This screening test measures how well blood flows through your heart. It may be used to diagnose coronary artery disease or to assess damage caused by a heart attack.

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If you’re experiencing chest pain or other symptoms of coronary artery disease (CAD), a doctor or healthcare professional may recommend at least one test that includes a heart perfusion imaging scan. This is a noninvasive look at heart circulation, and it’s a measurement of how well the heart is pumping.

A heart perfusion scan can be used to help diagnose heart disease or determine the impact of a heart attack or heart surgery. The procedure is considered safe with few potential risks, though it does involve the injection of a dye and a special camera to scan blood moving through the heart.

This article will provide more detail about the heart perfusion scan itself and how you and a healthcare team can use the results of this scan and other heart tests to decide on a treatment plan.

Known also as a myocardial perfusion scan, this procedure uses a tiny amount of radioactive material (nuclear tracer) to help reveal how well or how poorly blood travels through the heart’s valves and chambers. It also provides information about the coronary arteries’ ability to supply blood to the heart muscle.

With the nuclear tracer in the bloodstream, a special gamma camera can more easily track blood as it circulates within the heart. That’s used to identify areas of blockage or other obstacles to healthy circulation in your heart.

The heart perfusion scan can be done when your heart is at rest or during physical activity. The test during physical activity is often known as a stress test. During that stress test, you walk or jog on a treadmill or ride a stationary bicycle.

Images from the scan are analyzed, and the heart’s performance is graded based on well or poorly blood moves throughout the heart. Heart perfusion scans are valuable tools in making accurate diagnoses and steering treatment decisions.

The heart perfusion scan may be used for a number of heart-related conditions or suspected issues. Some of those include:

CAD: This is usually caused by atherosclerosis, and it’s the stiffening and narrowing of arteries because of the buildup of plaque along the inner artery walls. A heart perfusion scan can help determine if you’re experiencing CAD, and it can also rule out CAD if no impediments to blood flow are found.

Heart attack: A doctor may order a heart perfusion imaging scan after a heart attack to assess how much the event affected blood flow and the heart’s pumping ability.

Stents and bypass surgery: If you’ve been treated for heart disease by having one or more cardiac stents placed in blocked arteries or undergoing coronary artery bypass grafting to have a new blood vessel attached to the heart to reroute blood flow around blockage in a coronary artery, a scan can gauge how effective those treatments are and whether additional treatments are necessary.

Before the procedure, you’ll have electrodes placed on your chest to record your heart rhythm and find any sudden changes. You’ll also wear a blood pressure cuff so your blood pressure will be monitored throughout the process.

That’s when the procedure begins:

  1. You’ll then have an intravenous line placed in your arm to receive the nuclear tracer later.
  2. You’ll start walking or riding to get your heart rate up. If you’re unable to exercise, you’ll be given a medication that increases blood flow, essentially duplicating the effects of exercise.
  3. Once a doctor determines your heart is working hard, the tracer will be administered, and you’ll lie down on a table. The gamma camera will get cross-sectional images of your heart, so it’s important that you lie as still as possible.
  4. Once your heart is back at its resting rate, a doctor may choose to assess blood flow in the heart during rest. This often means an additional tracer must be administered.

A heart perfusion imaging scan is considered to be a safe and well-tolerated screening tool.

However, because the test does involve exposure to a small amount of radiation, there’s always some concern about the long-term risk of cancer.

A 2018 study compared the radiation exposure of the two main types of heart perfusion scans: positron emission tomography (PET) and single photon emission computed tomography (SPECT). The study found that PET myocardial perfusion scans use significantly lower amounts of radiation. However, there are certain advantages to SPECT such as its lower cost.

Other risks can occur during the exercise portion of the test. The exertion may trigger chest pain or an abnormal heart rhythm (arrhythmia).

In rare cases, some people have allergic reactions to the tracer material.

Medications used to induce stress can also cause potential risks, including seizures, low blood pressure, or temporary heart rate slowing.

Abnormal heart perfusion means the heart isn’t pumping as efficiently as it should to meet the body’s demand for oxygenated blood.

Perfusion is graded on a scale of 0 to 4, based on the uptake of blood through the coronary arteries. Artery blockage can cause reduced uptake or abnormal perfusion, meaning the heart muscle isn’t getting the blood supply it needs.

Heart perfusion scan grading scale

Heart perfusion scan grades can be interpreted this way:

  • 0: normal uptake
  • 1: mildly reduced uptake
  • 2: moderately reduced uptake
  • 3: severely reduced uptake
  • 4: no uptake
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The results of your heart perfusion scan will be considered along with other factors such as additional imaging, blood tests, and a review of your symptoms and family medical history.

Once a relatively complete picture of your cardiovascular health is established, a healthcare team should discuss treatment options with you if any treatment appears necessary.

A CAD diagnosis may trigger additional tests to get more detailed information about your condition.

A 2017 research review suggests that proper interpretation of SPECT scan results isn’t only helpful in diagnosing CAD but also has prognostic value when making treatment decisions.

Additionally, a 2019 study suggests that a heart perfusion scan may be a wiser first-line diagnostic screening choice than other options such as cardiac angiography, in part because cardiac angiography isn’t as cost effective as perfusion imaging and often reveals that no CAD is present.

The 2022 chest pain guidelines from the American Heart Association and American College of Cardiology recommend the same, noting that evaluation for chest pain — including stress tests and perfusion imaging — are preferred in people with low to intermediate risk ahead of more invasive procedures. This is because of both cost and less risk to the person.

A heart perfusion scan is a widely used and helpful test to assess your heart health if you’re at high risk of CAD or have had a heart attack. The commonly used tests are helpful in many ways.

Along with being a generally safe, low risk test, a heart perfusion imaging scan can usually provide a healthcare team with reliable images and information about your heart health.