Diagnostic potential of CT in neurotological disorders.

The reliability of a neurotological evaluation in differentiating labyrinthine (end organ) lesions from retrolabyrinthine lesions has been well established. The purpose of this communication is to determine the diagnostic potential of computed tomography (CT) in patients suspected of having retrolabyrinthine lesions on the basis of their neurotological evaluations. Our study indicates that the validity of central vestibular and audiometric signs can be best substantiated with CT. The anatomy of neurovascular bundles within the internal auditory canal and cerebellopontine cistern can be readily visualized and identified by CT pneumocisternomeatography. By obtaining appropriate thin CT sections not only can very small lesions be identified but their anatomic locations can also be accurately established. CT pneumocisternomeatography is the method of choice to diagnose an intracanalicular acoustic neuroma. An unusually large vascular loop of the internal auditory canal may be responsible for sensorineural hearing loss and tinnitus in some patients.