The role of NMR imaging in the diagnosis and management of acoustic neuroma.

Nuclear magnetic resonance (NMR) scans of 15 patients with acoustic neuroma are compared with the results of computed tomography (CT). The absence of signal from bone has meant that the images are unaffected by artifacts and that small intracanalicular tumors can be visualized. The multiplanar facility of NMR is emphasized as this allows precise assessment of both tumor volume and its relationship to the ventricular system, brainstem, and tentorial hiatus. The different appearances produced by alternative scan sequences are illustrated and the possibility of predicting the physical constitution from scan appearances is discussed.