[Evaluation of unilateral renal function in urinary obstruction. A comparison of various radioisotope methods...

The catheter-free determination of the unilateral 131I-hippuran clearance correlates well with the unilateral clearance determination with 99mTc-DMSA in patients without obstruction. In patients with unilateral chronic obstruction the clearance of 131I-hippuran on the average is 13% higher than the clearance determined by the DMSA method. After successful correction of the obstruction the two values are identical. 123I-hippuran is foundin the renal pelvis already after 90 seconds in some cases of marked chronic obstruction. The functioning part of the involved kidney is therefore possibly overestimated whereas the DMSA uptake reflects the actual function. Both radioisotope methods should be applied preoperatively in order to evaluate the individual renal function. Functional scintigraphy in patients with obstruction should preferably be carried out with 123I-hippuran.