congenital Anomalies of the Urethra
10
10.1 Posterior Urethral Valves Although usually diagnosed in childhood, they can occasionally present in adult life. The cause is unknown, and they may be classified anatomically (type 1–3) or according to the degree of upper tract dilatation (mild, moderate, or severe). Presentation is usually with symptoms of bladder outflow obstruction, but other described symptoms are recurrent infections, infertility, perineal pain, and postejaculatory dysuria. Anterior urethral valves are especially rare, and also most commonly recognized in children. These are found anywhere along the length of the urethra, with no particular preponderance. They may present in adulthood with symptoms of bladder outflow obstruction. Diagnosis rests on the findings of a dilated posterior urethra on micturating cystourethrography (ureteric reflux may also be seen in approximately 50%). The valve is seen as a filling defect just above the point of transition between a dilated posterior urethra and a normal or attenuated anterior urethra (Fig. 10.1). Oblique views are important, and the filling catheter should be removed, as it may compress the flap and render it nonvisible. Sonography can also be used to diagnose valves, either by the transabdominal or transperineal route. In the adult, TRUS can also be used. Ascending urethrography, however, will not always show the valve, as it can be flattened by the jet of contrast.
10.2 Urethral Duplication This is a rare anomaly, and may be partial or complete (Fig. 10.2). A blind duplicated urethra may also occur
Fig. 10.1 A micturating cystogram showing a posterior urethral valve (arrow) resulting in outflow obstruction
(Fig. 10.3) and, rarely, there may also be a duplicated bladder. One system of classification divides this entity into three subgroups: Type 1 being incomplete urethral duplication, Type 2 representing complete urethral duplication with either 1 or 2 meatus, and Type 3, which signifies urethral duplication as a component of caudal duplication. In the largest available study of 16 cases, four cases had a blind ending duplicated urethra, six cases had totally duplicated urethras with separate bladder necks, but a single bladder, a further four cases had duplicated urethras originating from a single bladder neck, and the final two cases had the most complete duplication, with separate urethras draining duplicated and entirely separate bladders. Multimodality imaging is recommended. Diagnosis is best demonstrated by thorough ascending and descending urethrography; this may require catherization of both urethras. MRI studies
U. Patel, Imaging and Urodynamics of the Lower Urinary Tract, DOI: 10.1007/978-1-84882-836-0_10, © Springer-Verlag London Limited 2010
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10 Congenital Anomalies of the Urethra
Fig. 10.3 A partly duplicated anterior urethra
Fig. 10.2 A partly duplicated urethra lies posteriorly (thick arrow). The “normal” urethra (thin arrow) has a stricture, and a bladder diverticulum is also present (open arrow)
should also be helpful, although not many such studies have been described.
The catheter is manipulated past the narrowed meatus and good distended views are possible, although further occlusion can be achieved by pinching the bulb of the penis (this can be achieved by tying a length of ribbon gauze around the distal penis). A micturating study is also useful, as the full length of the urethra will be demonstrated (Fig. 10.4). Congenital urethral stenosis is also uncommon, and occurs at the junction of the posterior and anterior urethras. Its cause is not known. A true congenital urethral stenosis can also occur, presenting as a localized narrowing just below the external sphincter, in the junction between the anterior and posterior urethra. Much less commonly, it may present along other parts of the urethra.
10.3 Congenital Meatal or Urethral Stenosis The meatus may be pinpoint in caliber from birth, but this anomaly is much less common than acquired meatal stenosis. Meatal stenosis may be associated with hypospadias, but it may also occur as a complication of circumcision. If radiological evaluation is required, (e.g., to assess the length of the stenosis and to exclude any further unsuspected urethral strictures), then ascending urethrography is best carried out by a small gauge catheter, for instance, a 6–8F feeding catheter or a small pediatric Foley bladder catheter.
10.4 Hypospadias In this condition, the urethral meatus opens onto the ventral aspect of the penis or the perineum, and there may also be a ventral curvature. Other associations are undescended testicles, inguinal hernia, urinary tract anomalies (duplication, PUJ obstruction), imperforate anus, and Müllerian duct remnants. There may be an associated meatal stenosis, as explained above.
10.7 Cowper’s Duct Cyst or Diverticulum, or A Syringocele
89
Fig. 10.5 Partial megalourethra of the bulbar urethra (arrow) Fig. 10.4 A micturating cystogram demonstrating meatal stenosis (arrow)
10.6 Urethral Diverticulum 10.5 Megalourethra In this curious condition, both the urethra and the corpus spongiosum are maldeveloped. The urethra is massively dilated, and may involve the whole anterior urethra because the entire spongiosum is maldeveloped, or be localized secondary to a focal defect in the spongiosum. The more severe variety is less common, and usually associated with other severe maldevelopments, such as when both the corpus spongiosum and cavernosa are underdeveloped. The less common localized megalourethra (Fig. 10.5) (sometimes called the scaphoid megalourethra) may also present with upper urinary tract anomalies and the prune belly syndrome. The scaphoid magalourethra is also called anterior urethral diverticulum by some.
