Improved accuracy and precision with three-parameter simultaneous myocardial T 1 and T 2 mapping using multiparametric SASHA

To develop and validate a three-parameter model for improved precision multiparametric SAturation-recovery single-SHot Acquisition (mSASHA) cardiac T and T mapping with high accuracy in a single breath-hold. The mSASHA acquisition consists of nine images of variable saturation recovery and T preparation in 11 heartbeats with T and T 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 -T technique. The mSASHA acquisition was compared with MOLLI, SASHA, and T -prepared balanced SSFP in 10 volunteers. The mSASHA technique had high accuracy in phantoms compared to spin echo, with -0.2 ± 0.3% T error and -2.4 ± 1.3% T error. The mSASHA coefficient of variation in phantoms for T was similar to MOLLI (0.7 ± 0.2% for both) and T -prepared balanced SSFP for T (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 -T for both T and T (46% and 11% reductions in T and T interquartile range for native myocardium). In vivo myocardial mSASHA T 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 was 37.1 ± 1.1 ms with similar precision to T -prepared balanced SSFP (6.7 ± 1.7% vs 6.0 ± 1.6%, adjusted p > .05). Three-parameter mSASHA provides high-accuracy cardiac T and T quantification in a single breath-hold with similar precision to MOLLI and T -prepared balanced SSFP. Further study is required to both establish normative values and demonstrate clinical utility in patient populations.