Diagnostic Criteria for Stomal Obstruction of Tubeless Cutaneous Ureterostomy by Use of 99mTc-Mercaptoacetyltriglycine Diuretic Renography

PURPOSE To evaluate (99m)Tc-mercaptoacetyltriglycine diuretic renograms for diagnosing stomal obstruction in tubeless cutaneous ureterostomy. MATERIALS AND METHODS Cutaneous ureterostomy was performed in 29 patients (56 renal units) with a minimum follow-up period of 12 months. Stomal obstruction was evaluated with (99m)Tc-mercaptoacetyltriglycine diuretic renography 3 months after surgery. Regions of interest were drawn that completely encircled and snugly fit the kidney, renal pelvis, and ureter. The data analyses were performed with half-times to tracer clearance following furosemide (0.5 mg/kg) administration. RESULTS The mean half-times to tracer clearance were 6.90±6.30, 5.25±4.29, and 8.75±7.63 minutes in the total, ipsilateral, and contralateral kidneys, respectively, in side relationships between the ureter and the stoma. There were significant differences between the ipsilateral and contralateral kidneys in the mean half-time to tracer clearance (p=0.038). Forty-eight renal units (85.7%) had a half-time to tracer clearance of less than 15 minutes, and all 48 renal units had no hydronephrosis. On the other hand, 5 renal units (8.9%) had a half-time to tracer clearance of more than 20 minutes, and these 5 renal units required the insertion of stent catheters or became atrophic. CONCLUSIONS (99m)Tc-mercaptoacetyltriglycine diuretic renography was very useful for diagnosing stomal obstruction of tubeless cutaneous ureterostomy. The upper limit of the half-time to tracer clearance for unobstructed systems was 15 minutes, which allowed for the confident exclusion of stomal obstruction in tubeless cutaneous ureterostomy.