RGU and MCU – Procedure and interpretation in commonly encountered disease conditions..pptx

retrograde urethrogram and micturating cystourethrogram

1. RGU and MCU – Procedure and interpretation in commonly encountered disease conditions. Dr . P Borah (Moderator) Dr. D J Borpatragohain Dr. L Nath Dr. PN Taye Dr. SS Biswas Presenter: Dr. Shreyosi Datta

2. RETROGRADE URETHROGRAPHY

3. Definition Retrograde urethrography is a radiographic imaging technique used to visualize the urethra by injecting a contrast medium retrogradely (against the natural flow) through the external urethral meatus . This procedure is primarily employed to diagnose and evaluate conditions affecting the urethra.

4. Normal anatomy In females, length of urethra is 3-4 cm. The male urethra measures, on average, 18-20 cm in length. It commences at the internal urethral orifice in the trigone of the bladder and opens in the navicular fossa of the glans penis at the external urethral meatus , which is the narrowest part of the urethra. The male urethra can be divided into anterior and posterior portions. The anterior urethra is composed of the penile and bulbar urethra to the level of the  urogenital diaphragm. The posterior urethra is composed of the membranous and prostatic urethra.

5. Anterior urethra Penile (spongy, pendulous) urethra (~16 cm long): encased by corpus spongiosum of the penis the longest portion the fossa navicularis  is a small normal dilatation of the distal penile urethra Bulbar (bulbous) urethra: traverses the root of the penis it receives the ducts from the bulbourethral glands and the glands of littre . it has bulbous dilatation named intrabulbous fossa.

6. Posterior urethra Membranous urethra (2 cm long): passes through the urogenital diaphragm, surrounded by external urethral sphincter. The shortest and narrowest portion. Cowper's gland surrounds the membraneous urethra.

7. Prostatic urethra (3 cm long): surrounded by the prostate gland; on its posterior wall runs the urethral crest and the prominent smooth muscle  verumontanum . the verumontanum receives the prostatic utricle in the midline and the ejaculatory ducts just distal to the prostatic utricle; on either side of it lie the prostatic sinuses, where numerous small prostatic ducts drain. The lower part of the prostatic urethra is fixed by puboprostatic ligament.

8. MALE URETHRA

9. Indications Urethral stricture : To evaluate the location, length, and severity of a urethral stricture. Trauma : In cases of suspected urethral injury, often due to pelvic fractures. Post-surgical stricture evaluation : To assess the urethra after surgical procedures such as urethroplasty . Urethral diverticulum : To diagnose or confirm the presence of a urethral diverticulum.

10. Urethral fistula : To identify any abnormal connections between the urethra and other structures. Recurrent Urethritis : In cases of chronic or recurrent urethritis where an anatomical abnormality is suspected. Obstructive symptoms : When patients present with lower urinary tract symptoms and an obstruction is suspected. Congenital abnormalities : To evaluate congenital anomalies of the urethra in pediatric patients.

11. Contrast media Water soluble iodinated contrast media are commonly used due to their favorable safety profile and imaging characteristics. The commonly used contrast agents include: Meglumine diatrizoate ( eg : Uroscan ) Iohexol ( eg : Omnipaque ) Iopamidol Iodixanol

12. Procedure 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 syringe local anesthetic helps to relax the sphincter as the patient may contract it during the procedure thus leading to a diagnosis of a stricture some advocate against the use of lidocaine gel on the basis that an inadequate seal is formed

13. The patient position should be oblique to visualize the full length of the urethra Place the tip of the metallic adaptor into the urethral orifice and attach the contrast loaded syringe to it an alternative is to place a Foley catheter tip in the navicular fossa and gently inflate the balloon with 2 to 3 ml of sterile water until a seal is formed making sure not to cause the patient pain or damage the distal urethra gently pull the catheter to straighten the penis and prevent overlapping on the urethra.

14. The patient is placed in supine 45 degree oblique position. The penis should be placed laterally over the proximal thigh with moderate traction. The patient should be reassured about the discomfort that is experienced during the balloon inflation. Then, 20-30 mL of 60% iodinated contrast media is injected so that the anterior urethra is filled. Commonly, spasm of the external urethral sphincter will be encountered, which prevents filling of the deep bulbar, membranous, and prostatic urethra. Slow, gentle pressure is usually needed to overcome the resistance.

