Usefulness of diffusion tensor imaging of white matter in Alzheimer disease and vascular dementia

To evaluate the usefulness of diffusion tensor imaging in detecting the water diffusivity caused by neuropathological change in Alzheimer disease and vascular dementia.

Twenty patients with Alzheimer disease, 20 with vascular dementia, and 10 control subjects were examined. Diffusion tensor imaging applied diffusion gradient encoding in six non-collinear directions. Fractional anisotropy values were compared in the genu and splenium of the corpus callosum, and anterior and posterior white matter among the three groups.

In the patients with Alzheimer disease, fractional anisotropy values of the posterior white matter were significantly lower than those of controls. In patients with vascular dementia, fractional anisotropy values of the anterior white matter tended to be lower than those of the posterior white matter (P=0.07).

Diffusion tensor imaging reflects the neuropathological changes in the white matter, and may be useful in the diagnosis of Alzheimer disease and vascular dementia.