Single-shot distortion-corrected water-fat separation using multi-echo blip-rewound EPI for diffusion-weighted imaging

Motivation: Single-shot EPI(ss-EPI) is widely used in diffusion-weighted imaging(DWI) but suffers from geometric distortion and failure of fat suppression especially in inhomogeneous B0/B1 regions. Dixon-based water-fat separation allows robust fat suppression but is prone to echo-to-echo phase variation in DWI. Goal(s): Develop a single-shot water-fat separation to achieve motion-robust fat suppression and distortion correction for DWI. Approach: We integrated multi-echo blip-rewound EPI(rEPI) with chemical-shift encoding to acquire three TE-shifted DWI images in a single readout, followed by water-fat separation and distortion correction. Results: Effective fat suppression and distortion correction were achieved in phantom and in-vivo scans, producing high-quality DWI images across multiple anatomies. Impact: This method provides a time-efficient, motion-robust approach for water-fat separation and distortion correction in DWI, improving diagnostic reliability in complex anatomical regions. Its single-shot acquisition design holds promise for expanding DWI applications in both routine clinical and challenging environments.