RESUMEN
OBJECTIVES: No objective parameters for renal allograft evaluation have yet been described for Tc99m-Ethylenedicystine. This study evaluates the diagnostic significance of different quantitative and semi-quantitative parameters of renal allograft scintigraphy using Tc99m-Ethylenedicystine. METHODS: A total of 72 renal dynamic scintigraphic studies were performed within 2-weeks of renal transplantation in 42 patients. The graft perfusion, kidney/aorta ratio, washout index and retention index were derived from all studies. All these parameters were evaluated for their ability to distinguish between a normal graft, a graft with acute rejection (AR), and a graft with acute tubular necrosis (ATN). Histopathological verification of diagnosis was obtained in all cases. RESULTS: Studies were subdivided into 3 groups according to histopathological findings: acute rejection (n = 42), normal (n = 18) and acute tubular necrosis (n = 12). Normal allografts were visualized with in 2.66 +/- 0.59 seconds of visualization of abdominal aorta. The K/A ratio, wash out index and retention index was 15.22 +/- 6.86, 1.67 +/- 0.45, and 5.48 +/- 0.98 respectively. Allografts with ATN were visualized with in 3.36 +/- 0.80 seconds of visualization of abdominal aorta. The K/A ratio, wash out index and retention index was 12.73 +/- 6.74, 0.60 +/- 0.14, and 9.18 +/- 1.48 respectively. In AR, allografts were visualized 15.18 +/- 9.48 seconds after visualization of abdominal aorta. The K/A ratio, wash out index and retention index was 7.07 +/- 2.15, 0.63 +/- 0.11, and 2.26 +/- 1.28 respectively. CONCLUSIONS: Retention index can separate all the three condition of normal, acute rejection and acute tubular necrosis from each other. Retention index of < 4 suggests acute rejection, a value between 4 and 7 suggests normal allograft and a value of > or = 7 is suggestive of acute tubular necrosis. However, perfusion, K/A ratio and washout index can not segregate all the three groups.