Distortion-free diffusion-weighted imaging using echo planar time-resolved imaging with prospective motion correction: a feasibility study in motion-sensitive patients

Background: Diffusion-weighted imaging (DWI) has been widely used in clinical applications with single-shot or multi-shot echo planar imaging (EPI), but suffers from geometric distortions and motion artifacts. This study aimed to evaluate the clinical feasibility and image quality of combining echo planar time-resolved imaging (EPTI) with markerless prospective motion correction (PMC) in motion-sensitive patients. Methods: We evaluated 3-shot EPTI-DWI with PMC against single-shot EPI-DWI in one healthy volunteer who performed controlled head movements and in 38 patients (24 adolescent patients with anxiety disorder and 14 with Alzheimer’s disease). Two radiologists independently rated image quality on a five-point scale. Interreader agreement was evaluated using the intraclass correlation coefficient (ICC), and image quality scores were compared with the Wilcoxon signed-rank test. Apparent diffusion coefficients (ADC) were derived and compared between EPI-DWI and EPTI-DWI in predefined regions of interest using linear regression and Bland-Altman analysis. Results: In the volunteer experiment, enabling PMC during EPTI-DWI effectively corrected motion-induced artifacts compared with EPTI without PMC. Across 38 patients, EPTI-DWI with PMC significantly reduced geometric distortion vs. EPI-DWI (4.74±0.43 vs. 3.46±0.54; P