What Is a Heart CT Scan? A computed tomography scan — commonly called a CT scan or CAT scan — is a test that uses X-rays to view specific areas of your body. These scans use safe amounts of radiation to create detailed images of the body, which can help your doctor to detect any problems. A heart, or cardiac, CT scan is used to view your heart and blood vessels. During the test, a specialized dye will be injected into your bloodstream. The dye is then viewed under a special camera in a hospital or testing facility. A heart CT scan may also be called a coronary CT angiogram if it’s meant to view the arteries that bring blood to your heart. The test may be called a coronary calcium scan if it’s meant to determine whether there is a buildup of calcium in your heart. Advertisement Advertisement Uses Why a Heart CT Scan Is Performed Your doctor may order a heart CT scan to look for certain conditions, including: birth defects in the heart (congenital heart disease) buildup of a hard substance known as lipid plaque that may be blocking your coronary arteries defects or injury to the heart’s four primary valves blood clots within the heart’s chambers tumors in or on the heart A heart CT scan is a common test for people experiencing heart problems, since it allows your doctor to explore the structure of the heart and the adjacent blood vessels without making any incisions. Advertisement Risks The Risks of a Heart CT Scan A heart CT scan carries very few risks. Most of the dyes used for CT scans contain iodine, which is later flushed from the body by the kidneys. If your kidneys have been impacted by disease or infection, such as diabetes, you may need to drink extra fluids after the test to help your kidneys remove the dye. However, newer dyes carry much less risk to the kidneys. As with any X-ray, there is some exposure to radiation. While typically harmless, this is an important issue for women who are pregnant or could be pregnant. The levels of radiation are considered safe for adults — there have been no documented side effects from low levels of radiation — but not for a developing fetus. Advertisement Advertisement Preparation How to Prepare for a Heart CT Scan Your doctor will typically ask you to fast for four to eight hours before the scan. You’ll be able to drink water. However, avoid caffeinated drinks since caffeine can affect your heart rate. You will be required to lie down on a table during the exam, so you may want to wear loose, comfortable clothing. You will also need to remove any jewelry and other metal items from your body, such as piercings. After the test, you will be able drive yourself home. There is no need to arrange for transportation. Advertisement Procedure How a Heart CT Scan Is Performed A heart CT scan is performed in a hospital’s radiology department or a clinic that specializes in diagnostic procedures. You may be given a beta-blocker before the scan. This medication will slow down your heart so that clearer pictures can be taken. You’ll also be given an IV so that the technician can inject the radioactive dye into your arm. Small, sticky discs called electrodes will be placed onto your chest to record the scan. At the start of the scan, you’ll lie down on a bench. The technician may want you to lie in a specific position. He or she may use pillows or straps to ensure that you stay in the correct position for long enough to get a quality image. You may also have to hold your breath during brief individual scans, which last only 10 to 20 seconds. To start the scan, the technician will move the table — via a remote from a separate room — into the CT machine. A CT machine looks like a giant doughnut made of plastic and metal. You will most likely go through the machine several times. Although you will be in the room by yourself, the technician will be able to talk to you via an intercom. After a round of scans, you may be required to wait for a few minutes while the technicians review the images to ensure they are clear enough for your doctor to read. The whole test should take no longer than 10 minutes. Advertisement Advertisement Follow-Up After a Heart CT Scan After the procedure, you’ll be able to leave and go about your day. The dye will naturally work its way out of your body. Drinking more water will help speed up this process. Getting the results from your heart CT scan doesn’t take long. Your doctor or the technician will go over the results with you. Depending on what the images show, your doctor will advise you of any lifestyle changes, treatments, or procedures that need to be done.
Also known as computed tomography; computed axial tomography scan (CAT scan). A cardiac CT scan is a painless imaging test that uses x rays to take many detailed pictures of your heart and its blood vessels. Computers can combine these pictures to create a three-dimensional (3D) model of the whole heart. This imaging test can help doctors detect or evaluate coronary heart disease, calcium buildup in the coronary arteries, problems with the aorta, problems with heart function and valves, and pericardial disease. This test also may be used to monitor the results of coronary artery bypass grafting or to follow up on abnormal findings from earlier chest x rays. Different CT scanners are used for different purposes. A multidetector CT is a very fast type of CT scanner that can produce high-quality pictures of the beating heart and can detect calcium or blockages in the coronary arteries. An electron beam CT scanner also can show calcium in coronary arteries. Your cardiac CT scan may be performed in a medical imaging facility or hospital. The scan usually takes about 15 minutes to complete, but can take more than an hour including preparation time and, if needed, the time to take medicines such as beta blockers to slow your heart rate. Before the test, a contrast dye, often iodine, may be injected into a vein in your arm. This contrast dye highlights your blood vessels and creates clearer pictures. You may feel some discomfort from the needle or, after the contrast dye is injected, you may feel warm briefly or have a temporary metallic taste in your mouth. The CT scanner is a large, tunnel-like machine that has a table. You will lie still on the table, and the table will slide into the scanner. Talk to your doctor if you are uncomfortable in tight or closed spaces to see if you need medicine to relax you during the test. During the scan, the technician will monitor your heart rate with an electrocardiogram (EKG). You will hear soft buzzing, clicking, or whirring sounds when you are inside the scanner and the scanner is taking pictures. You will be able to hear from and talk to the technician performing the test while you are inside the scanner. The technician may ask you to hold your breath for a few seconds during the test. Cardiac CT scans have some risks. In rare instances, some people may have an allergic reaction to the contrast dye. There is a slight risk of cancer, particularly in people younger than 40 years old, because the test uses radiation. Although the amount of radiation from one test is similar to the amount of radiation you are naturally exposed to over one to five years, patients should not receive more CT scans than the number that clinical guidelines recommend. Another risk is that CT scans may detect an incidental finding, which is something that doesn’t cause symptoms now but may require more tests after being found. Talk to your doctor and the technicians performing the test about whether you are or could be pregnant. If the test is not urgent, they may have you wait to do the test until after your pregnancy. If it is urgent, the technicians will take extra steps to protect your baby during this test. Let your doctor know if you are breastfeeding because contrast dye can pass into your breast milk. If you must have contrast dye injected, you may want to pump and save enough breast milk for one to two days after your test or you may bottle-feed your baby for that time. People with asthma, chronic obstructive pulmonary disorder (COPD), or heart failure may have breathing problems during cardiac CT scans if they are given beta blockers to slow their heart rates for this imaging test. Visit CT Scans for more information about this topic. Related reading Aneurysm Asthma Atrial Fibrillation Cardiac MRI Clinical Trials COPD Coronary Angiography Coronary Artery Bypass Grafting Coronary Calcium Scan Coronary Heart Disease Echocardiography Electrocardiogram Heart Attack Heart Failure Pulmonary Embolism