Evaluation of 99Tcm-DTPA glomerular filtration rate by the Gates method in patients with type 2 diabetes

Objective To study the changes of GFR measured in different time intervals after the injection of 99Tcm-DTPA and to evaluate the clinical value of GFR in patients with type 2 diabetes.Methods Eleven healthy volunteers (6 males,5 females; mean age (61.45±7.90) years,age range:47-79 years)and 56 patients with type 2 diabetes (31 males,25 females; mean age (60.98±6.96) years,age range:45-75 years) were recruited.99Tcm-DTPA was used to measure GFR for all subjects.ROI was drawn at 2 and 3 min post-injection and GFR was calculated by Gates method.Two-sample t test and Pearson correlation analysis were performed with SPSS 15.0.Results SCr ((84.90±14.38) μmol/L) was significantly correlated with GFR in patients with type 2 diabetes.There was negative correlation between SCr and GFR for both,left and right kidneys at 3 min post-injection (r=-0.652,-0.636,-0.470,all P≤0.001) and at 2 min post-injection (r=-0.599,-0.553,-0.529,all P＜0.001).Total GFR,GFR for left kidney and GFR for right kidney at 3 min post-injection in diabetes group ((69.77 ± 11.00),(33.12 ± 5.74),(37.34 ± 9.81) ml/min) were lower than those in control group ((97.89±5.98),(46.60±4.91),(51.28±4.20) ml/min ; t =-8.212,-7.233,-4.069,all P＜0.001).Conclusions To calculate the GFR of the patients with type 2 diabetes,3 min post-injection is the optimal time.Measurement of GFR by 99Tcm-DTPA is useful in early diagnosis of diabetic nephropathy. Key words: Diabetic nephropathies ;  Glomerular filtration rate;  Gates method; Radionuclide imaging;  DTPA