Test Overview

Magnetic resonance imaging (MRI) is a test that uses a magnetic field and pulses of radio wave energy to take pictures of the head. In many cases, MRI gives information that cannot be seen on an X-ray, ultrasound, or computed tomography (CT) scan.

For an MRI of the head, you lie with your head inside a special machine (scanner) that has a strong magnet. The MRI can show tissue damage or disease, such as infection, inflammation, or a tumor. Information from an MRI can be saved and stored on a computer for more study. Photographs or films of certain views can also be made. See MRI images of a person who has had a stroke or a seizure.

In some cases, a dye (contrast material) may be used during the MRI to show pictures of structures more clearly. The dye may help show blood flow, look for some types of tumors, and show areas of inflammation.

MRI of the head may be used to look for the cause of headaches. For more information, see:

Should I have imaging tests to find out what's causing my headaches?

See pictures of a standard MRI machine and an open MRI machine.