- A coronary calcium scan is a test that looks for specks of calcium in the walls of the coronary (heart) arteries. These specks of calcium are called calcifications (KAL-sih-fih-KA-shuns).
- Calcifications in the coronary arteries are an early sign of coronary heart disease (CHD). CHD is a disease in which a waxy substance called plaque (plak) builds up in the coronary arteries. As the plaque absorbs calcium, the plaque becomes hard (hardening of the arteries).
- Over time, plaque can harden or rupture (break open). Hardened plaque narrows the coronary arteries and reduces the flow of oxygen-rich blood to the heart. This can cause chest pain or discomfort called angina (an-JI-nuh or AN-juh-nuh).
- If the plaque ruptures, a blood clot can form on its surface. A large blood clot can mostly or completely block blood flow through a coronary artery. This is the most common cause of a heart attack. Over time, ruptured plaque also hardens and narrows the coronary arteries.
- You don’t need to take any special steps before having a coronary calcium scan. However, your doctor may ask you to avoid caffeine and smoking for 4 hours before the test.
- For the scan, you’ll remove your clothes above the waist and wear a hospital gown. You also will remove any jewelry from around your neck or chest.
HOW THE PROCEDURE IS PERFORMED
- A coronary calcium scan is done in a hospital or outpatient office. The x-ray machine that’s used for the scan is called a computed tomography (CT) scanner.
- There are no needles or medications needed for this test. There may be dietary restrictions, which you will be informed of while your appointment is being scheduled.
- The technician who runs the scanner will clean areas of your chest and apply sticky patches with sensors called electrodes.
- The patches are connected to an EKG (electrocardiogram) machine.
- The EKG will record your heart’s electrical activity during the scan. This makes it possible to take pictures of your heart when it’s relaxed between beats.
- The CT scanner is a large machine that has a hollow, circular tube in the center. You’ll lie on your back on a sliding table.
- The table can move up and down, and it goes inside the tunnel-like machine.
- The table will slowly slide into the opening in the machine. Inside the scanner, an x-ray tube will move around your body to take pictures of your heart. The technician will control the CT scanner from the next room. He or she will be able to see you through a glass window and talk to you through a speaker.
- The technician will ask you to lie still and hold your breath for short periods while each picture is taken. You may be given medicine to slow your heart rate. This helps the machine take clearer pictures of your heart. The medicine will be given by mouth or injected into a vein.
- The coronary calcium scan will take about 10-15 minutes, although the actual scanning will take only a few seconds. During the test, the machine will make clicking and whirring sounds as it takes pictures. The scan causes no discomfort, but the exam room might be chilly to keep the machine working properly.
- If you get nervous in enclosed or tight spaces, you might receive medicine to help you stay calm. Your head will remain outside the opening in the machine during the test.
AFTER THE PROCEDURE
- You’ll be able to return to your normal activities after the coronary calcium scan is done. Your doctor will discuss the results of the test with you.
- Coronary calcium scans have very few risks. The test isn’t invasive, which means that no surgery is done and no instruments are inserted into your body.
- Unlike some CT scans, coronary calcium scans don’t require an injection of contrast dye to make your heart or arteries visible on x-ray images.
- Coronary calcium scans involve radiation, although the amount used is considered small. Electron beam computed tomography (EBCT) uses less radiation than multidetector computed tomography (MDCT).
- In either case, the amount of radiation is about equal to the amount of radiation you’re naturally exposed to in a single year.
- There may be other possible risks. When you meet with your doctor, please ask questions to make sure you understand why the procedure is recommended and what the potential risks are.