What To Expect During Cardiac MRI

MRI machines usually are located at hospitals or special medical imaging facilities. A radiologist (ra-de-OL-o-jist) or other doctor who has special training in medical imaging oversees MRI testing.

Cardiac MRI usually takes 45 to 90 minutes, depending on how many pictures are needed. The test may take less time with some newer MRI machines.

The MRI machine will be located in a specially constructed room. This will prevent radio waves from disrupting the machine. It also will prevent the MRI machine's strong magnetic fields from interfering with other equipment.

Traditional MRI machines look like a long, narrow tunnel. Newer MRI machines, called short-bore systems, are shorter, wider, and don't completely surround you. Some of the newer machines are open on all sides. Your doctor will help decide which type of machine is best for you.

Cardiac MRI is painless and harmless. You'll lie on your back on a sliding table that goes inside the tunnel-like machine. The technician will control the machine from the next room. He or she will be able to see you through a glass window and talk to you through a speaker. Tell the technician if you have a hearing problem.

A Patient Having Cardiac MRI

The photo shows a patient lying on a sliding table outside of a cardiac MRI machine. The table will slide into the machine, and the patient will lie quietly while pictures of the heart are taken.

The MRI machine makes loud humming, tapping, and buzzing noises. Earplugs may help lessen the noises made by the MRI machine. Some facilities let you listen to music during the test.

You will need to remain very still during the test. Any movement may blur the pictures. If you're unable to lie still, you may be given medicine to help you relax.

You may be asked to hold your breath for 10 to 15 seconds at a time while the technician takes pictures of your heart. Researchers are studying ways that will allow someone having a cardiac MRI to breathe freely during the exam, while achieving the same image quality.

A contrast agent, such as gadolinium (gad-oh-LIN-e-um), may be used to highlight your blood vessels or heart in the pictures. Contrast agent usually is injected into a vein in your arm with a needle.

You may feel a cool sensation during the injection and discomfort where the needle was inserted. Gadolinium doesn't contain iodine, so it won't cause problems for people who are allergic to iodine.

Your cardiac MRI may include a stress test to detect blockages in your coronary arteries. If so, you'll get other medicines to increase the blood flow in your heart or to increase your heart rate.