Acute cerebral microbleeds at the edge of lacunar strokes: cause or result.

We investigated the pathogenic relationship between cerebral microbleeds and lacunar strokes. Two cases of lacunar strokes in the region of the basal ganglia, a 72-year-old man and a 67-year-old man, were studied; both cases showed cerebral microbleeds in the stroke areas. The cerebral microbleeds were surrounded by oedema, and the oedema faded out over time, suggesting the cerebral microbleeds had developed acutely. The cerebral microbleeds were located at the ventrolateral edge of the lacunar infarctions, and the locations appeared to be at or near the sites of occlusion of the lenticulostriatal branches. Although a cerebral microbleed and a lacunar infarction may be two unrelated events on juxtapositioned vessels, or a cerebral microbleed may be haemorrhagic conversion of an infarction, a cerebral microbleed could cause an occlusion of the arterial branch, leading to lacunar infarction of its supplying territories.