RGU, MCU & Its interpretation in pathology of Urinary bladder &

Urethra

Presenter :Dr. Dinanath Chavan

First year PGTDepartment of Radiology,

SMCH

Moderator : Dr. K. Hazarika Professor Department of Radiology, SMCH

EMBRYOLOGY OF BLADDER & URETHRA• 4th – 7th week – cloaca divides into urogenital sinus anteriorly and anal canal

posteriorly.• Urogenital sinus – can be divided into 3 portions.

• Upper and largest part – forms urinary bladder.

• Pelvic part – in the male – forms prostatic and membranous urethra.

• Phallic part- Bulbar and penile urethra , differs greatly between the two sexes.

• During differentiation of the cloaca, the caudal portions of the mesonephric ducts are absorbed into the wall of the urinary bladder - TRIGONE

• Since both the mesonephric ducts are mesodermal in origin, the mucosa of the bladder formed by incorporation of the ducts ( trigone ) is also mesodermal.

Urogenital sinus

Anorectal canal

Upper part - bladder

Middle part – prostatic & membranous urethra

Lower part – bulbar & penile urethra

ANATOMY OF URINARY BLADDER

Hollow, distensible, muscular organ located within the pelvic cavity, posterior to

the symphysis pubis and inferior to the parietal peritoneum.

Shape is that of a flattened tetrahedron when empty and round/oval when

distended with fluid.

The size of the bladder varies: when filled, the upper border of the bladder, should not rise above the level of the lumbosacral junction in the child and the second or third sacral segment in the adult.

Normal bladder wall is thickness is 2-3mm in fully distended bladder.

Apex(superoanterior portion) of the bladder attached to anterior abdominal wall by

median umbilical ligament(remnant of urachus).

Base(posterioinferior portion) is continuous with the bladder neck.

Bladder wall consists of mucosa, submucosa,lamina propria and smooth muscle. The mucosa consists of multilayered transitional epithelium and the muscle layer consists of longitudinal and circular muscle bundles.

Transitional epithelium stretch greatly without loosing its integrity. Cells become flattened without changing their relationship with each

other , as they are firmly connected by numerous Desmosomes. Normally epithelium is 7to 8 cell layer but in full bladder it appears to

become 2 to 3 cell layer. Epithelium shows transition between stratified cuboidal and stratified

squamous epithelium. Bladder capacity is between 500-600 ml. First urge to void is felt at a bladder volume of 150ml . The max capacity of bladder is up to 1200 ml. ( F > M ).

ANATOMY OF URETHRA

In females: Length of 3–4 cm.In males: 20 cm in length . It has four named regions:

Prostatic urethra: Is approximately 3 cm in length. Passes through the prostate gland. Membranous urethra: Is approximately 1 cm in length. Passes through the urogenital

diaphragm. Bulbar urethra

From inferior aspect of urogenital diaphragm to penoscrotal junction.

Spongy (penile) urethra: Passes through the length of the penis.

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The interior of the prostatic urethra:

On the posterior wall of the prostatic urethra there are:• Urethral crest: A longitudinal ridge.• Seminal colliculus / Verumontanum:An enlargement of the urethral crest.( act as a normal filling defect on RGU )• Prostatic sinus:The groove on either side of theseminal colliculus.• Prostatic utricle:A small opening on the midlineof the seminal colliculus.• Opening of the ejaculatory duct: One on either side of the prostatic utricle.

Membranous Urethra :-• It is the shortest , narrowest and least distensible part of

urehra.

Bulbar Urethra :-• Widest• Opening of Cowper’s gland

Penile Urethra :-• Fossa navicularis – last part of the urethra shows squamous

epithelium.

Female urethra :-

• Widest at bladder neck.

• Narrowest & least distensible at meatus.

• This forms the Spinning top configuration of urethra on normal MCU.

Imaging modalities for urinary bladder and urethra

Plain films

Cystography

Retrograde urethrography(RGU)

Voiding cystourethrography(VCUG)

Ultrasonography

Computed Tomography(CT)

Magnetic Resonance Imaging(MRI)

Urodynamic studies

Radionuclide imaging

Contrast media

•Currently used all CM are based on tri-iodinated benzene ring.•The iodine provides - radio-opacity•Other molecule - no radio-opacity but act as carriers of the iodine.•Commonly used carriers- Sodium or Meglumin.

