2012 Radiology Exam - Spec Proced/NM Case 2

History

  • 7-year-old MC Australian Shepherd Dog
  • Straining to urinate and defecate
  • Recent exploratory laparotomy and castration

Images

  • Survey radiograph, urethrogram, IVP

Survey Radiograph

  • Major findings - The bladder neck is in an intrapelvic position, and there is perineal soft tissue swelling with granular material superimposed.
  • Minor findings - There are postoperative changes (soft tissue swelling, free gas, effusion) consistent with the history of recent surgery.

Cystourethrogram

  • The bladder neck is in an intrapelvic position and is compressed within the pelvis on the v/d projection
  • The prostatic urethra has a serpentine shape and appears kinked and dilated
  • The prostate is located in the right perineum, confirmed on the v/d projection, with linear reflux of contrast medium
  • The filling defects within the urethra are mobile and consistent with air bubbles

Excretory Urogram

  • The left ureter overlies the bladder in the caudal abdomen and travels in an abnormally ventral position into the pelvic canal
  • The left and right renal pelves are dilated.
  • The left ureter is dilated and completely filled with contrast
  • The right ureter is dilated proximally, however absence of complete filling is normal with peristaltic waves

Conclusion

  • Perineal hernia with herniation of bladder, prostate, and proximal urethra
  • Partial ureteral obstruction secondary to perineal hernia and compression of the ureters within the pelvic canal. The compression also relates to the malposition of the left ureter.
  • Appearance of prostate most likely consistent with BPH and recent neuter but prostatitis and other diseases cannot be ruled out.

Recommendation

  • Surgical repair of the perineal hernia

Challenges

  • Candidates failed to recognize the abnormal position of one or all of the bladder, prostate, and urethra, and did not correlate the right perineal position of the prostate and soft tissue swelling with a perineal hernia.
  • Many candidates concluded that the ureteral and pelvic dilation was secondary to pyelonephritis without recognizing the obstructive nature of the perineal hernia
  • The increased contrast in the GI tract after the excretory urogram is due to normal circulation of contrast injected intravenously. There was no disruption of the right ureter or urinary bladder resulting in contrast leakage.
  • Lack of filling of a ureter is normal due to the peristaltic motion of urine through the ureters, and does not necessarily indicate ureteral obstruction
  • Normal filling defects due to air bubbles from contrast injection are mobile in the urethra.