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Origin and minimization of residual motion‐related artifacts in navigator‐corrected segmented diffusion‐weighted EPI of the human brain
Author(s) -
Jiang Hangyi,
Golay Xavier,
van Zijl Peter C.M.,
Mori Susumu
Publication year - 2002
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.10102
Subject(s) - echo planar imaging , computer vision , artificial intelligence , residual , motion (physics) , computer science , diffusion mri , nuclear magnetic resonance , diffusion , sensitivity (control systems) , artifact (error) , physics , magnetic resonance imaging , algorithm , medicine , radiology , electronic engineering , engineering , thermodynamics
Motion sensitivity in diffusion‐weighted imaging (DWI) can be effectively suppressed using single‐shot echo‐planar imaging (EPI). However, segmented (multishot) EPI is often used to increase resolution and reduce spatial distortions, which in turn increases susceptibility to brain motion. The sources of these residual motion artifacts in navigator‐echo‐corrected segmented EPI images of the brain were investigated. The results indicate that the dominant source of these artifacts is cardiac pulsation with occasional involuntary movement of the subject. The relationship between the cardiac cycle and motion artifacts shows that optimum timing for the data acquisition is possible. In addition it is shown that the effects of involuntary motion can be removed by swapping k ‐space data between redundant datasets. Magn Reson Med 47:818–822, 2002. © 2002 Wiley‐Liss, Inc.