Magnetic Resonance Imaging

History and Science Behind MRI: Open or Closed Case? Magnetic Resonance Imaging (MRI) has been called one of the most comprehensive and efficacious diagnostic imaging modalities in medical history. It became a viable clinical technique in 1982 and during its relatively short lifetime has become the primary imaging modality for investigations of the brain, spinal cord, spine, cancellous bone, and joints. It is widely used for the identification and staging of tumors, investigations of large blood vessels, and in pediatric studies. Cardiac MR, with its unique ability to provide simultaneous information about anatomy, function, and tissue character, has become a primary or complimentary modality in a wide range of pathologies, such as aortic
No other imaging modality has ever required such an astute ability to factor out those circumstances which would, when exposed to strong magnetic fields, have the potential to cause harm to the patient (Woodard 1). Ferromagnetic objects will experience a rotational force or torque, upon entering the magnetic field. Therefore, they will attempt to align with the magnetic field. Once in the bore of the magnet, no additional force is experienced. When the same ferromagnetic object is being removed from the magnetic field, it will try to regain its original orientation, therefore experiencing torque once again. It is this force that may cause internal damage to tissues. Although no known biological hazards exist with MRI, there is a substantial risk associated with large magnetic fields and their ability to forcibly attract ferromagnetic and some paramagnetic materials. This causes loose metal objects to become flying projectiles, which may impact with the patient and cause serious, life-threatening
Cardiac pacers have a reed switch that can be activated by an external magnet. Movement of the pacer closer to the magnetic field can cause malfunction and render the pacer inoperable. Patients with implanted pacers should be excluded from the magnet room (Woodard 2). Most instances associated with MR-related injuries have been a direct result of deficiencies in screening methods. Unfortunately, not all MR users perform a rigorous screening procedure and there tends to be a lack of agreement on what constitutes an appropriate or necessary protocol that will ensure the safety of individuals and patients in the MR setting