15. Spot radiographs are obtained when there is visual confirmation of contrast material flowing into the bladder, If properly administered, contrast material can be seen to jet through the bladder neck into the bladder.

16. The anterior urethra extends from its origin at the membranous urethra to the urethral meatus. There is usually mild angulation of the urethra where the penile and bulbar segments can join at the penoscrotal junction. Contraction or spasm of the constrictor nudae muscles, a deep musculotendinous sling of the bulb cavernous, may cause anterior or circumferential indentation of the proximal bulbous urethra at the RGU.

17. This bulbous urethral indentation should not be confused with urethral stricture. Filling of cowpers ducts should not be misinterpreted as extravasation.

18. Filming Contrast medium is injected and spot films are taken in following positions: 30 ˚ LAO Supine AP 30 ˚ RAO

19. Complications Contrast reaction (Due to absorption through bladder mucosa) UTI Urethral trauma Intravasation of contrast- due to use of excessive pressure in stricture .

20. Urethral trauma Anterior urethral injury MC iatrogenic (due to instrumentation) May occur if patient falls on a blunt object or direct injury to perineum Straddle injury- compression of urethra against anterior pelvic ring Posterior urethral injury Crushing force to the pelvis Associated with pelvic fractures

21. Goldman & sander classification (Based on RGU findings) TYPE I injury : Rupture of the puboprostatic ligaments which stretches the prostatic urethra Continuity of the urethra is maintained.

22. TYPE II injury (15 %) The membranous urethra is torn above an intact urogenital diaphragm, which prevents contrast material extravasation from extending into the perineum.

23. TYPE III injury (MC) The membranous urethra is ruptures but the injury extends into the proximal bulbous urethra because of laceration of the urogenital diaphragm. Extravasation not only into the pelvic extra peritoneal space but also into the perineum.

24. TYPE IV: Bladder neck injury with extravasation to the urethra

25. TYPE V injury: Injury to the anterior urethra- partial or complete Extravasation seen to penile soft tissue

26. Strictures RGU accurately delineates the anatomy of urethra. Strictures are described: Location Number Extent

27. Common causes of urethral stricture INFECTION: Gonococcal urethritis (MC) Non gonococcal urethritis TRAUMA

28. IATROGENIC: Instrumentation Prolonged catherisation Trans urethral resection of the prostate Open radical prostatectomy Urethra reconstruction ( hypospadiasis / epispadiasis )

29. Although gonorrhea remains the most common STD, urethral strictures are far less common than previously due to early treatment. Instrumentation related strictures usually occur in the bulbomembranous region and, less commonly, at the penoscrotal junction.

30. Stricture in bulbar urethra

31. MICTURATING CYTSOURTEHRORGRAPHY

32. DEFINITION The cysto urethrogram demonstrates the lower urinary tract and help to detect an existence of any vesicoureteral reflux, bladder pathology and congenital or acquired anomalies of bladder outflow tract.

33. 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. The size of bladder varies when filled, the upper border of the bladder should not rise above the level of the lumbosacral junction in child and second or third sacral segment in the adult. Normal bladder wall thickness is 2-3 mm in fully distended bladder.

34. Apex of the bladder is attached to the abdominal wall by median umblical ligament (remnant of urachus ) Base is continuous with the bladder. First urge to void is felt at a bladder volume of 150 mL. Bladder capacity is between 500-600 mL. The maximum capacity of bladder is upto 1200 mL (F > M)

35. Female urethra Widest at bladder neck 4- 5 cms in length Narrowest and least distensible at meatus Spinning top configuration in normal MCU

36. Indications in children UTI Voiding difficulties likes; Dysuria, dribbling, frequency, urgency Vesico - ureteric reflux Congenital anomalies; Meningomyelocele , Rectal anomalies. Pelvic trauma Boys with hematuria

37. Indications in adults Trauma to urethra Urethral stricture Suspected urethral diverticula

38. 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 8F or 10F catheters with end holes are used.

39. In girls after an initial inspection of the perineum to identify any local genital abnormalities (like cystoceles, or labial fusion etc.) the urethral catheter is inserted. When it enters the bladder a varying amount of urine will flow through it. If there is no flow the catheter is advanced until urine is obtained. Suprapubic pressure is sometimes helpful in expressing a small amount of urine in the near empty bladder. If no urine is obtained the catheter may have been inserted into the vagina.

