Small vessel disease more than Alzheimer's disease determines diffusion MRI alterations in memory clinic patients
Sofia Finsterwalder1, Naomi Vlegels2, Benno Gesierich1
1Institute for Stroke and Dementia Research, University Hospital, LMU Munich, Munich, Germany.
Introduction:
Microstructural alterations as assessed by diffusion tensor imaging (DTI) are key findings in both Alzheimer's disease (AD) and small vessel disease (SVD). We determined the contribution of each of these conditions to diffusion alterations.
Methods:
We studied six samples (N = 365 participants) covering the spectrum of AD and SVD, including genetically defined samples. We calculated diffusion measures from DTI and free water imaging. Simple linear, multivariable random forest, and voxel-based regressions were used to evaluate associations between AD biomarkers (amyloid beta, tau), SVD imaging markers, and diffusion measures.
Results:
SVD markers were strongly associated with diffusion measures and showed a higher contribution than AD biomarkers in multivariable analysis across all memory clinic samples. Voxel-wise analyses between tau and diffusion measures were not significant.
Discussion:
In memory clinic patients, the effect of SVD on diffusion alterations largely exceeds the effect of AD, supporting the value of diffusion measures as markers of SVD.
Insights
Small vessel disease (SVD) significantly impacts brain microstructural changes more than Alzheimer's disease (AD). Diffusion tensor imaging (DTI) measures effectively highlight SVD's effects in memory clinic patients.
Area of Science:
- Neuroimaging
- Neurology
- Biomarkers
Background:
- Microstructural alterations are characteristic of Alzheimer's disease (AD) and small vessel disease (SVD).
- Diffusion tensor imaging (DTI) is crucial for assessing these microstructural changes.
Purpose of the Study:
- To quantify the distinct contributions of AD and SVD to diffusion alterations.
- To validate diffusion measures as sensitive indicators for SVD.
Main Methods:
- Analysis of six samples (N=365) encompassing the AD and SVD spectrum.
- Calculation of diffusion measures using DTI and free water imaging.
- Application of linear, random forest, and voxel-based regression models to assess biomarker associations.
Main Results:
- Small vessel disease (SVD) markers demonstrated a stronger association with diffusion measures compared to AD biomarkers.
- Multivariable analysis indicated SVD's greater contribution to diffusion alterations across memory clinic samples.
- Voxel-wise analysis revealed no significant link between tau and diffusion measures.
Conclusions:
- In patients attending memory clinics, SVD exerts a more substantial influence on diffusion alterations than AD.
- Diffusion measures are valuable imaging markers for detecting SVD.