In the existing literature, it is not clear whether the urethral diverticulum and megalourethra are truly separate entities. A diverticulum is believed to develop as a result of maldevelopment of the corpus spongiosum, and it is said that the diverticulum may be associated with a lip like “anterior urethral valve” that may be obstructive during voiding studies.
10.7 Cowper’s Duct Cyst or Diverticulum, or A Syringocele The Cowper’s ducts are periurethral glands, and are accessory sex glands that help to lubricate the semen. They are located in the membranous or the bulbar urethra, and their ducts open, as separate units or singly,
90
a
10 Congenital Anomalies of the Urethra
b
c
Fig. 10.6 Images demonstrating the urethrographic (indentation of the ventral surface of the anterior urethra, (a), sonographic (b), and T2-weighted MRI (c) appearances of a Cowper’s duct cyst (arrowed )
into the proximal bulbar urethra. The commonest anomaly is the Cowper’s duct cyst or diverticulum, which is sometimes termed a syringocele. It is a retention cyst, is believed to be a congenital abnormality, and usually presents in childhood, but in the occasional case may be first encountered in the adult male (Fig. 10.6a–c). It is postulated that the adult Cowper’s duct cyst is the result
of postinflammatory stricturing of the duct, either the result of infection or instrumentation. The underlying fault is obstruction of the duct of the Cowper’s gland, which results in cystic dilatation. It may be an incidental finding, or it may present with urinary infections, obstructed voiding, postmicturition dribbling, or lower urinary tract symptoms (frequency, urgency).
Bibliography
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(Fig. 10.6c). It may (Fig. 10.7) or may nor communicate (Fig. 10.6a) with the urethra. Communication may be spontaneous or the result of previous instrumentation/ surgery.
Bibliography
Fig. 10.7 A urethrogram showing a communicating Cowper’s duct cyst (the arrowhead points to the cyst; the long arrow indicates the posterior urethra and the short arrow a compressed bulbar urethra)
Characteristically, it is seen as a smooth indentation of the ventral surface of the anterior urethra on contrast urethrography, but may be recognized on ultrasound or MRI as a thin-walled, high T2 signal cystic structure
Appel RA, Kaplan GW, Broc WA, Streit D (1986) Megalourethra. J Urol 135:747 Berrocal T, Lopez-Pereira P, Arjonilla A, Gutierrez J (2002) Anomalies of the distal ureter, bladder and urethra in children: embryologic, radiologic and pathologic features. Radiographics 22:1139–1164 Effman EL, Lebowitz RL, Colodny AH (1976) Duplication of the urethra. Radiology 119:179 Gonzales ET (1992) Posterior urethral valves and other urethral anomalies. In: Walsh PC, Retik AB, Stamey TA, Vaughan ED (eds) Campbell’s urology, 6th edn. WB Saunders, Philadelphia, pp 1872–1892 Kirks DR, Grossman H (1981) Congenital saccular anterior urethral diverticulum. Radiology 140:367 Macpherson RI, Leithiser RE, Gordon L, Turner WR (1986) Posterior urethral valves: an update and review. Radiographics 6:753 Merchant SA, Amonkar PP, Patil JA (1997) Imperforate syringocoeles of the bulbourethral duct: appearance on urethrography, sonography and CT. AJR Am J Roentgenol 169: 823–824
Intraluminal Abnormalities and Filling Defects of the Urethra
Intraluminal or mucosal abnormalities of the urethra are best appreciated during well-distended contrast or ultrasound urethrography. With its superior contrast and tissue resolution, MRI should be especially informative, but has not yet been well described. Overall, they are uncommon findings compared to urethral strictures or traumatic abnormalities, but some of these abnormalities, in particular calculi, may occur in common with stricture disease. Table 11.1 lists the causes of filling defects seen on urethrography.
