Magnetic Resonance Imaging (MRI) of the Knee

Knee MRI, MRI of the Knee

What Affects the Test

Factors that can interfere with your test or the accuracy of the results 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 medication infusion pump. The MRI magnet may cause problems with these devices.
• Inability to remain still during the test.
• Obesity. A person who is very overweight may not fit into the opening of some standard MRI machines.

Many modern medical devices that do not use electronics, such as heart valves, stents, or clips, can be safely placed in most MRI machines. But some newer MRI machines have stronger magnets. The safety of MRI scans with these stronger MRI magnets in people with medical devices is not completely known.

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Author:	Maria G. Essig, MS, ELS	Last Updated: April 10, 2007
Medical Review:	Paul D. Traughber, MD - Radiology Kenneth B. Sutherland, CD, BSc, MD, FRCPC - Diagnostic Radiology
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