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Magnetic Resonance Imaging (MRI) of the Knee

Risks continued...

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 patch.

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.

Results

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 knee camera.gif.

The 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.

Magnetic resonance imaging (MRI) of the knee
Normal:

The ligaments, meniscus camera.gif, tendons, bones, and joints look normal in size, shape, and location.

No growths, such as tumors, are present.

No broken bones (fractures), extra fluid, or loose bodies are present.

No signs of inflammation or infection in bones, joints, or soft tissues are present.

Abnormal:

Bones show an injury or a fracture. The MRI also may show a collection of fluid, which could mean an infection is present.

Ligament or meniscus tears are present.

Tendon tears are present. The MRI may also show a thickening, meaning surgery or a tear you had in the past or repeated stress.

Growths, such as tumors, are present.

Changes common to arthritis are present.

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 leg from previous surgery. These may make the MRI pictures blurry and prevent your doctor from seeing what is wrong with your knee.
  • Pregnancy. An MRI test usually is not done during pregnancy.
  • Medical devices that use electronics, such as a pacemaker or medicine infusion pump. The MRI magnet may cause problems with these devices.
  • If you are not able to remain still during the test.
  • Obesity. A person who is very overweight may not fit into the opening of some standard MRI machines.

WebMD Medical Reference from Healthwise

Last Updated: November 29, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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