•Classification ;- Nonionic or Ionic Monomer or Dimer HOCM or LOCM

Ionic monomer ( HOCM )•Cation -salts with sodium or meglumine •Anion- tri-iodinated benzoic acid ring.•Dissociates in water solution into 1 anion & 1 cation. •Each anion contains 3 atoms of iodine.• Iodine: particle ratio = 3:2 /(1.5) .• Ex: Urograffin

Nonionic monomer ( LOCM )

•Tri-iodinated nonionizing com-pounds .•Provides 3 atoms of iodine to 1 osmotically active particle .• Iodine:particle ratio = 3:1 .•Not dissociated in water solution.• Ex: iohexol

Ionic dimer ( LOCM )•Mixture of sodium & meglumine salts.•Ionizing double benzene ring. •Each benzene ring having 3 atoms of iodine.• So total molecule contains 6 atoms of iodine.• In solution dissociates into 1 hexa-iodinated anion and 1 cation.•Iodine: particle ratio = 6:2 or 3:1.•Ex: Ioxaglic acid ( Hexabrix )

Nonionic dimer ( LOCM )•Each molecule containing 2 nonionizing tri-iodinated benzene rings.•Provides 6 atoms of iodine per one particle.• Iodine:particle ratio = 6:1.•Ex : Iotrol

Adverse Reactions To contrast mediaMinor reactions- •Flushing, nausea, vomiting, , arm pain and mild urticaria.•Of short duration & self-limiting. •No specific treatment other than reassurance. • Rx- oral antihistaminic.

Intermediate reactions –•More serious degrees of the above symptoms.•Hypotension. •Bronchospasm. •Rx- Chlorpheniramine for urticaria. Diazepam for anxiety. Salbutamol inhalation for bronchospasm. Hydrocortisone&Adrenaline for anaphylasis.

Severe life-threatening reactions ;-• Severe manifestations of all symptoms discussed above.• Convulsions& Unconsciousness.• Laryngeal oedema & pulmonary oedema.• Bronchospasm.• Pulmonary &cardiac arrest.Rx;- Must be urgently & follow the ABC of resucitation.

The airway must be secured. if require-oxygen, artificial respiration , defibrillation. Atropine& Adrenaline - cardiac failure. Hydrocortisone Adrenaline for anaphylasis .

Choice of contrast media•Always prefer nonionic LOCM over HOCM.• The only factor inhibiting replacement of HOCM by LOCM is financial.

URETHROGRAPHY

TYPES Antegrade -VCUG / MCU- Bladder is filled with contrast via suprapubic or retrograde catheterization and the

urethra is assessed during voiding.

Retrograde urethrography (RGU) – Contrast is retrogradely injected with the urethral orifice occluded to prevent reflux

of contrast.

Following IVU

For both, static images can be obtained, but preferably assessed dynamically under

fluoroscopy.

The male urethra - best seen in the oblique position.

Female urethra - lateral or anteroposterior position.

VCUGs - prostatic urethra , changes in the bladder neck.

RGU - membranous and anterior urethra , inflammatory lesions and diverticula.

Some patients are assessed with both techniques, usually the RGU is performed

first, followed by the VCUG.

RETROGRADE / ASCENDING URETHROGRAPHY

• INDICATIONS Urethral stricture. Urethral tear. Congenital abnormalities. Periurethral / prostatic abscess. Fistula / false passages.

• CONTRAST MEDIUM Urograffin 60%. Pre warming the contrast helps to

prevent external urethral sphincter spasms

• EQUIPMENT Tilting radiography table. Fluroscopy / spot film device. Foley catheter no 8 / knutsson`s clamp.

• PREPARATION Patient micturates prior to the

procedure

• TECHNIQUE

Preliminary film – coned supine PA view of bladder base and urethra.

In supine position penile clamp is applied or tip of the catheter is inserted so that the balloon

lies on the fossa navicularis

Balloon is inflated with 1 – 2 ml of water.

Contrast medium is injected under fluoroscopic control.

• FILMING

30* left anterior oblique.

Supine PA.

30* right anterior oblique.

• COMPLICATIONS

Contrast reaction ( due to absorption through bladder mucosa )

UTI

Urethral trauma.

Intravasation of contrast – due to use of excessive pressure in stricture.

