Trumpeted internal acoustic meatus sign

A trumpeted internal acoustic meatus (IAM) is an indirect sign of an acoustic schwannoma and is useful in helping differentiating between one and other cerebellopontine angle entities, especially from a meningioma which typically does not extend into the meatus 1.

It is characterized by widening of the IAM which appears similar to a trumpet.

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Article Information

rID: 2216
Section: Signs
Tags: refs, stub
Synonyms or Alternate Spellings:
  • Trumpeted IAM sign

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    Figure 1: trumpet
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    Case 1
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    Case 2: trumpeted IAM
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    Case 2: normal IAM for comparison
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