Cerebral Microbleeds: Imaging and Clinical Significance

Area of Science:

• Neuroradiology
• Neuroimaging
• Pathology

Background:

• Cerebral microbleeds (CMBs) are small lesions visible on MRI, often indicating underlying vasculopathy and iron accumulation.
• Their detection has increased due to advancements in MRI technology, including higher field strengths and susceptibility-weighted imaging (SWI).

Purpose of the Study:

• To review the imaging characteristics, detection rates, and clinical significance of cerebral microbleeds.
• To discuss factors influencing CMB detection and their association with various neurological conditions.

Main Methods:

• Review of MRI techniques, particularly T2*-weighted and SW imaging, for CMB detection.
• Analysis of reported true-positive and false-positive rates for CMB detection across different field strengths and sequences.
• Correlation of CMB presence with pathological findings and clinical outcomes in various diseases.

Main Results:

• CMBs are visualized as hypointense foci on T2*-weighted and SW MRI, reflecting iron deposition.
• Detection rates vary (48%-89%) depending on field strength (1.5 T or 3.0 T) and imaging sequences.
• False positives (11%-24%) include microdissections and microcalcifications, though phase imaging can help differentiate.
• Detection improves with higher field strength, 3D sequences, and advanced postprocessing methods.
• CMBs are increasingly found in normal aging and conditions like Alzheimer's disease, stroke, and trauma.
• CMBs are associated with poorer outcomes in stroke patients.

Conclusions:

• Advanced MRI techniques enhance the detection of cerebral microbleeds, revealing their prevalence in aging and disease.
• CMBs serve as important imaging biomarkers for neurological disorders and prognosis, particularly in stroke.
• Further research is needed for clinical management, including guidelines for anticoagulant therapy adjustment.