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CT Angiogram
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CT angiography uses a special X-ray machine to check blood flow all over the body. Read this document to learn how the exam works, how to prepare for the exam, how the exam is performed, what to expect during the exam, what will I feel during the exam, and how do I get the results.
What is CT angiography?
CT (computed tomography) angiography (CTA) is an exam that uses a special X-ray machine to view blood flow all over the body.
CT takes pictures from different angles, and then joins them together to show detailed pictures of the vessels.
How does the scan work?
Before the exam, you will receive contrast material, injected into a vein, to make the blood vessel easy to see in the pictures.
During the exam, a rotating device will move around you, making a fanshaped beam of X-rays, while a sensor takes snapshots of the beam after it passes through your body. After the pictures are
taken, a computer displays them in different ways, in crosssectional slices, for example, or as three-dimensional "casts" of the blood vessels.
How should I prepare for the scan?
- Eat your regular diet until 6 hours before your scan. Continue to drink clear liquids (water, juices, tea) until your scan. It is important for you to continue to drink frequently before and after your scan. Drinking water is very helpful in protecting your kidneys. Continue to take your regular medications as prescribed by your doctor.
- Tell the doctor or CT technologist if you have asthma or any allergies to foods or drugs, and what medicines you are currently taking.
- If there is a chance you may be pregnant, tell the CT technologist before the exam.
- You probably won’t have to undress if you are having an exam of the head, neck, arms, or legs, but you must remove any jewelry, hair clips, dentures, and other metal objects that could show up on the X-rays and make them hard to read. If you
must undress, you will be given a gown.
How is the scan performed?
Most of the time for a CTA exam is spent setting up. The scan itself takes only seconds.
- You will be asked questions about things that might cause problems during the exam (such as allergies).
- A dose of contrast material will be then be injected into your arm vein.
- You will then lie down on a narrow table. The part of your body to be scanned will be placed inside the opening of the CT unit.
- A test picture is taken to set the best placement, and a small dose of contrast material is given to see how long it takes to reach the target area.
- The IV is then hooked up to an automatic injector, contrast material is injected, and the scan begins.
- Afterwards, the pictures will be reviewed and, more scans will be
done as needed. - CTA takes about 10 to 25 minutes from the time the actual exam begins. Overall, expect to be in or near the exam room for 20 to 60 minutes.
What will I feel during the scan?
- CT is painless, though you may feel some discomfort from staying still.
- If contrast injection is needed, you may feel discomfort at the injection site.
- You may notice a warm, flushed sensation during the injection of contrast material. You may also notice a metallic taste in your mouth that lasts for about 2 minutes. These reactions are normal, and go away within 1 to 2 minutes.
- Once in a while, a patient will develop itching and hives for up to a few hours after the injection; this can be relieved with medication. Light-headedness or shortness of breath may be due to a more severe allergic reaction – a doctor or nurse will be nearby during the exam to help you, if needed.
- Because CT uses X-rays, you may not have a family member or friend in the CT room during the exam.
- Once enough pictures have been recorded, you will be free to leave. You can eat right away. It is also a good idea to drink plenty of fluids in the first few hours after the exam to help flush contrast material out of your system.
Who interprets the results and how do I get them?
A radiologist skilled in CT scanning will interpret the CT findings. The radiologist will send a detailed report to your primary care or referring doctor, who will give you the results. The radiologist will not discuss the results with you.