MR imaging in assessment of cardiac transplant rejection in humans

To evaluate the efficacy of myocardial T2 values in the assessment of allograft rejection, we performed magnetic resonance (MR) imaging at 0.5 T serially in seven cardiac transplant recipients and singly in seven normal volunteers. Cardiac-gated multi-echo spin echo images were obtained; T2 values were estimated by a two-point method from regions of interest in the myocardium. Patients underwent MR and cardiac biopsy at various times after transplantation. Forty-two patient exams were performed. All biopsies showed either no rejection or early stages of rejection: grade 0 in 8 examinations, grade 1 in 28, and grade 2 in 6. Myocardial T2 values in patients in early stages of cardiac rejection were slightly higher (but not statistically significant) than those in non-rejecting patients and normal volunteers. Although this study did not allow prospective detection of cardiac rejection in our patient group, it demonstrated a trend toward higher T2 values at higher biopsy grades that may indicate an ability to assess more severe stages of transplant rejection.