Cerebral Microbleeds: Incidence, Imaging Characteristics, Common and Uncommon Causes

Abstract

Cerebral microbleeds (CMBs) are considered as a marker of cerebral microangiopathy. CMBs can be detected in various clinical conditions, with the most common being cerebral amyloid angiopathy and chronic hypertension. Uncommon causes of CMBs include cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, Moyamoya disease, Fabry disease, fat embolism, infective endocarditis, prosthetic heart valves, posterior reversible encephalopathy syndrome, brain radiation, cocaine abuse, thrombotic thrombocytopenic purpura, traumatic brain injury, obstructive sleep apnea, and genetic syndromes related to missense mutations of collagen. In this review, after discussing the causes related to CMBs, we present two cases of patients with a history of aortic dissection that underwent brain magnetic resonance imaging for the investigation of acute onset neurological symptoms. Susceptibility-weighted-imaging (SWI) sequences disclosed multiple, small-sized CMBs located predominantly within hemispheric cortical and subcortical areas, with a pattern of preferential involvement of watershed arterial territories. Although both patients had a history of well-controlled arterial hypertension, the pattern of CMB distribution was distinct to that typically observed in chronic hypertension, which is mainly associated with deep or infratentorial CMBs, as well as with matter hyperintensities and lacunes. The differential diagnosis of diffuse CMBs on brain SWI may also include the history of aortic dissection. The patient's history, in association with the pattern of spatial distribution of the lesions on magnetic resonance imaging-SWI, is usually informative.

Distinct pattern of microsusceptibility changes on brain magnetic resonance imaging (MRI) in critically ill patients on mechanical ventilation/oxygenation

“…Susceptibility-weighted imaging (SWI) is a recently introduced magnetic resonance imaging (MRI) technique that provides improved detection of substances that cause susceptibility effects, such as iron, blood products, calcification, and air [ 1 ]. Studies have shown the superiority of SWI when compared with T2* for the detection of microsusceptibility changes in the brain, such as microhemorrhages in microangiopathy, moyamoya syndrome, angiitis, diffuse axonal injury, anticoagulant therapy, cerebral amyloid angiopathy, Fabry disease, embolism, brain radiation, and posterior reversible encephalopathy syndrome (PRES) [ 2 , 3 ]. Cerebral microbleeds (CMBs) are small-sized (less than 10 mm in diameter), focal, perivascular, hemosiderin depositions that are detected as round or ovoid, SWI-hypodense foci within the cerebral parenchyma.…”

Number of cerebral microbleeds after intracranial/extracranial stenting and dual antiplatelet therapy

“…Thus, some uncommon causes of CMB formation were not uncovered in our case series, such as amyloid angiopathy, anemia, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, or Fabry's disease. 4 In previous research, [18][19][20][21][22][23] a trend of the increased risk of symptomatic ICH after thrombolysis for ischemic stroke was noted if CMBs were present in pretreatment MRI. In our study, no new symptomatic acute stroke or ICH occurred, even with new CMB development.…”

Massive microbleeds in posterior circulation territory in an immunocompromised patient with sepsis

“…Microbleeds in the brain are detected in conditions such as microangiopathy, Moyamoya disease, vasculitis, and posterior reversible encephalopathy syndrome [2]. Meanwhile, Thurnher et al [3] reported diffuse microsusceptibility changes, including in the brainstem and cerebellum, in critically ill immunocompromised patients undergoing mechanical ventilation and oxygenation.…”