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.