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Microbleed Topography, Leukoaraiosis, and Cognition in Probable Alzheimer Disease From the Sunnybrook Dementia Study
Jacqueline A. Pettersen, MD, MSc, FRCPC;
Gayathri Sathiyamoorthy, BSc;
Fu-Qiang Gao, MD;
Gregory Szilagyi;
Neelesh K. Nadkarni, MD;
Peter St George-Hyslop, MD, DSc;
Ekaterina Rogaeva, PhD;
Sandra E. Black, MD, FRCPC
Arch Neurol. 2008;65(6):790-795.
Background Microbleeds are hemosiderin deposits around small vessels and are well visualized with T2*-weighted gradient-recalled echo (GRE) imaging.
Objectives To determine frequency and topography of microbleeds in Alzheimer disease (AD) and to assess their association with leukoaraiosis and cognition.
Design Case-control cross-sectional analysis. Microbleeds were counted using GRE imaging. Leukoaraiosis was rated on T2-weighted and proton density–weighted scans using the Age-Related White Matter Changes Rating Scale (ARWMC). Neuropsychological tests indexed cognition.
Setting The Cognitive Neurology Clinic, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Patients Individuals with probable AD (n = 80) and healthy controls (n = 25) from a longitudinal cohort with GRE sequences as part of standard imaging protocol (2002-2006).
Results Microbleeds occurred in 29% of patients with AD and 12% of controls and were multiple (> 1) in 48% of patients with AD and 33% of controls. There was lobar (vs centrencephalic) predominance in 92% of AD patients, with occipital lobes accounting for 57% of these microbleeds. The ARWMC scores (P < .005) were significantly higher in AD patients with microbleeds than in those without, and microbleeds correlated with total (r = 0.39, P = .01) and parietooccipital (r = 0.28, P < .01) ARWMC scores. We were unable to demonstrate an association between microbleeds (or leukoaraiosis) and cognitive performance.
Conclusions Occipital predominance of microbleeds with corresponding parietooccipital leukoaraiosis has not been well described in prior imaging studies of AD. Microbleeds were frequent, often multiple, and predicted greater leukoaraiosis. These findings illustrate the complexity of AD vasculopathy and the need for additional studies in dementia and stroke populations.
Author Affiliations: LC Campbell Cognitive Neurology Research Unit and the Heart and Stroke Foundation Centre for Stroke Recovery, Neuroscience Research Program, Sunnybrook Research Institute, Division of Neurology, Department of Medicine, Sunnybrook Health Sciences Centre (Drs Pettersen, Gao, Nadkarni, and Black, Ms Sathiyamoorthy, and Mr Szilagyi) and the Centre for Research in Neurodegenerative Diseases (Drs St George-Hyslop and Rogaeva), University of Toronto, Toronto, Ontario, Canada.
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