A magnetic resonance imaging (MRI) scan is an imaging test that uses powerful magnets and radio waves to create pictures of the body. It does not use radiation (x-rays).
Single MRI images are called slices. The images can be stored on a computer or printed on film. One exam produces dozens or sometimes hundreds of images.
For more information, see the specific MRI topics:
Magnetic resonance imaging; Nuclear magnetic resonance (NMR) imaging
How the Test is Performed
You may be asked to wear a hospital gown or clothing without zippers or snaps (such as sweatpants and a t-shirt). Certain types of metal can cause blurry images.
You will lie on a narrow table, which slides into a large tunnel-shaped scanner.
Some exams require a special dye (contrast). Most of the time, the dye will be given through a vein (IV) in your hand or forearm before the test. The dye helps the radiologist see certain areas more clearly.
Small devices, called coils, may be placed around the head, arm, or leg, or around other areas to be studied. These help send and receive the radio waves, and improve the quality of the images.
During the MRI, the person who operates the machine will watch you from another room. The test lasts about 30 to 60 minutes, but may take longer.