Free-breathing simultaneous myocardial T1and T2mapping with whole left ventricle coverage

Purpose To develop a free-breathing sequence, that is, Multislice Joint T-1-T-2, for simultaneous measurement of myocardial T(1)and T(2)for multiple slices to achieve whole left-ventricular coverage. Methods Multislice Joint T-1-T(2)adopts slice-interleaved acquisition to collect 10 single-shot electrocardiogram-triggered images for each slice prepared by saturation and T(2)preparation to simultaneously estimate myocardial T(1)and T(2)and achieve whole left-ventricular coverage. Prospective slice-tracking using a respiratory navigator and retrospective image registration are used to reduce through-plane and in-plane motion, respectively. Multislice Joint T-1-T(2)was validated through numerical simulations and phantom and in vivo experiments, and compared with saturation-recovery single-shot acquisition and T-2-prepared balanced Steady-State Free Precession (T-2-prep SSFP) sequences. Results Phantom T(1)and T(2)from Multislice Joint T-1-T(2)had good accuracy and precision, and were insensitive to heart rate. Multislice Joint T-1-T(2)yielded T(1)and T(2)maps of nine left-ventricular slices in 1.4 minutes. The mean left-ventricular T(1)difference between saturation-recovery single-shot acquisition and Multislice Joint T-1-T(2)across healthy subjects and patients was 191 ms (1564 +/- 60 ms versus 1373 +/- 50 ms;P< .05) and 111 ms (1535 +/- 49 ms vs 1423 +/- 49 ms;P< .05), respectively. The mean difference in left-ventricular T(2)between T-2-prep SSFP and Multislice Joint T-1-T(2)across healthy subjects and patients was -6.3 ms (42.4 +/- 1.4 ms vs 48.7 +/- 2.5;P< .05) and -5.7 ms (41.6 +/- 2.5 ms vs 47.3 +/- 2.7;P< .05), respectively. Conclusion Multislice Joint T-1-T(2)enables quantification of whole left-ventricular T(1)and T(2)during free breathing within a clinically feasible scan time of less than 2 minutes.