FASt single-breathhold 2D multislice myocardial T₁ mapping (FAST1) at 1.5T for full left ventricular coverage in...

Conventional myocardial T₁ mapping techniques such as modified Look-Locker inversion recovery (MOLLI) generate one T₁ map per breathhold. T₁ mapping with full left ventricular coverage may be desirable when spatial T₁ variations are expected. This would require multiple breathholds, increasing patient discomfort and prolonging scan time.

To develop and characterize a novel FASt single-breathhold 2D multislice myocardial T₁ mapping (FAST1) technique for full left ventricular coverage.

Prospective.

Numerical simulation, agarose/NiCl₂ phantom, 9 healthy volunteers, and 17 patients.

1.5T/FAST1.

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.

Kruskal-Wallis, Wilcoxon signed rank tests, intraclass correlation coefficient analysis, analysis of variance, Student's t-tests, Pearson correlation analysis, and Bland-Altman analysis.

In simulation/phantom, FAST1-BS, FAST1-IR, and MOLLI had an accuracy (expressed as T₁ 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 T₁ 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 T₁ repeatability (P = 0.18). In vivo native and postcontrast myocardial T₁ times in both healthy volunteers and patients using FAST1-BS/FAST1-IR were highly correlated with MOLLI (Pearson correlation coefficient ≥0.93).

FAST1 enables myocardial T₁ 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 T₁ precision/spatial variability, no significant difference of T₁ repeatability, and highly correlated T₁ times. FAST1-IR provides improved T₁ precision/spatial variability but reduced accuracy when compared with FAST1-BS.

1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:492-504.