How It Is Done continued...
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
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.
Iron pigments in tattoos or tattooed eyeliner can
cause skin or eye irritation.
An MRI can cause a burn with some
medicine patches. Be sure to tell your doctor if you are wearing a
There is a slight chance of an
allergic reaction if contrast material is used during
the MRI. But most reactions are mild and can be treated using medicine.
Contrast material that contains gadolinium may cause a serious problem (called
nephrogenic systemic fibrosis) in people with
kidney failure. If you have decreased kidney function
or serious kidney disease, tell your doctor before having an MRI scan.
There also is a slight risk of an infection at the IV site if contrast
material was used.
Magnetic resonance imaging (MRI) is a test done with a large machine that uses a magnetic
field and pulses of radio wave energy to make pictures of organs and structures
inside the belly.