Risks

Because MRI uses powerful magnets, the presence of metal in your body may be a safety hazard or affect a portion of the MRI image. Before having an MRI, tell the technologist if you have any metal or electronic devices in your body, such as:

  • Metallic joint prostheses
  • Artificial heart valves
  • An implantable heart defibrillator
  • A pacemaker
  • Metal clips
  • Cochlear implants
  • A bullet, shrapnel or any other type of metal fragment

If you have tattoos, ask your doctor whether they might affect your MRI. Some of the darker inks may contain metal.

Before you schedule an MRI, tell your doctor if you think you're pregnant. The effects of magnetic fields on fetuses aren't well-understood. Your doctor may recommend choosing an alternative exam or postponing the MRI.

It's also important to discuss any kidney or liver problems with your doctor and the technologist, because problems with these organs may limit the use of injected contrast agents during your scan.

Aug. 19, 2016
References
  1. Neurological diagnostic tests and procedures. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/misc/diagnostic_tests.htm. Accessed June 30, 2016.
  2. Patient safety: Magnetic resonance imaging (MRI). American College of Radiology, Radiological Society of North America. http://www.radiologyinfo.org/en/safety/index.cfm?pg=sfty_mr. Accessed June 30, 2016.
  3. Chernoff D, et al. Principles of magnetic resonance imaging. http://www.uptodate.com/home. Accessed June 30, 2016.
  4. Magnetic resonance imaging (MRI) of the body. American College of Radiology, Radiological Society of North America. http://www.radiologyinfo.org/en/info.cfm?pg=bodymr. Accessed June 30, 2016.
  5. Brain and spinal cord tumors in adults. American Cancer Society. http://www.cancer.org/cancer/braincnstumorsinadults/detailedguide/brain-and-spinal-cord-tumors-in-adults-diagnosed. Accessed June 30, 2016.
  6. Magnetic resonance imaging (MRI). American Heart Association. http://www.heart.org/HEARTORG/Conditions/HeartAttack/SymptomsDiagnosisofHeartAttack/Magnetic-Resonance-Imaging-MRI_UCM_441632_Article.jsp. Accessed June 30, 2016.
  7. AskMayoExpert. MRI of the breast. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2016.
  8. MRI of the musculoskeletal system. American College of Radiology, Radiological Society of North America. http://www.radiologyinfo.org/en/info.cfm?pg=muscmr. Accessed June 30, 2016.
  9. AskMayoExpert. MRI and implanted cardiac devices. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2016.
  10. AskMayoExpert. Cochlear implant and magnetic resonance imaging. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2016.
  11. Wadhwa V, et al. Bone and joint modeling from ED knee MRI: Feasibility and comparison with radiographs and 2D MRI. Clinical Imaging. 2016;40:765.