Computed tomography angiography (CTA) is a specialized x-ray that examines blood flow in arteries when they are filled with a contrast material (a substance that makes the blood vessels show on an x-ray). Computed tomography (CT) uses a complex machine to take x-rays from many different views, producing detailed two-dimensional images that can be combined by a computer to form three-dimensional images.

CTA can be used to view blood vessels throughout the body. It is most commonly used to study the:

  • Brain
  • Heart
  • Lungs
  • Kidneys
  • Legs or arms

Blood Vessel in Brain

Blood Flow Brain
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Reasons for Test

This test is used to help doctors identify diseased, narrowed, enlarged, and blocked blood vessels and locate where internal bleeding may be occurring. Some specific uses include:

  • Detecting atherosclerosis]]> (narrowing of the arteries) or an aneurysm (ballooning out of a section of a blood vessel)
  • Examining arteries in the lungs to check for blockage of a blood vessel by a blood clot or other foreign substance
  • Evaluating disease in kidney arteries

Heart Attack

Heart Attack
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Possible Complications

Some possible complications with this test include:

  • Allergic reactions to contrast material
  • Bleeding
  • Kidney damage

There are certain factors that may put you at risk for complications during this test:

  • Allergies—especially to x-ray dye, iodine, medicines, or ]]>certain foods]]>, including shellfish
  • Underlying kidney problems or ]]>diabetes]]>—You may have a higher risk of decreased kidney function from the x-ray dye.
  • Bleeding disorder


What to Expect

Prior to Test

  • Before the test, your doctor will likely ask about:
    • Your medical history
    • Medicines you take
    • Allergies
    • Whether you are pregnant or trying to get pregnant
  • In the days before your test, follow your doctor’s instructions regarding any changes in how you take your medicines and any restrictions on your eating and drinking.
  • At the healthcare facility:
    • A healthcare professional will explain the test and answers any questions you may have.
    • You will remove your clothes and put on a gown or robe.
    • You will remove all jewelry, hair clips, dentures, and other objects that could show on the x-rays and make the images hard to read.

Description of Test

An intravenous line (IV) is placed in a vein, and you will lie down on a narrow table. Pillows and straps may be used to keep you in a certain position. The part of your body that will be studied is moved inside the opening of the CT machine, and a test image is taken. You will be given a small amount of contrast material through the IV to check how long it takes to get to the area to be studied. Next, the IV is connected to an automatic injector and contrast material is injected. Then, the scan begins.

You must stay still during the scan. The technologist may ask you to hold your breath for 10-25 seconds to ensure that the images are not blurred by any movement. It only takes seconds to record all the images needed.

After Test

The images are checked. If needed, some are repeated.

After the procedure, be sure to follow your doctor's instructions. During the hours after the procedure, drink extra fluids to help flush the contrast material from your body.

How Long Will It Take?

20-60 minutes

Will It Hurt?

Although the procedure is not painful, you may feel warm and flushed when contrast material is injected.


The radiologist (a doctor who specializes in working with medical images) will look at the images and report the findings to your doctor, usually within 24 hours. Your doctor will discuss the findings with you and any treatment needed.

Call Your Doctor

After the test, call your doctor if any of the following occurs:

  • Signs of allergic reaction, including flushing, hives]]>, and itching
  • Swollen or itchy eyes
  • Difficulty breathing or a feeling of tightness in your throat
  • Nausea

In case of an emergency, CALL 911 immediately.