WHAT IS NUCLEAR CARDIOLOGY SCAN?
A nuclear cardiology scan is a non-invasive method to determine the flow of blood to the cardiac muscles through a coronary artery. It is also known as cardiac nuclear stress scans or heart perfusion imaging tests. This method helps in the diagnosis of several diseases of the heart. Expert technicians or radiologists perform this diagnostic test. Nuclear cardiology scan makes use of a radioactive tracer and gamma camera. The doctor uses several types of radioactive tracers in nuclear cardiology scans. The scan also helps in determining the functional status of your heart.
WHEN DO YOU REQUIRE A NUCLEAR CARDIOLOGY SCAN?
There are several reasons when a doctor may recommend nuclear cardiology scan. Some of them are:
Damaged heart muscles: A nuclear cardiology scan helps the doctor evaluate the damaged heart muscles that may cause a heart attack. Doctors, through the results, analyze the risk of future heart attack and manage it accordingly.
Blocked artery: The methods also help in diagnosing coronary artery disease. The doctor, through the nuclear scan, also evaluates the extent of blockage in the artery. The results of the scan also help the doctor to determine the impact of coronary ischemia or calcium deposition on the heart muscles.
Prediction of procedural benefits: The doctor, through the nuclear scan, predicts if the additional procedure, such as bypass surgery or cardiac catheterization may benefit the patients.
Treatment efficacy: A nuclear cardiology scan also analyzes the efficacy of the cardiac procedure, such as bypass surgery or cardiac catheterization.
Type of treatment: Through the nuclear cardiology scan, the doctors create the treatment strategy. The doctor can decide if the patients require medicines, cardiological intervention, or lifestyle changes to manage the cardiac disease.
WHAT ARE THE VARIOUS TYPES OF NUCLEAR CARDIOLOGY SCANS?
Following are some of the types of nuclear cardiology scans:
Cardiac SPECT (single-photon emission computed tomography): It is also known as myocardial perfusion testing. This test helps to evaluate the flow of blood in the coronary artery. Doctors perform the test after the patient has completed a treadmill exercise or is having a chemical or pharmacological stress test.
MUGA (Multiple Gated Acquisition) Scan: This test is also known as radionuclide cineangiograms. The doctor performs this test to determine ejection fraction. Ejection fraction is the amount of blood that the ventricles pump out of the ventricles.
Viability Imaging: A heart attack may damage the muscles. Some of the muscles are permanently damaged. However, the other regions are injured but not damaged permanently. These regions are known as hibernating regions. The doctors cannot view these regions through an echocardiogram. Viability imaging, through thallium tracer, helps the doctor in identifying those regions and predict if treating those regions may have an improvement in heart function.
Amyloid Pyrophosphate (PYP) Imaging: Cardiac amyloid increases the risk of heart attack and heart muscle weakening. Determining the type of amyloid, whether transthyretin proteins or misfolded light chain proteins, help to develop a treatment strategy and predict prognosis. SPECT with Tc-99m PYP is an accurate, non-invasive procedure for diagnosing TTR-type cardiac amyloid.
HOW SHOULD I PREPARE FOR A NUCLEAR CARDIOLOGY SCAN?
SPECT takes around three to four hours, while PET takes two to three hours for completion. Follow all the instructions of your doctor. Avoid taking products that contain caffeine, such as coffee, chocolate, etc., 24 hours before the procedure. Your doctor may also advise you to avoid eating two to three hours before the procedure. You can drink water. Inform the doctor about all the medicines you are taking. The doctor may withdraw beta-blockers for 48 hours and calcium channel blockers for 24 hours before the procedure.
HOW THE DOCTOR PERFORMS A NUCLEAR CARDIOLOGY SCAN?
The doctor performs the myocardial perfusion test in two steps. The first step is the resting scan, while the second step is the stress scan. During the first step, the doctor injects the radioactive tracer into your vein. The heart muscle takes this radioactive material in the ratio of the total blood flow. The doctor advises you to rest for 40 minutes. After this, the doctor will scan the heart through the gamma camera and take the images.
During the stress test, the doctor asks you to run on the treadmill. For those who cannot run on the treadmill, the doctor injects a drug in the vein that acts on the blood vessels like exercise. Once the arteries are dilated, the doctor injects the radioactive tracer into the vein. After 40 minutes, the doctor takes the images of the heart through a gamma camera. He then compares the rest scan and stress scan images to determine the blockage and evaluate the functional status of the heart.