Nonrigid registration improves MRI T2 quantification in heart transplant patient follow-up

Background To evaluate the use of a nonrigid registration technique for detecting acute heart transplant rejection by MRI T2 quantification. Methods Myocardial T2 quantification was achieved in 279 consecutive examinations from 78 different patients. The protocol consisted of 10 successive black‐blood fast spin echo sequences with varying echo times, and a postprocessing based on image registration and exponential fitting. An automatic nonrigid registration method was applied to correct for myocardium misalignment. Finally T2 values were compared with those obtained with a conventional rigid registration followed by manual correction. Results Nonrigid registration was feasible in 98% of the datasets and was judged of higher quality compared with conventional processing (P