Journal
NMR IN BIOMEDICINE
Volume 30, Issue 4, Pages -Publisher
WILEY
DOI: 10.1002/nbm.3513
Keywords
T-2(*) anisotropy; myelin water imaging; magnetic susceptibility; susceptibility anisotropy; gradient echo
Funding
- National Research Foundation of Korea (NRF)
- Ministry of Science,ICT and Future Planning [NRF2015M3C7A1031969]
- Korean Government (MSIP) [NRF-2015R1A5A7037676, NRF-2015R1A2A1A15052174]
Ask authors/readers for more resources
In MRI, structurally aligned molecular or micro-organization (e.g. axonal fibers) can be a source of substantial signal variations that depend on the structural orientation and the applied magnetic field. This signal anisotropy gives us a unique opportunity to explore information that exists at a resolution several orders of magnitude smaller than that of typical MRI. In this review, one of the signal anisotropies, T-2(*) anisotropy in white matter, and a related imaging method, gradient echo myelin water imaging (GRE-MWI), are explored. The T-2(*) anisotropy has been attributed to isotropic and anisotropic magnetic susceptibility of myelin and compartmentalized microstructure of white matter fibers (i.e. axonal, myelin, and extracellular space). The susceptibility and microstructure create magnetic frequency shifts that change with the relative orientation of the fiber and the main magnetic field, generating the T-2(*) anisotropy. The resulting multi-component magnitude decay and nonlinear phase evolution have been utilized for GREMWI, assisting in resolving the signal fraction of the multiple compartments in white matter. The GRE-MWI method has been further improved by signal compensation techniques including physiological noise compensation schemes. The T-2(*) anisotropy and GRE-MWI provide microstructural information on a voxel (e.g. fiber orientation and tissue composition), and may serve as sensitive biomarkers for microstructural changes in the brain. Copyright (C) 2016 John Wiley & Sons, Ltd.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available