Role of imaging in temporal bone and cerebellopontine-angle lesions. A surgeon's perspective.

In recent years, with the advances in imaging technology, the gold standard for diagnosis of lesions of the temporal bone and cerebellopontine angle has shifted from histologic identification of the lesion from surgical specimens or autopsy material to noninvasive identification, localization, and characterization of the tissue by imaging. The symptoms caused by such lesions usually provide clues as to their location and probable nature. Clinical tests such as the vestibular evaluation, audiometry, auditory brain stem response, and otoacoustic emissions further help with topodiagnosis of the lesion. If this information is covered to the neuroradiologist, the most diagnostically productive imaging study can be obtained, and the neuroradiologist will apply the most appropriate technical parameters necessary for any individual patient. An eclectic algorithm can be applied for each clinical situation, and illustrative examples are provided in the article. The algorithms will no doubt change with advances in diagnostic tests. Application of imaging studies without adequate clinical investigations often makes the task of interpreting the scans difficult for the neuroradiologist. Furthermore, the positive diagnostic yield from a widespread use of imaging technology is small and would be considered an inappropriate use of health care dollars.