A cardiac PET scan is a diagnostic imaging procedure that uses radioactive substances to visualize the blood flow to the heart and the functioning of the heart muscles. A cardiac PET scan stress test is more accurate in assessing blood flow (perfusion) defects and evaluating the functioning of the left ventricle.
A cardiac PET scan is an elective procedure.
Some of the common indications for a cardiac pet scan include:
Myocardial perfusion imaging is recommended for the following conditions:
A cardiac pet scan is usually done after an echocardiogram or a cardiac stress test, especially if the results from these tests are inconclusive or need further evaluation.
Before performing a cardiac PET stress test, the following may be done
Before the start of the procedure, an ECG is performed, an IV line is inserted, and a radiotracer is injected through it. The radiotracer may be thallium (TI-201) or technetium (Tc-99). After 20-45 minutes, the individual is moved to the PET scan machine room, allowing the radiotracer to be absorbed and circulate in the body. The individual then lies on a table that slides into the cardiac PET scan machine. The machine has a rotating gamma camera that captures images of the coronary arteries and heart muscle. A vasodilator may be administered to study the heart's response to the drug, and additional images are taken. ECG recordings are also taken during the procedure. Once the images are captured, and the testing is complete, the table is moved out of the PET scan machine, and the ECG leads and IV line are removed.
As physical activity and exercise place additional stress on the heart muscle, increase the heart rate and blood pressure, and increase the requirement of blood flow to it, a stress test is a procedure that can induce ischemia (absence of blood flow) in the heart muscle if there is a presence of coronary artery disease. A cardiac PET scan stress test may be done by making the individual perform physical activity (such as cycling or walking on a treadmill) to increase the heart activity while monitoring the ECG and the blood pressure and then injecting the radiotracer to capture images of the blood flow and the heart muscle. The radiotracer is injected at the peak of exercise or shortly after a drug to simulate physical activity is injected. Images are taken immediately after the radiotracer injection and again after a gap of 3-4 hours (called delayed imaging). Areas of the heart muscle at risk of damage are filled with the radiotracer in the delayed imaging, while dead heart tissue does not take up any radiotracer (called a fixed defect). This helps to differentiate between the areas of the heart that are damaged beyond repair due to a previous myocardial infarction (heart attack) and those at risk of damage due to a future myocardial infarction.
A cardiac PET scan is an outpatient procedure, individual can leave after the test is completed. Soreness at the IV line insertion site and in the back muscles may be noticed. The reports of a cardiac PET stress test are typically available for interpretation by attending specialists within a day or two after the procedure.
There are no complications after a cardiac PET scan which is a very safe procedure.
Cardiac PET scans are safe procedures, and no complications are seen. They are useful in detecting the severity and extent of known or suspected coronary artery disease and the after-effects of a heart attack.
Hospitalization is not required for a cardiac PET scan.