Assessment of cardiac rejection by MR-imaging and MR-spectroscopy

Background: Detection of cardiac rejection is a major problem in cardiac tr ansplantation. The gold standard is, and remains, endomyocardial biopsy. Pu rpose: Evaluation of MR-imaging and MR-spectroscopy for detection of cardia c rejection. Methods: Orthotopic cardiac transplantation (HTX) was performe d in 13 pigs (body weight 30 kg). All animals obtained immunosuppressive (t riple) therapy for I week after the operation. Thereafter immunosuppression was stopped to induce cardiac rejection. MRI and MRS (1.5 Tesla General El ectrics Signal were performed pre- and post-operatively on days 10, 17, 24 and 31. The degree of rejection was determined postoperatively using endomy ocardial biopsy (Texas grading score). Results: (1) MR-imaging: LV function remained unchanged after HTX. LV mass increased (+42%; P < 0.05) with card iac rejection. (2) MR-spectroscopy: a marked reduction in the ratio of phos phocreatine and adenosine triphosphate, respectively, to inorganic phosphat e was observed in the rejecting hearts. (3) Histologic grading confirmed ca rdiac rejection after stopping immunosuppression. The Texas score was 5.7 /- 0.8 at autopsy, Conclusions: MR-imaging and MR-spectroscopy allow the de tection of changes associated with cardiac rejection. Both techniques are c orrelated with histologic rejection. However, endomyocardial biopsy remains the gold standard for reliable detection of cardiac rejection, (C) 1998 El sevier Science B.V. All rights reserved.