Renal function after tumor enucleation: Assessment by quantitative SPECT of Tc-99m-dimercaptosuccinic acid uptake by the kidneys

The purpose of this study was to evaluate the amount of functioning. renal- mass removed and the amount of remaining individual renal function after tu mor enucleation. Methods: Renal functional volume, percentage injected dose (%ID) per cubic centimeter of renal tissue and individual renal uptake of 24 operated and 24 contralateral kidneys were studied by two sequential SPE CT quantitations of Tc-99m-dimercaptosuccinic acid (DMSA) uptake by the kid neys (QDMSA). The first study was before surgery and the second study was 1 to 6 mo (mean 3.5 mo) after surgery. Mean tumor size was 3.4 +/- 0.99 cm a nd all tumors were confined to the renal parenchyma (stages pT1 and pT2). R esults: In the operated kidneys, there was a statistically significant decr ease in renal cortical volume (170 +/- 46 mL after surgery versus 207 +/- 4 5 mL before surgery, t = 6.2, P < 0.001) and individual renal uptake (10.3% +/- 3.0% after surgery versus 13.0% +/- 2.9% before surgery, t = 5.4, P < 0.001). There was no statistically significant change after surgery compare d with before surgery in the %ID per cubic centimeter of renal tissue of th e operated kidneys, and in the volume, %ID per cubic centimeter and uptake of the contralateral normal kidneys. Conclusion: The results suggest that Q DMSA is a noninvasive method able to assess changes in separate renal funct ion. The limited functioning parenchymal loss after tumor enucleation had n o effect on the opposite kidneys.