Magnetic Resonance Imaging (MRI) of the Knee
How It Is Done continued...
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.
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
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.
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.