40. In males, the foreskin is retracted and catheter is introduced. The catheter should be lubricated with an anesthetic jelly and inserted slowly and gently into the urethra holding the penis in a vertical position. The normal bladder capacity in children: Newborns: 30-50 cc Girls >3 years: 200-250 cc Boys >3 years: 100-150 cc Adequate capacity is reached when the child becomes uncomfortable and begins voiding around the catheter.

41. Filming In children , upto the age of 2 years bladder is filled by hand injection. For older children contrast medium is instilled from a bottle elevated one metre above examination table. If reflux appears, films are taken in the appropriated oblique projection. If bladder appears normal, one film is taken in the frontal projection at the end of filling.

42. 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 the termination of voiding and may reach the upper collecting system. In adult male, bladder is filled in the usual way as in an older child and voiding filming is done in both oblique projection.

43. Modifications For stress incontinence, following additional films are taken Lateral full bladder, at rest Lateral bladder, straining Lateral bladder, during micturition. For fistulae, a series of films in AP, lateral and oblique positions may be required.

44. Causes of incomplete bladder emptying Effect of sedation Dysuria following catheterization Neurogenic bladder Refilling of bladder from above where there is significant VUR

45. Complications Danger of attendant infection due to catheterization of bladder. Adverse reactions may result from absorption of contrast medium by bladder mucosa. Due to technique: Acute urinary tract infection Catheter trauma causing dysuria, frequency hematuria and urinary retention Complications of bladder filling- Perforation by the catheter of from over distension.

46. VESICO-URETERIC REFLUX Vesicoureteric reflux is the term for abnormal flow os urines from the bladder into the upper urinary tract and is typically a problem encountered in young children. MCU is indicated after a first UTI only if USG reveals hydronephrosis , scarring or other abnormalities suggestive of high grade VUR or obstructive uropathy or in patients with complex clinical conditions.

47. MCU identifies: Presence and grade of VUR Whether refluc occurs during micturition or during bladder filling Associated anomalies

48. Etiology of VUR Primary reflux: Fundamental deficiency in the function of VUJ. Reflux occurs despite an adequately low pressure urine storage in bladder. Secondary Reflux: Cause of this form of reflux is most often from failure of the bladder to empty properly , either due to blockage or failure of the bladder muscle or damage to nerves that control normal bladder emptying.

49. Anatomical causes Posterior urethral valve Prostatomegaly Ureterocele Ureteral duplications Neurogenic bladder Dysfunctional voiding Uninhibited bladder contractions

50. GRADES OF VESICOURETERIC REFLUX

51. 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 fornices but preserved papillary impressions. Grade 5: Tortuous ureter with severe dilatation of ureter and PCS: loss of fornices and papillary impressions.

52. GRADE 1: Reflux limited to ureter

53. GRADE 2 : Reflux into renal pelvis

54. GRADE 3: Mild dilatation of ureter and pelvicalyceal system

55. GRADE 4: Tortuous ureter with moderate dilatation, blunting of fornices but preserved papillary impressions.

56. GRADE 5 : Tortuous ureter with severe dilatation of ureter and PCS: loss of fornices and papillary impressions.

57. Posterior urethral valve

58. Posterior urethral valve are the most common congenital obstructive lesion of the urethra and a common cause of obstructive uropathy in infancy. Congenital thick folds of mucous membrane located in the posterior urethra distal to verumontanum . MCC of severe obstructive uropathy in children. Almost exclusively in males. Leading cause of end stage renal disease in boys. The valves can be identified on MCU or USG associated with proximal dilatation of the posterior urethra.

59. CLASSIFICATION According to Young's classification, there are three types of posterior urethral valves  : Type 1 most common occurs when the two mucosal folds extend anteroinferiorly from the bottom of the  verumontanum  and fuse anteriorly at a lower level

60. Type 2 Rare No longer considered as a valve but a normal variant Mucosal folds extend along posterolateral urethral wall from the internal urethral orifice to the verumontanum Type 3 Circular diaphragm with central opening in membranous urethra Located below the verumontanum and occurs due to abnormal canalization of the urogenital membrane Sometimes referred to as  Cobb’s collar.

