IMAGING OF THE LABYRINTH AND VESTIBULAR N ERVE - CLINICAL RELEVANCE FOR DIFFERENTIAL-DIAGNOSIS OF VESTIBULAR DISORDERS

High resolution magnetic resonance imaging (HR-MRI) and computed tomog raphy (HR-CT) of the inner ear are becoming more important for the dia gnosis of peripheral vestibular lesions. Modern HR-MRI techniques allo w visualization of detailed anatomic features of the vestibulo-cochlea r regions as well as pathologic findings in the inner ear such as, neo plastic lesions (e.g., small intracanalicular acoustic neuromas),anoma lies causing vertigo and hearing loss (e.g. Mondini's-malformation, pe rilymph fistula, vestibular paroxysmia), and inflammatory diseases (e. g., Cogan's syndrome, labyrinthitis, tester neuritis). HR-CT is still the first examination that should be performed in patients with middle ear diseases (e.g., tumor, infection),trauma (e.g. temporal bone frac tures), or fibro-osseous diseases. Although the imaging of the vestibu lo-cochlear system has dramatically improved, there are still several peripheral vestibular disorders that cannot be visualized so far, e.g. , benign paroxysmal positioning vertigo, idopathic vestibular neuritis or Meniere's disease.