Magnetic resonance imaging (MRI) is a scan of your body that uses a magnetic field and pulses of radio wave energy. In many cases an MRI provides information that cannot be obtained from an x-ray, ultrasound, or CT scan.

For this test, you are positioned in an MRI scanner. The pictures made by the pulses of radio waves can help to detect changes in the normal structure and characteristics of your head and body. The MRI can also detect tissue damage or disease, such as infection, inflammation, or a tumor. Information from an MRI scan can be saved and stored on a computer for further study.