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Updated: May 11, 2025
Visualization of Amyloid β Deposits in the Human Brain with Matrix-assisted Laser Desorption/Ionization Imaging Mass Spectrometry
Published on: March 7, 2019
Cerebral Amyloid Angiopathy Is Associated With Higher R2 Relaxation Rate: An MRI and Pathology Study
Md Tahmid Yasar1, Arnold M Evia2, Mahir Tazwar1
1Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, Illinois, USA.
Objective:
Cerebral amyloid angiopathy (CAA) involves β-amyloid deposition in the walls of cortical and leptomeningeal small vessels. Transverse relaxation rate (R2) is a major source of contrast in MRI. This study tested the hypothesis that CAA is associated with R2, extracted the spatial pattern of CAA-related R2 abnormalities, and evaluated R2 at different CAA severity levels in a large number of community-based older adults.
Methods:
Cerebral hemispheres from 804 older adults who came to autopsy were included. All hemispheres underwent ex vivo MRI and detailed neuropathologic examination. R2 maps were generated from ex vivo MRI data. Voxel-wise and region-based regression analyses were conducted to investigate the association of R2 with CAA, controlling for other neuropathologies and demographics. R2 values at different CAA severity levels were also investigated.
Results:
CAA severity was associated with a higher transverse relaxation rate R2 in cortical and juxtacortical frontal and medial temporal lobe regions, and in deep brain structures, independently of other neuropathologies and demographics. R2 abnormalities were significant in severe CAA, but were limited in terms of spatial extent and magnitude in moderate CAA, and were not detectable in mild CAA.
Interpretation:
This is to our knowledge the first investigation of the link between CAA and R2, one of the major contrast mechanisms in MRI. R2 is sensitive to CAA-related brain abnormalities, primarily in moderate and severe stages of the disease. In vivo detection of CAA is an important challenge, and the present work contributes new knowledge that may aid toward this goal.
Insights
Cerebral amyloid angiopathy (CAA) is linked to altered MRI transverse relaxation rates (R2) in older adults. These R2 changes are most prominent in moderate to severe CAA, offering potential for in vivo detection.
Area of Science:
- Neuroimaging
- Neuropathology
- Geriatric Medicine
Background:
- Cerebral amyloid angiopathy (CAA) involves β-amyloid deposition in small brain vessels.
- Transverse relaxation rate (R2) is a key MRI contrast mechanism.
Purpose of the Study:
- To investigate the association between CAA and R2.
- To map the spatial distribution of R2 abnormalities related to CAA.
- To assess R2 values across different CAA severity levels.
Main Methods:
- Analysis of ex vivo MRI and neuropathology from 804 older adults.
- Generation of R2 maps from MRI data.
- Voxel-wise and region-based regression analyses controlling for confounders.
Main Results:
- CAA severity correlated with increased R2 in cortical, juxtacortical, and deep brain regions.
- R2 abnormalities were significant in severe CAA, less so in moderate, and undetectable in mild CAA.
- Associations were independent of other neuropathologies and demographics.
Conclusions:
- This study establishes a link between CAA and R2, a major MRI contrast mechanism.
- R2 is sensitive to CAA-related brain abnormalities, particularly in moderate to severe stages.
- Findings may contribute to the development of in vivo methods for detecting CAA.