ANTEROGRADE URETHROGRAPHY/MICTURATING CYSTOURETHROGRAPHY• INDICATIONS

CHILDREN - UTI - Voiding difficulties. - Vesico ureteric reflux. - Baseline study prior to urinary tract surgery. - Post operative evaluation of ureteric abnormalities. - Trauma. - Suspected anatomic abnormalities of bladder neck & urethra. ( posterior urethral valve )

ADULTS - Functional disorders of bladder & urethra. - Suspected vesicovaginal / vesicocolic fistula. - Suspected bladder / urethral trauma. - Urethral diverticula

EQUIPMENT

- Preferably under fluroscopy.

- Foley`s catheter.

- In infants – feeding tube no 5 – 7 F.

CONTRAST MEDIA

-Water soluble media -Urograffin 76% , conray 420 , Trivedeo 400

with dilution of 1:3 in normal saline.

PREPARATION

Not required.

PROCEDURE - Patient micturates prior to the procedure. - Preliminary film – coned view of the bladder using undercouch table - Catheterisation. - Residual urine is drained. - Contrast is slowly instilled & bladder filling moniterd by intermittent fluroscopy and any reflux recorded on spot films.. - Infants < 2 months – hand injection until micturition starts – sedation may be used.. - Older children / adults – Instilled from a bottle elevated 1 meter above the level of table. -Catheter should not be removed until the radiologist is convinced that patient will micturate or until no more contrast medium drips into the bladder. - Catheter withdrawm immediately after the micturition commences. Feeding tube

does not obstruct voiding. - When possible male patient can void in standing and female patient in sitting

position.

• ALTERNATE TECHNIQUES

1) SUPRAPUBIC BLADDER PUNCTURE. Sometimes in PUV & pelvic trauma – not possible to catheterize.

2) URETHROCYSTOGRAPHY Contrast medium introduced into the bladder during RGU.

3) EXCRETION MCU ( MCU followed by IVU ) Advantage – avoid catheterization and related risk of infection.

Disadvantage - VUR can not be visualized properly . takes longer time.

• COMPICATIONS Contrast reaction. Contrast induced cystitis. UTI. Catheter trauma. Bladder perforation – overfilling. Retention of a foley catheter. Catheterisation of vagina / ectopic ureter.

• CONTRAINDICATIONS Acute UTI.

• AFTERCARE Warned – of rare dysuria , retention. Reflux - Antibiotcs.

Filming

• Spot films – to demonstrate reflux.

• Males -left anterior oblique position with right hip and knee flexed – entire urethra , lower ureter.

• Finally – a full length film – to show reflux and post void residual volume.

• Vesico vaginal / vesico rectal fistula – lateral , oblique view

SPECIFIC DISEASES OF THE URINARY BLADDER

Congenital Bladder agenesis Bladder hypoplasia Bladder duplication Congenital diverticulum of bladder Urachal anomalies

• Urachal sinus• Urachal cyst• Urachal diverticulum• Patent urachus

Bladder exstrophy etc.

Acquired Acquired bladder diverticulum Bladder calculi Cystitis Bladder fistula Bladder injury Detrusor hyperreflexia Detrusor areflexia etc.

Congenital(Hutch) diverticulum

Sac formed by herniation of bladder mucosa and submucosa through muscular wall

Weakness in detrusor muscle posterolateral to ureteral orifice Congenital diverticula usually are narrow necked.

Urachal anomalies Urachus is a connection between

bladder apex and allantois at level of umblicus.

Closes in 2nd trimester. Extends anterosuperiorly between

peritoneum & transversalis fascia. Urachal remnants usually lined by

transitional epithelium. But 1/3 rd may show coloumnar type. Patent urachus – 50% Urachal cyst – 30% Urachal sinus – 15% Urachocele – 5%

1) Urachal sinus Presentation :

Infection and/or periodic discharge

Imaging : Sinography shows blind ended

sinus

2) Urachocele [urachal divericulum] Usually incidental finding

3) Urachal cyst Presents with infection Rarely as abdominal mass Midline cyst above bladder dome May show rim calcification on CT

4) Patent urachus : Presents at early age with urine

leakage at the umbilicus. Easily demonstrated with sinography

or cystography. A fluid-filled tubular structure on

ultrasound , CT or MRI

Bladder exstrophy Mmost common congenital bladder

lesion ( 1:50000 ) M:F=2:1 Deficiency in the development of the

lower abdominal wall musculature, so that the bladder is open and the mucosa of the bladder is continuous with the skin.

