High-resolution highly-accelerated free breathing 3D joint T1/T2 and fat fraction mapping of the liver at 0.55T

Motivation: Quantitative MRI at low-field offers an affordable, accessible, non-invasive alternative to characterize liver tissue by correlating tissue parameters with liver disease stages. Goal(s): To enable high-resolution 3D joint T1/T2 and fat-fraction liver mapping at 0.55T in clinically feasible scan times. Approach: A Dixon GRE sequence with three interleaved 3D volumes preceded by preparation pulses for T1/T2 encoding was optimized for liver. Motion-corrected reconstruction with image-navigators and 4-fold acceleration enables isotropic high-resolution liver scan in ~8 min. Results: Good agreement for T1, T2 maps and slight underestimation for fat-fraction is observed in phantoms. In-vivo T1, T2 and fat-fraction maps show values comparable to literature. Impact: High-resolution free breathing 3D joint T1/T2 and fat-fraction mapping of the entire liver is feasible in a single scan of 8 min at low-field and may enable more affordable and comprehensive assessment of liver disease.