High-resolution CT and air CT cisternography in the diagnosis of acoustic neuromas.

High-resolution thin-section computed tomography (CT) is helpful in determining the real extent of large acoustic neuromas by means of multiplanar reconstructions. High-resolution CT has to be performed early in the work-up of any patient suspected of acoustic neuroma. Small acoustic neuromas, however, can easily be overlooked because a high percentage of these tumors has an almost isodense appearance (54%), and because 53% enhances after intravenous contrast injection. High-resolution air CT cisternography has to be considered the method of choice for the detection or exclusion of small acoustic neuromas. This procedure also demonstrates ingrowth of the tumor into the neurovascular bundle.