Classically associated with epispadias. Skeletal and gastrointestinal anomalies

are commonly associated. In full-blown exstrophy, the pubic

bones are widely separated. The distance between pubic bones

should be no more than 10 mm at any age.

Bladder duplicationComplete :

Both bladders lie side by side, separated by a peritoneal fold. Each bladder has normal musculature and mucosa,

Ipsilateral ureter drains into each bladder.

Each bladder has a separate urethral orifice that may drain into a common urethra with a single penis, or there may be complete duplication of the urethra and penis

Partial duplication : Coronal or sagittal septum completely

or incompletely divides the bladder A single urethra for drainage

Vesicoureteral reflux(VUR)

Refers to retrograde passage of urine from the bladder into the ureter and often into the calyces.

Most significant risk factor for childhood renal scarring and its sequelae. VUR in most cases is the result of a primary maturation abnormality of the

vesicoureteral junction resulting in a short distal ureteric submucosal tunnel. Imaging of VUR:

• VCUG• Radionuclide cystography• MR voiding cystography

Primary diagnostic procedure for evaluation of VUR is VCUG. However radionuclide cystography is better as a screening tool as the radiation

dose is lower.

Grading of VUR

• Grade 1 : reflux limited to ureter • Grade 2 : reflux into renal pelvis • Grade 3 : mild dilatation of ureter

and pelvicalyceal system.  • Grade 4 :  tortuous ureter with

moderate dilatation, blunting of fornicies but preserved papillary impressions.  

• Grade 5 :  tortuous ureter with severe dilatation of ureter and pelvicalyceal system, loss of fornicies and papillary impressions

Bladder diverticulum (acquired) Sac formed by herniation of

bladder mucosa and submucosa through muscular wall

Mostly acquired : males : bladder outlet obstruction.

In the early stages, multiple small protrusions of the bladder lumen appear between the trabeculae (sacculations).

As they enlarge above 2 cm they become defined as diverticula

Most found close to the ureteric orifices

Stasis in diverticula may lead to stone formation.

2% cases leads to carcinoma • MC tumour is Squamous cell

carcinoma• Tumors in diverticula have worse

prognosis; poorly formed wall leads to more rapid local spread

• A wide-necked diverticulum empties readily when the bladder empties while A narrow-necked diverticulum empties slowly

• Classical symptom of double micturition; when the patient empties the bladder a significant amount of urine is stored in the diverticulum, which then empties back into the bladder, causing a desire to micturate almost immediately after the first micturition.

Bladder herniation• At least 95% of bladder herniation is

into the inguinal or femoral canals, • Inguinal : femoral = 2:1• usually small(2-3 cm)& asymptomatic• Painful, partly obstructed micturition

because the trigone tends to remain in normal position,

• Usually narrow neck and fill poorly on routine contrast images

• So best seen on prone or erect films• Most commonly is paraperitoneal in

location, bladder remaining extraperitoneal and medial to a true inguinal hernia sac

Bladder stones

Most are mixture of calcium oxalate and calcium phosphate

Primary : forming de novo in bladder Secondary : drop from kidneys Primary by stasis by far MC cause Stasis: Bladder outlet obstruction,

neurogenic bladder, bladder diverticula

Infection, especially Proteus mirabilis Foreign bodies: Nidus for stone

• Suture material, migrated IUDs

• Pubic hairs introduced by catheterization

Usually midline with patient supine

Bacterial cystitisAcute bacterial cystitis : Infection of bladder is difficult to

diagnose radiologically alone. Requires history, culture, cystoscopic

examination and sometimes even biopsy.

Most frequently seen in young & middle aged females

Associated with sexual activity In males usually associated with

Bladder outlet obstruction and urinary stasis.

There is little reason to do imaging studies in female patients with uncomplicated cystitis.

If repeated bouts of infection have occurred, an IVP may be indicated to exclude anatomic abnormalities.

Because cystitis is rare in male patients, an IVP may be indicated after an initial infection.

Imaging of bacterial cystitis

Virtually all acute infections of the bladder can, if severe, result in diffuse bullous edema of the urothelium, leading to a nodular irregular contour of the bladder on imaging studies.

USG : Hypoechoic thickened bladder

wall with echogenic debris within bladder

IVP : Usually normal. May show

cobblestone pattern especially in partly filled or post void films

Tuberculous cystitis An interstitial process Tuberculosis can affect the bladder,

but this is extremely rare without strictures and stenosis of the ureters and stenosis of the calyces of the renal collecting system.

