Direct estimation of absolute glomerular filtration rate from dynamic renal scintigraphy using gamma camera

Absolute glomerular filtration rate (GFR), which can serve as a useful parameter of renal function, is not applied in clinical practice due to various technical constraints. We estimated GFR in 20 subjects (10 controls, 10 patients) by two different techniques simultaneously with a single intravenous injection of TC99m DTPA. The GFR results obtained by a conventional plasma clearance technique were compared with that of a simpler, scintigraphic technique which does not require any blood or urine sample, and these were found to correlate significantly (r = 0.75, p less than 0.001). The linear relationship between the fraction of the dose injected taken up by the kidneys during the parenchymal phase of the dynamic imaging study and the overall plasma clearance was also found to be significant (r = 0.932, p less than 0.001) our study shows that reliable estimation of absolute GFR is possible from the routine dynamic renal scinti-scanning procedure using the gamma camera - computer system, and hence might prove applicable in clinical practice.