Comparison between Tc-99 m DTPA and Tc-99 m MAG3 Renal Scintigraphy for Prediction of Early Adverse Outcome After Kidney Transplantation

Purpose Renal scintigraphy (RS) with either technetium-99 m diethylene-triamine-pentaacetate (Tc-99 m DTPA) or technetium-99 m mercaptoacetyltriglycine (Tc-99 m MAG3) has both been used to evaluate early allograft function after kidneytransplantation (KT). This study was done to compare the predictive performance of RS using these two radiopharmaceuticalsfor prediction of outcomes during first 3 months of KT. Methods This retrospective study included patients who received KT then underwent both Tc-99 m DTPA and Tc-99 mMAG3 RS, successively. Receiver operating characteristic (ROC) curve analysis was used to determine the predictivenessof RS parameters on early clinical adverse outcomes of either (1) graft-related death, (2) need for graft resection, (3) delayedgraft function requiring temporary dialysis, or (4) a serum creatinine level of≥2.0 mg/dL at three months post-KT, as wellas to predict biopsy-confirmed acute tubular necrosis and acute rejection. Results Of 187 patients included, 77 (41.2%) had at least one early adverse clinical outcome. Tc-99 m MAG3 RS was morepredictive than Tc-99 m DTPA RS, in terms of AUCROC, in three parameters including time to peak (0.754 vs. 0.516, p-value0.0001), 20-min to peak ratio (0.762 vs. 0.651, p-value 0.006), and 20-min to 3-min ratio (0.823 vs. 0.699, p-value 0.0005). Acute tubular necrosis was better predicted by Tc-99 m MAG3 RS while both were at best only modest in predicting acuterejection. Conclusion Three parameters which, when obtained from Tc-99 m MAG3 RS, had superior predictiveness compared withTc-99 m DTPA RS, including time to peak, 20-min to peak ratio, and 20-min to 3-min ratio.