Average field map image template for Echo-Planar image analysis.

Magnetic resonance field map images are normally used in characterizing the magnetic field inhomogeneity for distortion correction in Echo-Planar Imaging (EPI) and accurate localization in functional MRI (fMRI). In this paper, the computation and applications of an average field map image template is investigated based on real field maps. The introduced methodology and the obtained field map image templates may be used in EPI and fMRI image analysis, distortion correction, registration, and functional localization when high-resolution field map images are not available for individual datasets. The introduced methodology involves three stages of pre-processing, registration, and spatial normalization. The analysis and results presented in this paper show the impact and usefulness of the investigated methodology in several applications.