We have investigated degeneration of the nerve fibers in chronic cerebral hypoperfusion model mice using DTI. Simple t-tests indicated that there are significant differences in CBF between the control and occluded sides of the brain, but there was no significant difference for MD. However, analysis of covariance showed that MD was strongly correlated with CBF, and that there were significant differences in MD between the contra- and ipsilateral sides. The result suggests degeneration of the nerve fibers due to chronic hypoperfusion. It is also suggested that CBF-related signal changes might be important for pathological diagnosis with DTI.