RT Journal Article SR Electronic T1 Potential of Noninvasive Serial Assessment of Acute Renal Allograft Rejection by 18F-FDG PET to Monitor Treatment Efficiency JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1644 OP 1652 DO 10.2967/jnumed.110.078550 VO 51 IS 10 A1 Reuter, Stefan A1 Schnöckel, Uta A1 Edemir, Bayram A1 Schröter, Rita A1 Kentrup, Dominik A1 Pavenstädt, Hermann A1 Schober, Otmar A1 Schlatter, Eberhard A1 Gabriëls, Gert A1 Schäfers, Michael YR 2010 UL http://jnm.snmjournals.org/content/51/10/1644.abstract AB We propose 18F-FDG PET as a method to monitor acute rejection of allogeneic renal transplants in a rat model. Methods: Allogeneically transplanted (aTX) rats (binephrectomized Lewis–brown Norway to Lewis) served as the renal transplant model. aTX rats treated with cyclosporine A (CSA) served as a therapy monitoring group. Healthy control rats, rats with acute CSA nephrotoxicity, rats with acute tubular necrosis, syngeneically transplanted (sTX) rats, and aTX rats treated with CSA since postoperative day 0 served as controls. After surgery, renal glucose metabolism was assessed in vivo serially up to postoperative day 7 by performing small-animal PET 3 h after intravenous injection of 30 MBq of 18F-FDG. Mean radioactivity (cps/mm3 of tissue) was measured and the percentage injected dose calculated. Results were confirmed by histologic, functional, and autoradiographic analysis. Results: Renal 18F-FDG uptake was significantly elevated at postoperative day 4 in aTX rats, when compared with control, sTX, acute tubular necrosis, or CSA-treated rats (P < 0.05). In vivo 18F-FDG uptake correlated with the results of autoradiography and with inflammatory infiltrates observed on histologic examination. Notably, 18F-FDG PET assessed the response to therapy 48 h earlier than the time at which serum creatinine decreased and when histologic examination still showed signs of allograft rejection. In aTX rats, the CSA-susceptible graft infiltrate was dominated by activated cytotoxic T cells and monocytes/macrophages. Conclusion: 18F-FDG PET is an option to noninvasively assess early response to therapy in rat renal allograft rejection.