Magnetic resonance imaging ( MRI) is a test done with a large machine that uses a magnetic field and pulses of radio wave energy to make pictures of the shoulder. Muscles, ligaments, cartilage, and other joint structures are best seen with an MRI. In many cases MRI gives information about structures in the body that cannot be seen as well with an X-ray, ultrasound, or CT scan.

For an MRI test, you are placed inside the magnet so that your shoulder is inside the strong magnetic field. MRI can find changes in the structure of organs or other tissues. It also can find tissue damage or disease, such as infection or a tumor. Pictures from an MRI scan are digital images that can be saved and stored on a computer for further study. The images also can be reviewed remotely, such as in a clinic or an operating room. Photographs or films of selected pictures can also be made. See MRI images of the rotator cuff .

In some cases, a contrast material may be used during the MRI scan to show certain structures more clearly in the pictures. The contrast material may be used to check blood flow, find some types of tumors, and show areas of inflammation or infection. The contrast material may be put in a vein ( IV) in your arm or directly into your shoulder joint.

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

Why It Is Done

Magnetic resonance imaging (MRI) of the shoulder is done to:

• Check unexplained shoulder pain.
• Find problems in the shoulder, such as arthritis, bone tumors, worn-out cartilage, torn ligaments, torn tendons, or infection. An MRI can detect tears in the cartilage ( labrum) in the shoulder. Labral tears often are caused by injury and can lead to shoulder pain.
• Find rotator cuff disorders, including tears and impingement.

MRI may also help diagnosis a bone fracture when X-rays and other tests are not clear. MRI is done more commonly than other tests to check for certain bone and joint problems.