1. A method for determining an increased likelihood that a subject has Alzheimer's Disease (AD) relative to a normal subject, said method including: imaging an area of the hippocampus of the brain of a subject to acquire a diffusion tensor age of said area; determining the Fractional Anisotropy (FA) from said diffusion tensor image; comparing said Fractional Anisotropy to normative data; and identifying an increased likelihood of the presence of AD relative to a normal subject when said FA is less than said normative data by a statistically significant amount, wherein said statistically significant amount has a p-value of less than 0.05.