Claim: Fractional anisotropy, a scalar value between zero and one that describes the degree of anisotropy of a diffusion process, is a measure often used in diffusion imaging, the use of specific MRI sequences as well as software that generates images from the resulting data that uses the diffusion of water molecules to generate contrast in MR images, where it is thought to reflect fiber density, axonal diameter, and myelination in white matter.
Evidence: Fractional anisotropy (FA) is a scalar value between zero and one that describes the degree of anisotropy of a diffusion process. FA is a measure often used in diffusion imaging where it is thought to reflect fiber density, axonal diameter, and myelination in white matter. Diffusion-weighted magnetic resonance imaging (DWI or DW-MRI) is the use of specific MRI sequences as well as software that generates images from the resulting data that uses the diffusion of water molecules to generate contrast in MR images.