Necrosis of the allograft ureter--evaluation of different examination methods in early diagnosis.

After renal transplantation, 16 of 1,109 patients (= 1.5%) developed an operatively confirmed necrosis of the allograft ureter. A review of these cases reveals that noninvasive ultrasonography, which was applied regularly with all patients, gave early indications of urologic complication. In cases of peritransplant fluid collection, renal transplant scintigraphy may be helpful in diagnosing a urinoma. In cases of renal graft failure with sonographic findings of perinephric fluid collection or hydronephrosis, antegrade pyelography--though more invasive--should always be performed given its low complication rate and improved visualization and pathological localization compared to other techniques. However, ureteral extravasation can be demonstrated only in cases of advanced necrosis; with necrosis just beginning and the wall still intact, frequently only the image of an obstruction is found.