Detection and prediction of acute heart transplant rejection with the myocardial T2 determination provided by a black-blood magnetic resonance imaging sequence

OBJECTIVES This study aimed to determine whether the myocardial T2 relaxation time, determined using a black-blood magnetic resonance imaging (MRI) sequence, could predict acute heart transplant rejection. BACKGROUND The use of black-blood MRI sequences allows suppression of the confusing influence of blood signal when myocardial T2 is calculated to detect myocardial edema. METHODS A total of 123 investigations, including cardiac MRI and myocardial biopsy, were performed 8 ± 11 months after heart transplantation. Myocardial T2 was determined using an original inversion-recovery/spin-echo sequence. RESULTS A higher than normal T2 (≥56 ms) allowed an accurate detection of the moderate acute rejections evidenced at baseline biopsy (≥International Society for Heart and Lung Transplantation grade 2): sensitivity, 89% and specificity, 70% (p <0.0001). T2 was increased in grade 2 (n = 11) compared with grade 0 (n = 49, p < 0.05), grade 1A (n = 34, p < 0.05) and grade 1B (n = 21, p < 0.05); T2 was further increased in grade 3 (n = 8) compared with grade 2 (p < 0.05). In addition, in patients without rejection equal to or greater than grade 2 at baseline, a T2 higher than normal (≥56 ms) was correlated with the subsequent occurrence of equal or greater than grade 2 rejection within the next three months: sensitivity 63% (12/19) and specificity 78% (64/82) (p = 0.001). CONCLUSIONS Myocardial T2, determined using a black-blood MRI sequence, is sufficiently sensitive to identify most of the moderate acute rejections documented with biopsy at the same time, but is also a predictor of the subsequent occurrence of such biopsy-defined rejections.