Diffusion tensor imaging changes correlate with cognition better than conventional MRI findings in patients with subcortical ischemic vascular disease.

BACKGROUND/AIMS: To investigate whether diffusion tensor imaging (DTI) is more sensitive than conventional MRI at detecting cognitive deterioration in patients with subcortical ischemic vascular disease (SIVD).
METHODS: Forty-two SIVD patients had a diagnosis of no cognitive impairment (NCI), vascular cognitive impairment/no dementia or vascular dementia (VaD). Whole-brain DTI histography and routine MRI were performed on these participants.
RESULTS: There were significant differences between cognitively impaired patients and NCI subjects in mean diffusivity and fractional anisotropy in either whole-brain white matter (WBWM) or in normal-appearing white matter (NAWM). All DTI indices within either WBWM or NAWM were found to be significantly correlated with both the attention-executive and memory measures in SIVD subjects. Lacune numbers and T₂-weighted lesions correlated only with attention-executive measures, whereas hippocampal volumes correlated only weakly with memory measures. Whole-brain gray matter volumes correlated with Z scores for all cognitive domains but language. After VaD patients had been excluded from the analysis, cognitive measures remained significantly correlated with some of the DTI indices, but not with conventional MRI findings.
CONCLUSIONS: Compared with conventional MRI, whole-brain DTI is a more reliable and sensitive technique for the early detection of cognitive impairment in SIVD patients.