Cerebral microbleeds in neurological practice: concepts, diagnostics and clinical aspects

Due to the widespread use of magnetic resonance imaging (MRI) in neurological diagnostics, the number of patients detected as having cerebral microbleeds (CMBs) continues to increase. However, their clinical impact still remains controversial, especially the question of whether CMBs significantly increase the risk of life-threatening intracerebral haemorrhage (ICH) in patients undergoing intravenous thrombolysis (IVT) or endovascular thrombectomy (EVT), or in patients on anticoagulant therapy or statins.

The term 'CMB' is a radiological concept that aims to illustrate microscopic pathology of perivascular hemosiderin deposits corresponding most probably to small foci of past bleeding. MRI images in sequence T2*-GRE and susceptibility-weighted imaging (SWI) are used for a diagnosis of a CMB. This review summarises the current knowledge regarding the definition, prevalence, genetics, risk factors, radiological diagnosis and differential diagnosis of a CMB. We discuss its role as an indicator of future ischaemic or haemorrhagic events in high risk patients or those on antiplatelet or anticoagulant therapy, and its prognostic value for reperfusion strategies and for the development of dementia.

The place of CMBs in current guidelines is explored herein. It must be emphasised that the recommendations relating to CMBs are expert opinions. Therefore, at the end of this review, we pose a number of questions that future clinical trials should answer.