PET stands for positron emission tomography, and CT stands for computed tomography. PET/CT cardiac stress testing is a nuclear imaging test that evaluates blood flow to the heart muscle at rest and during medication-induced stress. It can help investigate stable chest discomfort or shortness of breath and guide care for coronary artery disease.
What does a PET/CT stress test show?
A small amount of radioactive tracer is given through an intravenous (IV) line in a vein. PET images show its distribution in the heart muscle. Comparing rest and stress images helps identify areas with reduced blood supply. The study can also assess pumping function.
Some PET protocols measure myocardial blood flow and myocardial blood flow reserve: how much blood flow increases with stress. These measurements can add information about the coronary circulation, including smaller vessels. A low flow reserve requires interpretation alongside the images, symptoms, and medical history; it does not by itself identify one particular blockage.
The CT component helps the imaging team align and correct the PET images. It is not the same as a coronary CT angiogram. Ask whether a separate calcium score is included. This guide concerns perfusion stress testing; PET studies for inflammation or heart-muscle viability may use different tracers and preparation.
What happens during the visit?
The team reviews your history, places an intravenous (IV) line in a vein and electrocardiogram (ECG) patches on the skin, and monitors your heart rhythm and blood pressure. You lie on a scanner table for the images. PET perfusion testing commonly uses medication to increase coronary blood flow rather than treadmill exercise.
The stress medicine may briefly cause flushing, breathlessness, headache, or chest discomfort. Tell the staff immediately about any symptoms. The team monitors you during stress and recovery. Confirm the total appointment time with the testing center.
What should I confirm before the test?
- Caffeine and fasting: Ask exactly when to stop caffeine and food, and what fluids are permitted. Mention decaffeinated drinks, chocolate, supplements, and caffeine-containing medicines.
- Medicines: Provide your full list, including inhalers and theophylline. Ask which medicines to take. Do not stop prescriptions on your own.
- Diabetes: Obtain a plan for meals and diabetes medicines if fasting is required.
- Safety: Report asthma or wheezing, previous test reactions, pregnancy or possible pregnancy, and breastfeeding before the appointment.
Follow the testing center’s written instructions for your exact protocol. If you do not have them, call before traveling. Ask about medicines, recovery, activity, and any breastfeeding precautions.
What happens after the test?
The ordering clinician reviews the report with your symptoms and other findings. Ask what the result answers and whether it changes your medicines, activity advice, or need for another test. PET/CT involves radiation; the team weighs that exposure and the risks of stress medicine against the expected benefit.
Use our questions before a planned test worksheet and read the overview of stress-testing options.
Call 911 for possible heart-attack symptoms, including new severe or persistent chest pressure. Do not wait for a scheduled test.
Sources and further reading
- American Heart Association: PET and SPECT imaging
- RadiologyInfo: Cardiac nuclear medicine
- ASNC: PET myocardial blood flow practice points
This guide provides general education and does not replace individualized instructions from your care team. Back to Test Instructions.
About this patient guide
This guide provides general education to help you prepare for a conversation with your care team. The sources and further reading link to additional information from medical organizations.
A medical-review date refers to review of the clinical information. Wording, formatting, and link updates do not by themselves change that date. Your own care depends on your symptoms, medical history, and discussion with your clinician.
Found something unclear? Contact our office. Please do not include private medical details in the general appointment form.
