2. ANATOMY OF URETHRA
• MALE URETHRA IS 18-20 cms LONG
• EXTENDS FROM BLADDER NECK TILL THE MEATAL OPENING AT PENIS
• 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.
3. Bulbar urethra
From inferior aspect of urogenital diaphragm to
penoscrotal junction.
Spongy (penile) urethra:
Passes through the length of the penis.
4. PARTS OF URETHRA
ANTERIOR URETHRA
-PENILE URETHRA
-BULBAR URETHRA
POSTERIOR URETHRA
- MEMBRANOUS URETHRA
- PROSTATIC URETHRA
5. SPHINCTERS OF URETHRA
INTERNAL URETHRAL SPHINCTER -
• involuntary in nature
• Supplied by sympathetic nerves
• It controls the neck of the bladder & prostatic
urethra above the opening of ejaculatory ducts
EXTERNAL URETHRAL SPHINCTER-
• voluntary in nature
• Supplied by perineal branch of the pudendal nerve (s2-s4)
• Controls the membranous urethra & is responsible for voluntary holding of urine
6. Female urethra :-
• Widest at bladder neck.
• 4-5cms in length
• Narrowest & least distensible at meatus.
• This forms the Spinning top configuration of urethra
on normal MCU.
7. Urethrography is of 2 types:
1. Ascending/Retrograde urethrography - Contrast is retrogradely injected
in the ureter with the urethral orifice occluded to prevent reflux of contrast.
2. Descending /MCU- Bladder is filled with contrast via suprapubic or
retrograde catheterization and the urethra is assessed during voiding.
8. • Voiding cystourethrogram/ Micturating cystourethrogram demonstrates the lower
urinary tract
• Helps in detection of:
vesico-ureteral reflux
bladder pathology
congenital or acquired anomalies of bladder outflow tract.
Micturating Cystourethrogram (MCU)
9. INDICATIONS
Children:
1. UTI
2. Voiding difficulties like dysuria, thin stream, dribbling, frequency, urgency.
3. Vesico ureteric reflux.
4. Other congenital anomalies : Meningomyelocele, Sacral agenesis,Rectal anomalies.
5. For post operative evaluation of ureteric abnormalities.
6. Pelvic Trauma.
7. In renal failure to exclude reflux.
8. Boys with hematuria-MCU can demonstrate posterior uretheral valve or polyp.
11. CONTRAST MEDIA
• Water soluble constrast media like Urograffin 60% are used which is diluted with
normal saline in 1 :3 ratio.
• The estimated volume of contrast medium to be given:
Less than one year
Weight (kg) x 7 = capacity (ml)
Less than two years
(2 x age in years + 2) × 30 = capacity (ml)
More than two years
(Age in years/2 + 6) × 30 = capacity (ml)
12. Procedure
• Using a sterile technique, a catheter is introduced into the bladder.
• A 5f feeding tube with side holes are used for children and in older children or
adults 8f or 10 f catheters are used.
• In girls after initial inspection of perineum to identify any local genitilia
abnormalities (cystoceles or labial fusion ) the catheter is introduced.
• When it enters the bladder a varying amount of urine will flow through it .if no
flow a catheter is introduced till urine is obtained.
13. • Suprapubic pressure Is sometimes helpful.
• In males, foreskin is retracted and catheter is introduced.
• The catheter should be lubricated with anaesthetic jelly and inserted slowly and
gently into the urthera holding the penis is vertical position.
• The normal bladder capacity in children is estimated to be 1 ounce i.e 29 cc.
• For newborns -30 to 35 cc can be instilled.
• For upto 3 yrs - 200 to 250 cc
• Adequate capacity is reached when the child becomes uncomfortable and begins
voiding around the catheter.
14. Filming
In children
• In children up to the age of 2 yrs bladder is filled by hand injection.
For older children contrast medium is instilled from a bottle elevated one metre above examination table.
• During filling, fluoroscopic screening is performed at short intervals to see if vesicoureteral reflux, diverticuli
or other abnormalities are present. The child is turned oblique on both sides to ensure that minimal reflux
is not overlooked.
• If reflux appears, films are taken in the appropriate oblique projection. If the bladder appears normal, one
film is taken in the frontal projection at the end of filling.
• Voiding starts in infants the moment the catheter is removed.
• At the end of voiding, a frontal film is made of the entire abdomen including the kidney region in order to
prevent overlooking the vesicoureteral reflux which is apparent only on termination of voiding and may
reach the upper collecting system.
15. In adult male :
• Bladder is filled in the usual way as in older child and voiding filming is done in both oblique
projection views.
• The voiding study in male adults can be modified by getting the patient to void against resistance
i.e. by compression of distal part of penis or using penile clamp thus enhancing the visualization
of urethra by artificial distention.This is known as CHOKE CYSTOURETHROGRAPHY
In adult female:
• The procedure is essentially the same
• In addition to the standard exposures, a double exposed film taken at rest and during straining
demonstrates the degree of bladder descent if any.