By descending infection from kidneys 10-20% of genitourinary tuberculosis Produces irregular mural thickening

with subsequent fibrosis Thus bladder capacity decreases and

ureters may get obstructed Alternatively, traction on the ureteric

orifices may lead to VUR 10% cases show wall calcification.

Emphysematous cystitis

Almost always found in diabetic or immunocompromised patients

Mostly E. coli, which ferments glucose to produce carbon dioxide and hydrogen.

Gas is initially formed in the bladder wall and subsequently transgresses the mucosa into the lumen of the bladder.

Cystoscopic examination reveals a red and edematous mucosa with multiple blebs that rupture easily, releasing gas.

Plain film typically shows gas within the bladder and irregular streaky radiolucencies within the bladder wall

Haemorrhagic cystitis Radiation cystistis :

Usually seen after external beam irradiation doses of 3,000 rads or more, this acute form of radiation cystitis is usually self limiting

Imaging reveals edema that is indistinguishable from other causes of bladder mucosal edema

Cyclophosphamide cystitis : 40% treated patients may

develop an acute hemorrhagic cystitis.

Acute form- by i.v use Chronic form – by oral use Rarely bladder wall calcification

& transitional cell carcinoma of bladder

Urinary schistosomiasis

One of the most common parasitic infections worldwide

Only Schistosoma hematobium affects the urinary tract.

Flukes reach the smallest venules in the wall of the bladder probably through the hemorrhoidal plexus.

Eggs are trapped in the bladder walls where they die, producing a severe granulomatous reaction. The granulomas calcify, causing linear streaks of calcium in the bladder wall.

In initial stages, the bladder mucosa is edematous and hemorrhagic

50% cases show calcification on plain x-ray

Imaging in schistosomisis• Urographic findings in patients with

early schistosomiasis may show an irregular bladder outline caused by edema and granulomatous reaction.

• Characteristic manifestation is sheet like / eggshell calcification in submucosa of the bladder

• Cystoscopic examination is mandatory to exclude squamous cell carcinoma of the bladder

• A bladder tumor should be suspected when follow-up studies show absence of wall calcification in areas that were previously calcified. ( focal disruption of mural linear calcification )

Bladder fistula

Colovesical > enterovesical Most frequent- rectosigmoid colon Diverticulitis MC cause >>colon CA Crohn’s MC cause of enterovesical

fistula. Hence common on right side. Penetrating trauma, surgical

misadventures, other inflammatory processes such as appendiceal abscess or PID

Leads to faecaluria, pneumaturia, persistent UTI

Only grossly wide Fistulous track may be shown on contrast studies

All these modalities, will miss at least 40% of fistulas.

Plain x-ray : Gas within bladder lumen

Cystography Fistula tract outlined by contrast

material in < 50% of cases May find only bladder wall

irregularity .

Vesicovaginal fistula

MC cause in developing countries =>prolonged obstructed labour

MC cause in developed countries =>abdominal hysterectomy

Rarely due to pelvic malignancy, radiation ,

Painless constant dribbling of urine from the vagina.

Relatively easy to demonstrate during urography or cystography

Lateral and oblique films best Vesicouterine fistulae are a rare result

of cesarean delivery May present with cyclic hematuria

pattern (Youseff s syndrome)

Bladder traumaCauses :

External penetrating agents (such as bullets, stab wounds and bone fragments)

Internal penetrating agents (such as cystoscopes or resectoscopes), lower abdominal surgery or blunt trauma: Blows to the lower abdomen, steering wheel/seat belt

More the bladder distension => more severe the injury

Clinically : Suprapubic pain, Hematuria, Urge to void may be present or absent

Traditionally retrograde cystography Minimum 300 ml dilute(30%)

contrast Post drainage film important

Bladder injury classification Type 1-Bladder contusion Type 2-Intraperitoneal rupture Type 3-Interstitial bladder injury Type 4-Extraperitoneal rupture

a. Simple b. Complex Type 5-Combined bladder injury

Bladder contusion : ( Type 1 ) MC bladder injury – but minor Incomplete or partial tear of bladder

mucosa; Ecchymosis of a localized segment of

bladder wall Cystography normal. So diagnosis of exclusion

Only finding may be pelvic hematomas

If unilateral , may displace bladder to one side

But mostly bilateral they will compress and elevate the inferior portion of the bladder so that it looks like an upside-down teardrop (tear drop bladder)

