Magnetic Resonance Imaging (MRI): About This Test

What is it?

Magnetic resonance imaging (MRI) is a test that uses a magnetic field and pulses of radio wave energy to make pictures of organs and structures inside the body. When you have an MRI, you lie on a table and your body is moved into the MRI machine, where an image is taken of the area of the body being studied.

Why is this test done?

There are many reasons to have an MRI test. This test can find problems such as tumors, bleeding, injury, conditions that some children are born with, and infection. An MRI also may provide more information about a problem seen on an X-ray, ultrasound scan, CT scan, or nuclear medicine exam.

How can you prepare for the test?

For some MRI pictures of the belly, you may be asked to not eat or drink for several hours before the test.

Tell your doctor if you get nervous in tight spaces. You may get a medicine to help you relax. If you think you'll get this medicine, be sure to arrange a ride home. It may be unsafe for you to drive or get home on your own.

How is the test done?

• You may have contrast materials (dye) put into your arm through a tube called an I.V.
• You will lie on a table that is part of the MRI scanner.
• The table will slide into the space that contains the magnet.
• Inside the scanner you will hear a fan and feel air moving. You may hear tapping, thumping, or snapping noises. You may be given earplugs or headphones to reduce the noise.
• You will be asked to hold still during the scan. You may be asked to hold your breath for short periods.
• You may be alone in the scanning room. But a technologist will watch you through a window and talk with you during the test.

What are the risks of the test?

• Contrast material that contains gadolinium may be used in this test. But for most people, the benefit of its use in this test outweighs the risk. Be sure to tell your doctor if you have kidney problems or are pregnant.
• If you breastfeed and are concerned about whether the dye used in this test is safe, talk to your doctor. Most experts believe that very little dye passes into breast milk and even less is passed on to the baby. But if you are concerned, you can stop breastfeeding for up to 24 hours after the test. During this time, you can give your baby breast milk that you stored before the test. Don't use the breast milk you pump in the 24 hours after the test. Throw it out.

How long does the test take?

The test usually takes 30 to 60 minutes. But it can take as long as 2 hours.

What happens after the test?

You will probably be able to go home right away, depending on the reason for the test.