3D myocardial T1 mapping at 3T using variable flip angle method: Pilot study

Abstract

Myocardial T1 mapping is an emerging technique that could improve cardiovascular magnetic resonance diagnostic accuracy. In this study, a variable flip angle approach with B1 correction is proposed at 3T on the myocardium, employing standard 3D spoiled fast gradient echo and echo planar imaging sequences. The method was tested on phantoms to determine the set of standard 3D spoiled fast gradient echo angles adapted to myocardial T1 measurements and was compared to the inversion-recovery spin-echo reference T1 method. Seven volunteers underwent magnetic imaging resonance to acquire myocardial T1 maps and T1 values of the human heart. This original method demonstrated good reproducibility in phantoms and a significant correlation between variable flip angle T1 values and reference inversion-recovery spin-echo T1 values. It yielded myocardial T1 values consistent with expected T1 and an increasing homogenization of myocardial segments owing to B1 correction. The mean myocardial T1 value was 1341 ± 42 ms. Myocardial 3D T1 mapping using the variable flip angle approach can potentially be useful for evaluating fibrosis on the entire myocardium using a standard clinical sequence.