[Imaging of the cerebello-pontine angle and skull base]

Lesions of the internal auditory meatus, cerebello-pontine angle and skull base have benefited greatly from the progress made in imaging techniques. There are now three methods of examination at our disposal. MRI scan is the primary method of choice, and includes T1 spin echo sequences without and with the injection of contrast, and the T2-weighted sequence (with spin echo or gradient echo CISS-3DFT); other sequences, such as angio-MRI and FLAIR, are used more rarely. CTscanning is complementary to MRI, but gives a better definition of bony structures. Arteriography is more rarely indicated. Imaging usually allows a diagnosis of the type of lesion encountered. The typical features on MRI and CT scan of the various pathological lesions of the internal auditory meatus, cerebello-pontine angle and skull base are discussed, together with the fact that by far the commonest among them is the vestibular neuroma.