Disenchantment with the limitations, and in some cases the morbidity, of currently used radiologic techniques for the demonstration or exclusion of small
acoustic neuromas prompted development of an examination using small amounts of intrathecal air and computed tomography (CT). A prospective study was designed to evaluate air CT cisternography/canalography, wherein patients with the clinical symptoms of
acoustic neuroma but with negative enhanced CT, were evaluated by
metrizamide CT cisternography followed by air CT cisternography/canalography.
Pantopaque cisternography was then performed as a control procedure. Four patients had surgically proven
tumors. In 13 others, accumulated evidence indicated no
tumors were present. Results suggest that air-CT cisternography is superior to all other diagnostic methods in defining small
acoustic neuromas, and may exclude an intracanalicular lesion without the potential hazards of
Pantopaque cisternography or high concentration
metrizamide tomocisternography. With air-CT cisternography, there were no errors in this series.