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

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.