11.1 Calculi Stones can form in situ within the urethra, or migrate down from the upper urinary tract or bladder. Passage of stones is usually only a temporary event, as the stone is evacuated naturally unless there is a structural abnormality present, such as a stricture or a diverticulum that prevents stone expulsion. “Primary” urethral calculi usually form as a result of an underlying urethral abnormality. Examples are stricture, diverticulum, prior urethroplasty with an area of redundancy, or secondary diverticulum. Occasionally, after urethroplasty using a flap of hair-bearing skin, hair follicles overgrow into a hairball that may calcify. Secondary calculi migrate down from the bladder, are more common, and may present acutely with obstruction. In comparison, primary calculi present with chronic symptoms, such as urethral bleeding or infections. Both types may be seen on a precontrast radiograph, but they are usually only faintly opaque and easily missed. On ascending urethrography, they may be easily overlooked or mistaken for air bubbles,
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because they are small and poorly opaque (Fig. 11.1). All urethrograms that show a diverticulum or stricture should be carefully evaluated for missed calculi. Naturally, the value of a precontrast control radiograph cannot be overstated. Stones are much more readily appreciated on ultrasound urethrography as a typical shadow-casting, high reflectile object.
11.2 Foreign Bodies A plethora of intraurethral (and intravesical) foreign bodies have been described in the literature. They are almost all self-inserted and, beyond marveling at the imaginative variety of the objects chosen, there is little more to say on this subject. Most are radiopaque and obvious on plain radiographs (Figs. 11.2 and 11.3). Small objects, however, may have been forgotten, and may be encountered on later urethrography, either as a filling defect or as a formed calculus.
11.3 Hair Balls These are much less commonly seen now, but they first came to general notice after a vogue for urethroplasty using myo-fascial flaps for urethral surgery and reconstruction. Once shed, the retained hair follicles of the epidermis built up into a foreign body that may eventually have calcified. They are sometimes referred to as urethral bezoars, but, strictly speaking, the latter term refers to objects of similar origin found within the alimentary tract.
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Table 11.1 Filling defects in the urethra Calculi Foreign body Bezoar or hair ball Blood clot Posterior urethral valve Congenital urethral polyp Acquired urethral polyp Ureterocele Urethritis cystica Neoplastic Fig. 11.2 Foreign bodies (wire material ) in the anterior urethra
a
b
Fig. 11.3 Another example of foreign bodies (wire material ) in the anterior urethra and bladder
11.4 Polyps of the Male Urethra
Fig. 11.1 Two urethrographic images showing urethral calculi (thick arrow). (b) Also shows a membranous stricture posttrauma (thin arrow)
These are usually congenital polyps, most commonly seen in the posterior urethra, and often referred to as fibroepithelial polyps, although some are of prostatic origin. Polyps of the anterior urethra are also rare, but may be due to inverted papilloma, transitional cell cancer, or squamous cell papilloma (dealt with in the last chapter). They are distinct from adenomas or areas of regrowth of the prostate post-TURP that may be seen on urethrography (Fig. 11.4). At both sites, conventional urethral polyps are histologically benign, and covered with transitional epithelium, occasionally with areas of squamous metaplasia. They usually present in childhood with
Bibliography
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obstructive symptoms, because the polyp is usually on a long stalk and acts as a ball valve, obstructing urine flow during micturition. The obstruction may be severe and prolonged, such that there may be associated features of long-standing high-pressure voiding with bladder trabeculation or retention, hydroureter, and hydronephrosis. Occasionally, presentation may be delayed to adulthood. The diagnosis is usually made on ascending or descending urethrography. The stalk of the polyp may be long, and the polyp may protrude into the bladder and be seen as an intravesical filling defect. This can mimic an ureterocele on contrast studies, but is easily differentiated on ultrasound, as a polyp is seen to be a solid structure unlike the transonic, cystic appearance of an ureterocele.
Bibliography
Fig. 11.4 A retrograde urethrogram showing a bulbar stricture (arrowhead ), and a prostatic adenoma/regrowth within the posterior urethra (arrow )
Kimche D, Lask D (1982) Congenital polyp of the prostatic urethra. J Urol 127:134 McCallum RW (1979) The adult male urethra: normal anatomy, pathology and method of urethrography. Radiol Clin North Am 17:227 Peterson RO, Sesterhenn IA, Davis CJ (2008) Urologic pathology, 3rd edn. Lipincott Williams and Wilkins, New York
Intrinsic Abnormalities of the Urethral Wall
12.1 Urethritis Inflammation of the urethral mucosa is very common, but most cases are easily treated and do not come to radiological attention. The three main causes are uncomplicated gonococcal urethritis, chalmydia trachomatis infection, and other nonspecific types of urethritis, due to ureaplasma urealyticum, trichomas vaginalis, and (rarely) herpes simplex virus. Some further simplify the classification into either gonococcal or nongonococcal urethritis. Another common cause is posttraumatic urethritis, for example after instrumentation or post urethral catherization, especially after the use of latex-based catheters. All these conditions seldom present for imaging, but if imaging is carried out in the acute stage, a subtle irregularity is seen related to the anterior urethra. An example is shown in Fig. 12.2. More chronic cases result in urethral strictures.
