Rapid Free-Breathing 3D MRI of the Liver for Simultaneous Quantification of PDFF, R2*, and Water-Specific T1 at 0.55 Tesla

Motivation: 0.55T MRI may be a promising platform for quantitative multiparametric liver imaging with improved cost-effectiveness and robustness. Goal(s): This study demonstrates the feasibility of rapid free-breathing 3D MRI of the liver with simultaneous quantification of PDFF, R2*, and water-specific T1 at 0.55 Tesla. Approach: We tested free-breathing GraspT1-Dixon sequence with in vivo experiment and the quantitative maps are validated using R2* and PDFF phantoms. Results: We show that (1)the estimated parameters are accurate; (2)the influence of fat on liver T1 mapping can be effectively mitigated to ensure accurate and robust T1 quantification; and (3)R2* mapping may be insensitive to respiratory motion at 0.55T. Impact: 0.55T MRI offers a cost-effective platform for quantitative multiparametric MRI of the liver to improve the management of various chronic disease conditions. In particular, the improved magnetic field homogeneity at 0.55T may enable more robust estimation of R2* maps.