Technetium-99m sulfur colloid accumulation as a predictor of acute renal transplant rejection

Renal transplantation is the preferred treatment for end-stage renal disease in children. Most transplant failures are due to allograft rejection. To date, only histopathological findings on renal biopsy can establish this diagnosis. Prior to the availability of cyclosporine, technetium-99m sulfur colloid nuclear scans (TSC) were used in a limited number of institutions to detect rejection episodes. The purpose of this study was to determine whether TSC could predict acute rejection in the cyclosporine era. A prospective study involving 41 pediatric renal transplant patients (M = 25, F = 16) was conducted from 6/1/89 to 10/31/91. Patients who received a TSC and biopsy (41 patients, 62 studies) within one week of clinical and laboratory evidence of acute rejection were included in the study. A qualitative method of determining sulfur colloid uptake was used by comparing allograft uptake with that of the fifth lumbar vertebrae (L5) marrow uptake: 3(+)--allograft with greater than L5 marrow uptake, 2(+)--same as, 1(+)--less than, and 0--no allograft uptake. Transplant accumulation of > or = 2+ was considered consistent with acute rejection (P < 0.001). Acute rejection was noted in 53 of 62 renal biopsies. Of those with biopsy-proved acute rejection, SC was positive (> or = 2+) in 46 of 53. SC of > or = 2+ has proved to be a good predictor of acute rejection. This technique has a sensitivity of 98%, specificity of 53%, positive predictive value of 87%, and negative predictive value of 89%.