Side Effects and Risks of CT Angiogram
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Side Effects

Side Effects and Risks of CT Angiogram

When considering a CT-Angiogram imaging study, it is important to consider the associated risks.  All computed tomography scans carry the risk of radiation exposure, and a CT angigoram also carries the risk of a reaction to contrast media that is used to highlight the coronary arteries.


CT angiograms produce "ionizing radiation" in the process of creating an image, which can be harmful to the body.  Computed Tomography technology is based on x-rays, and works by capturing x-ray images from multiple angles and using these to re-create a three dimensional image.  Overall, the risk of radiation is relatively low.  In fact, all humans are actually exposed to radiation through "cosmic rays."   Radiation places patients at a higher risk for cancer, however, and thus a CT angiogram should only be completed if there is a good medical reason for the scan.  At the present time, a CT angiogram is not recommended for routine prevention practice. 

Radiation is especially harmful to an unborn child, and pregnant women should not have a CT scan due to this risk.  You should inform your physician if you feel that you may be pregnant or if you are breast feeding.


A CT angiogram uses a "contrast agent" to make the arteries and veins look brighter on the scan.  Two of the main side effects of contrast are allergic reactions and damage to kidneys.  Contrast allergies are relatively rare, but may be serious if they occur.  Your physician will ask about your allergies to try to minimize this risk.  In addition, there should always be a physician present during the scan in case an allergic reaction occurs. 

Contrast may also be damaging to kidneys.  Contrast does not usually affect normal kidneys, but patients with kidney problems may be damaged by contrast material.  Your physician will ask you about any kidney problems.  In addition, your physician will look at a set of lab values to ensure that you are not at high risk for damage to your kidneys.  Patients with an elevated creatinine level are at high risk for kidney damage.  Many physicians use 1.2 to 1.5 as a basic guideline, where a CT scan is generally contraindicated if the level is higher than this.

Your physician may also use additional steps to ensure that your kidneys are not affected by the contrast used in the scan.  These include certain drugs that prevent the toxic effect of contrast and adequate hydration before the scan.

Should you have a CT Scan?

A recent article in Time magazine asks the question: Should you have a CT scan?  The article discusses a recent study published in the Journal of the American Medical Association.  Overall, the article notes that there is a much greater risk of cancer from radiation during the scan if the patient is younger.  For example, the relative risk of getting cancer is 0.02% for an 80-year old man, but 1% for a 20-year-old female. 

As the article points out, you should always speak with your physician before obtaining a CT Angiogram to make sure that the benefits of disease diagnosis outweigh the risks associated with the exam.

Useful Links :
    • Computed Tomography Info from Medline Plus
    • RSNA (See section on benefits and risks)

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