12.2 Urethral Strictures The majority of urethral strictures occur in the anterior male urethra. Stricture of the female urethra is uncommon, and more usually the result of mobility and kinking of the urethra rather than as a result of fibrosis – the so-called urethral hypermobility described in Chap. 8. This is an example of a “functional” stricture of the urethra. Table 12.1 lists the various other causes of urethral strictures encountered in current practice. Irrespective of the cause of the urethral stricture, on imaging, certain general rules apply, all of which are directed at providing appropriate information to guide the management of the patient, rather than to specifically diagnose the underlying cause. Indeed, the cause may always remain obscure in a given patient. The
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most important information for guiding treatment is to accurately locate the site of the stricture, the length of the stricture (Figs. 12.1 and 12.2), and the proximity of the stricture to the external urethral sphincter. A one-stage imaging pathway that can provide all this information is important. Conventionally, an ascending and descending cystourethrogram is chosen, and is ideally suited for this purpose. The exact location and length of the stricture is seen, particularly on oblique views (Figs. 12.2 and 12.3). A thickened trabeculated bladder is an indirect indication of high pressure voiding, and ureteral reflux with hydronephrosis may be seen. Finally, any incomplete bladder emptying with a postvoid residue is seen on micturition studies. Further important information is the presence of urethral diverticula, false passages, stones (Fig. 11.1b), and abscesses. Analysis of the outline of the nonstrictured urethra around the narrowing will demonstrate if the extent of diseased mucosa is longer than suspected from the narrowed area alone. This is better visualized on ultrasound urethrography. However, the value of diagnosing such ultrasonographically defined unhealthy mucosa (Fig. 12.4a, b) has not been proven. Of course, the purpose of this information is to provide information to help the surgeon guide management. Unfortunately, at the time of writing there is no clear consensus as to the best treatment for urethral strictures. In general terms, anterior urethral strictures 2 mm between the prostatic apex and the urogenital diaphragm is seen with Type 1 injuries. Types 2 and 3 may be distinguished by contrast extravasation above and below the urogenital diaphragm, respectively. However, the experience with CT is still not sufficient, and it cannot replace contrast urethrography. MRI is seldom carried out in the acute phase, and ultrasound urethrography is not sufficiently well evaluated to recommend as yet. The above relates to imaging in the acute situation. For later imaging prior to delayed urethral reconstruction, contrast urethrography is again the investigation of choice. If there is discontinuity of the urethra, then simultaneous ascending and descending studies (the latter carried out by using a suprapubic catheter to fill the bladder) or the so-called “up and downogram” will show the length of the defect to best advantage (Fig. 13.5). MRI has also been used for delayed evaluation of urethral trauma, and can show the length of the defect just as accurately, as well as the status of the surrounding tissues (Fig. 13.5a, b). This was demonstrated in a recent study. The authors further reported that MR urethrography more accurately depicted the length of urethral distraction when compared to conventional urethrography.
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a
d
13 Lower Urinary Tract Trauma
b
c
e
f
Fig. 13.3 A photomontage of the various grades of urethral injuries. (a) Shows a type 1 injury, and the arrows demonstrate the stretched prostatic urethra with no urethral leak. Image (b) and (c) are an example of type 2 injures (disruption of the posterior urethra above the urogenital diaphragm). (d) Shows an
ascending (top) and descending study (bottom) with a grade 3 injury (tear of both anterior and posterior urethra with disruption of the urogenital diaphragm). (e) Is a grade 4 injury (injury of the bladder base) and (f) is an injury of the anterior urethra or a grade 5 injury
13.4 Injury of the Female Urethra
to suggest under-diagnosis. When it occurs, the injuries are severe, and they often have associated rectal and vaginal injuries. Diagnosis is difficult, and micturating cystourethrography is probably of most use. Retrograde urethrography may be feasible, and if a specialized double-balloon catheter is not available, then positive
Because of its shorter length, higher elasticity, and the absence of any substantial ligamentous attachments to the pubic bones, the female urethra is uncommonly injured during blunt trauma, although there is evidence
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a
Fig. 13.4 Another example of an anterior urethral or grade 5 injury
pressure injection using a hysterosalpingogram catheter may be attempted. However, some have suggested that vaginoscopy and urethroscopy can be helpful. Other more common causes of injury to the female urethra are instrumentation, vaginal surgery, and obstetric complications.
