High-Throughput Liver Fat Quantification Using a Novel MRI Suite Design and Motion-Insensitive Imaging
Abstract
Purpose
To validate a high-throughput workflow for quantifying liver proton-density fat-fraction (PDFF), using a novel two-door/two-bed MRI suite and a focused, AI-assisted, motion-insensitive chemical-shift-encoded (CSE) MRI protocol.
Methods
An MRI suite with two doors and two mobile beds was designed and constructed at our institution. Study participant preparation (eg. coil setup) occurred in a separate room, while their bed was detached from the MRI. Participant preparation thereby occurred simultaneously with another participant’s imaging. Transitioning between participants involved rolling the imaged participant out of the MRI room through one door, then immediately rolling the prepared participant in through another door. This workflow was validated with a focused protocol for measuring PDFF, consisting of a localizer and free-breathing CSE-MRI with AI-based automatic image prescription. In a HIPAA-compliant/IRB-approved prospective study, twelve participants of varying BMI were recruited. Participants were imaged in a fixed cycle repeated three times (36 total consecutive exams), to characterize imaging throughput and between-exam PDFF quantification repeatability. Workflow intervals (e.g. exam duration and time between successive exams) were recorded by video and image metadata. One radiologist placed and averaged ROIs in the nine Couinaud liver segments to produce one whole-liver PDFF measurement per exam. Repeatability was assessed by computing the repeatability coefficient (RC) as 2.77 times the within-participant standard deviation of whole-liver PDFF. Two radiologists also independently evaluated all images for diagnostic quality and liver coverage completeness.
Results
36 exams were completed in 2h14m, representing >16 exams/hour throughput. Mean±SD exam duration was 1m56s±21s. Mean between-exam time was 1m45s±26s. RC of whole-liver PDFF was 1.21 PDFF%. Both radiologists rated all exams as diagnostic quality and offering complete liver coverage.
Conclusion
Combining the two-door/two-bed MRI suite and free-breathing CSE-MRI enabled remarkable imaging throughput and highly repeatable PDFF measurements. This may broaden access to quantitative MRI and help address highly-prevalent steatotic liver diseases.