Free‐breathing simultaneous myocardial T<sub>1</sub> and T<sub>2</sub> mapping with whole left ventricle coverage
Rui Guo, Xiaoying Cai, Selçuk Küçükseymen, Jennifer Rodriguez, Amanda Paskavitz, Patrick Pierce, Beth Goddu, Richard B. Thompson, Reza Nezafat
Abstract
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.