b
Bibliography Ali M, Safriel Y, Sciafani SJA, Schulze R (2002) CT signs of urethral injury. Radiographics 23:951 Ali M, Safriel Y, Sclafani SJA, Schulze R (2003) CT signs of urethral injury. Radiographics 23:951–966 Chapple CR (2000) Urethral injury. BJU Intern 86:318–326 Goldman SM, Sandler CM, Corriere JN, McGuire EJ (1997) Blunt urethral trauma a unified, anatomical mechanical classification. J Urol 157:85–89 Gomez RG, Ceballos L, Coburn M et al (2004) Consensus statement on bladder injuries. BJU Intern 94:27–32 Hartanto VH, Nitti VW (2003) Recent advances in the management of female lower urinary tract trauma. Curr Opin Urol 13:279–284 Ingram MD, Watson SG, Skippage PL, Patel U (2008) Urethral injuries after pelvic trauma: evaluation with urethrography. Radiographics 28(6):1631–1643 Sung DJ, Kim YH, Cho SB, Oh YW, Lee NJ, Kim JH, Chung KB, Moon DG, Kim JJ (2006) Obliterative urethral stricture: MR urethrography vs. conventional retrograde urethrography with voiding cystourethrography. Radiology 240:842–848 Vaccoro JP, Brody JM (2000) CT cystography in the evaluation of major bladder trauma. Radiographics 20:1373–1381
Figs. 13.5 A simultaneous ascending and descending contrast study (a) with MRI correlation (b). MRI can be potentially more informative than the contrast study, as it also demonstrates the surrounding structures. The arrow points to the extraperitoneal leak from the bladder base, but the MRI shows that the injury extends into the urethra (the thick arrow in (b) points to the disrupted prostatic urethra, and the thin arrow indicates the prostate gland) conforming that this is a type 4 injury. However, so far MRI has not been proven to be superior to contrast urethrography, and is a difficult study to carry out immediately after trauma
Neoplasms of the Urethra
These may be encountered as filling defects on urethrography or strictures, but whether benign or malignant, both are rare findings. They account for much less than 1% of all reported malignancies. Table 14.1 lists the various types of urethral tumors that may be seen.
14.1 Benign Tumors The commonest benign tumor of the anterior or posterior urethra is the urethral polyp, as discussed in Chap. 11. Sometimes also called the fibrous urethral polyp, it presents with obstructive symptoms, and is seen as a smooth, mobile filling defect. Of the rest, rare cases of hemangioma or leiomyoma have been described, with no particular distinguishing features, but MRI has the potential to be diagnostically discriminating in these situations.
14.2 Urethral Carcinoma Much less than 1% of all urinary tract cancers occur within the urethra, but they are more common in males (by a ratio of 7:3), with a peak age of onset in the seventh decade. Nearly 80% are squamous cell carcinoma, some 15% are of transitional cell origin, and the rest are adenocarcinoma. In the male, the commonest site is the anterior urethra, and of these, most occur in the bulbar urethra (60% in bulbomembranous urethra, 30% in penile urethra, 10% within prostatic urethra).
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Of the recognized risk factors, there may be history of venereal disease in a third, a history of urethral stricture in a further third, and 5–7% may report a history of urethral trauma. Adenocarcinomas arise in the glands of Littré or Cowper’s gland. Transitional cell urethral cancer is an association of bladder TCC – up to 10% of patients who undergo cystectomy for bladder TCC may later develop urethral TCC, and it is standard practice in some centers for such patients to undergo prophylactic urethral resection. Presentation may be with obstructive symptoms, a palpable mass, a periurethral abscess, or fistula. Diagnosis is often delayed, and 50% have metastatic disease at presentation. On urethrography, a long, narrow, irregular stricture is seen (Figs. 14.1 and 14.2). A filling defect or mass lesion is a less common appearance, and this is more often seen with benign lesions such as a polyp. Sometimes, urethral carcinoma presents as a change in appearance of a known or longstanding urethral stricture, or as a new stricture occurrence after previous urethroplasty. In the female, squamous cell urethral carcinoma occurs in 60%, transitional cell carcinoma in 20%, but adenocarcinomas and undifferentiated tumors are more common at 20%. They may occur within a female urethral diverticulum. Most squamous cell tumors occur in the distal third of the urethra, while the other cell types are more common in the proximal urethra. Presentation is usually with a bleeding urethral mass, best assessed with cross-sectional imaging, particularly MRI. Radiological staging of both male and female urethral cancers is best carried by MRI, as well (Fig. 14.3). The TNM staging system is given in Table 14.2, and further illustrated in Figs. 14.4–14.7.
