Assessment of cardiac rejection by MR-imaging and MR-spectroscopy.
BACKGROUND
Detection of cardiac rejection is a major problem in cardiac transplantation. The gold standard is, and remains, endomyocardial biopsy.


OBJECTIVE
Evaluation of MR-imaging and MR-spectroscopy for detection of cardiac rejection.


METHODS
Orthotopic cardiac transplantation (HTX) was performed in 13 pigs (body weight 30 kg). All animals obtained immunosuppressive (triple) therapy for 1 week after the operation. Thereafter immunosuppression was stopped to induce cardiac rejection. MRI and MRS (1.5 Tesla General Electrics Signa) were performed pre- and post-operatively on days 10, 17, 24 and 31. The degree of rejection was determined post-operatively using endomyocardial biopsy (Texas grading score).


RESULTS
(1) MR-imaging: LV function remained unchanged after HTX. LV mass increased (+42%; P < 0.05) with cardiac rejection. (2) MR-spectroscopy: a marked reduction in the ratio of phosphocreatine and adenosine triphosphate, respectively, to inorganic phosphate was observed in the rejecting hearts. (3) Histologic grading confirmed cardiac rejection after stopping immunosuppression. The Texas score was 5.7+/-0.8 at autopsy.


CONCLUSIONS
MR-imaging and MR-spectroscopy allow the detection of changes associated with cardiac rejection. Both techniques are correlated with histologic rejection. However, endomyocardial biopsy remains the gold standard for reliable detection of cardiac rejection.
Walpoth
B H
BH
Thoracic and Cardiovascular Surgery, Cardiology, Radiology and Pathology, University Hospital, Insel, Berne, Switzerland. beat.walpoth@insel.ch
Müller
M F
MF
Celik
B
B
Nicolaus
B
B
Walpoth
N
N
Schaffner
T
T
Althaus
U
U
Carrel
T
T
D000255:Adenosine Triphosphate / Q000032:analysis; D000818:Animals; D001706:Biopsy; D006084:Graft Rejection / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D006346:Heart Septum / Q000473:pathology; D016027:Heart Transplantation / Q000473:pathology; D006352:Heart Ventricles / Q000473:pathology; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D009206:Myocardium / Q000737:chemistry / Q000473:pathology; D010710:Phosphates / Q000032:analysis; D010725:Phosphocreatine / Q000032:analysis; D015203:Reproducibility of Results; D013318:Stroke Volume / Q000502:physiology; D013552:Swine; D016277:Ventricular Function, Left / Q000502:physiology
D007166:Immunosuppressive Agents; D010710:Phosphates; D010725:Phosphocreatine; D000255:Adenosine Triphosphate