Diffusion tensor imaging on white matter in normal adults and elderly patients with hypertension

摘要

Diffusion-weighted magnetic resonance imaging (MRI) exploits the properties of randomly moving water molecules in the presence of magnetic field gradients. Within tissue, diffusion of water molecules is restricted by cell membranes, small vessels, axon cylinders, membrane, chemical interactions of water and macromolecules. In the brain, water diffusion exhibits directionality in the orientation along the long axis of white matter. This is referred to as "diffusion anisotropy". Diffusion anisotropy can be measured via diffusion tensor imaging (DTI). There is a class of anisotropy indices that reflect the degree of anisotropy of water diffusion which are related to the degree of architectural and structural coherence within each voxel of the tissue. Fractional anisotropy (FA) was the most frequently used index of anisotropy. This study was to explore whether the sex, age differences of diffusion existed in white matter of normal adults, and to examine whether the diffusion properties were changed in normal appearing white matter (NAWM) of elderly patients with hypertension.