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Table 14.1 Tumors of the urethra Benign Benign prostatic epithelial polyp Hemangioma Leiomyoma Malignant Squamous cell carcinoma Transitional cell carcinoma Adenocarcinoma Sarcoma Melanoma Metastatic Prostate Bladder Testes Colon Kidney
Fig. 14.1 Ascending urethrogram demonstrating irregularity and extravasation (arrow) from the bulbar urethra, as well as further bulbar urethral strictures. This was a urethral carcinoma that had developed in a patient with chronic postinflammatory urethral strictures. The arrowhead indicates periurethral glands
Fig. 14.3 A T2-weighted MRI scan of the penis, demonstrating a carcinoma at the tip involving the glans (arrow). This was a penile cancer, but MRI is the modality of choice for staging of urethral cancers
Fig. 14.2 Ascending urethrogram demonstrating a squamous cell carcinoma of the bulbar urethra with a fistula (arrow)
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Table 14.2 TNM classification of urethral carcinoma T – primary tumor TX – Primary tumor cannot be assessed T0 – No evidence of primary tumor Ta – Noninvasive papillary, polypoid or verrucous carcinoma Tis – Carcinoma in situ T1 – Tumor invades subepithelial connective tissue T2 – Tumor invades corpus spongiosum, prostate, periurethral muscle T3 – Tumor invades corpus cavernosum, anterior vagina, bladder neck T4 – Tumor invades other adjacent organs N – regional lymph nodes NX – Regional nodes cannot be assessed N0 – No regional node metastasis N1 – Metastasis in single lymph node (2 cm in diameter), or multiple lymph nodes M – distant metastases MX – Metastasis cannot be assessed M0 – No metastasis M1 –Evidence of distant spread
Fig. 14.4 An ascending urethrogram showing mucosal irregularity affecting the full length of the urethra, due to diffuse urethral carcinoma
Fig. 14.5 A T2-weighted sagittal MRI scan of the penis, showing a locally extensive urethral carcinoma. The arrowheads outline the tumor and the arrow points to a dilated penile urethra. The tumor invades the cavernosa, and this is a T3 stage tumor
Fig. 14.6 A sagittal MRI study showing extensive prostate cancer metastasis (arrows) invading the urethra
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Bibliography Kawashima A, Sandler CM, Wasseramn NF, LeRoy AJ, King BF, Goldman SM (2004) Imaging of urethral disease: A pictorial review. Radiographics 24:195–216 Mostofi FK, Davis CJ, Sesterhenn IA (1992) Carcinoma of the male and female urethra. Urol Clin North Am 19:257–276 Ryu JA, Kim R (2001) MR imaging of the male and female urethra. Radiographics 21:1169–1185 Wasserman NF (2000) Urethral neoplasm. In: Pollack HM, McClennan BL (eds) Clinical urography, 2nd edn. WB Saunders, Philadelphia, pp 1699–1715
Fig. 14.7 An axial MRI scan showing locally advanced urethral cancer invading the cavernosa (grade T3 tumor; arrow)
Index
A Abnormal bladder emptying, 63, 69–73 Abnormal bladder shape, 57–58 Acute cystitis, 36–37, 42 Allantois, 3 Amyloidosis, 36, 38 B Bladder absent, 23, 78 anatomy of, 3–6, 10, 13 assessment of, 9–21, 61 blood supply of, 5 congenital anomalies of, 23–27 development of, 3, 23 displacement of, 58, 59 embryology of, 3 functional abnormalities of, 19, 61–78 imaging computed tomography, 9, 13–14, 16, 51–52 cystography, 11–12, 38, 103 intravenous urogram, 9–10, 43 magnetic resonance imaging (MRI), 9, 13–15, 17 plain abdominal radiograph, 9 ultrasound, 3, 9, 12–14, 18–19, 31, 33, 36, 37, 39, 41–43, 45, 46, 51, 59, 60, 71, 74, 83–86, 91, 93, 95, 97, 99–101, 105 intraluminal abnormalities, 29–33, 37 intravesical gas in, 31–33 nerve supply of, 5 normal shape and size, 57 physiology of, 5–6 relations of, 4–5 Bladder cancer adenocarcinoma, 23, 25, 43, 46, 50, 98 classification of staging, 50 methods of staging, 49–50 paraganglioma, 42 radiological staging, 50–55 rhabdomyoscarcoma, 43, 46, 50 squamous cell carcinoma, 23, 42, 43, 45–46, 50 staging of, 12, 16, 49–55 transitional cell carcinoma, 25, 42–45 Bladder exstrophy, 3, 9, 23, 46 Bladder haemorrhage, 30, 77 Bladder infections
