An antrochoanal polyp (ACP) is a solitary polyp that arises within the maxillary sinus but passes to the nasopharynx through the sinus ostium and posterior nasal cavity,
The MRI signal characteristics of this case are typical:
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T1: intermediate to low signal
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T2
- high homogeneous T2 signal
- signal may vary if they are chronic and/or if fungal infection is present
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T1 C+ (Gd): peripheral enhancement is seen on post-contrast images.