Diagnosis of cerebellopontine angle tumors with small quantities of air.

Difficulty in detecting small acoustic neuromas has encouraged us to study patients suspected of having a tumor by air cisternography augmented with computed tomography. Ninety patients were examined without complication. Five cubic centimeter of air was introduced via lumbar puncture and manipulated into the cerebellopontine angle cisterns. Scanning is commenced immediately. Filling of both internal auditory canals and identification of the neurovascular bundle in the cerebellopontine angle cistern was possible in all patients except those with tumors. The diagnostic accuracy, speed, and lack of morbidity have made this procedure the initial radiologic examination at our institution for patients suspected of having acoustic neuroma.