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Model for the correction of motion‐induced phase errors in multishot diffusion‐weighted‐MRI of the head: Are cardiac‐motion‐induced phase errors reproducible from beat‐to‐beat?
Author(s) -
O'Halloran R. L.,
Holdsworth S.,
Aksoy M.,
Bammer R.
Publication year - 2012
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.23245
Subject(s) - beat (acoustics) , diffusion mri , motion (physics) , physics , repeatability , phase (matter) , nuclear magnetic resonance , computer vision , biomedical engineering , magnetic resonance imaging , computer science , mathematics , acoustics , medicine , radiology , quantum mechanics , statistics
In diffusion‐weighted imaging, multishot acquisitions are problematic due to intershot inconsistencies of the phase caused by motion during the diffusion‐encoding gradients. A model for the motion‐induced phase errors in diffusion‐weighted‐MRI of the brain is presented, in which rigid‐body and nonrigid‐body motion are separated. In the model, it is assumed that nonrigid‐body motion is due to cardiac pulsation, and that the motion patterns are repeatable from beat‐to‐beat. To test the validity of this assumption, the repeatability of nonrigid‐body motion‐induced phase errors is quantified in three healthy volunteers. Nonrigid‐body motion‐induced phase was found to significantly correlate ( P < 0.05) with pulse‐oximeter waveforms in ∼83% of the pixels tested across all slices and subjects. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.