Canadian Association of Nuclear Medicine l’Association canadienne de médecine nucléaire

A 23 year-old-female patient with a history of renal transplantation at the left iliac fossa 12 years ago underwent a recent renal transplantation to the right side, one month prior to our evaluation. The graft is carrying an ureteropelvic duplication with 2 ureterovesical anastomosis described by pelvic ultrasound. In the early postoperative course, a technetium-99m mercaptoacetylglycine-3 (Tc-99m MAG3) renal scan demonstrated a normal transplant kidney perfusion without complication.The follow up ultrasound showed a new mild hydronephrosis, 10 days after surgery and stent removal, predominant at the superior pole of the graft with dilatation of the upper ureter down to the level of the ureterovesical anastomosis. It also demonstrated a stable fluid collection inferiorly to the graft attributed to a residual hematoma. Because of the progression of hydronephrosis and the deterioration of the renal function, a Tc-99m MAG3 renal scan with Lasix is performed to rule out an obstruction. The graft was well perfused and functional. There was a mild stasis at the superior collecting system but also gradual accumulation of tracer adjacent to the lower part of the graft, near the distal anastomosis. A urinary leak is suspected then confirmed by SPECT/CT imaging which showed tracer accumulation in a pelvic collection, lateral to and distinct from the right aspect of the bladder, close to the anastomotic site. The follow up ultrasound demonstrated a dilatation of the superior collecting system and a hypoechoic fluid collection laterally to the bladder. Percutaneous nephrostomies were installed for the two collecting systems. A leak from the ureterovesical anastomosis of the superior system was demonstrated. This case report underlines the usefulness of renal scintigraphy in the early evaluation of renal transplants with SPECT/CT imaging to accurately depict and characterize a leak at the ureteral anastomosis.