We report 12 cases of tumors the cerebellopontine angle demonstrated by magnetic resonance imaging (MRI). T1-, T2-, and T2*-weighted imaging and gadoliniumdiethylenetriamine pentaacetic acid (Gd-DTPA) contrast medium radiography were carried out with a superconducting-type MR apparatus with a static magnetic field of 1.5 tesula. The tumor images were demonstrated by signals of lower intensity than those of the white matter of the brain in T1-weighted images, and by slightly higher-intensity signals in T2-and T2*-weighted images, but were very strongly depicted with Gd-DTPA. It was sometimes possible to identify the nerve from which the tumor developed, depending on the direction of the MRI, but it was necessary to select the imaging conditions carefully in order to avoid false negatives. We know of past cases of such tumors that have been treated as sudden deafness or other conditions.
