The internal auditory canal revisited. The high-definition approach

Area of Science:

• Neuroimaging
• Otolaryngology
• Pathology

Background:

• The internal auditory canal (IAC) is a critical bony passage housing vital nerves and vessels, lined by meninges.
• Pathologic processes can originate from the bone, nerves, vessels, or meninges within or adjacent to the IAC.
• Congenital, developmental, and acquired conditions can cause IAC narrowing or expansion, impacting its contents.

Purpose of the Study:

• To review the diverse range of pathologic conditions affecting the internal auditory canal (IAC) and cerebellopontine angle (CPA) cisterns.
• To highlight the diagnostic capabilities of modern imaging modalities for IAC and CPA lesions.

Main Methods:

• Review of imaging findings for various IAC and CPA pathologies.
• Discussion of advanced imaging techniques including high-definition computed tomography (HD-CT) and magnetic resonance imaging (MRI), including MR angiography (MRA).

Main Results:

• Pathologies include congenital, developmental, and acquired conditions affecting the IAC bone, nerves (facial and acoustic), meninges, and vascular structures.
• Lesions encompass hemangiomas, vascular malformations, inflammatory processes, neoplasms, choristomas, and metastases.
• High-definition CT and advanced MRI/MRA enable the identification of lesions previously undetectable with older techniques.

Conclusions:

• A broad spectrum of lesions can affect the IAC and CPA, originating from its normal contents or occurring as rare entities.
• Advanced neuroimaging techniques like HD-CT and MRI/MRA are crucial for accurate diagnosis and characterization of these complex pathologies.