MRI has become a standard diagnostic imaging examination for soft tissue and musculoskeletal injuries but some question the safety following a total joint replacement of using an imaging technique that is based on a strong magnetic field. The main concern is that the metal in the joint replacement will react to the magnet and cause extensive damage to the joint replacement, the patient or the MR unit. There is also concern that the strong magnetic field could distort the image and render the examination unreadable and useless.
The radiologists in the Department of Radiology and Imaging at Hospital for Special Surgery have been studying the effectiveness of MR following total joint replacements and routinely produce clear and precise imaging of these joints by adjusting the MR's scanning parameters. MR is not only safe, but the images provide detailed information and diagnosis of impending complications earlier than is feasible with X-ray and computed tomography (CT) and without exposing the patient to harmful radiation.
MRI has the ability to image soft tissues and can accurately detect early signs of complications or causes of pain associated with a joint replacement. The MR examination is important because early diagnosis allows the doctor and patient to determine potential treatment options that may prolong the anticipated benefits expected from the joint replacement.
The only 'rule of thumb' for the relative MRI safety of implants for patients is that 'there is no rule of thumb.' Patients should make sure that they get the card(s) that identify the specific implant placed within them so that - should they ever be prescribed an MRI exam - they can share the details of the implant with the MR Technologist or Radiologist who will help assess the safety of proceeding with the exam.
http://mrimetaldetector.com/blog/?p=439