OBJECTIVETo study the actual glomerular filtration rates (GFR) in patients with nonfunctioning kidneys as shown by intravenous pyelography (IVP) using single photon emission computed tomography (SPECT) dynamic renal scintigraphy and dual-plasma sample clearance method.

METHODSWe retrospectively analyzed 107 patients with nonfunctioning kidneys shown by IVP who underwent renal dynamic 99Tcm-DTPA SPECT imaging. GFR was measured by Gates' methods (GFRGates') and dual-plasma sample clearance method (GFRdual-plasma). Based on the dynamic functional images and GFRdual-plasma measurements, the patients were categorized into mild renal impairment (GFRdual-plasma≥30 mL/min), moderate renal impairment group (GFRdual-plasma of 20-30 mL/min), severe renal impairment group (GFRdual-plasma of 10 to 20 mL/min), and nonfunctioning kidney group (GFRdual-plasma≤10 mL/min), and GFRGates' were compared among the groups.

RESULTSAccording to GFRdual-plasma, the numbers of patients having mild, moderate, and severe renal impairment and nonfunctioning kidneys were 12(11.2%), 33(30.8%), 41(38.3%), and 21(19.6%), respectively. GFRdual-plasma and GFRGates' were not significantly different in mild and moderate renal impairment groups, but in patients with severe renal impairment, GFRdual-plasma was significantly lower than GFRGates' (13.9∓6.2 vs 18.8∓4.2 mL/min; t=-2.73, P=0.03), which was also the case with patients with nonfunctinging kidneys (4.5∓2.1 vs 7.2∓3.2 mL/min; t=-3.81, P=0.005).

CONCLUSIONOf the patients with nonfunctinging kidneys shown by IVP, only 58% of them actually have severe renal impairment or worse, and further SPECT dynamic renal scintigraphy is necessary to assess the actual risk of renal function impairment before operation.