Diffusion Weighted Fast Spin Echo With RF ‐Encoded Slabs for Portable Low‐Field MRI Systems

作者：Philip K Lee, Yueqi Qiu, Suen Chen, Changyue Wang, Z. S. Zhang · 发表于：Magnetic Resonance in Medicine · 年份：2026 · DOI：10.1002/mrm.70292 · 被引用次数：1 · 研究领域：Advanced MRI Techniques and Applications、NMR spectroscopy and applications、Magnetic properties of thin films

ABSTRACT Purpose To develop a robust diffusion weighted (DW) acquisition with clinically feasible scan times for portable MRI systems. Methods A linear reconstruction model including: tailored RF‐encoding schemes, motion‐induced phases, and systematic phase errors was developed for slab diffusion weighted fast spin echo (FSE) data acquired with quadratic phase increment. Systematic phases imparted by diffusion gradients were obtained using a calibration phantom. Trace‐weighted DW‐FSE was compared to DW‐EPI in vivo on a portable 110 mT H‐based system. A high‐NEX DW‐FSE acquisition was performed in healthy volunteers followed by Monte Carlo retrospective undersampling to evaluate expected image quality and mean diffusivity variation in a DWI protocol with clinically feasible scan times. Results CPMG calibration and polynomials fitted to systematic phase errors enabled accurate estimation of motion‐induced phases. Accounting of different phase sources reduced ghosting artifacts and improved SNR efficiency by enabling RF‐encoding. RF‐encoded slab DW‐FSE obtained in vivo trace‐weighted images without distortion artifacts and with voxel sizes 5× smaller than DW‐EPI. The retrospectively undersampled acquisition showed that 12 cm slice coverage with voxel size 2.5 × 2.5 × 5 mm 3 could be achieved in 12 min scan time. The mean diffusivity standard deviation between Monte Carlo trials was 0.2 × 10 −3 mm 2 /s. Conclusion Diffusion weighted FSE is a robust, distortionless approach for hi...