Magnetic resonance imaging artifacts and the magnetic attachment system.

The use of a rare earth magnetic attachment system as a means of retaining dentures or maxillofacial prostheses results in artifacts, when magnetic resonance imaging (MRI) is used as a diagnostic tool. In such cases, the artifact is not caused by the magnet itself, but by the ferromagnetic stainless steel keeper that is placed in the body. This report evaluates such ferromagnetic stainless steel devices with respect to magnetic resonance imaging artifacts. A grid phantom and a 0.2 Tesla superconducting system were used to assess the imaging artifacts. The magnetic properties, shape, composition and size of ferromagnetic stainless steel devices were analyzed to study the relation MRI artifacts and ferromagnetic materials. The higher the magnetic permeability was, the greater the artifact produced. The size and volume of the material directly influence the artifact produced. The artifact size can be attenuated by the sequence used to obtain the images.