A computed tomography angiogram (CT angiogram) is a test that uses X-rays to provide detailed pictures of the heart and the blood vessels that go to the heart, lung, brain, kidneys, head, neck, legs, and arms.
A CT angiogram can show whether a blood vessel is blocked, where the blockage is, and how big the blockage is. The test can also show whether there is a bulge (aneurysm) or a buildup of fatty material called plaque in a blood vessel.
During a CT angiogram, you lie on a table that passes through a doughnut-shaped opening in the scanner. A special dye (contrast material) is put in a vein (IV) in your arm or hand to make the blood vessels easier to see on the scan. If you are having a CT angiogram to look at your heart and the blood vessels that go to it (coronary arteries), you may be given a medicine called a beta-blocker to slow your heart rate during the test.
A CT angiogram is done to look for:
Before you have a CT angiogram, tell your doctor if you:
You may be asked not to eat or drink anything for several hours before the test. Your doctor will let you know if there are certain foods or liquids you should avoid.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?).
A CT angiogram usually takes 30 to 60 minutes but could take up to 2 hours.
Drink plenty of fluids for 24 hours after the test to help flush the dye out of your body.
A CT angiogram is not painful. The table you lie on may feel hard, and the room may be cool. It may be hard to lie still during the test.
When the dye is given, you may:
Tell the technologist or your doctor how you are feeling.
The risk from having a CT angiogram is small. But some risks include:
The dye may also cause problems for people who take metformin (such as Glucophage) to control their diabetes. Your doctor will tell you when to stop taking metformin and when to start taking it again after the test so you won't have a problem.
Results of a CT angiogram are usually ready for your doctor in 1 to 2 days.
The blood vessels look normal, and blood flow is not reduced.
The heart and heart valves look normal.
One or more blood vessels are partially or completely blocked.
The heart or the heart valves look abnormal.
A narrow spot in an artery may suggest that a blood clot or a deposit of fat and calcium is reducing blood flow through the blood vessel.
An abnormal pattern of blood vessels may be a sign that a tumor is present.
You may not be able to have a CT angiogram if:
A CT angiogram is a less invasive test than a standard angiogram. A standard angiogram involves threading a thin tube called a catheter through an artery in your arm or leg up to the area being studied. But with a CT angiogram, no tubes are put in your body. To learn more, see the topic Angiogram.
If your doctor sees that one or more of your blood vessels are blocked, you may need a standard angiogram anyway to double-check the abnormal results from the CT angiogram. This is more likely to happen if your doctor is considering surgery to treat the blockage.
If your doctor finds a major blockage in one of your blood vessels during a CT angiogram, you won't be able to get an immediate angioplasty to clear the blockage. You will need a separate procedure. But if you have a standard angiogram and the doctor finds a major blockage, he or she can perform an angioplasty during the angiogram.
Certain things can make CT angiograms hard to read. For example, a fast heart rate may make it hard to get a clear picture of the coronary arteries. Or a large buildup of calcium may show a narrowing of the arteries when there isn't one (false-positive) or show that the arteries are fine when they are not (false-negative). But with a standard angiogram, these things don't interfere with the test.
Another test, called a coronary calcium scan, also uses a CT scan to show how much calcium is in your coronary arteries. This test is for people who have no symptoms of heart disease but may be at risk for getting it. To learn more, see the topic Coronary Calcium Scan.
If your doctor suggests a CT angiogram, you may want to ask what kind of scanner will be used. In most cases, a 16– or 64–multi-slice (or multi-detector) CT scanner is used for the CT angiogram. These scanners provide more detailed images of the blood vessels and organs in less time than other imaging tests. But they may not be available in all medical centers.
- Einstein AJ, et al. (2007). Estimating risk of cancer associated with radiation exposure from 64-slice computed tomography coronary angiography. JAMA, 298(3): 317–323.
Other Works Consulted
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- Bluemke, D, et al. (2008). Noninvasive coronary artery imaging: Magnetic resonance angiography and multidetector computed tomography angiography. A scientific statement From the American Heart Association Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention, and the Councils on Clinical Cardiology and Cardiovascular Disease in t
- Budoff M, et al. (2006). Assessment of coronary artery disease by cardiac computed tomography: A scientific statement from the American Heart Association Committee on Cardiovascular Imaging and Intervention, Council on Cardiovascular Radiology and Intervention, and Committee on Cardiac Imaging, Council on Clinical Cardiology. Circulation, 114(16): 1761–1791.
- Einstein A. (2009). Radiation Protection of Patients Undergoing Cardiac Computed Tomographic Angiography. JAMA, 301(5): 545-547.
- Mark DB, et al. (2010). ACCF/ACR/AHA/NASCI/SAIP/SCAI/SCCT 2010 expert consensus document on coronary computed tomographic angiography. Circulation, 121(22): 2509–2543.
- Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
- Taylor AJ, et al. (2010). ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 – Appropriate use criteria for cardiac computed tomography. Journal of the American College of Cardiology, 56(22): 1864–1894.
|Primary Medical Reviewer||Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology|
|Specialist Medical Reviewer||George Philippides, MD - Cardiology|
|Last Revised||June 13, 2012|
Last Revised: June 13, 2012
Author: Healthwise Staff
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