Can renal blood flow, glomerular filtration rate or 99mTc-DMSA uptake predict outcome in experimental unilateral...

Single kidney glomerular filtration rate (SK GFR), single kidney blood flow (SK BF) and differential renal function (DRF), using both technetium labelled diethylene-pentaacetic acid (99mTc-DTPA) and dimercaptosuccinic acid (99mTc-DMSA), were examined as predictors of outcome in a pig model of complete unilateral ureteric obstruction. SK GFR and SK BF were unable to predict outcome following relief of obstruction but there was a high curvilinear correlation between DRF assessed at the end of defined periods of obstruction and after relief of obstruction using 99mTc-DMSA. Functional recovery was near complete using DMSA when the loss in DRF did not exceed 30%, after which there was an exponential decline in expected recovery. There was no difference between DRF using 99mTc-DTPA or 99mTc-DMSA in controls or before or after obstruction but significant differences between assessment by these radionuclides existed in the obstructed kidney at 24 h, 5 days, 10 days and 20 days. 99mTc-DMSA is a sensitive agent in the prediction of outcome following acute complete obstruction in the pig but its assessment of DRF in the obstructed kidney differs markedly from that of 99mTc-DTPA.