Home > Health & Wellness > Health Library > Computed Tomography Angiogram (CT Angiogram)
computed tomography angiogram (CT angiogram) is a test
X-rays to provide detailed pictures of the heart and
the blood vessels that go to the heart, lung, brain, kidneys, head, neck, legs,
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
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
A CT angiogram is done to look
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 is usually done by a
radiology technologist. The pictures are usually read
radiologist. But some other types of doctors may also
review the test results.
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
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
No narrowing, blockage,
bulging (aneurysm), or large buildup of
plaque is seen.
One or more blood vessels are
partially or completely blocked.
The heart or the heart valves
An aneurysm or tear (dissection) in the
aorta is present.
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
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
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
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
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
Blankenstein R (2012). Introduction to noninvasive cardiac imaging. Circulation, 125(3): e267–e271.
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 the Young. Circulation, 118: 586–606.
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: A Report of the American
College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. Journal of the American College of Cardiology, 56(22): 1864–1894.
Current as of:
March 12, 2014
Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology & George Philippides, MD - Cardiology
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