P2-245: White matter changes associated with dementia development in patients with subcortical ischemic white matter lesions: A diffusion tensor image study

Abstract

Diffusion tensor MRI (DTI) is a new technique that may provide a better index of white matter damage in central nervous system. Both discrete lacunar infarcts and leukoaraiosis are important mechanisms in developing dementia in patients with subcortical ischemic vascular lesions. But the location and severity of white matter changes associated with development of dementia has not been established yet. We investigate the difference of location and severity of white matter damage in patients with subcortical ischemic vascular lesions with and without dementia. Eleven demented patients(age: 74.80 yrs, MMSE: 22.10) who fulfill the criteria of Erkinjuntti's subcortical ischemic vascular dementia (SIVD) criteria, ten patients (age: 67.50 yrs, MMSE: 26.63) with subcortical vascular cognitive impairment no dementia (SVCIND) and twelve healthy volunteers(age: 70.64 yrs, MMSE: 28.73) were recruited. They underwent DTI, neuropsychological assessment and clinical interview. Fractional anisotropy (FA) and mean diffusivity (MD) were measured in temporal, frontal, parietal and occipital white matter regions as well as in the corpus callosum (genu, body and splenium), cingulate white matter(anterior and posterior), internal capsule(anterior and posterior limb), superior and inferior longitudinal fasciculus, centrum semiovale, hippocampus, and anterior thalamus. SVCIND and SIVD patients showed lower FA and higher MD values in the both frontal, occipital, right anterior thalamus, centrum semiovale, superior longitudinal fasciculus and in both hippocampi than the control group. Compared to SVCIND patients, SIVD patients had decreased FA values and increased MD values in both frontal areas and decreased MD in left superior longitudinal fasciculus. The findings support the white matter damage and disruption in the frontal region and superior association fiber is important for the cognitive dysfunctions associated with dementia development in patients with subcortical ischemic lesions. This study was supported by a grant of the Korea Health 21 R&D Project, Ministry of Health & Welfare, Republic of Korea(A050079).