MRI evidence of past cerebral microbleeds in a healthy elderly population

Incidental foci of signal loss suggestive of past microbleeds are a frequent finding on gradient-echo T2-weighted MRI of patients with nontraumatic intracerebral hemorrhage and have been associated with bleeding-prone microangiopathy. If and to what extent such lesions may also occur in the normal population is unclear. To determine focal hypointensities in asymptomatic elderly individuals and their relation to other clinical and morphologic variables. T2-weighted MRI of the brain was performed in a consecutive series of 280 participants (mean age 60 years, range 44 to 79) of the Austrian Stroke Prevention Study. This cohort consisted of randomly selected individuals without history or signs of neuropsychiatric disorder. Past microbleeds ranging from one to five foci of signal loss were seen in 18 (6.4%) individuals. They were strongly associated with higher age, hypertension, and lacunes (p < 0.001), and extensive white matter damage was more frequently noted (p = 0.02). Hypertension was present in all individuals with focal hypointensities in the basal ganglia and infratentorially but in only 5 of 10 volunteers with microbleeds limited to cortico-subcortical sites (p = 0.04). MRI evidence of past microbleeds may be found even in neurologically normal elderly individuals and is related, but not restricted, to other indicators of small vessel disease. The predictive potential of this finding regarding the risk of intracerebral bleeding requires further investigation.