The precision of glomerular filtration rate determined by Gates method and compared with the results from renal pathological changes

Objective To evaluate the precision of GFR using Gates method and compared with the results from renal pathological changes. Methods Twenty-seven patients whose 99Tcm-DTPA renograms had no obvious uptake phase were enrolled in Group A, and 27 patients whose 99Tcm-DTPA renograms had obvious uptake phase were enrolled in Group B. The measurement of GFR by Gates method was compared to the creatinine clearance measured and predicted by Cockroft-Gault (C-G), modification of diet in renal disease (MDRD) and SCr level. Renal pathological changes in two groups were compared using Pearson correlation and t test analysis. Results In Group A, GFR determined by Gates method did not show correlation with that estimated by C-G or 1/SCr (r = 0. 357,0. 376, both P ＞0.05), but was significantly correlated with GFR estimated by MDRD(r = 0. 440, P ＜ 0.05). In Group B, GFR determined by Gates method showed significantly correlation among GFR estimated by MDRD, C-G, and 1/SCr (r =0. 471, 0. 527,0. 452, all P ＜ 0.05). Renal tubulointerstitial damage score in Group A was higher than that in Group B (7.15±2.32, 3.70±3.06, t=4.66, P ＜0.001). Conclusions GFR determined by Gates method is less precise when 99Tcm-DTPA renogram has no obvious uptake phase than that when 99Tcm-DTPA renogram has obvious uptake phase. Renal tubulointerstitial damage is a strong indicator of no obvious uptake phase in 99Tcm-DTPA renogram. Key words: Kidney diseases;  Glomerular filtration rate;  Radionuclide imaging;  DTPA