Comparison of renal transplant scintigraphy with renal resistance index for prediction of early graft dysfunction and evaluation of acute tubular necrosis and acute rejection.

PURPOSE: We discuss whether resistance index (RI) and renal scintigraphy obtained within 48 hours after operation could predict the early graft dysfunction. We also aimed to assess the uses of scintigraphy and RI in diagnosis of acute rejection (AR) and acute tubular necrosis (ATN).
METHODS: A total of 153 studies were performed in 109 patients. T½ of perfusion peak, perfusion curve grades, and accumulation index (R20/3) were used as scintigraphic parameters. Baseline studies obtained within 48 hours after transplantation were evaluated for prediction of early graft dysfunction. All data were then assessed for specific diagnosis.
RESULTS: Scintigraphic parameters were significantly higher in patients with delayed graft function (DGF) and slow graft function (SGF) than in patients with immediate graft function. These parameters in DGF were also considerably different from those in SGF. The mean RI was significantly high in DGF, but there was no difference between SGF and immediate graft function. In diagnostic groups, the mean values of all tests were significantly different between normal functioning grafts and pathological grafts (ATN + AR). There was no significant difference between AR and ATN. However, renal scintigraphy has higher sensitivity and specificity for AR as compared with RI of Doppler ultrasonography (US).
CONCLUSIONS: In predicting graft dysfunction and separating normal functioning graft from pathological graft (ATN + AR), renal scintigraphy provides more accurate information than Doppler US. Even though it is superior to Doppler US, renal scintigraphy also cannot reliably separate ATN from AR. The major advantage of renal scintigraphy is the early detection of reduced renal function.