Cortical Microstructural Alterations in Mild Cognitive Impairment and Alzheimer’s Disease Dementia

Authors:
Open Access
Publisher website
Google Scholar
Abstract
In Alzheimer’s disease (AD), neurodegenerative processes are ongoing for years prior to the time that cortical atrophy can be reliably detected using conventional neuroimaging techniques. Recent advances in diffusion-weighted imaging have provided new techniques to study neural microstructure, which may provide additional information regarding neurodegeneration. In this study, we used neurite orientation dispersion and density imaging (NODDI), a multi-compartment diffusion model, in order to investigate cortical microstructure along the clinical continuum of mild cognitive impairment (MCI) and AD dementia. Using gray matter-based spatial statistics (GBSS), we demonstrated that neurite density index (NDI) was significantly lower throughout temporal and parietal cortical regions in MCI, while both NDI and orientation dispersion index (ODI) were lower throughout parietal, temporal, and frontal regions in AD dementia. In follow-up ROI analyses comparing microstructure and cortical thickness (derived from T1-weighted MRI) within the same brain regions, differences in NODDI metrics remained, even after controlling for cortical thickness. Moreover, for participants with MCI, gray matter NDI—but not cortical thickness—was lower in temporal, parietal, and posterior cingulate regions. Taken together, our results highlight the utility of NODDI metrics in detecting cortical microstructural degeneration that occurs prior to measurable macrostructural changes and overt clinical dementia.
Funding Information
  • National Institutes of Health (F30AG059346, R01AG037639, R01AG027161, P50AG033514)
  • Geriatric Research, Education, and Clinical Center of William S. Middleton Memorial Veterans Hospital
  • National Institute of Child Health and Human Development (U54HD090256)
  • BRAIN (R01EB022883)
  • University of Wisconsin Center for Predictive Computational Phenotyping (AI117924)
  • University of Wisconsin Institute for Clinical and Translational Research (NCATS UL1TR002373)

This publication has 67 references indexed in Scilit: