details about RGU and MCU

1. Micturating Cystourethrography (MCU)
&
Retrograde Urethrography (RGU)

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. Micturating Cystourethrogram (MCU)
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.

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

10. Adults Main indications: 1. Trauma to urethra.
2. Urethral stricture. 3. Suspected urethral
diverticula

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. 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

20. Vesicoureteric reflux
(VUR) grading divides vesicoureteric reflux
(VUR) according to the height of reflux up
the ureters and degree of dilatation of the
ureters:
grade 1: reflux limited to the ureter
grade 2: reflux up to the renal pelvis
grade 3: mild dilatation of ureter and
pelvicalyceal system
grade 4
tortuous ureter with moderate dilatation
blunting of fornices but preserved
papillary impressions
grade 5
tortuous ureter with severe dilatation of
ureter and pelvicalyceal system
loss of fornices and papillary
impressions 2

21. Retrograde/Ascending Urethrography (RGU)
Definition: • It is retrograde demonstration of
the renal pelvis and ureter by the retrograde
injection of radio-opaque material through the
ureters.

22. INDICATIONS:- • Stricture • Urethral Trauma •
Fistulae or false passages • Congenital
abnormalities Periurethral / prostatic abscess
CONTRAINDICATIONS:- • Acute UTI • Recent
instrumentation

23. 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

24. 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

25. IMAGING:- • Supine PA before injecting
contrast medium. • 30º left anterior oblique •
30º right anterior oblique

26. 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

27. 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

28. 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

29. 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

30. 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 vesicoureteric 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