What is an MRI?

An MRI (magnetic resonance imaging) is a diagnostic scanning tool that can produce images of organs and structures within your body. The MRI scanner uses strong magnetic fields, not x-rays, to create these images. Hydrogen atoms in the patient react to the magnetic fields and a computer analyzes the results to produce a picture.

Why would I need an MRI?

An MRI is used to check for damage or abnormalities in soft tissue, joints, the brain and the spinal cord. It has some advantages over a computed tomographic imaging (CAT) scan. While CAT scans are better at imaging bones, MRIs provide better contrast in soft tissues, which helps to distinguish between normal and diseased tissue, and MRIs do not show confusing bone artifacts. An MRI provides highly detailed information without exposing the body to radiation. In many instances, it provides more useful images than CAT scanning and ultrasound.

How is an MRI performed?

You lie on a table that slides into a tunnel in the scanner. Beforehand, your doctor may inject you with a contrast solution called gadolinium. The dye will help the doctor to see parts of your body more clearly when looking at the images.

The table will then be moved so that the area of your body to be viewed is in the center of the machine's "tube." You will hear a series of loud knocking sounds. Remain still while the pictures are being taken. Typically, the MRI takes about 40 to 80 minutes. Results are usually available in a few hours.

An MRI is non-invasive and does not hurt. You may become uncomfortable or claustrophobic, but you should feel no pain. You can communicate with the MRI technician. Let that person know if you are uncomfortable. If you are anxious about confined spaces, ask about an open MRI.

You will be able to resume your normal activities right after the exam.

How should I prepare for an MRI?

Don't eat or drink six hours before the exam. At the examination room, you should remove buttons, zippers, jewelry and any other metal objects. Also remove any credit cards with magnetic strips from your pocket before you have the test.