[Nuclear spin tomography of the petrous bone and cerebellopontiLe angle. Methods and normal anatomy]

Proton nuclear resonance tomography, also called magnetic resonance imaging, is a new imaging procedure which makes it possible to obtain tomographic cuts of the petrous bone in three planes. It is complementary to CT and is able to demonstrate the small structures of the inner ear and of the cerebello-pontine angle, without bone artefacts and without overlap or distortion. By using special surface coils combined with thin sections and a gradient-zoom technique, it is possible to obtain high resolution images which equal those of modern CT. By choosing suitable exposure parameters and a multi-echo technique, one can obtain excellent tissue contrast without using positive or negative contrast media.