[Inner ear and subarachnoid spaces: relations and diseases]

Area of Science:

• Neuroimaging
• Otolaryngology
• Radiology

Background:

• Understanding physiological connections between the inner ear and subarachnoid spaces (SAS) is vital for diagnosing neurological and otological conditions.
• Abnormal communications can lead to serious complications, including spread of infection and neurological deficits.

Observation:

• Five clinical cases illustrate the anatomical and physiological relationships between the inner ear and SAS.
• Imaging findings reveal abnormal pathways in cochlear and internal acoustic meatus (IAM) malformations.
• Specific imaging features demonstrate the potential for bacterial meningitis to reach the inner ear via the cochlear aqueduct or IAM.

Findings:

• Imaging can depict the diffusion pathway of bacterial meningitis to the membranous labyrinth.
• Skull base tumors near the cochlear or vestibular aqueduct apertures are identified in patients with cochleovestibular symptoms.
• Abnormal communications between SAS and perilymphatic fluids are visualized in malformations.

Implications:

• Routine MR and CT studies for cochleovestibular symptoms should include detailed scrutiny of the IAM, cochlear aqueduct, vestibular aqueduct apertures, and cerebellopontine meninges.
• Accurate imaging is essential for early diagnosis and management of conditions affecting the inner ear and SAS.
• This research emphasizes the importance of considering the SAS-inner ear continuum in diagnostic imaging protocols.