A heart MRI, also called a cardiac MRI, is an imaging test that creates images of your heart and nearby blood vessels. Your doctor may order a heart MRI to check for heart issues such as structural irregularities, problems with blood flow, or conditions like heart failure.

MRIs don’t use radiation and are generally very safe. Allergic reactions to the contrast dye, which your radiologist or technician may administer intravenously (into a vein) to help make your heart more visible in the images, can occur but are rare.

Heart MRIs may also not be right for some people, including those with certain types of pacemakers or other implanted devices containing metal.

Depending on the scan results, your doctor may order additional tests or recommend a management plan for any heart issues.

A magnetic resonance imaging (MRI) machine uses magnets and radio waves to create images of the inside of your body without surgery. These images show your body’s soft tissues and bones.

You can get an MRI of any body part. A heart MRI focuses on your heart and nearby blood vessels.

Unlike CT scans, MRIs do not use ionizing radiation, meaning MRIs can be safer options for pregnant people.

Your doctor might order a heart MRI if they think you’re at risk of heart failure or may have other heart problems, including:

Your doctor may also recommend an MRI scan if you have had a CT scan or X-ray and the results are unclear. MRIs show cross-sections of your body, which can help your doctor understand the results of other imaging tests.

Before your MRI, tell your doctor if you have a pacemaker or cardioverter defibrillator. In some cases, your doctor might recommend a different imaging test. However, some newer cardiac devices are safe for MRIs.

Since MRIs use magnets, they can affect metal. It’s essential to tell your doctor about any other metal implants from past surgeries you may have in your body, including:

  • stents
  • artificial heart valves
  • cochlear (inner ear) implants
  • neuromuscular stimulators
  • plates
  • staples
  • dentures or dental implants
  • intrauterine devices
  • clips
  • implanted drug infusion pumps
  • screws or pins

Your doctor may also ask you to stop eating, drinking, or taking certain medications before the scan. Tell your doctor about all medications and supplements you take.

Right before the scan, a healthcare professional may inject you with a special gadolinium-based contrast agent to highlight your heart. This dye, which is administered in IV form, is different from the dye used in CT scans.

Allergic reactions to the dye aren’t common, but tell your doctor if you have any concerns or if you have experienced allergic reactions in the past.

Some MRI machines look like long metal tubes, while others look like thinner rings. Some machines have narrow openings, so before the scan, tell your doctor if you’re uncomfortable in tight spaces.

A radiologist or MRI technician performs the scan using special equipment in a hospital, clinic, or imaging center.

Before the procedure starts, they will ask you to lie on the MRI table that slides into the scanner. The scanner may look like a long metal tube or a ring.

If the machine has a narrow opening and you’re uncomfortable in tight spaces, your care team may give you a sedative beforehand to make you more comfortable.

Once you are in the MRI scanner, the radiologist will leave the room and watch you from another room, but you will be able to talk with them. During the exam, you must stay still to prevent blurry images, so if you feel uncomfortable, tell the healthcare professionals performing the scan.

The MRI machine creates a strong magnetic field around you and sends radio waves to the part of your body being imaged. While taking images of your heart, the technician may ask you to hold your breath for a few seconds at a time.

MRI machines can be loud, so your care team may have you wear earplugs during your scan.

An MRI usually takes between 30 and 90 minutes.

In some cases, your doctor may order a stress test along with your cardiac MRI. This means your care team will give you additional medications to make your heart work harder, allowing the MRI to capture images of your heart working under stress.

When the scan is complete, the radiologist will slide the table out of the MRI machine and remove your IV if you have one. Then you can get your belongings, get dressed, and go home.

You may be able to drive yourself home after undergoing an MRI scan. However, if you received a sedative, someone else will need to drive for you.

Your care team may also ask you to drink plenty of water for 24 hours after the test to flush the contrast dye out of your body.

After the scan is complete, the radiologist sends the images collected to a cardiologist or another team of specialists for analysis. They review and interpret the images, which takes time. You might get preliminary results in a few days, but complete results can take up to a week or more.

Your doctor will review the results with you during an appointment. They may need to order additional tests, or they may have enough information to recommend treatment.

MRI scans are typically safe. The test does not use radiation, and there are no known side effects from the radio waves.

Some people may experience an allergic reaction to the dye, but this is uncommon. Your care team will be prepared to manage any adverse reactions.

If you have any metal implants, the MRI machine can damage or move them. Devices like pacemakers that aren’t safe for MRIs may also be reset during the scan.

If you have claustrophobia, you might be uncomfortable in the MRI machine. Talk with your doctor about your concerns before the test. They might give you an anti-anxiety medication or sedative to help reduce your discomfort.

Cardiac MRIs can help your doctor evaluate your heart structure and function and potentially diagnose various heart conditions.

These scans are generally safe, but your doctor needs a complete understanding of your health status and medical history to determine whether a heart MRI is right for you.