Abstract
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<0.001), improved diagnostic confidence (4.66±0.56 vs. 4.26±0.38; P<0.001), and increased overall image quality (4.76±0.41 vs. 4.39±0.44; P<0.01) with no difference in anatomical clarity (4.66±0.57 vs. 4.74±0.45; P=0.49). Interreader agreement was moderate-to-excellent (ICC =0.77-0.88). ADC values showed strong correlation between EPTI-DWI and EPI-DWI (r=0.89, P<0.001). Bland-Altman analysis revealed a small positive bias of EPTI-DWI relative to EPI-DWI (mean bias, 63.72×10(-6) mm(2)/s; 95% limits of agreement, 0.20×10(-6)-127.25×10(-6) mm(2)/s). CONCLUSIONS: EPTI-DWI with PMC provided high-resolution, distortion-free diffusion imaging improved overall image quality compared to EPI-DWI. The technique proved feasible in motion-sensitive patients, highlighting its potential for broader clinical application.