Optimization of Parallel Imaging in Flip Angle Modulated 2D Sequential CSE-MRI for SNR-Efficient and Motion-Robust Liver Fat Quantification

Motivation: Flip-angle modulation (FAM) in a 2D sequential acquisition is one potential means to improve the motion-robustness and SNR of CSE-MRI for liver fat quantification, and the motion-robustness and SNR-efficiency of FAM can be further improved through parallel imaging and capturing respiratory motion in-plane. Goal(s): To determine the feasibility and performance (with respect to SNR, repeatability, and bias) of FAM-based free-breathing liver fat quantification acquired across imaging orientations and accelerations. Approach: Trials of various parameters of FAM in volunteers and in a phantom with controlled PDFF and T1 values. Results: Accelerated FAM demonstrates few artifacts, low bias, and increased SNR-efficiency compared to unaccelerated FAM. Impact: Increasing the motion-robustness and SNR-efficiency of FAM may enable and enhance its use for improved detection, staging, and monitoring of steatotic liver disease. Non-axial acquisitions may mitigate through-plane respiratory motion compared to axial acquisitions.