In recent years, interest in cerebral microbleeds (CMs) has increased based on advances in magnetic resonance imaging (MRI) technology. Both MRI T2-weighted gradient-echo (GRE) and susceptibility-weighted imaging may be sensitive techniques for the detection of past and more recent brain hemorrhage.1,2 For example, GRE sequences may identify microbleeds because hemosiderin remains in macrophages for years after hemorrhage, and such deposits rim hemorrhage cavities. In addition, CMs may be defined as rounded foci 5-10 mm or smaller that appear hypointense (dark holes) on appropriate MRI sequences. They may appear larger on GRE sequences compared with actual tissue lesion size because a blooming effect of the MRI signal may occur at the lesion border.1 The Microbleed Study Group provides an up-to-date guide to the detection and interpretation of CMs and suggests possible future approaches for elucidating the role of these lesions.3
Gorelick PB. Cerebral Microbleeds: Evidence of Heightened Risk Associated With Aspirin Use. Arch Neurol. 2009;66(6):691–693. doi:10.1001/archneurol.2009.85
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