A positron emission tomography (PET) scan of the heart is an imaging test that uses specialized dye to allow doctors to view problems with the heart.
The dye contains radioactive tracers, which concentrate on areas of the heart that may be injured or diseased. Using a PET scanner, your doctor can spot these areas of concern.
A heart PET scan is typically an outpatient procedure, meaning you will not have to stay at the hospital overnight. This is typically a same-day procedure.
Your doctor may order a heart PET scan if you are experiencing symptoms of heart trouble. Symptoms of heart trouble include:
- irregular heartbeat (arrhythmia)
- pain in the chest
- tightness in the chest
- trouble breathing
- profuse sweating
Your doctor may also order a heart PET scan if other heart tests, such as an echocardiogram (ECG) or cardiac stress test, do not provide your doctor with enough information. They can also be used to track the effectiveness of heart disease treatments (NLM).
While the scan does use radioactive tracers, the exposure is minimal. According to the Mayo Clinic, the exposure level is too low to affect the normal processes of the body and so is not regarded as a major risk (Mayo).
Other risks of a heart PET scan include:
- uncomfortable feelings if you are claustrophobic
- slight pain from the needle prick
- muscle soreness from laying on the hard exam table
This test’s benefits far outweigh the minimal risks.
However, radiation may be harmful to a fetus or newborn, so women who are pregnant, who think they may be pregnant, or who are nursing should discuss with their doctor whether this test is necessary. Your doctor may recommend another form of testing.
Your doctor will provide you with complete instructions about preparing for your heart PET scan. Alert your doctor to any medications you may be taking, whether they are prescription, over-the-counter, or even nutritional supplements.
You may be instructed not to eat anything for up to eight hours before your procedure. You will, however, be able to drink water.
If you are pregnant, believe you may be pregnant, or are nursing, tell your doctor. This test may be unsafe for your unborn or nursing child.
Also, tell your doctor about any medical condition you have. For example, diabetics have special instructions for the test, as the fasting beforehand could affect their blood sugar levels.
Immediately before the test, you may be asked to change into a hospital gown and to remove all of your jewelry.
First, you will be seated in a chair. A technician will then insert an IV into your arm. Through this IV, a special dye with radioactive tracers will be injected into your veins. Your body needs time to absorb the tracers, so you will wait about an hour. During this time, a technician will affix electrodes for an electrocardiogram (ECG) onto your chest so your heart rate can also be monitored.
Next, you will undergo the scan. This involves lying on a narrow table attached to the PET machine. The table will glide slowly and smoothly into the machine. You will have to lie as still as possible during the scans. At certain times, the technician will tell you to remain motionless. This allows the clearest pictures to be taken.
When the correct images are stored in the computer, you will be able to slide out of the machine. The technician will then remove the electrodes, and the test is finished.
It’s a good idea to drink plenty of fluids after the test to help flush the tracers out of your system. Generally, all tracers are naturally flushed out of your body after two days.
A trained specialist in reading PET scans will then interpret the images and share the information with your doctor. Your doctor will then go over the results with you at a follow-up appointment.
A heart PET scan provides your doctor with a detailed image of your heart. This allows him or her to see which areas of the heart are experiencing decreased blood flow and which areas are damaged or contain scar tissue.
Coronary Artery Disease (CAD)
Using the images, the doctor may diagnose coronary artery disease (CAD), which means that the arteries that carry blood and oxygen to your heart have become hardened, narrowed, and/or blocked. He or she might then order an angioplasty or, in more serious cases, coronary artery bypass surgery.
An angioplasty involves placing a thin catheter (soft tube) with a balloon at its tip through a vessel until it reaches the narrowed, blocked artery. Once the catheter is in the desired location, the doctor will inflate the balloon. This balloon will press the plaque (the cause of the blockage) against the artery wall. Blood can then flow smoothly through the artery.
In more serious cases of CAD, coronary bypass surgery will be ordered. This surgery involves attaching a part of a vein from your leg or an artery from your chest or wrist to the coronary artery above and below the narrowed or blocked artery. This newly attached vein or artery will then allow blood to “bypass” the damaged artery.
Heart failure is diagnosed when the heart is no longer able to provide enough blood to the rest of the body. A severe case of coronary artery disease is often the cause.
Heart failure can also be caused by:
- cardiomyopathy (an infection that causes weakening of the heart muscles)
- congenital heart disease
- heart attack
- heart valve disease
- abnormal heart rhythms (arrhythmias)
- diseases such as emphysema, overactive or underactive thyroid, or anemia
In the case of heart failure, your doctor may prescribe medications and/or order surgery. He or she may order an angioplasty, coronary bypass surgery, or heart valve surgery. Your doctor may also want to insert a pacemaker or a defibrillator (devices that maintain a regular heartbeat).