Simultaneous Water-Specific T1 and Fat Fraction Mapping of the Liver using Look-Locker Dixon MRI

Motivation: Hepatic tissue architecture and water-fat content change concurrently with liver disease progression. Simultaneous measurement of water-specific T1 (T1-W) and proton density fat fraction (PDFF) can serve as a quantitative metric for assessment of liver disease. Goal(s): To develop and validate a Look-Locker multi-echo Dixon (LLmDIXON) technique to simultaneously measure T1-W and PDFF in a single breath-hold. Approach: Simultaneous T1-W and PDFF measurements were obtained using LLmDIXON and reference sequences in a phantom (0-40 % PDFF) and four volunteers (4.0-18.2% PDFF). Results: The LLmDixon-based T1-W and PDFF values agreed with simulations and reference sequences in a phantom, and provided comparable PDFF values in volunteers. Impact: LLmDixon provides simultaneous measurement of water-specific T1 and PDFF in a single 15s breath hold. This technique has the potential to characterize liver disease, where both cellular architecture and fat content can concurrently change as disease progresses.