RGU (Retrograde urethrogram), MCU (Micturating cystourethrogram) and its interprretation

RGU, MCU & Its interpretation in
pathology of Urinary bladder &
Urethra
Presenter :
Dr. Gobardhan Thapa
First year
Department of Radiodiagnosis, NAMS

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 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, smooth muscle and adventita.
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 7 to 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 ).

RGU (Retrograde urethrogram), MCU (Micturating cystourethrogram) and its interprretation

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.

8
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 the
seminal colliculus.
• Prostatic utricle:
A small opening on the midline
of 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
urethra.
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 Meglumine.
•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 compounds .
•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 media
Minor reactions-
•Flushing, nausea, vomiting, arm pain and mild urticaria.
•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 resuscitation.
 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.

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/fistula
 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 columnar 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
 Most 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 duplication
Complete :
 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 cystitis
Acute 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
(thimble bladder ) 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 trauma
Causes :
 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 abdomen
B. +/_ pelvic fractures
C. 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)
 90% ( M/C ) 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
 Molar tooth sign – contrast close to
UB and have sharp irregular
margin (in space of Retzius)
 Frequently (90%) 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 urethra
persisting 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 anomaly 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 by meatal 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 Diverticulum
Congenital:
 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

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 urethritis -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 (watering can
perineum).
• 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.
• Instrumentation /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.

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 & Sandler 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 injury
Injury 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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