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.

In many cases, MRI gives different information about structures in the body than can be seen with an X-ray, ultrasound, or computed tomography (CT) scan. MRI also may show problems that cannot be seen with other imaging methods.

For an MRI test, the area of the body being studied is placed inside a special machine that has a strong magnet. In some cases, a dye (contrast material) may be used during the MRI to show pictures of organs or structures more clearly.

Photographs or films of certain views can also be made. Information from an MRI can be saved and stored on a computer for more study.

MRI can be used to look for problems such as bleeding, tumors, infection, blockage, or injury in the brain, organs and glands, blood vessels, and joints.