Distortion Correction Using the Susceptibility Based Field Map Estimation in Echo Planar Imaging Reconstruction

Hiroyuki Takeda¹, Boklye Kim¹

Reconstructed EPI images suffer from geometric distortion often due to the magnetic field inhomogeneity and significantly undermine the performance of activity analyses. In this work, we focus on a fundamental approach of the susceptibility-induced magnetic field inhomogeneity map to retrospectively recover the spin density map for EPI image reconstruction. By modeling the acquisition process, we identify the effect of the field inhomogeneity to the EPI reconstruction, and then obtain distortion-free density images using a regularized least-square method. Result shows that our approach works effectively for recovering the original undistorted image with an accurate estimate of the field map.