61. MCU is the best imaging technique for the diagnosis of posterior urethral valve. The diagnosis is made during the micturition phase in lateral or oblique views, so that posterior urethra can be visualized properly. Finding include: Dilatation and elongation of posterior urethra Linear radiolucent band corresponding to the valve VUR Bladder trabeculation / diverticula

62. Meatal stenosis Congenital narrowing of the urethral orifice/ may be caused by meatal webs. Can occur in both males and females. Associated with hypospadiasis Acquired more common C/f: Weakness of urinary stream and straining during micturition Diagnosis: Clinical, imaging if obstructive features are present

63. Bladder diverticula Sac formed by herniation of bladder mucosa and submucosa through muscular wall Mostly acquires in males In early stages, multiple small protrusions of the bladder lumen appear between the trabeculae ( sacculation ) As the enlarge above 2 cm they become defined as diverticula

64. Mostly found close to ureteric orifice Stasis in diverticula may lead to stone formation 2 % cases lead to carcinoma, MC tumor is Squamous cell carcinoma. A wide necked diverticulum empties readily when the bladder empties while narrow neck diverticula empties slowly.

65. Classical symptom of double micturition: When the patient empties bladder a significant amount of urines is stored in the diverticulum which then empties back into bladder, causing a desire to micturate almost immediately after the first micturition.

66. Bladder herniation At least 95% of bladder herniation is into the inguinal or femoral canals Usually small (2-3 cm) and asymptomatic Painful, partly obstructed micturition Usually narrow neck and fill poorly on routine contrast images

67. Vesico -vaginal fistula MCC in developing countries: Prolonged obstructed labour MCC in developed countries: Abdominal hysterectomy Rarely due to pelvic malignancy, radiation

68. C/f : painless constant dribbling of urine from vagina Lateral and oblique films are best May present with cyclical hematuria pattern ( Youseff’s syndrome)

69. BLADDER TRAUMA

70. CAUSES External penetrating agents (such as bullets, stab wounds) Internal penetrating agents such as cystoscopies, lower abdominal surgery or blunt trauma More the bladder distension, more severe is the injury C/f : Suprapubic pain, Hematuria

71. BLADDER INJURY CLASSIFICATION TYPE 1: Bladder contusion TYPE 2: Intraperitoneal rupture TYPE 3: Interstitial bladder injury TYPE 4 : Extra peritoneal rupture TYPE 5: Combined

72. Bladder contusion (Type 1) This is commonly seen but sometimes not classed as true rupture, since it involve an incomplete tear of the mucosa. If unilateral, bladder maybe displaced to another side. But mostly bilateral, they will compress and elevate the inferior portion of the bladder so that it looks an upside down teardrop (Tear drop bladder)

73. Intraperitoneal rupture ( Type 2 ) Occurs in approximately 15 % of major bladder injuries, and typically is the result of a direct blow to the already distended bladder. MCU demonstrates intraperitoneal contrast material around bowel loops, between mesenteric folds and in the paracolic gutters. Treatment is surgical repair

74. Interstitial injury (Type 3) Very rare type Intramural or partial thickness laceration with intact serosa Incomplete perforation; seen on either intra- or extraperitonea l portion of bladder Intramural and submucosal extravasation of contrast without transmural extension. Subserosal rupture causes elliptical extravasation adjacent to the bladder.

75. Extraperitoneal injury (type 4) Extraperitoneal rupture is the most common type of bladder injury accounting for 85% of cases. It is usually the result of pelvic fracture or penetrating trauma. Cystography reveals variable path of extravasated contrast material.

76. Simple (Type IVA) : Flame shaped extravasation around the bladder Complex (Type IV B): Extravasation extends beyond the pelvis

77. Combined rupture (Type 5) Simultaneous intraperitoneal and extraperitoneal injury. Cytography must be performed in all patients with gross hematuria associated with pelvic fractures Cystography is performed after urethral injury has been excluded and when retrograde bladder catherisation is safe. The accuracy of cystography for the diagnosis of bladder injury varies from 85% to 100%

78. RGU vs MCU Generally, a RGU is carried out to visualize anterior urethral abnormalities and MCU for posterior urethral abnormalities. Additionally, although the bladder is not generally the main target of the exam, as with a cystogram , a MCU may be useful in detection of bladder abnormalities and vesico -ureteric reflux (VUR).

79. In a trauma situation, an RGU should be performed first. A 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.

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