Cardiac Imaging

What is cardiac imaging?

Cardiac imaging, also called cardiovascular imaging, is a broad term that includes several ways to take pictures of your heart and surrounding anatomy.

The main types of cardiac imaging are:

• Echocardiogram (echo).
• Cardiac computed tomography (CT).
• Nuclear cardiac stress test.
• Single-photon emission computed tomography (SPECT).
• Cardiac positron emission tomography (PET).
• Coronary angiogram or left heart catheterization (“heart cath”).
• Cardiac MRI.
• Multigated acquisition (MUGA) scan.

Some cardiac imaging procedures may be combined, such as CT scan with coronary angiogram or PET and CT scans. Your healthcare provider might recommend several different tests to better understand your heart health.

When is cardiac imaging performed?

Healthcare providers use cardiovascular imaging for many reasons, including to:

• Screen for heart conditions to detect any problems early.
• Diagnose heart conditions.
• Determine if a heart attack occurred and the extent of the damage.
• Find the cause of symptoms like chest pain and shortness of breath.
• Monitor the heart to evaluate whether treatments are working.

Cardiac imaging can be helpful in diagnosing and managing many heart conditions, including:

• Arrhythmia.
• Coronary artery disease.
• Heart attack.
• Heart failure.
• Pediatric and congenital heart conditions such as structural abnormalities.
• Heart valve disease.
• Pericardial disease, or disease of the heart lining.

What is an echocardiogram?

An echocardiogram (echo) uses ultrasound (high-frequency sound waves) to produce images. It creates videos of your heart’s chambers, valves, walls and blood vessels. Doppler echocardiograms can also be used to measure the flow of blood through different chambers of your heart.

An echocardiogram helps measure your heart’s pumping action and the severity of heart failure. It can also help identify a valve problem, infection, blood clot or hole in your heart. Since this test can give a lot of information without using radiation or radioactive substances, heart doctors frequently use it.

What is cardiac computed tomography?

A cardiac CT scan uses a computer to combine multiple X-rays. This creates many different, detailed images at different locations in your heart, which can be read directly, or reconstructed to form three-dimensional views of your heart and surrounding structures from many angles.

Your provider may order a CT scan to look for artery blockages or structural problems. They may also order this test when other tests don’t provide enough information. Heart surgeons or interventional cardiologists may use it to help map your heart to see if a procedure or surgery is right for you.

What is a nuclear cardiac stress test?

A nuclear cardiac stress test uses a radioactive substance called a tracer to show blood flow in and around your heart. Your healthcare provider injects the tracer into your bloodstream and then uses a special camera to take pictures of your heart. The test is performed once when you’re resting and once after you exercise.

The test is also called myocardial perfusion imaging (MPI).

Types of nuclear cardiac stress tests include:

• Cardiac PET (positron emission tomography).
• Cardiac SPECT (single-photon emission computed tomography).

What is a cardiac PET scan?

A PET scan is another type of nuclear imaging test. It uses a radioactive tracer, which diseased areas of your heart absorb. The PET camera can then detect where the tracer was absorbed.

A cardiac PET scan focuses on the metabolic function of heart tissues. It can detect heart damage after a heart attack in the form of scar tissue, and can also be used in cardiac stress testing. A PET scan is often combined with a CT scan.

What is a cardiac SPECT scan?

A SPECT scan is a nuclear imaging test. It uses a radioactive tracer to show blood flow and metabolic function of heart tissues. Your provider injects the tracer into a vein, and the tracer travels to your heart. The SPECT camera can then detect where the tracer was absorbed.

What is a coronary angiogram?

A coronary angiogram is a special X-ray test that's performed during cardiac catheterization. Your healthcare provider inserts a long, thin tube (catheter) through an artery in your groin or wrist that travels up to your heart. The provider injects dye through the catheter into your bloodstream. Then the X-ray machine takes videos as the dye moves through the blood vessels around your heart. The test is used to locate clogged or blocked arteries.

What is a cardiac MRI?

A heart MRI uses radio waves and magnets to scan your heart instead of radiation. An MRI creates very detailed images. It can show all the different parts of your heart in detail and give an accurate picture of how well they’re working. It can help diagnose many conditions by detecting heart damage like scar tissue or inflammation.

What is a MUGA scan?

A MUGA scan evaluates the function of the lower chambers of your heart (ventricles). The scan is also called radionuclide ventriculography.

A healthcare provider injects a radioactive tracer into a vein. A special camera detects the radiation and uses it to create moving images of the beating heart. A MUGA scan takes pictures at specific times during every heartbeat.

The test measures ejection fraction, the amount of blood your heart pumps out during each heartbeat (contraction). Providers rarely use this test, but it can be a way to measure your heart’s pumping function. It's most often used to measure ejection fraction at different times, during long courses of chemotherapy or other medications that can have side effects on your heart.

How do I prepare for cardiovascular imaging?

Your healthcare provider will explain how to prepare for your specific tests. Instructions may include:

• For stress testing and coronary angiograms, avoid foods, beverages and medications that contain caffeine.
• For cardiac CT scans and cardiac MRIs, leave jewelry at home.
• For cardiac MRIs, remove hearing aids if applicable, as well as glasses, clips and other items that might contain metal.
• Wear comfortable clothing with no metal on it.

Be sure to tell your healthcare providers:

• About all your medical conditions.
• Every medication you take, including prescriptions, over-the-counter medicines, supplements and recreational drugs.
• If you have any medical devices, such as pacemakers, mechanical valves, rods or screws implanted in your body.
• If you have any pieces of metal inside your body.
• If you’re pregnant.

What are the risks of cardiac imaging?

Cardiovascular imaging is safe because the procedures are non-invasive or minimally invasive. Rarely, people have allergic reactions to the dye used in some cardiac imaging tests.

A note from Cleveland Clinic

Cardiac imaging allows healthcare providers to take pictures of your heart, blood vessels and surrounding anatomy. It shows blood flow to and around your heart. Cardiac imaging tests can help your provider diagnose and manage heart conditions. Talk to your healthcare provider about why they recommend certain tests and what they’re looking for.