Cerebral Amyloid Angiopathy-Related Microbleeds Correlate with Glucose Metabolism and Brain Volume in Alzheimer's Disease.

BACKGROUND

Microbleeds (MBs) are frequently observed in Alzheimer's disease (AD); however, the relevance to AD pathophysiology has not been elucidated.

OBJECTIVES

We investigated correlation of MBs, especially cerebral amyloid angiopathy (CAA)-related MBs with cognitive function, gray matter volume, and glucose metabolism in AD.

METHODS

We performed magnetic resonance imaging including T2*-weighted imaging sequence for 206 patients with AD. Among them, 158 AD patients with no focal brain lesions except for MBs were investigated with cognitive tests, voxel-based morphometry, and 18F-fluorodeoxyglucose positron emission tomography in a cross-sectional observational study.

RESULTS

Of the 158 patients with no hemorrhagic and/or ischemic stroke lesions except for MBs, 27 patients had MBs, in which 17 patients showed CAA-related MBs that located only in cortex/subcortex (CAA-related MBs), and 10 patients showed CAA-unrelated MBs that located in deep regions regardless of the presence of MBs in cortical/subcortical regions. There were slightly but significant differences in cognitive functions between the patients without MBs, those with CAA-related MBs, and those with CAA-unrelated MBs. MBs were recognized frequently in the occipital lobe in the patients with CAA-related MBs. The patients with CAA-related MBs showed gray matter atrophy in the temporal lobe and cerebellum, and glucose hypometabolism in the temporal lobe compared with those without MBs.

CONCLUSIONS

Our results indicate that MBs, particularly CAA-related MBs would cause gray matter atrophy and glucose hypometabolism in AD.