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Reduction of eddy‐current‐induced distortion in diffusion MRI using a twice‐refocused spin echo
Author(s) -
Reese T.G.,
Heid O.,
Weisskoff R.M.,
Wedeen V.J.
Publication year - 2003
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.10308
Subject(s) - eddy current , distortion (music) , anisotropic diffusion , pulse sequence , image quality , imaging phantom , nuclear magnetic resonance , spin echo , diffusion , signal (programming language) , attenuation , anisotropy , physics , diffusion mri , materials science , computational physics , optics , magnetic resonance imaging , image (mathematics) , computer science , artificial intelligence , medicine , radiology , optoelectronics , amplifier , cmos , quantum mechanics , programming language , thermodynamics
Abstract Image distortion due to field gradient eddy currents can create image artifacts in diffusion‐weighted MR images. These images, acquired by measuring the attenuation of NMR signal due to directionally dependent diffusion, have recently been shown to be useful in the diagnosis and assessment of acute stroke and in mapping of tissue structure. This work presents an improvement on the spin‐echo (SE) diffusion sequence that displays less distortion and consequently improves image quality. Adding a second refocusing pulse provides better image quality with less distortion at no cost in scanning efficiency or effectiveness, and allows more flexible diffusion gradient timing. By adjusting the timing of the diffusion gradients, eddy currents with a single exponential decay constant can be nulled, and eddy currents with similar decay constants can be greatly reduced. This new sequence is demonstrated in phantom measurements and in diffusion anisotropy images of normal human brain. Magn Reson Med 49:177–182, 2003. © 2003 Wiley‐Liss, Inc.