Metal Artifacts Suppression in Diffusion Imaging Using Point-Spread-Function Encoded EPI

Motivation: Fast DWI near metal implants remains a substantial challenge. Goal(s): To reduce metal artifacts in DWI using an efficient 2D imaging approach. Approach: We proposed a tailored reconstruction method for point-spread-function encoded EPI (PSF-EPI) to improve metal artifacts correction. By taking the advantage of the additional phase encoding (PSF encoding) in PSF-EPI, the intrinsic echo-shifted image series along ky can be used to separate the spectral components of off-resonance frequency and eventually resolve the signal displacements induced by implants. Results: The results of phantom experiment and in-vivo spinal cord DWI of post-operative CSM patients with implants demonstrate effective metal artifacts reduction. Impact: The metal artifacts in DWI can be effectively reduced using our proposed reconstruction method for highly accelerated PSF-EPI. This benefits the post-operative evaluations of patients with spinal fusions and allows high-resolution (1.0×1.0 mm2), large-coverage DWI within clinically feasible scan time.