Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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May 21, 2020
Intracranial Metal Emboli
- Background:
- The combination of clinical history (recent left heart valve repair) and multiple new spherical foci of T2* signal dephasing (larger ones with targetlike appearance) is highly characteristic of metal emboli.
- This finding was more prevalent in the era of early-version detachable coils.
- Incidence is difficult to estimate but is believed to be uncommon.
- Apart from metal, periprocedural foreign body emboli can be seen in a variety of clinical settings.
- Clinical Presentation:
- Varies from asymptomatic (as in this case) to focal deficits, seizure, and headaches, depending on location and size of emboli and immune response
- Key Diagnostic Features:
- History of cardiac procedure (open or endovascular) or cerebrovascular catheterization (diagnostic or therapeutic) and multiple new, round ferromagnetic susceptibility foci, especially targetlike lesions, which are atypical for other entities
- Tiny size and marked ferromagnetism may explain the lack of x-ray attenuation, therefore rendering these typically invisible on CT.
- Differential Diagnoses:
- There is no real differential diagnosis. The appearance can be misinterpreted as microbleeds, such as cavernous angiomas, amyloid, axonal injury, etc.
- A perfectly round and targetlike appearance in the appropriate clinical context excludes the above physiologic processes from the differential diagnosis.
- Treatment:
- Usually noninvasive; symptom control