A New Quantitative Index for Baseline Renal Transplant Scintigraphy With 99mTc-DTPA in Evaluation of Delayed Graft Function and Prediction of 1-Year Graft Function

Purpose The aims of this study were to assess quantitative indices of baseline renal transplant scintigraphy (RTS) with Tc-99m-DTPA for evaluation of delayed graft function (DGF) and prediction of 1-year graft function and to describe a new inclusive index for RTS. Patients and Methods A total of 179 patients to whom RTS with Tc-99m-DTPA was performed within 2 days after kidney transplantation were analyzed retrospectively. Hilson perfusion index, perfusion time (Delta P), peak-to-plateau ratio, peak perfusion-to-iliac artery ratio, T1/2 of graft washout, peak perfusion-to-uptake ratio, and ratio of uptake at 20 to 3 minutes (R20/3) were obtained. In addition, we first described the following formula defined as graft index (GI): GI = (Delta P x arterial peak x plateau)/(perfusion peak x uptake at 3 minutes). At 1 year, a serum creatinine level of more than 1.5 mg/dL was considered to be abnormal. Mann-Whitney U, Spearman coefficient of correlation test, and receiver operating characteristic curve were used for statistical analyses. P < 0.05 was considered statistically significant. Results Mean values of all the indices were significant. The most accurate, sensitive, and specific index for both identification of DGF and prediction of 1-year serum creatinine level of more than 1.5 mg/dL was GI. Area under the curve of GI was 0.94 for identification of DGF and 0.79 for 1-year prediction. Conclusions The question is, "Which index is the best indicator?" This study demonstrated that the parameters of Delta P, plateau, arterial peak, perfusion peak, and uptake at 3 minutes of RTS could be assessed together by the formula of GI, which provides more accurate information to identify DGF and predict 1-year graft function.