[Interactions of external magnetic fields and metallic middle ear implants].

Magnetic resonance imaging is being used increasingly to provide information unobtainable by other imaging techniques. Clinicians have been reluctant to use this technique on patients who have had a stapedectomy because the prosthesis is composed of metal and may move in the electromagnetic fields. We investigated the materials used with respect to their ability to become magnetized and the forces acting on them in a static electromagnetic field, using the SQUID technique. We concluded that there is no danger of a metallic stapedectomy prosthesis becoming displaced by the magnet of a 1.0 or 1.5 T magnetic resonance imaging unit.