Use of radionuclide imaging in the early diagnosis and treatment of renal allograft rejection.

Data are presented on the clinical application of radionuclide imaging to evaluate changes in cadaver transplant function in the immediate postoperative period. The method uses orthoiodohippuric acid (hippuran) administered IV, with scintillation imaging, and curve analysis by a digital computer. An initial study is always obtained 24 hours after transplantation. Serial studies are then obtained, as needed, to interpret the clinical course. Selected cases are presented which illustrate the use of this protocol in various clinical settings. In the oliguric patient serial studies have been of particular value. They have identified ATN so that over-enthusiastic treatment for rejection could be avoided. They have also identified acute rejection complicating ATN so that high dose steroid therapy could be administered appropriately. In the non-oliguric patient they have frequently contributed to the early diagnosis of acute rejection, and they have been useful in monitoring the effect and duration of treatment for severe rejection crisis. It is concluded that radionuclide imaging studies, when carefully applied and interpreted, are a valuable adjunct to the management of patients in this complex clinical setting.