Magnetic resonance imaging (MRI) is a safe, noninvasive test that creates detailed pictures of your organs and tissues. “Noninvasive” means that no surgery is done and no instruments are inserted into your body.
MRI uses radio waves, magnets, and a computer to create pictures of your organs and tissues. Unlike CT scans and standard x-rays, MRI doesn’t use ionizing radiation or carry any risk of causing cancer.
Cardiac MRI creates pictures of your heart as it is beating, producing both still and moving pictures of your heart and major blood vessels. Doctors use cardiac MRI to get pictures of the beating heart and to look at its structure and function. These pictures can help them decide how to treat people who have heart problems.
Cardiac MRI is a common test. It’s used to diagnose and evaluate a number of diseases and conditions, including:
- Damage caused by a heart attack
- Heart failure
- Heart valve problems
- Congenital heart defects
- Pericarditis (a condition in which the membrane, or sac, around your heart is inflamed)
- Cardiac tumors
Cardiac MRI can help explain results from other tests, such as x-rays and CT scans. Sometimes, cardiac MRI is used to avoid the need for invasive procedures or tests that use radiation (such as x-rays) or dyes containing iodine (these dyes may be harmful to people who have kidney problems).
Often during cardiac MRI, a contrast agent is injected into a vein to highlight portions of the heart or blood vessels. This contrast agent often is used for people who are allergic to the dyes used in CT scanning.
People who have severe kidney or liver problems may not be able to have the contrast agent. As a result, they may have an MRI that doesn’t use the substance (a noncontrast MRI).
What do you need to prepare for your Cardiac MRI?
You’ll be asked to fill out a screening form before having cardiac MRI. The form may ask whether you have had previous surgeries, have any metal objects in your body, or have any medical devices (like a cardiac pacemaker) surgically implanted in your body.
Most, but not all, implanted medical devices are allowed near the MRI machine. Talk to your doctor or the technician operating the machine if you have concerns about any implanted devices or conditions that may interfere with the MRI.
MRI can seriously affect some types of implanted medical devices.
- Implanted cardiac pacemakers and defibrillators can malfunction.
- Cochlear (inner-ear) implants can be damaged. Cochlear implants are small electronic devices that help people who are deaf or who can’t hear well understand speech and the sounds around them.
- Brain aneurysm clips can move due to MRI’s strong magnetic field. This can cause severe injury.
Your doctor will let you know if you shouldn’t have a cardiac MRI because of a medical device. If this happens, consider wearing a medical ID bracelet or necklace or carrying a medical alert card that states that you shouldn’t have an MRI.
The technologist will tell you whether you need to change into a gown for the test. Don’t bring hearing aids, credit cards, jewelry and watches, eyeglasses, pens, removable dental work, and anything that’s magnetic near the MRI machine. Lockers will be available to secure your personal items.
Tell your doctor if being in a fairly tight or confined space causes you anxiety or fear. This fear is called claustrophobia. If you have this condition, your doctor might give you medicine to help you relax. Your doctor may ask you to fast (not eat) for 6 hours before you take this medicine on the day of the test.
Your doctor will let you know whether you need to arrange for a ride home after the test.