A scintillation camera technique for quantitative estimation of separate kidney function and its use before nephrectomy

A scintillation camera technique was used for measuring renal uptake of [131I]Hippuran 80-110 s after injection. Externally measured Hippuran uptake was markedly influenced by kidney depth, which was measured by lateral-view image after injection of [99Tc]iron ascorbic acid complex or [197Hg]chlormerodrine. When one kidney was nearer to the dorsal surface of the body than the other, it was necessary to correct the externally measured Hippuran uptake for kidney depth to obtain reliable information on the true partition of Hippuran between the two kidneys. In some patients the glomerular filtration rate (GFR) was measured before and after nephrectomy. Measured postoperative GFR was compared with preoperative predicted GFR, which was calculated by multiplying the preoperative Hippuran uptake of the kidney to be left in situ, as a fraction of the preoperative Hippuran uptake of both kidneys, by the measured preoperative GFR. The measured postoperative GFR was usually moderately higher than the preoperatively predicted GFR. The difference could be explained by a postoperative compensatory increase in function of the remaining kidney. Thus, the present method offers a possibility of estimating separate kidney function without arterial or ureteric catheterization. (auth)