APOE and dementia: CMB incidence was higher than earlier reports in healthy populations, likely due to (1) more sensitive detection of CMB afforded by thin slice 3T SWI, which detects up to 3 times the number of CMB compared with conventional 1.5 T GRE (Nandigam et al., 2009), and (2) oversampling of participants with a family history of dementia and, by extension, APOE4 carriership, a well established risk factor for CMB in older adults (Poels et al., 2010).