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.
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 MRI magnet. If
feeling nervous keeps you from lying still, you can be given a medicine
(sedative) to help you relax. Some MRI machines (called open MRI) are made so
that the magnet does not enclose your entire body. Open MRI machines may be
helpful if you are claustrophobic. See pictures of a
standard MRI machine and an
open MRI machine .
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.