Coronary CT angiography (CTA) 

How is the procedure performed?

A nurse will insert an intravenous (IV) line into a vein in your arm. You may be given a medication, either by mouth or through the IV, to help slow your heart rate. You may also receive nitroglycerin (via spray or a tablet under your tongue) to enlarge your coronary arteries (which may improve the images). You will be positioned on an examination table and electrodes (small, sticky discs) will be attached to your chest and to an electrocardiography (ECG) machine that records the electrical activity of the heart. You will be asked to raise your arms over your head for the duration of the exam. You will then be instructed on how and when to hold your breath. The examination table will move multiple times as the CT scanner obtains the images. During the exam, contrast material (dye) will be given through your IV.

What are the risks and benefits of this heart test?


  • Coronary CTA is not invasive. An alternative test, cardiac catheterization with a coronary angiogram, is invasive, has more complications related to the placement of a long catheter into the arteries and the movement of the catheter in the blood vessels, and requires more time for the patient to recover.
  • A major advantage of CT is that it is able to view bone, soft tissue and blood vessels all at the same time. It is therefore suited to identify other reasons for your discomfort such as an injury to the aorta or a blood clot in the lungs.
  • CT examinations are fast.
  • CT has been shown to be cost-effective for a wide range of medical problems.
  • CT is less sensitive to patient movement than MRI.
  • CT can be performed if you have an implanted medical device of any kind, unlike MRI.
  • No radiation remains in a patient's body after a CT examination.
  • X-rays used in standard CT scans have no immediate side effects.


  • In some people with abnormal kidney function, the contrast material used in CT scanning may worsen kidney function.
  • If a large amount of contrast material leaks out from the vessel being injected and spreads under the skin where the IV is placed, skin damage or damage to blood vessels and nerves, though unlikely, can result. If you feel any pain in your arm at the location of the IV during contrast material injection, you should immediately inform the technologist.
  • The amount of radiation for this procedure varies. See the Safety page for more information about radiation dose.
  • Women should always inform their physician and x-ray or CT technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.
  • CT scanning is, in general, not recommended for pregnant women unless medically necessary because of potential risk to the baby.
  • Manufacturers of intravenous contrast indicate mothers should not breastfeed their babies for 24-48 hours after contrast medium is given. However, both the American College of Radiology (ACR) and the European Society of Urogenital Radiology note that the available data suggest that it is safe to continue breastfeeding after receiving intravenous contrast. For further information please consult the ACR Manual on Contrast Media and its references.
  • The risk of serious allergic reaction to contrast materials for CT examinations is extremely rare, and radiology departments are well-equipped to deal with them. If you have a history of previous reaction to CT contrast, you may be required to take premedication with a steroid prior to the examination to limit risk of a second reaction occurring.
  • Radiation may slightly increase your life time risk of cancer. However, the benefit of an accurate diagnosis will generally outweigh the risk. The amount of radiation is minimized as much as possible.