Ureteral obstruction after ureteroneocystostomy in dogs assessed by technetium Tc 99m diethylenetriamine pentaacetic acid (DTPA) scintigraphy

Objective-To use technetium Tc 99m diethylenetriamine pentaacetic acid (Tc- 99m-DTPA) renal scintigraphy to monitor ureteral obstruction after ureteron eocystostomy in a canine model of partial ureteral obstruction. Study Design-Experimental study. Animals-Eight normal adult dogs. Methods-Partial ureteral obstruction was created in 8 dogs by incomplete li gation of the terminal right ureter. Two weeks later, ureteroneocystostomy was performed in 7 dogs with unilateral partial ureteral obstruction and in 1 dog that had developed bilateral partial ureteral obstruction. Tc-99m-DT PA scintigraphy was performed intermittently for 2 weeks after ureteroneocy stostomy. Renal transit time of each kidney, as assessed by the time to max imal uptake (time of peak), and glomerular filtration rate, as assessed by percentage of kidney uptake of the radiopharmaceutical between 1 and 3 minu tes, were estimated. Comparison between affected and nonaffected kidneys wa s performed with the Wilcoxon rank sum test. Results-Unilateral partial ureteral obstruction was induced successfully in 7 dogs. In 1 dog, bilateral partial obstruction was induced inadvertently. After ureteroneocystostomy, percentage of kidney uptake of Tc-99m-DTPA was low in 4 affected kidneys. The uptake returned to within normal limits in 2 of the kidneys during the observation period. The time activity curve had a more rounded appearance or was increasing continuously for all affected kidneys. A significant increase in renal transit time was observed 2 and 4 days after ureteroneocystostomy. Transit time progressively returned to nor mal by 4 to 11 days for all affected kidneys except 1. Conclusion-Ureteroneocystostomy resulted in persistent partial ureteral obs truction for 4 to 1 1 days as determined by Tc-99m-DTPA scintigraphy. Clinical Relevance-Tc-99m-DTPA scintigraphy may be a useful procedure for m onitoring renal function and ureteral obstruction after ureteroneocystostom y. Persistent partial ureteral obstruction may be seen 1 to 2 weeks after u reteral reimplantation in dogs with previously existing dilated ureters. (C ) Copyright 2000 by The American College of Veterinary Surgeons.