99mTc-aprotinin: comparison with 99mTc-DMSA in normal and diseased kidneys.

Aprotinin (A) and DMSA labelled with 99mTc were compared in patients with normal (NK, n = 12) and diseased kidneys (CRF, n = 13) by means of quantitative serial scans and measurements of blood clearance and urinary excretion. Serial scans only were obtained in additional 13 patients. Scan quality in the NK patients was essentially equal: faster blood clearances, reduced urinary excretions and higher fixations of A in the target compensated for the increased liver uptake. On the other hand, the scan quality in the CRF patients was definitely superior with A, allowing detection of residual functioning parenchyma also in severe kidney failure. Correlation between the net kidney uptake 6 hrs p.i. and the separate hippuran clearance rate was better with A than with DMSA, indicating the feasibility of A in evaluating relative renal function.