Related Experiment Video
Updated: May 23, 2026
Comprehensive Autopsy Program for Individuals with Multiple Sclerosis
Published on: July 19, 2019
Multimodal imaging evidence for axonal and myelin deterioration in amnestic mild cognitive impairment
Brian T Gold1, Yang Jiang, David K Powell
1Department of Anatomy and Neurobiology, Chandler Medical Center, University of Kentucky, Lexington, KY, USA. brian.gold@uky.edu
Abstract:
White matter (WM) microstructural declines have been demonstrated in Alzheimer's disease and amnestic mild cognitive impairment (aMCI). However, the pattern of WM microstructural changes in aMCI after controlling for WM atrophy is unknown. Here, we address this issue through joint consideration of aMCI alterations in fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity, as well as macrostructural volume in WM and gray matter compartments. Participants were 18 individuals with aMCI and 24 healthy seniors. Voxelwise analyses of diffusion tensor imaging data was carried out using tract-based spatial statistics (TBSS) and voxelwise analyses of high-resolution structural data was conducted using voxel based morphometry. After controlling for WM atrophy, the main pattern of TBSS findings indicated reduced fractional anisotropy with only small alterations in mean diffusivity/radial diffusivity/axial diffusivity. These WM microstructural declines bordered and/or were connected to gray matter structures showing volumetric declines. However, none of the potential relationships between WM integrity and volume in connected gray matter structures was significant, and adding fractional anisotropy information improved the classificatory accuracy of aMCI compared to the use of hippocampal atrophy alone. These results suggest that WM microstructural declines provide unique information not captured by atrophy measures that may aid the magnetic resonance imaging contribution to aMCI detection.
Insights
White matter microstructural declines, specifically reduced fractional anisotropy, are key indicators in amnestic mild cognitive impairment (aMCI). These changes offer unique diagnostic information beyond gray matter atrophy for detecting aMCI.
Area of Science:
- Neuroimaging
- Neurology
- Biomedical Engineering
Background:
- White matter (WM) microstructural integrity declines are observed in Alzheimer's disease and amnestic mild cognitive impairment (aMCI).
- The specific pattern of WM microstructural changes in aMCI, independent of WM atrophy, remains unclear.
- Understanding these changes is crucial for accurate diagnosis and understanding disease progression.
Purpose of the Study:
- To investigate WM microstructural alterations in aMCI while controlling for WM atrophy.
- To examine the relationship between WM microstructural integrity and gray matter volume.
- To assess the diagnostic utility of WM integrity measures in aMCI detection.
Main Methods:
- Diffusion tensor imaging (DTI) and tract-based spatial statistics (TBSS) were used to analyze WM microstructure (fractional anisotropy, mean diffusivity, axial diffusivity, radial diffusivity).
- Voxel-based morphometry (VBM) analyzed macrostructural gray and white matter volumes.
- Participants included 18 individuals with aMCI and 24 healthy seniors.
Main Results:
- After controlling for WM atrophy, reduced fractional anisotropy was the primary finding in aMCI.
- WM microstructural declines were adjacent to gray matter areas with volume loss.
- Fractional anisotropy measures improved aMCI classification accuracy compared to hippocampal atrophy alone.
Conclusions:
- WM microstructural declines, particularly in fractional anisotropy, are significant in aMCI.
- These microstructural changes provide unique information for aMCI detection via magnetic resonance imaging.
- WM integrity measures complement atrophy-based assessments for improved diagnostic accuracy.
Related Concept Videos
01:23Alzheimer Disease ll: Pathophysiology
01:22Dementia l: Introduction