Intraperitoneal rupture (type 2)

Direct blow to lower abdomen with a distended bladder

Horizontal tear along bladder wall; at dome of bladder covered by peritoneum

15-45% of major bladder injuries

A. No bowel sounds, acute abdomenB. +/_ pelvic fracturesC. Contrast in paracolic gutters, around bowel

loops, pouch of Douglas and intraperitoneal viscera

Interstitial injury (type 3)

Very rare type

Intramural or partial-thickness laceration with intact serosa

Incomplete perforation; seen on either intra- or extraperitoneal

portion of bladder

Intramural and submucosal extravasation of contrast without

transmural extension

Subserosal rupture causes elliptical extravasation adjacent to

the bladder

Extraperitoneal rupture (type 4) 50 – 85% ( MC ) of major bladder

injuries . Classic mechanism: Anterolateral

laceration at base of bladder by bony spicules (anterior pelvic arch fractures)

Simple (type 4A): Flame-shaped extravasation around bladder

Complex (type 4B): Extravasation extends beyond the pelvis

Extravasation best seen on post-drainage films

Frequently (89–100%) associated with pelvic fractures

Combined rupture (type 5) Cystography must be performed in all

patients with gross haematuria associated with pelvic fractures

Cystography is performed after urethral injury has been excluded and when retrograde bladder catheterization is safe.

Cystography ± CT still the procedure of choice

The accuracy of cystography for the diagnosis of bladder injury varies from 85% to 100%

Specific diseases of the urethra

Posterior urethral valves

Congenital thick folds of mucous membrane located in the posterior

urethra (prostatic + membranous) distal to the verumontanum.

Most common cause of severe obstructive uropathy in children.

Almost exclusively in males.

Leading cause of end stage renal disease in boys.

Now rare for them to present with severe UTI and septicaemia -diagnosis

is generally made in early infancy and antenatal period.

Types

Type I: Most common. Two folds extend anteroinferiorly from caudal aspect of verumontanum often

fusing anteriorly at a lower level.

Type II: No longer considered a valve. Hypertrophic band of muscle running from ureteric orifice to verumontanum along

postero lateral urethral wall.

Type III: Circular diaphragm with a central or eccentric narrow aperture in membranous

urethra.

Micturiting cystourethrography Procedure of choice for defining the valves.

Indication -Thick walled bladder & dilated ureters on USG.

Combination of ultrasound and MCU allows both urologist and nephrologist to plan immediate management.

Repeated 3 months after ablation.

Fusiform dilatation & elongation of proximal posterior urethrapersisting throught voiding

Transverse/curvilinear filling defect in posterior urethra

MCU – Lateral view.

Posterior urethral valve in newborn and in a 7 yr. Old boy

Anterior urethral valve Rare anamoly , but -Commonest cause of congenital anterior urethral obstruction .

In most cases, the valve is in fact the dorsal wall of a congenital urethral diverticulum.

Occasionally, a membranous valve is present without an associated diverticulum.

Etiology - Anomalous developmental membranes / congenital cystic dilation of normal or accessory urethral glands

Cusp / Iris / Semilunar shaped.

The degree of obstruction is variable - may be subclinical or rarely may result in severe obstruction.

PRESENTATION Infants / young children – obstruction. Older children – Diurnal enuresis , UTI.

Dilated proximal urethra

AUV

Normal distal urethra

Meatal stenosis Congenital narrowing of the urethral orifice / may be caused bymeatal webs.

• Can occur in both male and females.

• Associated with hypospadias.

• Acquired more common • Presentation - Weakness of the urinary stream, and straining during micturition.

• Some consider it a type of anterior urethral valve.

• Rarely can cause severe outlet obstruction similar to urethral valves

• Diagnosis – clinical , imaging if obstructive features are present.

Dilatation of proximal urethra

Stenosis

Urethral DiverticulumCongenital:

A rare abnormality of the anterior urethra seen only in males.

Etiology –

– Secondary to an obstructing valve.

– Lack of supporting corpus spongiosum.

– Defective closure of urethral folds.

– Rudimentary urethral duplication.

– Ectopic cloacal epithelium.

Typically ventral to the anterior urethra commonly near penoscrotal junction.

