Project 6

AD patients
Distribution of the uncorrected (left panel) and corrected (right panel) mean diffusivity for young (a,d), elderly (b,e) healthy subjects and AD patients (c,f) on the cortical surface. Color bar indicates the mean diffusivity values.

Regional changes of cortical mean diffusivities with aging and Alzheimer’s disease after correction of partial volume effects

Accurately measuring the cortical mean diffusivity (MD) derived from diffusion tensor imaging (DTI) at the comprehensive lobe, gyral and voxel level of the young, elderly healthy brains and those with Alzheimer’s disease (AD) may provide insights on heterogeneous cortical microstructural changes caused by aging and AD. Due to partial volume effects (PVE), the measurement of cortical MD is overestimated with contamination of cerebrospinal fluid (CSF). The bias is especially severe for aging and AD brains because of significant cortical thinning of these brains.

In this study, we aimed to quantitatively characterize the unbiased regional cortical MD changes due to aging and AD and delineate the effects of cortical thinning of elderly healthy and AD groups on MD measurements. Our study suggests that the cortical thinning in elderly healthy and AD groups is a significant contributor to the bias of uncorrected cortical MD measurement. The established comprehensive unbiased cortical MD profiles of young, elderly healthy subjects and AD patients at the lobe, gyral and voxel level may serve as clinical references for cortical microstructure.

For details, please see our Publication (Jeon et al., Neuroimage 2012).