Tract-based spatial statistical analysis of Alzheimer's disease and its correlation with cognition scores

Abstract

Objective To observe microstructural changes of white matter in Alzheimer's disease (AD), and to find out the relationship between white matters lesion and declined cognition. Methods Twenty-four AD patients and 24 controls with normal cognition performed diffusion tensor imaging MR scan. Tract-based spatial statistical analysis (TBSS) was used to investigate microstructural change of white matter, and then its correlation with Mini-Mental State Examination (MMSE) scores was analyzed. Results Fractional anisotropy (FA) values were decreased in corpus callosum, fornix, left corticospinal tract, bilateral cerebral peduncle, superior cerebellar peduncle, internal capsule, corona radiata, posterior thalamic radiation, sagittal stratum including inferior longitidinal fasciculus and inferior fronto-occipital fasciculus, external capsule, cingulate gyrus, hippocampus, superior longitudinal fasciculus and uncinate fasciculus, while mean diffusivity (MD) values were increased in fornix, left hippocampus, bilateral internal capsule, corona radiata, posterior thalamic radiation, sagittal stratum including inferior longitidinal fasciculus and inferior fronto-occipital fasciculus, external capsule, cingulate gyrus, superior longitudinal fasciculus, superior fronto-occipital fasciculus and uncinate fasciculus (all P<0.05, threshold-free cluster enhancement corrected). MMSE scores had a positive correlation with decreased FA values of left sagittal stratum (r=0.535, P=0.007) and negative correlations with increased MD values of left sagittal stratum (r=-0.427, P=0.037), left superior longitudinal fasciculus (r=-0.424, P=0.039) and left uncinate fasciculus (r=-0.505, P=0.012). Conclusions There exist widespread white matter lesions in AD with impairment of white matter connections of intra- and inter-hemispheres. Impaired white matters in left hemisphere may have close relationships with cognition decline. Key words: Alzheimer disease; Diffusion tensor image; Tract-based spatial statistics; Cognition