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Definition

By Mayo Clinic staff

Magnetic resonance imaging (MRI) is a technique that uses a magnetic field and radio waves to create detailed images of the organs and tissues within your body.

Most MRI machines are large, tube-shaped magnets. When you lie inside an MRI machine, the magnetic field temporarily realigns hydrogen atoms in your body. Radio waves cause these aligned atoms to produce very faint signals, which are used to create cross-sectional MRI images — like slices in a loaf of bread.

The MRI machine can also be used to produce 3-D images that may be viewed from many different angles.

Why it's done
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 1, 2013.
  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 1, 2013.
  3. Chernoff D, et al. Principles of magnetic resonance imaging. http://www.uptodate.com/home. Accessed June 1, 2013.
  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 1, 2013.
  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 1, 2013.
  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 1, 2013.
  7. Slanetz PJ. MRI of the breast and emerging technologies. http://www.uptodate.com/home. Accessed June 1, 2013.
  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 1, 2013.
  9. Williamson EE (expert opinion). Mayo Clinic, Rochester, Minn. July 17, 2013.
MY00227 Aug. 17, 2013

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