Distortion Correction for Echo Planar MR Imaging Using the Point Spread Function (PSF) Map with Bregman Iteration

Yu Cai¹, Weili Lin, Qingwei Liu, Craig Hamilton², Hongyu An

Point Spread Function (PSF) mapping techniques have shown promise for geometric distortion correction in Echo Planar Imaging (EPI)(1), where the distortion information is mapped by applying additional phase encoding gradients with a constant time (PSF encoding). Cai et al(2) introduced the inverse solution of the PSF map with the Tikhonov regularization method for EPI distortion correction. The smoothness penalty in the Tikhonov regularization causes it sensitive to the aliasing artifact in its reconstructed image and fine textile structure blurring. Here we apply the total variation (TV) regularization with Bregman iteration method(3) to the PSF map in which the penalty term is adaptively updated based on the Bregman distance, which is immune to the above effects. The proposed approach compared with the Tikhonov regularization methods were evaluated at 3.0T with human subjects while at 9.4T with rats.