MR cisternography of the cerebello-pontine angle and internal auditory canal in diagnosis of intracanalicular acoustic neuroma.

ABSTRACT

One hundred and fifteen patients, suffering from sensorineural hearing loss were tested with a 1.5 T superconducting magnet. The authors describe utility of both T1-weighted multiple slice and T2-weighted multiple echo images for the evaluation of cerebello-pontine angle, internal auditory canal and their neurovascular content. In seventy-three cases MR cisternography was normal. The remaining forty-two cases were subdivided into twenty extracanalicular masses, eleven small intra-extracanalicular and nine purely intracanalicular lesions. All the lesions were histologically proven acoustic neuromas, except one intracanalicular mass which was a meningioma. Examination was inconclusive only in two cases and decision was then made to follow the clinical course. Advantages of MR cisternography over CT and air CT cisternography, such as absence of ionizing radiation and contrast material, easy multiplanar evaluation of the region of interest and the possibility to delineate both the cisternal and canalar extremities of the tumor mass are pointed out.