Retrograde uretherogram and Micturating cysto-uretherogram

RGU MCU RADIOLOGICAL PROCEDURE

1. Retrograde Urethrogr aphy (RGU) AND Micturating Cystourethrogra phy (MCU) By Dr. Aniket Chugh DEPARTMENT OF RADIODIAGNOSIS ERA’S LUCKNOW MEDICAL COLLEGE AND HOSPITAL

2. INTRODUCTION: Urethrography refers to the radiographic study of the urethra using iodinated contrast media and is generally carried out in males. When the urethra is studied with instillation of contrast into the distal/anterior urethra it has been referred to as: Retrograde urethrography [RGU] Ascending urethrography [ASU] When the posterior urethra is studied during micturation, this has been referred to as: Voiding cystourethrography [VCUG] Micturating cystourethrography [MCU]

3. 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.

4. Bulbar urethra From inferior aspect of urogenital diaphragm to penoscrotal junction. Spongy (penile) urethra: Passes through the length of the penis.

5. PARTS OF URETHRA ANTERIOR URETHRA -PENILE URETHRA -BULBAR URETHRA POSTERIOR URETHRA - MEMBRANOUS URETHRA - PROSTATIC URETHRA

6. F e male urethra : - In females the urethra is relatively short 4-5cms in length It begins at the neck of bladder and passes inferiorly through the perineal membrane and muscular pelvic floor. Narrowest and least distensible at meatus. This forms the Spinning top configuration of urethra on normal MCU.

7. R GU /ASU vs VCUG/MCU R GU is carried out to visualize anterior urethral abnormalities 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 R GU /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

8. 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.

9. I NDICATIONS:- • Stricture • Urethral Trauma • Fistulae or false passages • Congenital abnormalities CONTRAINDICATIONS:- • Acute UTI • Recent instrumentation

10. CONTRAST MEDIUM :- - Iohexol (LOCM) - Iopamidol (LOCM) EQUIPMENT :- Tilting radiography table. Fluoroscopy/spot film device. Foley’s catheter/Infant feeding tube, Syringe, Gloves PREPARATION :- Patient is asked to micturate prior to the procedure

11. TECHINIQUE :- Preliminary film - Coned Supine AP view of Bladder Base and Urethra Place the patient in supine position . Retract the foreskin and clean the tip of the penis with Betadine® (povidone-iodine) or antiseptic solution Inject a small amount of topical local anesthetic (e.g., lidocaine gel) into the urethra with a 8-F foley catheter or syringe and ballon is inflated with 1-3 ml of water. Local anesthetic helps to relax the sphincter as the patient may contract it during the procedure thus leading to a diagnosis of a stricture. The patient position should be oblique to visualize the full length of the urethra. Contrast medium is then injected under fluoroscopy control and films are taken. Gently pull the catheter to straighten the penis and prevent overlapping on the urethra. The male urethra is best seen in the oblique position. Female urethra is best seen in lateral or antero-posterior position. Ideal images demonstrate the entire length of the urethra with contrast beginning to fill the bladder.

12. IMAGING:- Supine AP before injecting contrast medium. 30º left anterior oblique 30º right anterior oblique NORMAL RETROGRADE URETHROGRAM (RGU) : If the radio-opaque contrast is injected properly the entire anterior and posterior urethra should be filled with contrast and seen to jet into the bladder neck. The verumontanum is seen as an ovoid filling defect in the posterior urethra. The distal end of the verumontanum marks the proximal boundary of the membranous urethra and constitutes the urethra that passes through the urogenital diaphragm.

13. AFTER CARE :- 1. O bservation. 2. Prophylactic antibiotics may be used COMPLICATIONS :- Contrast reaction (due to absorption through bladder mucosa) UTI Urethral trauma. Ex travasation of contrast - due to use of excessive pressure in stricture.

14. Micturating Cystourethrogram (MCU) Voiding cystourethrogram / Micturating cystourethrogram demonstrates the lower urinary tract H elps in detect ion of: V esico-ureteric reflux Bladder pathology Congenital or acquired anomalies of bladder outflow tract.

15. INDICATIONS Children : 1. UTI 2. Voiding difficulties like dysuria, thin stream, dribbling, frequency, urgency. 3. Vesico ureteric reflux. 4. Neurogenic dysfunction of the bladder: Meningomyelocele, Sacral agenesis. 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 urethral valve 9. Hydronephrosis and/or Hydroureter.

16. Adults Main indications : 1. Suspected bladder/urethral trauma. 2. Suspected urethral diverticula. 3. Suspected vesicovaginal/ vesicocolic fistula. Functional disorders of bladder and urethra .

17. 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 the catheter is introduced till urine is obtained. 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 urethra holding the penis in a vertical position. The normal bladder capacity in children is estimated to be ~( 29)cc. For newborns -30 to 35 cc can be instilled. For up to 3 yrs - 200 to 250 cc can be given. Adequate capacity is reached when the child becomes uncomfortable and begins voiding around the catheter.

18. Contrast is diluted with normal saline before administration. 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) Adult: Around 500 ml

19. Filming In children 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 taken which includes 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 .

20. In Adult Male : B ladder 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.

21. 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.

22. 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 is necessary because it gives the determination of reflux because reflux may only happen with the pressure generated by voiding. NORMAL MCU (IN MALES) NORMAL MCU (IN FEMALES)

23. 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.

24. COM PL ICATIONS Contrast reaction. Contrast induced cystitis. UTI. Catheter trauma. Bladder perforation - overfilling. Retention of a foley catheter. Catheterization of vagina / ectopic ureter. Radiation exposure

25. Vesicoureteric reflux (VUR) grading 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

26. GRADE-III GRADE-IV GRADE- V

27. POSTERIOR URETHRAL VALVE IN NEWBORN POSTERIOR URETHRAL VALVE IN 7 YEARS OLD Transverse filling defect in the posterior urethra

28. HUTCH DIVERTICULUM NEUROGENIC BLADDER

29. 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.

30. 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 luminal size & stricture length for follow up is possible. 4. Extraluminal pathology can be detected 5. Good patient compliance 6. Ability to survey whole urinary tract from kidney to urethra

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