Renal system

1. Retrograde urethrography (RGU)
and
Micturating cystourethrography(MCU)
Dr. Sharmin Sultana
DMRD(2nd batch)
Radiology and Imaging
department
Rajshahi Medical College

2. Objectives:
 RGU and MCU are imaging techniques used to evaluate
lower urinary tract.
 RGU focuses the urethra and MCU visualizes the bladder and
urethra during micturition.
 These help identify the location and severity of strictures and
other diseases,guiding treatment decisions.

7. Membranous urethra
 Shortest,narrowest and least distensible part
 1-1.5cm
 Surrounded by external urethral sphincter
 The bubourethral glands of Cowper are placed one on each side
 Urethral glands also open here.

8. Bulbar urethra
 It is a segment of the male urethra located between the membranous
urethra and the penoscrotal junction.
 It's a widened portion of the urethra, surrounded by the bulbospongiosus
muscle and plays a role in both urination and ejaculation.
 It is approximately 4-5 cm long.

13. Urethrography
 It refers to the radiographic study of the urethra using iodinated contrast media.
 types:
 Retrograde urethrography (RGU)-contrast is retrogradely injected with the urethral
orifice occluded to prevent reflux of contrast.
 Antegrade(VCUG):bladder is filled with contrast via suprapubic or retrograde
catheterization and the urethra is assessed during voiding.
 Following IVU.
 For both static images can be obtained ,but preferably assessed dynamically under
fluoroscopy.
 Male urethra is best seen in the oblique position.
 Female urethra is best seen in lateral or AP position.

14.  Voiding cystourethrogram is mostly used to visualize and evaluate:-
prostatic urethra and changes in the bladder neck.
 Retrograde urethrography is mostly used to visualize and evaluate:-
membranous and anterior urethra, inflammatory lesions and diverticula.
 Some patients are assessed with both techniques,usually the RGU is
performed 1st
,followed by VCUG.

15. Retrograde/Ascending urethrography (RGU)
 Essentially confined to males
 Indications:
 Urethral Stricture
 Urethral tears/pelvic trauma
 Urethral obstruction/FB/diverticulum
 Periurethral/prostatic abscess
 Fistula/false passages
 Urethral mucosal tumors
 Post operative evaluation
 Congenital abnormalities

16.  Contraindications:
 Acute UTI
 Recent instrumentation
 Contrast medium:
 Iopamidol(LOCM)-5-10ml of 150 strength.
 Equipment:
 Tilting radiography table
 Fluoroscopy /spot film device
 Foley’s catheter(12-16G)
 Syringe ,gloves.

17. Preparation:-
 Patient is asked to micturate prior to the
procedure.
Technique:
 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 2-4cm 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.
 CM is injected slowly under fluoroscopic control.

20. Imaging:
 Supine PA before injecting CM
 30 degree left anterior oblique
 30 degree right anterior oblique
 Complications:
 Contrast reaction(due to absorption through bladder mucosa)
 UTI
 Urethral trauma/rupture
 Extravasation of contrast –due to use of excessive pressure in stricture.

24. Role of urethrography in stricture
 Accurately delineates the anatomy of urethra
 Location,number and strictures are very well displayed
 Secondary changes in the bladder
 Visualization of any associated fistulas.

26. The retrograde urethrogram showed a filling defect in the bulbous urethra
and ( arrow) and a high grade stricture of approximately 3 cm length of
the bulbous urethra (arrowhead).

30. Urethral calculi
 Mostly expelled from bladder into urethra during voiding-migrant calculi
 Primary calculi may be seen in association with urethrai stricture/diverticulum
 Symptoms include weak stream,dysuria and hematuria
 RGU usually depicts a rounded filling defect in the urethra

31. Urethral diverticula, or
urethroceles, are focal
outpouchings of the urethra.it
occurs far more frequently in
women than in men.
In the post void series, small
residual urine/contrast remains
within the diverticulum.

32. Retrograde urethrogram
shows urethral diverticulum
arising from the penile
urethra.

33. Tuberculous urethritis
 Descending infection and renal TB is evident
 In the acute phase,there is urethral
discharge with associated involvement of
epididymis,prostate and other parts of the
urinary system.
 In chronic phase,patients present with
obstructive symptoms secondary to urethral
stricture
 May lead to periurethral abscesses ,which
unless treated ,produce numerous perineal
and scrotal fistulas.-Watering can perineum
 RGU typically demonstrates an anterior
urethral stricture associated with multiple
prostalocutaneous and urethrocutaneous
fistulas.

