[Clinical relevance of cerebral microbleeds--update].

Cerebral microbleeds (CMBs) on paramagnetic-sensitive magnetic resonance sequences correspond pathologically to clusters of hemosiderin-laden macrophages and have emerged as an important new imaging marker of cerebral small vessel disease (SVD), including intracerebral hemorrhage (ICH). The prevalence of CMBs varies according to the specific disease settings (stroke subtypes and demented disorders) and is highest in ICH patients. The associations of CMBs with aging, hypertension and apolipoprotein E genotype are consistent with the two major underlying pathogenesis of CMBs: hypertensive arteriopathy and cerebral amyloid angiopathy (CAA). The distributional patterns of CMBs might help us understand the predominant SVD pathogenesis of the brain; the strictly lobar type of CMBs often reflects the presence of advanced CAA, while the other types of CMBs, such as "deep or infratentorial CMBs", including the mixed type, are strongly associated with hypertension.