ARTIFACTS IN MAGNETIC-RESONANCE-IMAGING FROM METALS

Metallic biomedical implants, such as aneurysm Clips, endoprostheses, and internal orthopedic devices give rise to artifacts in the magnetic resonance image (MRI) of patients. Such artifacts impair the informat ion contained in the image in precisely the region of most interest, n amely near the metallic device. Ferromagnetic materials are contraindi cated because of the hazards associated with their movement during the MRI procedure. In less-magnetic metals, it has been suggested that th e extent of the artifact is related to the magnetic susceptibility of the metal, but no systematic data appear to be available. When the sus ceptibility is sufficiently small, an additional artifact due to elect rical conductivity is observed. We present an initial systematic study of MRI artifacts produced by two low susceptibility metals, titanium (relative permeability mu(r) approximate to 1.0002) and copper (mu(r) approximate to 0.99998), including experimental, theoretical, and comp uter simulation results. (C) 1996 American Institute of Physics.