Chronic alcoholic adults show clear abnormalities in brain white matter volume as well as microstructural alterations in white matter tissue organization 40–42. Typically, less white matter suggests dissipation of myelin-coated axons 43. Diffusion tensor imaging (DTI) characterizes the integrity of water matter by examining the diffusion of water molecules in white matter tissue. Therefore, DTI provides information on the organization of localized white matter fiber tracts. Two commonly used scalar measurements are fractional anisotropy (FA), which reflects white matter coherence by providing an estimate of the directionally dependent movement of water molecules, and mean diffusivity (MD), an index of the overall displacement of water molecules.