acute cystitis, 36–37 emphysematous cystitis, 37 schistosomiasis, 35–38, 42, 45, 63, 65 tuberculosis, 32, 36, 38, 58, 63, 65 Bladder outflow obstruction, causes, 19, 24, 30, 35, 37, 57, 58, 61, 63, 65, 66, 69–71 Bladder trauma, causes, 103, 104 Bladder tumors, 25, 30, 32, 41–46 Bladder wall abnormalities of, 35–46 calcification, 35–36, 38 causes of, 35, 36, 42 Blood clot, 29–31, 37, 40, 45, 94 C Calculi bladder, 9, 12, 29–31, 33, 35, 38, 39, 41, 71, 93 urethra, 71, 84, 93, 94, 98 Candida spp., 32, 36 Cerebrovascular accident, 74 Chalmydia trachomatis, 97 Chemical cystisis, 30, 37, 38 Cloaca, 3, 23 Cloacal exstrophy, 3, 23 Cloacal membrane, 3 Cloacogenic bladder, 23 Colour Doppler imaging, 12, 13 Colour Doppler ultrasound, 12–13, 29–31 Computed tomography (CT), bladder, 9, 13–14, 16, 51–52 Congenital bladder diverticulum, 23–25 Contrast urethrography in the female, 83–84 in the male, 82–83 Cowper’s duct cyst or diverticulum, 89–91 CT cystography, 11–12, 38, 103 Cystitis acute, 36–37, 40, 42 chronic, 38, 58 emphysematous, 31–33, 37 haemorrhagic, 37, 40, 41 miscellaneous causes, 41 radiation, 30, 36–38, 40–41, 63 Cystitis cystica, 38–39, 42 Cystography, 10–12, 15, 24, 30, 32, 38, 39, 57, 83, 100, 103, 104 Cystourethrography, 11, 36, 82, 83, 85, 87, 100, 106
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114 D Denonvillier’s fascia, 5 Detrusor overactivity, 17, 20, 65–66, 68, 72, 74, 77, 78 weakness, 19, 63, 66, 68, 72–75, 77 Diffuse bladder wall thickening, 35, 45 E E. coli, 32, 36, 37, 39 Ehlers-Danlos syndrome, 23 Endometriosis, 40–42 Enterobacter, 36 Enterovesical fistula, 31, 32 Eosinophilic cystitis, 38, 39, 41, 58 Excretory urogram (EU), 9 Exstrophy, 3, 9, 23, 38, 46 Exstrophy-epispadias complex, 23 F Female urethral diverticulum, 84, 86, 98–101, 109 Fibrous urethral polyp, 109 Flowmetry, artefacts, 18 Focal bladder wall thickening, causes of, 42 Foreign bodies bladder, 12, 29, 33, 94 urethra, 33, 93, 94 G Genuine stress incontinence (GSI), 67, 69, 70 H Haemorrhagic cystitis, 37, 40, 41 Hair balls, 93 Hutch diverticulum, 23 Hypospadias, 82, 88, 98 I Incontinence assessment, 69 causes, 67, 69, 74 stress, 17, 66–70, 74, 83 urge, 65–69, 71 Infections. See Blader infections International Continence Society, 16, 20, 61, 65, 67, 69 International Prostate Symptom Score (IPSS), 61, 62, 65, 71 Interstitial cystitis, 38, 41, 58 Intravenous urogram (IVU), 9–11, 24, 26, 32, 39, 43, 45 K Kidney, ureter and bladder (KUB), 9 Klebsiella spp., 36 Klippel-Trenaunay syndrome, 36 L Large volume bladder, 57, 58 Leiomyosarcoma, 42, 43, 46, 50 Lower tract utodynamics, methods of assessment, 17 Lower urinary tract symptoms (LUTS), 37, 38, 40, 41, 58, 61, 63, 71, 72, 77, 90 Lower urinary tract trauma, 103–107 Lumbar disc prolapsed, 74
