Your doctor may suggest a test called an MRI (magnetic resonance imaging) to check for heart disease. It uses powerful magnets and radio waves to make pictures of organs and structures inside your body. The technique gathers info about your heart as it's beating and creates images throughout its pumping cycle.
Why Do I Need a MRI?
Your doctor will use the test to check the structures in your chest, including your heart, pericardium (outside lining of the heart), lungs, and major vessels. An MRI can also help your doctor see if there are signs of conditions like:
- Coronary artery disease
- Pericardial disease
- Cardiac tumors
- Heart valve disease
- Heart muscle disease (cardiomyopathy)
- Congenital heart disease
How Should I Get Ready?
If you're claustrophobic (have a fear of closed spaces), talk to your doctor about whether you should get a sedative -- a medication to help you relax -- before your MRI. If you take one, to avoid nausea, you shouldn't eat any solid food for 6 hours beforehand. But it's OK to have "clear" liquids -- like apple juice, Jell-O, black coffee, tea, or water -- up to 2 hours before you take the sedative. You may take your regular medicines (with sips of water) unless your doctor tells you not to. Arrange in advance for a friend or family member to drive you home after the MRI since you may feel drowsy.
If you're not taking a sedative, you can eat and take your regular medicine as usual before the MRI.
Because MRIs use strong magnets to help create images, you need to make sure you don't have any metallic or magnetic items on you. Let the technician know if you have any metallic implants or any metal under your skin. Most metallic implants, such as sternal wires and clips used for heart surgery, aren't a problem.
Your doctor may not let you get an MRI if you have some conditions or implants. Let him know if you have any of these:
- Implanted pacemaker or defibrillator
- Older model Starr-Edwards heart valve implant (metallic ball/cage type)
- Cerebral aneurysm clip (metal clip in a blood vessel in the brain)
- Implanted insulin pump, narcotic pump, or implanted nerve stimulators (TENS) for back pain
- Metal in the eye or eye socket
- Cochlear (ear) implant for hearing problems
Wear a shirt or blouse that you can easily take off. During the test, wear metal-free pants, such as sweatpants with elastic bands. Don't wear or carry belt buckles, metal zippers, snaps, watches, or wallets with bank or credit cards with magnetic strips.
What Happens During the Test?
You'll first change into a hospital gown. The technician will place small, sticky electrode patches on your chest and back. If you're a guy, you may need to get your chest partly shaved to help them stick. The electrodes get attached to an electrocardiogram (EKG) monitor that charts your heart's electrical activity during the test.
Most likely, a nurse will insert an intravenous (IV) line into a vein in your arm to inject a non-iodine-based dye, called contrast material. This makes your organs more visible in the pictures.
The MRI scanner unit is a long tube that scans your body as you lie on a platform bed. It's open at both ends, and it's ventilated and fully lit. You'll lie on your back on the scanner bed, with your head and legs raised for comfort. You can talk to the person operating the MRI during the test through an intercom system.
During the exam, you'll need to lie as still as possible. The technician will ask you to hold your breath now and then for short periods in to reduce blurring of the images from motion of your body when you breathe.
During scanning, the equipment may make loud banging noises. You can muffle the sound by wearing headphones or earplugs that you'll get before the exam.
You can expect an MRI to take about 30 to 75 minutes, depending on how much imaging you need.
What Happens After the MRI Test?
Your doctor will discuss the test results with you.
If you took a sedative, your doctor will tell you when you can eat, drink, and go back to your regular activities. A friend or family member should drive you home.
If you didn't get a sedative, you may go back to your usual activities and normal diet right away.