Diuretic renogram in a patient with a urinary diversion - Avoiding a false-positive diagnosis of obstruction with an indwelling catheter

A 57-year-old man with prostate adenocarcinoma had undergone a radical cystoprostatectomy and a urinary diversion with an Indiana reservoir. Abdominal computed tomography (CT) performed 2 years after the resection showed mild left-sided hydronephrosis. To investigate the possibility of an obstructive hydronephrosis, a standard diuretic renogram was performed, but the results were inconclusive. To evaluate further the possibility of obstruction, the diuretic renogram protocol was modified by the addition of an indwelling catheter placed into the ileal ostomy to eliminate any confounding reflux. By emptying the high-pressure urinary reservoir, ureteric obstruction was definitively ruled out.