Comparison of EPI Geometric Distortion Correction Using Field Mapping and Forward/reverse Phase Encoding Directional EPI Scans

Wanyong Shin¹, Erik Beall¹, Ken Sakaie¹, Mark Lowe¹

Since EPI images with forward (for.)/reverse (rev.) phase encoding (PE) directions provide voxel shifts in opposite directions, several approaches have been proposed to calculate voxel displacement (VD) map in PE direction using the two, in short, 2PE method here. Since both field map (FM) and 2PE methods generate VD maps, the direct voxel-wise comparison of VD maps between FM and 2PE method would provide the comprehensive insight of pros/cons of 2PE. In this study, we compare VD maps from FM and 2 PE methods, and demonstrate their performance and limitation.