Cho: Choline-containing compounds; MD: Mean diffusivity; DTI: Diffusion tensor imaging; NAA: N-acetylaspartate; FA: Fractional anisotropy; SLF: Superior longitudinal fasciculus; FWHM: Full width at half maximum of peak; tCr: Creatine plus phosphocreatine; 1H-MRS: Proton magnetic resonance spectroscopy; TE: Time of echo; MANOVA: Multivariate analysis of variance; TR: Time of repetition.
The properties of the developed phantom are demonstrated by means of diffusion tensor imaging and diffusion kurtosis imaging.
Differentiation of the SLF from the arcuate fasciculus and their respective cortical projections (see Glasser and Rillig [ 2008] for a meta-analysis) is not easily achieved by the current means of diffusion tensor imaging and interpretation of their functional roles must, therefore, await further empirical support.
Here we searched for possible structural changes in the thalamus of migraineurs by mean of acquiring diffusion tensor magnetic resonance imaging (MRI).
Mean diffusivity (MD), measured by diffusion tensor imaging (DTI), is the rate of diffusivity and a direction-independent measure of the average diffusivity reflecting water motility in a voxel.
Figure 6 illustrates the fornix and cingulum bundles and their mean tracts in the diffusion tensor images averaged over all the control subjects in this study.
A number of quantitative metrics can be obtained from diffusion MRI to characterise the tissue, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) derived using the diffusion tensor model (i.e. Diffusion Tensor Imaging, DTI) [ 21].
After correcting for distortions due to eddy current and head motion, maps of fractional anisotropy, mean diffusivity, axial diffusivity and radial diffusivity were calculated by fitting the diffusion tensor model within each voxel using the FDT software tool in FSL.
This assumption is further supported by previous studies describing visual pathway damage in MS by means of voxel-based morphometry, diffusion tensor imaging or magnetization transfer ratio[33] [35], and damage to other functional systems such as pathways involved in learning and memory [36] [37].
Thus, the diffusion tensor is a mean value and DTI cannot distinguish crossed white matter fibers [17].
