H. Ric Harnsberger MD, Presenter: CEO, Amirsys, Inc Stockholder, Amirsys, Inc

1) To review the imaging approaches to patients suspected of harboring lesions in the CPA-IAC area. 2) To develop an understanding of the critical anatomy of the CPA-IAC. 3) To identify and accurately report the imaging findings of the lesions found in the CPA-IAC area in the adult population.

Adults suspected of harboring CPA-IAC disease, usually as a result of complaining of sensorineural hearing loss (SNHL), can be imaged either with conventional enhanced T1 fat-saturated MR or with high-resolution T2 MR imaging. CPA-IAC anatomy that must be understood includes cochlear modiolus and aperture, AICA loop, and cranial nerve 7 and 8 relative IAC positions. CPA-IAC diseases that may be found in this setting include congenital lesions such as epidermoid cyst, arachnoid cyst and CPA-IAC lipoma. Benign tumors found in this location include acoustic schwannoma, meningioma, facial nerve schwannoma and IAC hemangioma. CPA aneurysm may also present with SNHL. Acoustic schwannoma alone accounts for greater than 85% of all lesions causing SNHL in adults. Since inner ear diseases can also present with SNHL, labyrinthitis, labyrinthine schwannoma and cochlear otosclerosis will also be reviewed in this presentation.

Harnsberger, H, Evaluation of CPA and IAC Masses.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/3020611.html