Symptoms – penile swelling only during voiding , terminal dribbling , UTI , with or

without dilation of upper urinary tract.

Acquired: Occurs more frequently in females. Thought to be the result from inflammation and trauma of periurethral Skene

glands and ducts – leading to local glandular dilatation and subsequent rupture into the urethra.

Most commonly occurs in the mid urethra on the posterolateral wall. May arise in association with a congenital anomaly such as cloacal epithelium or

wolffian/mullerian duct remnant. Reported in 1.4% women with stress incontinence. D/D-

• Vaginal cyst(Gartner duct cyst, Mullerian duct cyst)• Ectopic ureterocele• Endometrioma• Urethral tumors

May be complicated by infection, stone formation or malignancy.

Imaging of urethral diverticulum

MCU - Diverticulum fills with contrast – appears as rounded, oval or tubular sac, usually with a short neck.

RGU may be required to demonstrate the neck.

Proximal of the diverticulum may show as an arcuate filling defect.

Double balloon retrograde urethrogram or MRI should be performed,if there remains clinical concern of one.

CT - fluid density-filled structure arising from the urethra

http://www.emedicine.com/med/images/435575-443296-3812.jpg

Gonococcal and Nongonococcal Urethritis Gonococcal urethritis is associated with the gram negative diplococcus, Neisseria

gonorrhoeae. Chlamydia trachomatis is the most common pathogen of nongonococcal urethritis. Patients usually present with urethral discharge. Complications associated with gonococcal urethritis are more common and more

serious than those associated with nongonococcal urethritis and include urethral stricture, periurethral abscess, and periurethral fistula.

Pseudodiverticulum formation results from urethral communication with a periurethral abscess.

Gonococcal urethral stricture usually leads to irregular urethral narrowing several centimeters long.

Periurethral abscess arises initially when a Littre´ gland becomes obstructed by inspissated pus or fibrosis.

Urethroperineal fistulas are most often the consequence of a periurethral abscess.

Tuberculous urethritis Descending infection and renal tuberculosis is

evident. In the acute phase, there is urethral discharge

with associated involvement of the epididymis, prostate, and other parts of the urinary system.

In chronic phase patients present with obstructive symptoms secondary to urethral strictures.

May lead to periurethral abscesses, which, unless treated, produce numerous perineal and scrotal fistulas- Watering can perineum.

Retrograde urethrography typically demonstrates an anterior urethral stricture associated with multiple prostatocutaneous and urethrocutaneous fistulas.

Urethral stricture• Area of hardened tissue, which narrows the urethra sometimes making it

difficult to urinate.• Generally refers to the anterior urethra ( sphincter to tip of penis )• Rare in women , more common in men.• If returns after two or more treatments- recurrent stricture.

• Two main categories:o Anterior urethral ( sphincter to the tip of penis) o Posterior urethra (bladder to the urethral sphincter)

• Anterior urethral -usually a result of an injury to the urethra.

May not become evident for many months to years. Most common location -bulbar urethra - part that sits just Below the pubic bone.

INFLAMMATORY• Gonococcal urethriti -once the most common cause, antibiotic therapy

has reduced the incidence and less than half are now attributable.• Nonspecific urethritis – Chlamydia trachomatis.• Tuberculosis - Rare.

Almost always from a focus elsewhere. If severe – multiple urethroperineal fistulas.

• Reiter`s syndrome.• Chemical urethritis – podophyllin , 5-flurouracil.

• Always preceded by urethritis

• Majority - Catheterisation induced urethritis and periurethritis.• Most often involves bulb of the urethra - most dependent part and

contains the greatest number of paraurethral glands.

TRAUMATIC 1. IATROGENIC• Catheterisation Most common. Affects fixed narrow areas (Fulcrum sites) – membranous urethra penoscrotal junction.

• Instruementation /Urethral surgery. single/multiple variable length – usually short (< 2 cm )

2. ACCIDENTAL Usually associated with complete transection of urethra following pelvic fracture. Most frequently affects - membranous urethra, although the proximal bulbar urethra is often also involved . usually develop more quickly and are usually solitary Straddle injuries - bulbar urethra. Direct blows - penile urethra.

Role of urethrography

• Accurately delineates the anatomy of urethra.• Location, number and extent of the strictures are

very well displayed • Delineation of the bladder neck and urethra is best

achieved on the MCU in the oblique projection. • Secondary changes in the bladder.• To demonstrate the VUR• Visualisation of any associated fistulas.

