Changing concepts of acoustic neuroma diagnosis.

Three hundred five acoustic neuromas were reviewed to determine the sensitivity of combining the auditory brainstem response (ABR) and the intravenous contrast-enhanced computed tomogram (CT) as screening tests for acoustic neuroma diagnosis. The ABR detected 98% of the tumors. The enhanced CT demonstrated 97% of tumors larger than 1.5 cm, but only 48% of neuromas 1.5 cm or smaller. The combination of both ABR and enhanced CT, used as the initial screening tests, identified 99% of the neuromas. We conclude that ABR, with enhanced CT as needed, is an accurate screening protocol. This method can be used as an alternative to the traditional ABR, electronystagmography, and internal auditory canal tomograms.