Skip to content
My WebMD Sign In, Sign Up

Knee Pain Health Center

Font Size

Magnetic Resonance Imaging (MRI) of the Knee

How It Is Done continued...

You will need to take off all or most of your clothes, depending on which area is examined (you may be allowed to keep on your underwear if it is not in the way). You will be given a gown to use during the test. If you are allowed to keep some of your clothes on, you should empty your pockets of any coins and cards (such as credit cards or ATM cards) with scanner strips on them because the MRI magnet may erase the information on the cards.

During the test

During the test, you will lie on your back on a table that is part of the MRI scanner. The table will slide into the space that contains the magnet. A device called a coil may be placed over or wrapped around the area to be scanned.

Some people feel nervous (claustrophobic) inside the standard MRI machine camera.gif. If feeling nervous keeps you from lying still, you can be given a medicine (sedative) to help you relax.

Inside the scanner, you will hear a fan and feel air moving. You may also hear tapping or snapping noises as the MRI scans are taken. You may be given earplugs or headphones with music to reduce the noise. It is very important to hold completely still while the scan is being done. You may be asked to hold your breath for short periods of time.

During the test, you may be alone in the scanner room. But the technologist will watch you through a window. You will be able to talk with the technologist through a two-way intercom.

If contrast material is needed, the technologist will usually put it in through an IV in your arm or hand. The injection may be given over 1 to 2 minutes.

An MRI test usually takes 30 to 60 minutes but can take as long as 2 hours.

How It Feels

You won't have pain from the magnetic field or radio waves used for the MRI test. The table you lie on may feel hard and the room may be cool. You may be tired or sore from lying in one position for a long time.

If a contrast material is used, you may feel some coolness and flushing as it is put into your IV.

In rare cases, you may feel:

  • A tingling feeling in the mouth if you have metal dental fillings.
  • Warmth in the area being examined. This is normal. Tell the technologist if you have nausea, vomiting, headache, dizziness, pain, burning, or breathing problems.

Risks

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 magnet.

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.

Today on WebMD

knee exercise
If you're living with knee pain, try these.
knee in brace
Everything you wanted to know about it.
 
nurse helping woman on crutches
When it comes to knee pain.
man with knee pain
Read this first.
 
man biting a bullet
Article
6 Ways To Ruin Your Knees
Article
 
Keep Joints Healthy
SLIDESHOW
Knee exercises
SLIDESHOW