Index M Magnetic resonance imaging (MRI) of the bladder, 14, 15, 17 of the urethra, 86 Malakoplakia, 38–42 Male urethral diverticulum, 101 Meatal stenosis, 88, 89, 98 Median umbilical ligament, 3 Megalourethra, 89 Menkes syndrome, 23 Micturating cystourethrography female, 82, 84, 85, 100, 106 male, 82 Micturition, control of, 5–6, 17, 25, 42, 71, 82, 83, 95, 101. See also Incontinence Mixed urinary incontinence, 66 Multiple sclerosis, 72, 74, 77 Mural abnormalities, 11, 35–46 N Neuropathic bladder common urodynamic findings, 77 complications, 77 sonographic appearances, 12 Normal videourodynamics study, 20–21 O Overactive bladder (OAB), 65 P Parkinson’s disease, 72, 74, 77 Pear-shaped bladder, causes of, 58 Plain abdominal radiograph, 9 Post chemotherapy, 36, 58 Posterior urethral valves, 25, 87 Post-operative bladder appearances, 59–60 Post-prostate surgery dysfunction, 74 Post radiation therapy, 31, 36 Prostate, gross anatomy, 5 Prostatic urethra, 4, 5, 81–85, 101, 106, 107, 109 Prostatic utricle, 25, 81 Proteus mirabilis, 36 Proteus spp., 29, 36 Prune Belly syndrome, 25, 89, 98 R Radiation cystitis, 30, 38, 40–41, 63 Reduced functional bladder capacity, 37, 41, 57, 63–65 Retrograde urethrography, 106 Rhabdomyosarcoma, 43, 46, 50 Röentgen’s discovery of X-ray, 10 Royal College of Radiologists and the European Society of Radiology guidelines, 45 S Schistosoma haematobium, 37 Schistosomiasis, 11, 35–38, 42, 45, 50, 58, 63, 98 Simple flowmetry, 17–18 Small shrunken bladder, causes of, 58 Small volume bladder, 41, 57, 63, 65, 69 Space of Retzius, 4
Index Sphincter incompetence, 63, 66–69 Squamous cell carcinoma (SCC) bladder, 23, 35, 36, 38, 42, 43, 45 urethra, 98, 109, 110 Stones bladder, 11, 12, 24, 29, 37, 45, 60 urethra, 12, 29, 37, 93, 97 Streptococcal faecalis, 36 Stress incontinence, 17, 67, 69, 70, 74, 83 Stress urinary incontinence (SUI), 66–69 Syringocoele, 89–91 T Transectal ultrasound (TRUS), 71, 87 Transitional cell carcinoma, 24, 25, 35, 36, 42–45, 50, 60, 98, 109, 110 Transurethral resection of the prostate (TURP), defect, 59, 60 Trauma bladder trauma, 32, 83, 103–104 female urethra, 101, 106 male urethra, 82, 101, 104–105 pelvic trauma, 101, 103–105 Trichomas vaginalis, 97 Tuberculosis, 32, 36, 38, 58, 65, 98 Tumor-Nodes-Metastasis (TNM) classification bladder cancer, 50 urethral cancer, 111 U Ultra small superparamagnetic iron oxide particles (USPIO), 55 Ultrasound cystodynamogram (USCD), 17–19, 59, 60, 71, 74 Ultrasound urethrography female, 85–86 male, 84–85 Unstable bladder, 65–66 Up and downogram, 105 Urachal abnormalities, 25–27 Urachus, 3, 25, 27 Ureaplasma urealyticum, 97 Ureteric jets, 13 Ureters, reimplanted, 59, 60 Urethra anatomy of, 3–6, 81–82 congenital anomalies of, 87–91 female, 82–84, 86, 97–101, 106–107, 109 injury of the male, 104–105 intraluminal abnormalities and filling defects of, 93–95 male, 81–82, 97, 101, 104
115 neoplasms of, 109–112 normal, 81–86, 88, 99 polyps of the male, 94–95 radiological investigation contrast urethrography female, 83–84 male, 82–83 magnetric resonance imaging, 86 tumours of, 109, 110, 112 ultrasound of in the female, 85–86 in the male, 84–85 Urethral carcinoma, TNM classification of, 109–112 Urethral diverticulum, 84, 86, 89, 98, 100, 101 Urethral duplication, 87–88 Urethral hypermobility, 20, 69, 70, 97 Urethral injuries, 103, 105, 106 Urethral stenosis, 88 Urethral strictures, 88, 93, 97–98, 110 Urethral trauma, classification, 105 Urethral wall, intrinsic abnormalities, 97–101 Urethritis, 97 Urge urinary incontinence (UUI), 66–69 Urinary bladder, 3–4 Urodynamic measurements terminology, 17 Urodynamics abnormal emptying bladder outflow obstruction (BOO), 63 detrusor weakness, 63 poor sphincter relaxation (or dyssynergia), 63 abnormal storage incontinence and sphincter incompetence, 63 overactivity (unstable bladder or detrusor over activity), 65–66 reduced functional capacity, 63 small volume bladder, 63 neuropathic bladder, 63, 65, 73–78 post-prostate surgery dysfunction, 74 Urodynamic values and observations, 21 V Videourodynamics normal study, 20–21 study in incontinence, 69 technique, 20 (see also urodynamics) W Williams syndrome, 23