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Urethral calculi

Mostly expelled from bladder into the urethra during voiding- migrant calculi. Primary calculi may be seen in association with urethral stricture or urethral

diverticulum. Symptoms include weak stream, dysuria, and hematuria. RGU usually depicts a rounded filling defect in the urethra.

Blunt Urethral Trauma

Classified Anatomically as - Anterior - Posterior

Anterior urethral injury MC iatrogenic (due to instrumentation)May occur if pt falls on a blunt object or direct injury to perineum Straddle Injury - compression of urethra against anterior pelvic ring

Posterior urethral injury results from A crushing force to the pelvis Is associated with pelvic fractures.

Goldman & Sander classification (Based on findings at retrograde urethrography)

• Type I injury

Rupture of the puboprostatic ligaments which stretches the prostatic urethra

Continuity of the urethra is maintained

Type II injury (15%)

The membranous urethra is torn above an intact urogenital diaphragm, which prevents contrast material extravasation from extending into the perineum

Type III injury (MC)

The membranous urethra is ruptured but the injury extends into the proximal bulbous urethra because of laceration of the urogenital diaphragm

Extravasation not only into the pelvic extraperitoneal space but also into the perineum.

• Type IV

Bladder neck injury with extension to the urethra.

Type V injuryInjury to the Anterior urethra - partial or complete.Extravasation seen to penile soft tissue.

Malignant tumors of male urethra

Primary urethral cancer is an extremely rare lesion, comprising less than 1% of the

total incidence of malignancies.

Tumors of the male urethra are rare.

The most common symptom at presentation is a palpable mass in the perineum or

along the shaft of the urethra with or without obstructive voiding symptoms.

The bulbomembranous urethra is involved most frequently (60% of cases), followed

by the penile urethra (30%) and the prostatic urethra (10%).

80% of male urethral carcinomas are squamous cell carcinoma, 15% are transitional

cell carcinoma, and 5% are adenocarcinoma or undifferentiated carcinoma.

Chronic inflammation secondary to sexually transmitted infectious urethritis and

urethral stricture is the main predisposing factor.

Staging of male urethral carcinoma:

• Stage I : Tumor is confined to the subepithelial connective tissue.

• Stage II : Tumor invades the corpus spongiosum, prostate, or periurethral muscle.

• Stage III : Tumor invades the corpus cavernosum and bladder neck or beyond the

prostatic capsule.

• Stage IV : Tumor invades other adjacent organs.

Tumors of penile urethra drain into the deep inguinal lymph nodes and the external

iliac lymph nodes.

Tumors of the bulbar urehra and posterior urethra most commonly spread to the

internal iliac and obturator lymph nodes.

Imaging in male urethral carcinoma

Urethrography usually showing focal irregular narrowing of the urethra.

Margin of sticture is irregular and poorly defined.

MR imaging can depict invasion of the corpora cavernosa and is useful for demonstrating tumor location and size and local staging.

Malignant tumors of female urethra More common than that of the male urethra, with a female-to-male ratio of 4:1.

Causes include chronic irritation, urinary tract infection, and proliferative lesions such

as caruncles, papillomas, adenomas, polyps, and leukoplakia of the urethra.

Present with urethral bleeding, urinary frequency, obstructive symptoms, and a

palpable urethral mass or induration.

Classified as either “anterior” urethral cancer or “entire” urethral cancer.

Anterior tumors(46%) located exclusively in the distal third of the urethra.

Entire urethral carcinomas tend to be high grade and locally advanced, most frequently

with squamous cell carcinoma (60%), followed by transitional cell carcinoma (20%),

adenocarcinoma (10%), undifferentiated tumor and sarcoma (8%), and melanoma

(2%).

Distal third spread to superficial and deep inguinal And proximal two third to the

internal and external iliac lymph nodes.

Imaging in female urethral carcinoma

Urethrography demonstrates irregular narrowing of the urethra.

MR imaging has been reported to be accurate for evaluating local urethral tumors in 90% of patient.

CT can demonstrate a urethral mass with soft-tissue attenuation.

References

1) Textbook of Radiology and Imaging By David Sutton.

2) Grainger & Allison's Diagnostic Radiology.

3) Genitourinary Radiology- The Requisites

4) Jaypee’s Diagnostic Radiology – Berry series

5) Various online journals

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