DECONVOLUTION ANALYSIS OF RENAL BLOOD-FLOW - EVALUATION OF POSTRENAL TRANSPLANT COMPLICATIONS

Medical complications after renal transplantation cause problems in tr eatment decision making. To differentiate acute tubular necrosis from acute rejection when it occurs in the early posttransplant period is d ifficult. Renal scintigraphy offers a noninvasive means for renal bloo d flow (RBF) acid renal function assessment. Methods: This retrospecti ve study of RBF and renal function evaluation after kidney transplanta tion is an attempt to calculate the ''renal vascular transit time'' fr om the Tc-99m-diethylenetriaminepentaacetic acid renal vascular flow w ith a deconvolution technique. The results of 102 studies on 38 graft recipients were evaluated. Of these, 19 were diagnosed as acute reject ion, 12 as acute tubular necrosis, 4 as chronic rejection, 1 as vesico ureteric reflux, 1 as recurrent immunoglobulin A nephropathy, 1 as ili ac vein thrombosis, 1 as cyclosporine nephrotoxicity and 63 as normal. All diagnoses were established by clinical and/or pathologic criteria . Results: With renal vascular transit times more than 12.8 sec, the s ensitivity and specificity for the detection of acute rejection was 95 % and 94%, respectively. The sensitivity and specificity for the diffe rential diagnosis of acute rejection against acute tubular necrosis wa s 95% and 92%, respectively. Conclusion: The use of renal vascular tra nsit time in addition to I-131-labeled hippuran renogram provides a pr omising diagnostic parameter to differentiate between acute rejection and acute tubular necrosis.