What Happens During MRI?

This test is done in a hospital radiology department or in a health care provider’s office by a technician, supervised by a doctor.

You will be asked to lie on a narrow table. Your head will be placed in a padded plastic cradle or on a pillow. This table will slide into a large tunnel-like tube in the scanner, and you will be told to breathe quietly and normally but to stay very still.

Lying inside a large, hollow magnet, you will be exposed to radio waves. This energy is directed at water molecules in the body, "exciting" and then "relaxing" the protons in water molecules.

The MRI reads the energy from the water molecules and builds a 3-D image of the different types of tissue.

MRI often involves taking many sets of images, each lasting about 2 to 15 minutes.

Some people don’t feel comfortable in close or confined spaces. For this test, you do have to lie still on a hard table inside a narrow tube. If you have a history of anxiety or fear of closed spaces, you should talk to your doctor. You may be able to take a drug to relax you before the test. No other preparation is needed.

The technician will be able to talk to you during the test through an intercom. While the scanner is working, you will hear rapid, loud noises coming from the walls of the scanner. You may be given earplugs to help with the noise.

To get clearer images, your doctor may decide you may need an IV placed for gadolinium contrast.