Magnetic resonance imaging: fundamental safety issues

Medical practitioners have a variety of imaging modalities at their disposal. The exquisite soft tissue delineation available with magnetic resonance imaging (MRI) has resulted in the rising utilization of this particular modality. Increasingly, physical therapists around the world are actively involved in not only referring patients with musculoskeletal conditions for MRI but also in the acquisition of MRI data in both the clinical and research arenas. The MRI process involves the use of a very strong static magnetic field, time-varying (gradient) fields, and radiofrequency energy. To ensure the well-being of patients, staff, and visitors, an understanding of the primary hazards of this environment and the rigorous safety procedures that must be followed is imperative to the clinician. This paper describes the basic components of an MRI system, discusses various MRI safety issues, and presents the screening procedure necessary prior to using MRI. Primary hazards associated with the imaging process are also reviewed. J Orthop Sports Phys Ther 2011;41(11):820-828. doi:10.2519/jospt.2011.3906.