T2-WEIGHTED MR CHARACTERISTICS OF INTERNAL AUDITORY-CANAL MASSES

PURPOSE: To determine whether masses of the internal auditory canal ar e hypointense relative to cerebrospinal fluid, and therefore visible, on fast spin-echo T2-weighted MR images, METHODS: Forty-six patients h ad 50 masses of the internal auditory canal, identified initially on c ontrast-enhanced MR images, that were evaluated retrospectively for si gnal intensity of the mass with respect to cerebrospinal fluid and for visibility of the neural elements within the internal auditory canal on T2-weighted images. RESULTS: Forty-seven of 50 masses were clearly identified on T2-weighted images. Three small abnormalities (2 to 4 mm ) were not seen with confidence on T2-weighted images, However, on clo se inspection of these three masses, the small abnormality on contrast -enhanced MR images corresponded to a hypointense focus on T2-weighted images. All 50 masses were hypointense relative to cerebrospinal flui d on T2-weighted images. CONCLUSION: All masses of the internal audito ry canal in this study were hypointense relative to cerebrospinal flui d on T2-weighted images, and were therefore visible.