microhemorrhages
Small areas of bleeding in brain tissue, typically detected on gradient echo or susceptibility-weighted imaging sequences.
Full Definition
Microhemorrhages, also known as microbleeds, are small foci of bleeding within brain parenchyma that appear as punctate hypointense lesions on gradient echo and susceptibility-weighted imaging sequences. These represent hemosiderin deposits from prior bleeding episodes and are associated with cerebral amyloid angiopathy, hypertensive arteriopathy, and trauma. The distribution pattern can help distinguish between different underlying pathologies. Lobar microhemorrhages suggest amyloid angiopathy, while deep or infratentorial locations are more typical of hypertensive microangiopathy. Multiple microhemorrhages may indicate increased risk for future intracerebral hemorrhage.
Usage
Usage note: Describe the distribution pattern (lobar vs. deep) as it has diagnostic significance.
In Context
- "Multiple cortical and subcortical microhemorrhages were identified on the SWI sequence." — MRI report
- "The patient showed no evidence of microhemorrhages on gradient echo imaging." — Stroke evaluation