16. Filming Technique:
Scout film:
• The first image that is taken while performing the MCU and VCUG is the image of KUB that
is called scout film. We evaluate the spine, pelvis, and soft tissues on the scout film.
• After several seconds of the contrast media begins to flow, the image of minimally filled
bladder is taken in Antero-posterior (AP) projection.
• During early filling a ureterocele or tumor can be detected
and it may obscure as more contrast material enters
into the bladder.
17. Voiding phase
• The image taken during voiding may demonstrate the urethral strictures or obstructions.
• They will also give the details of the presence or absence of vesicoureteral reflux.
• Voiding film necessary because gives the determination of reflux because reflux may
only happen with the pressure generated by voiding.
18. Post-voiding film
• A post-voiding film may demonstrate the reflux or extravasation of
urine from the bladder or urethra.
• A normal post-void film has no reflux and no residual urine.
19.
20. COMPLICATIONS
• Contrast reaction.
• Contrast induced cystitis.
• UTI.
• Catheter trauma.
• Bladder perforation - overfilling.
• Retention of a foley catheter.
• Catheterisation of vagina / ectopic ureter.
• Radiation exposure
• Autonomic dysreflexia- in paraplegic patients due to spinal cord injury at or above t6
level, forceful injection of contrast causes severe headache ,sweating,hypertension
with bradycardia due to forceful opening of bladder neck
21. ALTERNATE TECHNIQUES
1) SUPRAPUBIC BLADDER PUNCTURE.
Sometimes in PUV & pelvic trauma - not possible to catheterize.
2) EXCRETION MCU (MCU followed by IVU)
• This method makes use of contrast media accumulated in the urinary bladdder during ivp
Advantages : avoidance of physical and psychological trauma of catherization
• Avoidance of infection
Disadvatanges : visualization is not usually adequate Takes longer time
• Vu reflux visualised poorly.
.
29. CONTRAST MEDIUM :-
• Iopamidol (LOCM)
EQUIPMENT :-
Tilting radiography table.
• Fluoroscopy/spot film device.
• Foley's catheter, Syringe, Gloves
PREPARATION :-
• Patient is asked to micturate prior to the procedure
30. TECHINIQUE :-
Preliminary film - coned supine PA view of bladder base and urethra
• Patient is made to lie in supine position and slightly tilted
with legs position as shown in the image.
• Using aseptic conditions, the tip of the Foley's catheter is
inserted in the urethra after applying lignocaine jelly
for 2 to 4 cm length.
• Pressure is applied over the glans penis to avoid expulsion of the catheter and also to
straighten the penis over the ipsilateral leg and prevent urethral overlap.
• Contrast medium is injected slowly under fluoroscopic control.
31. IMAGING:-
• Supine PA before injecting contrast medium.
• 30º left anterior oblique
• 30º right anterior oblique
32. AFTER CARE:-
1. Observation.
2. Prophylatic antibiotics may be used
COMPLICATIONS :-
• Contrast reaction (due to absorption through bladder mucosa)
• UTI
• Urethral trauma.
• Extravasation of contrast - due to use of excessive pressure in
stricture.
33. Advantages of MR - MCU and RGU
1. These studies are most valuable to detect congenital anomalies, posterior urethral
injuries, and with urethral and periurethral tumours.
2. It is a better imaging modality for assessing the post traumatic pelvic anatomy &
non-invasive method for measuring stricture length.
3. It clearly shows the extent of scar tissue as well as prostatic displacement.
4. MR uretherography is more accurate in estimating the length of obliterative
urethral stricture than RGU combined with Voiding cystouretherography
34. Limitations of conventional RGU combined with voiding
cystouretherography:
1. It does not provide accurate length of the defect because of poor prostatic
urethral filling.
2. It does not provide information regarding extent of fibrosis of corpora spongiosa
or prostatic displacement.
3. The stricture length is overestimated if bladder neck does not relax.
35. Advantages of CT urethrography
1. C.T. voiding uretherography is more comfortable to the patient
because it requires adaptation only in one position.
2. Less time consuming; takes only few seconds
3. Comparison of lurninal size & stricture length for follow up is possible.
4. Extralurninal pathology can be detected
5. Good patient compliance
6. Ability to survey whole urinary tract from kidney to urethra
36.
37.
38.
39. RGU/ASU vs VCUG/MCU
• RGU/ASU is carried out to visualise anterior urethral abnormalities
• VCUG/MCU for posterior urethral abnormalities.
• Additionally, although the bladder is not generally the main target of the exam, as with a
cystogram, a VCUG/MCU may be useful in detection of bladder abnormalities and vesico-
ureteric reflux (VUR).
• In a trauma situation, an RGU/ASU should be performed first. A VCUG/MCU should not be
performed first because blindly trying to introduce a Foley catheter into the bladder in a
trauma setting may lead to creating additional urethral damage with the catheter
