Cerebral Microbleeds in Patients with Amnesic Mild Cognitive Impairment and Alzheimer’s Disease

초록

Background & objectives: Cerebral amyloid angiopathy (CAA) and Alzheimer’s disease (AD) frequently co-occur. CAA is associated with leukoaraiosis and microbleeds in AD. Amnestic mild cognitive impairment (aMCI) is considered as a prodromal stage of AD dementia. Any studies of microbleeds in aMCI have not been reported. This study was aimed to evaluate the prevalence and topography of cerebral microbleeds in aMCI and AD. Methods: We retrospectively evaluated the medical records and brain MRIs of 90 patients with AD and 86 with aMCI who were diagnosed newly at a memory clinic from 2008 to 2010, and 57 normal elderly. Microbleeds were counted using T2-weighted gradient echo imaging. Two independent raters blinded to clinical information had to agree for a microbleed to be counted. Results: Microbleeds occurred in 38.9% of patients with AD, 34.9% of those with aMCI, and 19.3% of controls (p=0.04). Microbleeds were multiple (>1) in 45.7% of AD patients with microbleeds, 30.0% of aMCI patients with microbleeds, and 9.1% of controls with microbleeds (p=0.01). Lobar microbleeds occurred in 57.1% of AD patients with microbleeds, 66.7% of aMCI patients with microbleeds, and 36.4% of controls with microbleeds (p=0.03). Microbleeds were most common in temporoparietal lobes accounting for 30.7% of these micorbleeds in AD patients, and in temporal lobes accounting for 31.8% of these microbleeds in aMCI patients. Conclusions: Microbleeds were frequent, often multiple, and showed temporoparietal predominance in aMCI as well AD. This suggests that CAA may occur in prodromal AD. The impact of microbleeds on cognitive decline or conversion to dementia in aMCI and AD needs to be studied .