Premium
Microstructural correlates of 3D steady‐state inhomogeneous magnetization transfer (ihMT) in the human brain white matter assessed by myelin water imaging and diffusion tensor imaging
Author(s) -
Ercan Ece,
Varma Gopal,
Mädler Burkhard,
Dimitrov Ivan E.,
Pinho Marco C.,
Xi Yin,
Wagner Benjamin C.,
Davenport Elizabeth M.,
Maldjian Joseph A.,
Alsop David C.,
Lenkinski Robert E.,
Vinogradov Elena
Publication year - 2018
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.27211
Subject(s) - fractional anisotropy , white matter , diffusion mri , magnetization transfer , nuclear magnetic resonance , myelin , magnetic resonance imaging , human brain , voxel , chemistry , anisotropy , nuclear medicine , materials science , physics , medicine , radiology , neuroscience , optics , biology , central nervous system
Purpose To compare the recently introduced inhomogeneous magnetization transfer (ihMT) technique with more established MRI techniques including myelin water imaging (MWI) and diffusion tensor imaging (DTI), and to evaluate the microstructural attributes correlating with this new contrast method in the human brain white matter. Methods Eight adult healthy volunteers underwent T 1 ‐weighted, ihMT, MWI, and DTI imaging on a 3T human scanner. The ihMT ratio (ihMTR), myelin water fraction (MWF), fractional anisotropy (FA), radial diffusivity (RD), axial diffusivity (AD), and mean diffusivity (MD) values were calculated from different white matter tracts. The angle ( θ ) between the directions of the principal eigenvector, as measured by DTI, and the main magnetic field was calculated for all voxels from various fiber tracts. The ihMTR was correlated with MWF and DTI metrics. Results A strong correlation was found between ihMTR and MWF (ρ = 0.77, P < 0.0001). This was followed by moderate to weak correlations between ihMTR and DTI metrics: RD (ρ = −0.30, P < 0.0001), FA (ρ = 0.20, P < 0.0001), MD (ρ = −0.19, P < 0.0001), AD (ρ = 0.02, P < 0.0001). A strong correlation was found between ihMTR and θ (ρ = −0.541, P < 0.0001). Conclusion The strong correlation with myelin water imaging and its low coefficient of variation suggest that ihMT has the potential to become a new structural imaging marker of myelin. The substantial orientational dependence of ihMT should be taken into account when evaluating and quantitatively interpreting ihMT results.