[Brain microbleeds].

Brain microbleeds (MB) are small, rounded, homogeneous, focal lesions seen as hyposignal on T2* gradient echo MR sequences. The prevalence of MB is around 5% among healthy people, 34% among people with ischemic stroke and 60% among people with hemorrhagic strokes. MB are found in the whole brain parenchyma. There are biomarkers of the severity of the microangiopathy and are more frequent in people with hypertension. MB are associated with lacunae and the severe leukoaraiosis. They might be associated with an increased risk of future stroke but their diagnostic and prognostic values remain controversial.