Motion Induced Magnetic Susceptibility and Field Map Estimation in FMRI

Desmond Yeo¹, Jeffery Fessler², Boklye Kim³

Head rotation during fMRI time series acquisition may cause nonlinear field-inhomogeneity changes and lead to dynamic geometric distortion. The use of image registration to estimate dynamic field inhomogeneity maps from a static field map is not sufficient. This work retrospectively estimates magnetic susceptibility induced field maps of an object affected by out-of-plane rotation, given a static field map and the associated object motion parameters. It estimates a susceptibility map from a static field map using regularized image restoration techniques, and applies rigid body motion to the estimation. The dynamic field map is then computed using susceptibility voxel convolution.