Magnet Resonance Imaging
A magnetic resonance imaging scan is usually called an MRI. It is a medical
test that takes very clear, detailed pictures of the inside of the body.
Each picture, or slice shows only a few layers of body tissue at a time.
The MRI machine uses a large magnet, radio waves and a computer to take
images. Pictures taken this way can help physicians find and see problems
in the body more easily. This test may take up to 60 minutes per exam.
The pictures made during an MRI help physicians learn more about the cause
of your health problem. An MRI can be used to evaluate brain, neck and
spinal cord problems. It can also help physicians look at problems with
your chest, heart, abdomen, joints or blood vessels. Nearly every part
of the body can be studied with an MRI.
The pictures created are digital and can be viewed by your physician through
the computer, or they can be sent to them on a compact disc.
When should a person not have an MRI?
An MRI will not be performed on a person who is pregnant without clearance
from an IVCH radiologist.
Patients who have a cardiac pacemaker or implanted cardiac defibrillator
cannot have an MRI.
You may not be able to have an MRI if you have any of the following things
in or on your body (please notify your physician if you have any of the
- Aneurysm clips (unless the clip is compatible with magnets)
- Artificial or prosthetic limbs or joints (such as an artificial knee joint)
- Bullets or pieces of shrapnel
- Cochlear (ear) implants
- Artificial heart valve
- Implanted IV ports
- Implanted spinal stimulator
- Insulin pump
- Intrauterine device (IUD).
- Medication patch (transdermal or skin patch, including nicotine, birth
control and nitroglycerin patches)
- Metal pins, plates, screws or surgical staples
- Metal fragments in your eyes from welding
- Tattoos and permanent eyeliner
The staff may take x-rays to determine if it is possible to proceed with
your MRI if there is any question about whether you have any metal in
How does MRI work?
The MRI machine is large and looks like a hollow tube. The table that you
lie on goes into the tube during the test.
The machine is usually in a room by itself. The MRI technologist sits behind
a window on one side of the room during the MRI. From this spot, the technologist
can talk to you during your scan.
What happens during the MRI?
You may be asked to put on a gown, and the technologist will help you lie
down on the MRI table. The body part being tested may be kept in place
with a cradle or straps to hold it very still. You are not able to see
anything once you are inside the machine. You may speak to the technologist
at certain times during your test. You are also given an emergency call
button. The technologist will stop the test and move your bed out of the
MRI machine immediately if you press the button.
The bed slides into the round tube in the center of the machine. While
our new MRI equipment is much quieter than earlier models, you may hear
some noise while the pictures are being taken. The noise is caused by
gradient coils inside the magnet. You may be allowed to wear ear plugs
or headphones to help you relax and soften the noise of the machine.
Each MRI is made up of a number of sets of image scans. You must lie very
still during the actual scans, for a few seconds to a few minutes at a
time. You may be able to move a little in between the scan sets. The technologist
may put padding or cushions around and under you for comfort. The technologist
will tell you when the test is finished.
Some MRI tests need dye, sometimes called contrast, to help make your body
part show up better in the pictures. The contrast is put through an IV
in your hand or arm. Your skin around the IV may feel warm or cold as
the contrast is put into the IV. Tell the technologist if you feel any
unusual things as the contrast is given. You may have a metallic taste
in your mouth for a few seconds while the contrast is administered.
MRI scans are very safe, and complications are rare. There is no radiation.
Allergic reactions to the dye used are possible but not likely. It is very
important to inform your physician about any allergies that you have.
It is your responsibility to tell your physician and the technologist about
any possible implants or metallic fragments. It is
very important. This information can help avoid potentially deadly complications.
If you have a pacemaker or an implanted cardiac defibrillator, you must
not have an MRI.
There is no special preparation needed. You may eat and drink normally
and take any usual medications, unless you have received different instructions
from your physician or the hospital staff. For the test, wear loose, comfortable
clothing without any metal fastenings, such as zippers or clasps, because
metal will interfere with the test. Do not wear any jewelry.
Informed consent: You have the right to understand your health condition in words that
you know. You should be told what tests, treatments or procedures may
be done to treat your condition. Your doctor should also tell you about
the risks and benefits of each treatment. You may be asked to sign a consent
form that gives your physician and the hospital staff permission to do
certain tests, treatments or procedures. If you are unable to give your
consent, someone who has permission can sign this form for you. A consent
form is a legal piece of paper that tells exactly what will be done to
you. Before giving your consent, make sure all your questions have been
answered so that you understand what may happen.
You will be asked to fill out a screening sheet. Tell your physician if:
- You have any metal in your body, such as metal screws, pins or plates.
- You have a medication patch on your skin. Ask if your patch should be off
your skin during the MRI.
- You think you are pregnant. Your physician needs to know so he can decide
whether you should have the test.
- You are claustrophobic or afraid of being in closed or cramped places.
Your physician may then give you sedative medicine to help you relax during
the test. You must get a prescription for this medicine from the physician
who is ordering the MRI. You will also need an adult to drive you home
if you have a sedative.
Bring a family member or friend with you if you need to wait for test results.
They can talk with you and be there to support you during and after the
test. They can also drive you home if you have sedative medicine during the test.
Bring with you any papers your physician has given you to sign.
What will happen after the test?
When the test is over, you can go home.
Your physician will contact you with your test results. The results are
usually available within one business day after you have the test.
Call the Diagnostic Imaging Department (815.780.3431) If:
- You cannot make it to your MRI appointment on time.
- You have questions or concerns about having an MRI.
If you have to take medicine for claustrophobia, call the MRI desk at
815.780.3280 before you take the medicine to make sure we are running on time.