Improved accuracy and precision with three‐parameter simultaneous myocardial T<sub>1</sub>and T<sub>2</sub>mapping using multiparametric SASHA
Kelvin Chow, Genevieve Hayes, Jacqueline Flewitt, Patricia Feuchter, Carmen Lydell, Andrew G. Howarth, Joseph J. Pagano, Richard B. Thompson, Peter Kellman, James A. White
Abstract
Purpose To develop and validate a three‐parameter model for improved precision multiparametric SAturation‐recovery single‐SHot Acquisition (mSASHA) cardiac T 1 and T 2 mapping with high accuracy in a single breath‐hold. Methods The mSASHA acquisition consists of nine images of variable saturation recovery and T 2 preparation in 11 heartbeats with T 1 and T 2 values calculated using a three‐parameter model. It was validated in simulations and phantoms at 3 T with comparison to a four‐parameter joint T 1 ‐T 2 technique. The mSASHA acquisition was compared with MOLLI, SASHA, and T 2 ‐prepared balanced SSFP in 10 volunteers. Results The mSASHA technique had high accuracy in phantoms compared to spin echo, with −0.2 ± 0.3% T 1 error and −2.4 ± 1.3% T 2 error. The mSASHA coefficient of variation in phantoms for T 1 was similar to MOLLI (0.7 ± 0.2% for both) and T 2 ‐prepared balanced SSFP for T 2 (1.3 ± 0.7% vs 1.4 ± 0.3%, adjusted p > .05 for both). In simulations, three‐parameter mSASHA had higher precision than four‐parameter joint T 1 ‐T 2 for both T 1 and T 2 (46% and 11% reductions in T 1 and T 2 interquartile range for native myocardium). In vivo myocardial mSASHA T 1 was similar to SASHA (1523 ± 18 ms vs 1520 ± 18 ms) with similar coefficient of variation to both MOLLI and SASHA (3.3 ± 0.6% vs 3.1 ± 0.6% and 3.3 ± 0.5% respectively, adjusted p > .05 for all). Myocardial mSASHA T 2 was 37.1 ± 1.1 ms with similar precision to T 2 ‐prepared balanced SSFP (6.7 ± 1.7% vs 6.0 ± 1.6%, adjusted p > .05). Conclusion Three‐parameter mSASHA provides high‐accuracy cardiac T 1 and T 2 quantification in a single breath‐hold with similar precision to MOLLI and T 2 ‐prepared balanced SSFP. Further study is required to both establish normative values and demonstrate clinical utility in patient populations.