Magnetic Resonance Imaging (MRI) of the Shoulder
There are no known harmful effects from the
strong magnetic field used for MRI. But the magnet is very powerful. The magnet
may affect pacemakers, artificial limbs, and other medical devices that contain
iron. The magnet will stop a watch that is close to the magnet. Any loose metal
object has the risk of causing damage if it gets pulled toward the strong
Metal parts in the eyes can damage the
retina. If you may have metal fragments in the eye, an
X-ray of the eyes may be done before the MRI. If metal is found, the MRI will
not be done.
Iron pigments in tattoos or tattooed eyeliner can
cause skin or eye irritation.
An MRI can cause a burn with some
medicine patches. Be sure to tell your doctor if you are wearing a
There is a slight chance of an
allergic reaction if contrast material is used during
the MRI. But most reactions are mild and can be treated using medicine.
Contrast material that contains gadolinium may cause a serious problem (called
nephrogenic systemic fibrosis) in people with
kidney failure. If you have decreased kidney function
or serious kidney disease, tell your doctor before having an MRI scan.
There also is a slight risk of an infection at the IV site if contrast
material was used.
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.
radiologist may discuss preliminary results of the MRI
with you right after the test. Complete results are usually available for your
doctor in 1 to 2 days.
An MRI scan can sometimes find a problem in
a tissue or organ, even when the size and shape of the tissue or organ looks
Magnetic resonance imaging (MRI) of the shoulder
| Normal: |
The muscles, tendons, bones, and joints
look normal in size, shape, and location.
No growths, such as tumors, are
No cartilage problems or tears, broken
bones (fractures), or loose bodies are present.
rotator cuff injury or tear is present.
No signs of inflammation or infection are
| Abnormal: |
A growth, such as a tumor, inflammation,
or infection in the bone or joint is present.
A collection of fluid is found, which could
mean you have an infection.
cartilage is present.
Joint damage is present and bones may show
signs of disease or fracture.
What Affects the Test
Reasons you may not be able to
have the test or why the results may not be helpful include:
- Metal devices in your shoulder or chest from
previous surgery. These can make the MRI pictures blurry and prevent your
doctor from seeing what is wrong with your shoulder.
- Pregnancy. An MRI test usually is not done during
- Medical devices that use electronics, such as a
pacemaker or medicine infusion pump. The MRI magnet may cause problems with
- If you are not able to remain still during the
- Obesity. A person who is very
overweight may not fit into the opening of some standard MRI machines.