[Inner ear and subarachnoid spaces: relations and diseases].

The purpose of this article is to describe, with 5 clinical cases, the physiological communications between the inner ear and the subarachnoid spaces (SAS) and present the imaging features with regard to. Therefore we briefly illustrate abnormal communications between SAS and perilymphatic fluids in certain cochlear and internal acoustic meatus (IAM) malformations and their consequences. Imaging features may depict diffusion pathway of bacterial meningitis to membranous labyrinth via the cochlear aqueduct or via the IAM. Rarely, in some patients referred for cochleovestibular symptoms, imaging features may display skull base tumors involving the area of cochlear or vestibular aqueduct aperture. Therefore, in patients referred for cochleovestibular symptoms, MR and CT study should carefully scrutinise not only the IAM but also the aperture of the cochlear and the vestibular aqueducts and the cerebellopontine meninges.