Improved Motion Correction in fMRI by Joint Mapping of Slices into an Anatomical Volume
Motion correction in fMRI time series is essential for accurate statistical analyses. Typically motion correction is applied in a rigid fashion between time series volumes. Such corrections assume no relative motion between slices. An improved motion correction scheme, map-slice-to-volume (MSV), was developed previously using mutual information (MI) to register individual fMRI slices onto an anatomical volume to account for inter-slice motion . As each slice’s orientation represents a statistically independent sampling of the patient’s motion at multiple intervals throughout the acquisition, a smoothed estimate of the patient’s trajectory in time can be computed by jointly estimating each slice’s orientation while minimizing the implied acceleration of the patient’s head subject to applying a priori, slice-related weights based on known registration reliabilities. The results of this joint mapping of slices into a volume (JMSV) show further substantial improvement in slice registration and subsequent motion estimation.
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