Magnetic Resonance Imaging (MRI)

MRI is the newest, and perhaps most useful, medical imaging technology available. Doctors can see very clear pictures of the interior of the body, without surgery, using MRI. By using strong magnets and pulses of radio waves to manipulate the natural magnetic properties in the body, this technique makes better pictures of organs and other soft tissues inside the body than other radiologic methods. MRI is useful not only in looking at these tissues but is very good at searching for cancer throughout the body.

Contraindications

Before the test

What to expect

Risks

Afterward

Contraindications
Possible contraindications (reasons the procedure may not be performed) include metal in the patient’s body, such as a hip or knee replacement. Your radiologist and your doctor also must be made aware of these other conditions:

• Pacemakers, aneurysm clips, metal plates, pins, screws or rods
• Bullet fragments or other metal pieces that are in your body from old wounds
• If your job exposes you to metal particles (working with a metal grinder, for example)
• If you are pregnant or may be pregnant
  

In addition, obesity greatly interferes with the quality of an MRI.

Before the test
Patients must remove all metal objects (watches, jewelry, eye glasses, hair clips). Any magnetized objects such as credit cards, bank machine cards and audio tapes should be kept as far away as possible because they can be erased. You cannot bring your wallet or keys into the room. You can’t have metal snaps, buckles or zippers.

What to expect
You lie back on a narrow table and are made as comfortable as possible. Transmitters are positioned on your body, and the cushioned table that you are laying on moves into a long tube that houses the magnet. The tube is as long as most adults lying down, and it’s narrow and open at both ends. If you are claustrophobic, tell your doctor and the radiologist before the test.

Once the area to be examined has been properly positioned, a radio pulse is applied. (You don’t feel anything.) Then, a two-dimensional image, which is like a slice through the area, is taken. The table then moves a fraction of an inch and the next image is made. Each image takes several seconds, and the entire exam could last from 30 to 90 minutes. During the test, the patient is not allowed to move.

The whole process is very noisy and confining. The patient hears a thumping sound the whole time. Since it is noisy, music supplied via earphones can be used. Some patients get nervous or panic because they are in this small, enclosed tube. This is why the team monitors your vital signs, and you can talk to the technologists over an intercom. You may be asked to hold your breath several times for a few seconds, to make sure it’s a clear picture.

Risks
There are no known risks to the patient and there are no side effects. Any woman who is or may be pregnant should carefully discuss the issue with the doctor and radiologist before undergoing an MRI.

Afterward
You can go home and resume your normal activities. The technician will not give you the results of the test; your doctor’s office will notify you.