ANALYSIS OF ALLOGENEIC AND SYNGENEIC RAT-HEART TRANSPLANTS USING NA-23 MAGNETIC-RESONANCE SPECTROSCOPY

This study defines the total sodium-23 magnetic resonance spectroscopy (Na-23 MRS) signal from in vivo heterotopic rat heart transplants in the early post-transplant period and examines the utility of this noni nvasive method for monitoring allograft rejection. Measurements were p erformed at 4.7 T. Syngeneic (n = 6) and allogeneic (n = 6) donor hear ts were transplanted into the neck of recipient rats. There were 27 MR S observations between days 0 and 29 pose-transplant. Heart grafts wer e excised at various intervals post-transplant for histologic examinat ion. Allogeneic heart grafts rejected between days 4 and 5 post-transp lant while syngeneic grafts continued to beat. All hearts showed ische mic damage. Allogeneic hearts showed cellular rejection by Day 1. Na-2 3 MRS showed a steady elevation in signal in the 3 days prior to rejec tion and a sharp rise after rejection. Na-23 MRS accurately identified full rejection and was also sensitive to the rejection process. (C) 1 996 Academic Press, Inc.