How It Is Done continued...
During the test, you will lie on your back on a table that
is part of the MRI scanner. Your head, chest, and arms may be held with straps
to help you remain still. 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. A special belt strap may be used to sense your breathing. The belt
triggers the machine to take the scan at the right time.
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
You may be able to have an MRI with an open machine that doesn't enclose your entire body. But open MRI machines aren't available everywhere. The pictures from an open MRI may not be as good as those from a standard 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.
may be given a medicine, such as glucagon, to slow bowel movements for some MRI
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 put it in an
IV in your arm or hand. The material may be given over
1 to 2 minutes. Then more MRI scans are done.
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