Concurrent Geometric Distortion Correction in Mapping Slice-to-volume (MSV) Motion Correction of fMRI Time Series

D. Yeo, J. A. Fessler, B. Kim Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States, Radiology, University of Michigan Medical School, Ann Arbor, MI, United States Introduction: The accuracy of measuring voxel intensity changes between stimulus and rest images in fMRI echo-planar imaging (EPI) data, from which brain activation maps are computed, is severely degraded in the presence of rigid head motion. In addition, EPI is sensitive to susceptibility-induced geometric distortions, especially in the mid to lower brain images. Head motion causes image shifts as well as field-map changes which result in local changes in geometric distortion. Commonly, geometric distortion correction is performed, with a static field-map, independently of image registration. This does not account for field-map changes with head motion. Previously, the concept of a concurrent motion and field-inhomogeneity correction technique using quadratic penalized least squares (QPLS) reconstruction has been introduced as an enhancement to the map slice-to-volume (MSV) motion correction scheme that accounts for inter-slice motion [1-3]. This work is an extension of [1] and evaluates the technique under more realistic simulation conditions on an entire simulated 130-volume EPI time-series.