A heart PET scan is a noninvasive imaging test that uses a small amount of radiation. It helps doctors understand how the heart functions and whether it is healthy.

Cardiac or heart PET scans create images of the heart using a specialized machine and an injection of a radioactive substance called a tracer. The tracer releases energy, and the way it lights up the heart provides doctors with information about how blood flows through the heart and how healthy the organ is.

The test creates images of the heart from every angle and can provide information beyond other imaging tests. These images indicate whether all parts of the heart muscle are getting enough blood, show areas of damage or scar tissue, and help doctors identify buildups of abnormal substances.

This article explores heart PET scans and what a person can expect from this type of imaging study.

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A doctor orders a PET scan if they require a closer look into the function and health of a person’s heart.

When standard cardiac assessments raise concerns or fail to provide a complete picture, a PET scan provides additional information that helps with a diagnosis.

For instance, doctors use heart PET scans when assessing suspected coronary artery disease, as they can precisely map blood flow distribution and identify regions where blood is not flowing as well as it should.

Doctors may also order a heart PET scan to find out the following:

Learn more about PET scans.

To prepare for a heart PET scan and ensure accuracy in the results, it is best for individuals to follow specific guidelines their doctor provides.

Instructions for before the scan may include:

  • minimizing caffeine intake for 24 hours
  • not performing strenuous exercise for 12–24 hours
  • not eating for 4–6 hours
  • drinking only unflavored water
  • checking that the person is allowed to take their regular medications, vitamins, or supplements

If a person has diabetes and takes insulin, they will need to inquire about how much to take before the scan and what to eat.

A heart PET scan typically takes place at a hospital or specialized PET center. Performing the scan generally involves the following steps:

  1. The technologist attaches small metal disks called electrodes to the individual’s chest, arms, and legs. These electrodes connect to an electrocardiogram (ECG or EKG) machine, tracking the heart’s rhythm throughout the test.
  2. A healthcare professional inserts an intravenous line (IV) into a vein in the individual’s arm, where they will later administer the radioactive tracer.
  3. The individual reclines on a flat table linked to the PET scanner and a computer. This table slides into the doughnut-shaped scanner. To ensure image quality, the individual must remain completely still with their arms positioned above the head during each scan.
  4. Technicians take a baseline image of the heart before injecting the tracer.
  5. Following the tracer injection, technicians scan the heart again to assess its activity. Within the PET scanner, detectors capture the radioactive patterns the tracer emits within the heart.
  6. A computer converts the collected data into images on a screen. Multiple scans generate images of thin portions of the heart from various angles.

For individuals undergoing a nuclear chemical or pharmacologic stress test, the technician will also inject a medication to simulate increased blood flow within the heart, mimicking exercise.

Severe coronary artery disease can reduce tracer uptake in specific regions due to inadequate blood flow during stress.

How long does a heart pet scan take?

It takes the healthcare team 15–30 minutes to take a baseline image of the heart before injecting the tracer. After the tracer injection, they scan the heart again. The entire test generally takes 1–3 hours, depending on the precise tests the doctor orders.

Individuals should not experience any discomfort or pain during the heart PET scan. The radioactive tracer injection may induce a transient sensation similar to a routine injection, which quickly diminishes.

If a person is anxious or concerned about the procedure, they can discuss this with their doctor or medical team, who can provide support and address any questions. If necessary, a doctor can prescribe medications to help the person relax.

People can generally resume their regular activities without needing a specific recovery period after a heart PET. However, they will need to check this with their doctor.

The radioactive tracer will naturally exit the body over time.

If the person had a sedative, they will need to avoid the following activities for at least 24 hours:

  • driving
  • operating heavy machinery
  • drinking alcohol

After the test, the person will make an appointment with their doctor to discuss the results and next steps.

Heart PET scans are generally safe for most people. The body will naturally excrete the small amount of radiation that healthcare professionals use in performing the scan.

However, if a person is pregnant or nursing, they should tell their doctor as the test could harm the baby.

A doctor will interpret the results of a heart PET scan and discuss their findings with the individual. They will determine whether the results are normal or abnormal.

Normal results

When the results of a heart PET scan are normal, this indicates that blood flow to the heart muscle is evenly distributed and there are no significant areas of reduced flow. This suggests that the heart is functioning well and receiving adequate blood supply.

A normal result can provide reassurance that there are no severe blockages or areas of damaged heart muscle.

Abnormal results

Abnormal results suggest potential issues with blood flow distribution or heart muscle function.

For example, results might indicate areas of reduced blood flow, suggesting blocked or narrowed arteries. Blocked or narrowed arteries could be a sign of coronary heart disease.

Abnormal results could also point to regions of the heart muscle that have experienced damage or scarring, possibly from a previous heart attack.

An abnormal heart PET scan typically prompts further evaluation and discussions with doctors to determine appropriate management strategies. These may include:

  • additional tests
  • interventions
  • lifestyle modifications

Learn more about improving heart health.

The heart PET scan is an invaluable tool, offering information on the blood flow and health of the heart. This test helps doctors assess coronary artery disease, find scar tissue, and evaluate heart function.

A doctor can best advise how a person will need to prepare for this type of imaging. The scan can take a couple of hours. People can contact their doctor or the medical team in charge of their care if they have any concerns about the procedure or results.

Insights from a heart PET scan can empower individuals and their doctors to make informed decisions about cardiac care, leading to better outcomes.

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