34. Blunt urethral trauma
 Classified anatomically as-anterior
-posterior
 Anterior urethral injury
Iatrogenic (due to instrumentation)
May occur if pt falls on a blunt object/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

40. Micturating cystourethrography(MCU)/Anterior
urethrography
 Indications:-
 Children
 Recurrent UTI
 Voiding difficulties
 Vesico-ureteric reflux
 Baseline study prior to lower urinary tract surgery
 Pelvic /Urethral trauma
 Suspected anatomic abnormalities of bladder neck and
urethra(posterior urethral valve)

41. Adults
 Functional disorders of bladder and urethra
 Suspected vesicovaginal/vesicocolic fistula
 Suspected bladder/urethral trauma
 Urethral diverticula
 Contraindications:
 Acute UTI
 Contrast medium:
 Iopamidol(LOCM)
 Urovideo 76%,50cc(HOCM)
 With atleast 200ml of 150 strength contrast

42.  Equipment:
 Tilting radiography table
 Fluoroscopy /spot film device
 Foley’s catheter (10F)/infant feeding tube (no. 6)
 Syringe, gloves.
 Preparation:-
 Patient is asked to micturate prior to the procedure.

43. Procedure
 Under aseptic conditions,catheterize the UB with patient in supine position.
 Push the diluted CM slowly under fluoroscopic guidance
 Ask the patient to inform you when he has urge to micturate
 Ask the patient to micturate in a urine receiver in an erect oblique position.
 Spot images are taken during micturition in right and left oblique projections and
any reflux is recorded.
 Finally,a full length view of the abdomen is taken to show any undetected reflux
of the CM that might have occurred in the kidneys and to record the post-
micturition residue.

44. Imaging
 it is performed directly AP in females and in a 45degree
oblique projection in males.
 Lateral views are helpful when fistulation into rectum /vagina
are suspected.
 Oblique views are needed when evaluating for leaks.
 AP with full bladder to show presence or absence of VUR.
 Both obliques show bilateral vesicoureteric junctions.
 Post void film to check for a ureterocele.

47.  Complications:
 Contrast reaction
 Contrast induced cystitis
 UTI
 Catheter trauma
 Bladder perforation –due to overfilling of CM
 Retention of Foley’s catheter .
 After care:
 Patient shoud be warned of rare dysuria and retention of urine
 In case of reflux-antibiotics are to be prescribed.

55. Prune belly syndrome
 Prune belly or triad syndrome (PBS) describes a triad of laxity of abdominal
musculature, bilateral undescended testicles, and GU tract abnormalities,
which include hydronephrosis, renal dysplasia, and urethral dilation.
 Urethral dilation in PBS may arise from one of three etiologies. The first,
urethral obstruction, occurs early in gestation and is believed to occur in 20
% of cases, from urethral atresia, urethral valves, or urethral diverticulum.
Alternatively, the urethral dilation may be related to a functional
abnormality of bladder emptying without obstruction.
 In the absence of an obstructive lesion, the dilation may result from
prostatic hypoplasia. VCUG in PBS shows tapering of the dilated posterior
urethra to the membranous urethra. A prostatic utricle is often present

56. Prune belly
with wide
open bladder
neck, dilated
but short
posterior
urethra

57. Congenital megalourethra
 This is a rare congenital anomaly resulting from faulty
development of corpora cavernosa and corpus
spongiosum.

59. Urachal diverticulum
 Persistence of a
segment of the
urachus ,present as a
protrusion at the vertex
of bladder.it may
predispose to urolith
formation.

60. Prostatic utricle
 The prostatic utricle is a
small,blind ending
midline pouch arising
from the prostatic
urethra at the level of
the verumontanum.
 A large prostatic utricle
may be associated with
urinary retention,stasis
and infection.

61. Ureterocele
 It is the cystic dilatation of terminal ureter in the intravesical
intramural segment.
 Important cause-failure of resorption and canalization of an
embryonic membrane that covers ureteric orifice in fetus with
obstruction at VUJ and ballooning of the segment just proximal to it.
 On MCU,it is seen as a filling defect in a contrast filled bladder.

69. Fig—25-year-old man who
presented with hematuria
after blunt perineum
contusion. Retrograde
urethrogram shows contrast
medium extravasation
(arrow) in bulbous urethra.

70. Fig:-25-year-old man who
presented with hematuria
after blunt perineum
contusion. Volume-
rendered CT voiding
urethrogram obtained with
contrast infusion from
suprapubic tube shows
contrast extravasation and
irregular mucosal surface
(arrow) in bulbous urethra.
Urethrocavernous and
urethrovascular reflux
(arrowhead) also were
noted.

71. Take home message
 Verumontanum acts as a normal filling defect on the RGU.
 Rule out acute UTI prior to urethrogram.
 Always stretch the penis during RGU.
 Both procedures are generally safe, but potential risks are present include
infection, allergic reactions to the contrast dye, and discomfort during
catheter insertion or urination.