Microbleeds in Atypical Presentations of Alzheimer's Disease: A Comparison to Dementia of the Alzheimer's Type

Article type: Research Article

Authors: Whitwell, Jennifer L.^{a; *} | Kantarci, Kejal^a | Weigand, Stephen D.^b | Lundt, Emily S.^b | Gunter, Jeffrey L.^{a; c} | Duffy, Joseph R.^d | Strand, Edythe A.^d | Machulda, Mary M.^e | Spychalla, Anthony J.^a | Drubach, Daniel A.^d | Petersen, Ronald C.^d | Lowe, Val J.^a | Jack Jr., Clifford R.^a | Josephs, Keith A.^d

Affiliations: [a] Department of Radiology, Mayo Clinic, Rochester, MN, USA | [b] Department of Health Sciences Research (Biostatistics), Mayo Clinic, Rochester, MN, USA | [c] Department of Information Technology, Mayo Clinic, Rochester, MN, USA | [d] Department of Neurology, Mayo Clinic, Rochester, MN, USA | [e] Department of Psychiatry and Psychology (Division of Neuropsychology), Mayo Clinic, Rochester, MN, USA

Correspondence: [*] Correspondence to: Jennifer L. Whitwell, PhD, Associate Professor of Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA. Tel.: +1 507 284 5578; Fax: +1 507 284 9778; E-mail: whitwell.jennifer@mayo.edu.

Abstract: Background:Microbleeds in the brain have been shown to occur in Alzheimer’s disease (AD), affecting approximately a third of subjects that present with typical dementia of the Alzheimer’s type (DAT). However, little is known about the frequency or distribution of microbleeds in subjects with AD that present with atypical clinical presentations. Objective:To determine whether the frequency and regional distribution of microbleeds in atypical AD differs from that observed in subjects with DAT, and to determine whether microbleeds in atypical AD are associated with age, demographics, or cognitive impairment. Methods:Fifty-five subjects with amyloid-β deposition on Pittsburgh compound B (PiB) PET who presented with predominant language (n = 37) or visuospatial/perceptual (n = 18) deficits underwent T2*weighted MRI. These subjects were compared to 41 PiB-positive subjects with DAT. Microbleeds were identified and assigned a lobar location. Results:The proportion of subjects with microbleeds did not differ between atypical AD (42%) and DAT (32%). However, atypical AD had larger numbers of microbleeds than DAT. In addition, the topographic distribution of microbleeds differed between atypical AD and DAT, with atypical AD showing the highest density of microbleeds in the frontal lobes. Among atypical AD, number of microbleeds was associated with age, but not gender or cognition. Microbleeds were more common in subjects with language (51%) versus visuospatial/perceptual deficits (22%). Conclusions:Microbleeds are relatively common in both DAT and atypical AD, although atypical AD subjects appear to be at particular risk for developing large numbers of microbleeds and for developing microbleeds in the frontal lobe.

Keywords: Alzheimer's disease, amyloid-β, dementia of the Alzheimer's type, early-onset Alzheimer's disease, logopenic, magnetic resonance imaging, microbleeds, positron emission tomography, posterior cortical atrophy

DOI: 10.3233/JAD-142628

Journal: Journal of Alzheimer's Disease, vol. 45, no. 4, pp. 1109-1117, 2015