Cardiac MRI

What is a cardiac MRI?

A cardiac MRI is a scan of your heart in which radio waves and magnets create images. They do it without anything you can see or feel going into your body. A cardiac MRI can show the parts of your heart (including chambers, valves and muscles). It also shows how well they’re working ― including how your blood moves.

These detailed, high-quality images in two or three dimensions help your healthcare provider figure out what’s wrong and make a diagnosis.

When is a cardiac MRI needed?

A healthcare provider performs a cardiac MRI to get a complete analysis of your heart’s structure and function. For example, your provider may need to:

• Find out why you’re having heart symptoms like chest pain, shortness of breath or fainting
• Diagnose congenital heart disease, heart failure, heart masses, valve disease, irritation of the pericardium (outer membrane that covers your heart) and more
• Look for heart issues like muscle damage, infection, protein buildup, iron deposits and inflammation
• Check for damage to your heart after a heart attack or areas that lack blood flow because of heart artery blockages
• Pinpoint a location they need to treat during an ablation
• See how much your treatment is helping your heart
• Plan a procedure or treatment for your heart
• Evaluate the success of a recent surgery
• Check to see how a disorder has affected your heart since the last scan

How does the test work?

Unlike some other forms of cardiac imaging, cardiac magnetic resonance imaging doesn’t use any radiation. It uses a massive magnet and radio waves to detect changes in the molecules in your body. Then it creates high-quality images of your heart on a computer. Contrast dye you get in an IV can help make problem areas easier to see.

A heart MRI is very accurate. It provides detailed images from different views. A cardiac MRI scan can often help providers identify disease better than other imaging types, like a CT (computed tomography). A heart MRI can show how severe valve disease is or damaged tissue, for example.

Cardiac MRI scans should take a half hour to an hour and a half. Your healthcare provider may do several scans, with each one lasting a few minutes. They’ll ask you to hold your breath for part of the scan. Holding your breath is the difference between a cardiac MRI and a regular MRI.

How do I prepare for a cardiac MRI?

Your provider will ask about any allergies you have, as well as health problems and surgeries in your history. If your kidneys don’t work well, your provider may not want to give you contrast dye for a cardiac MRI. They want to make sure your kidneys can clear the dye from your system.

If you get nervous or uncomfortable in tight spaces, ask your provider a few days in advance for a pill that will relax you (sedative). You can usually pick it up at the pharmacy and take it a half hour before your cardiac MRI. Just remember that you’ll need someone to drive you to and from your appointment if you take a sedative to relax.

What should you avoid before a cardiac MRI?

On the day of your cardiac magnetic resonance imaging:

• Don’t wear any jewelry because it’ll cause problems with the machine’s magnets and images. Also, an MRI can damage jewelry.
• Don’t forget to remove any piercings, glasses, hearing aids or hair barrettes that contain metal. You can place your clothing, jewelry and other items in a locker.
• Don’t skip your normal medicines or meals unless your provider tells you to.
• Don’t wear clothes that have metal on them, like a zipper on jeans or metal in a bra. You can keep your underwear and socks on, but you may need to put on a hospital gown.
• Don’t bring anything valuable with you. Bring only what you need.
• Don’t go into the MRI with a full bladder. It’s a good idea to use the bathroom before you get into the machine because you’ll be lying still for a while.

What to expect when you arrive for your cardiac MRI scan

When you enter the MRI room, you’ll see that the machine looks like a large doughnut standing on its side. Some MRI machines (open MRI) don’t make a complete circle around you, which can be easier if you need or want more space during the procedure.

What happens during a cardiac MRI procedure?

The exact steps of a cardiac MRI depend on your health and the reasons you’re having this test. In general:

1. For a cardiac MRI with contrast, your provider may want to give you a contrast substance like gadolinium. This can make it easier to see some details in your scans. You’ll get this through an IV in your arm.
2. Your provider may put stickers with EKG leads on your chest and a belt below your chest to collect information about your heartbeats and breathing during your scan.
3. You’ll lie on a long platform that will slide your whole body into the empty space in the middle of the MRI machine.
4. After they help you get ready for your scan, your provider will go to a different part of the room that’s behind glass. They’ll be able to see you during your scan. And you’ll be able to communicate — through a microphone and headphones or intercom — with the person operating the machine. They may put a call button in your hand that you can squeeze if you need to contact the person doing the scan. You may be able to listen to music through headphones or use earplugs to block out the noise.
5. During scans, you’ll lie still on your back while the machine moves around you. It’s very loud and may sound like an electronic video game or something pounding around you. It can be hard to be still, but it’s very important because moving makes the images blurry.

What to expect after a cardiac MRI

Your provider will slide the table you’re on out of the MRI machine. If you had an IV, they’ll remove it. Then, you can get your belongings, get back into your clothes and go home. Drinking water after your test will help get the dye out of your system.

What are the potential risks and side effects of this test?

A heart MRI won’t harm you, but your healthcare provider may ask if you’re pregnant or if you have any metal inside your body. In some cases, an MRI may not be right for you.

Some medical devices don’t work right or can interfere while you’re inside an MRI. Be prepared to tell your provider what kind of device you have. Certain devices (like a stainless steel intrauterine device or some older pacemakers) may not be safe in the MRI machine. Your healthcare provider can check their database to see which devices are safe and compatible with having a heart MRI.

Metal in your body can create a cardiac MRI risk. If the powerful magnet in the machine makes metal in your body move, the metal can hurt you. It can also heat up.

If you took a sedative to relax, you may feel tired until the effects of the pill wear off. If not, you can return to your normal activities.

If you received contrast through an IV, you might have a metal-type taste in your mouth for a little while. You may have some bruising or irritation where the IV went in. Rarely, people may have nausea, a headache or an allergic reaction from the contrast they got in their IV.

What type of results do you get and what do the results mean?

The healthcare provider (usually a radiologist or cardiologist who interprets images) will review your scans. Then, they’ll send them to the provider who ordered your cardiac MRI. Your provider may show you images at your next appointment while explaining your diagnosis.

It may take a couple of days for you to get your results.

If the results of your cardiac MRI scan are abnormal, your provider may prescribe medication or discuss a procedure or surgery with you. This test can check many aspects of your heart. The next step is different for everyone, depending on the issue.

When should I call my healthcare provider?

If you’re having symptoms of a heart problem, call your provider right away.

If you’ve had a cardiac MRI and haven’t heard from your healthcare provider in a few days, it’s a good idea to follow up on your results.