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3 Cards in this Set
- Front
- Back
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What is ddx of a CPA mass?
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Most common:
- Vestibular schwannoma (AKA acoustic neuroma) - Meningioma Less Common: - Giant aneurysm: may arise from the PICA. Look for a lamellated appearance and phase artifact. - Epidermoid cyst : similar to CSF on all sequences except FLAIR and DWI; ENCASES neurovascular structures traversing the CPA rather than displacing them. - Arachnoid cyst: - Glioma: exophtic mass arising from the brainstem extending into the IAC; look for a irregular interface between the mass and adjacent brain. Fat containing: - Dermoid: displaces neurovascular structures; contains fat. - Lipoma: neurovascular structures traverse the lesion. Resection of the lipoma may injure these structures. |
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1. What is the most common CPA mass?
2. What are the imaging features of vestibular schwannoma? 3. What appears similar to a heterogeneously enhancing vestibular schwannoma? 4. What is a common complication of a vestibular schwannoma? |
1. Vestibular schwannoma (accounts for 75-80% of CPA mass).
2. - Enhancing extraaxial mass positioned in the CPA and/or IAC. - Widening of IAC. - Small lesions enhance homogeneously - Larger lesions enhance heterogeneous 2/2 cysts, hemorrhage, and fatty degeneration. 3. Large hemorrhagic vestibular schwannoma may mimic a giant aneurysm. NOTE: aneurysm will not enhance if thrombosed. 4. Acute 7th nerve palsy 2/2 hemorrhage.in the vestibular schwannoma. |
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What are the features of CPA meningioma?
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- Flatter than round
- Wide dural base with dural tails - Hyperostosis - RARELY widens or extends into IAC. |
