Structural Brain Tissue Abnormalities in Patients with Mild Cognitive Impairment as Assessed by Diffusion Tensor Imaging

The goal of this study was to provide new insights concerning neuroimaging measures that identify early indicators of amnestic mild cognitive impairment (a-MCI). Diffusion tensor imaging (DTI) scans from a previous study of adults age 58-78 were used to compare measures in the cingulum and 11 cortical structures in a-MCI cases (n=13) and age-matched controls (n=15). Fractional anisotropy (FA) and related measures of diffusivity were compared between a-MCI cases and controls using analyses of variance; correlations between DTI measures and measures of verbal memory were evaluated as well. Results showed FA was significantly reduced in the right hemisphere of the cingulum and significantly increased in the sagittal stratum (SS) for a-MCI cases compared to controls. Increased FA for the SS and reduced FA for the anterior segment of the corona radiata were significantly correlated with poorer performance on tests of verbal memory for a-MCI cases. A number of study results were compromised by bias in the application of analysis methods. Overall, however, findings indicate that greater degeneration was not consistently detectable in a-MCI cases as compared to controls.