Operational safety issues in MRI.

The clinical usefulness of a diagnostic modality is weighed by considering its potential diagnostic benefit against its potential risk for a patient in question. Magnetic resonance imagining appears to offer both high efficacy and safety under most circumstances. Our understanding of the conditions under which MRI is safe and effective has undergone continual refinement with technological advances and clinical experience. The early emphasis on safety issues of MR focussed on consideration of bioeffects of RF and magnetic fields. More recently, hundreds of operating clinical MR sites, performing hundreds of thousands of clinical examinations to date, have provided a greater awareness of operational safety issues. Much of this experience is summarized in device labeling provided by manufacturers of MR devices, summaries prepared by regulatory agencies, and case reports in the medical literature. The purpose of this article is to review a broad range of safety considerations involved in the operation of MR imagers. The discussion is in two parts: (1) a short update of reported incidents and (2) an analysis of safety issues.