Kantarci, Kejal

Abstract Background Microbleeds have been associated with Alzheimer's disease (AD), although it is unclear whether they occur in atypical presentations of AD, such as the logopenic variant of primary progressive aphasia (lvPPA). We aimed to assess the presence and clinical correlates of microbleeds in lvPPA. Methods Thirteen lvPPA subjects underwent 3T T2*‐weighted and fluid‐attenuated inversion recovery magnetic resonance imaging and Pittsburgh compound B (PiB) positron emission tomography imaging. Microbleeds were identified on manual review and assigned a regional location. Total and regional white matter hyperintensity (WMH) burden was measured. Results Microbleeds were observed in four lvPPA subjects (31%), most commonly in the frontal lobe. Subjects with microbleeds were older, more likely female, and had a greater burden of WMH than those without microbleeds. The regional distribution of microbleeds did not match the regional distribution of WMH. All cases were PiB positive. Conclusions Microbleeds occur in approximately one third of subjects with lvPPA, with older women at the highest risk.

BackgroundPrevalence and risk factors for focal hemosiderin deposits are important considerations when planning amyloid‐modifying trials for treatment and prevention of Alzheimer's disease (AD).MethodsSubjects were cognitively normal (n = 171), early‐mild cognitive impairment (MCI) (n = 240), late‐MCI (n = 111), and AD (n = 40) from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Microhemorrhages and superficial siderosis were assessed at baseline and on all available MRIs at 3, 6, and 12 months. β‐amyloid load was assessed with 18F‐florbetapir positron emission tomography.ResultsPrevalence of superficial siderosis was 1% and prevalence of microhemorrhages was 25% increasing with age (P < .001) and β‐amyloid load (P < .001). Topographic densities of microhemorrhages were highest in the occipital lobes and lowest in the deep/infratentorial regions. A greater number of microhemorrhages at baseline was associated with a greater annualized rate of additional microhemorrhages by last follow‐up (rank correlation = 0.49; P < .001).ConclusionsFocal hemosiderin deposits are relatively common in the ADNI cohort and are associated with β‐amyloid load.