Detection and prediction of acute heart transplant rejection with the myocardial T-2 determination provided by a black-blood magnetic resonance imaging sequence
Résumé
Abstract: OBJECTIVES This study aimed to determine whether the myocardial T-2 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 T-2 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 T-2 was determined using an original inversion-recovery/spin-echo sequence. RESULTS A higher than normal T-2 (greater than or equal to 56 ms) allowed an accurate detection of the moderate acute rejections evidenced at baseline biopsy (greater than or equal to International Society for Heart and Lung Transplantation grade 2): sensitivity, 89% and specificity, 70% (p < 0.0001). T-2 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); T-2 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 T-2 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 T-2 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.