FASt single‐breathhold 2D multislice myocardial T 1 mapping (FAST1) at 1.5T for full left ventricular coverage in three breathholds

Background Conventional myocardial T 1 mapping techniques such as modified Look–Locker inversion recovery (MOLLI) generate one T 1 map per breathhold. T 1 mapping with full left ventricular coverage may be desirable when spatial T 1 variations are expected. This would require multiple breathholds, increasing patient discomfort and prolonging scan time. Purpose To develop and characterize a novel FASt single‐breathhold 2D multislice myocardial T 1 mapping (FAST1) technique for full left ventricular coverage. Study Type Prospective. Population/Phantom Numerical simulation, agarose/NiCl 2 phantom, 9 healthy volunteers, and 17 patients. Field Strength/Sequence 1.5T/FAST1. Assessment Two FAST1 approaches, FAST1‐BS and FAST1‐IR, were characterized and compared with standard 5‐(3)‐3 MOLLI in terms of accuracy, precision/spatial variability, and repeatability. Statistical Tests Kruskal‐Wallis, Wilcoxon signed rank tests, intraclass correlation coefficient analysis, analysis of variance, Student's t ‐tests, Pearson correlation analysis, and Bland–Altman analysis. Results In simulation/phantom, FAST1‐BS, FAST1‐IR, and MOLLI had an accuracy (expressed as T 1 error) of 0.2%/4%, 6%/9%, and 4%/7%, respectively, while FAST1‐BS and FAST1‐IR had a precision penalty of 1.7/1.5 and 1.5/1.4 in comparison with MOLLI, respectively. In healthy volunteers, FAST1‐BS/FAST1‐IR/MOLLI led to different native myocardial T 1 times (1016 ± 27 msec/952 ±22 msec/987 ± 23 msec, P  < 0.0001) and spatial variability (66 ± 10 msec/57 ± 8 msec/46 ± 7 msec, P  < 0.001). There were no statistically significant differences between all techniques for T 1 repeatability ( P = 0.18). In vivo native and postcontrast myocardial T 1 times in both healthy volunteers and patients using FAST1‐BS/FAST1‐IR were highly correlated with MOLLI (Pearson correlation coefficient ≥0.93). Data Conclusion FAST1 enables myocardial T 1 mapping with full left ventricular coverage in three separated breathholds. In comparison with MOLLI, FAST1 yield a 5‐fold increase of spatial coverage, limited penalty of T 1 precision/spatial variability, no significant difference of T 1 repeatability, and highly correlated T 1 times. FAST1‐IR provides improved T 1 precision/spatial variability but reduced accuracy when compared with FAST1‐BS. Level of Evidence: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:492–504.