Computerized tomographic angiography, also called CTA or CT angiography, uses x-rays and computers to create detailed images of the blood vessels and the blood flow within them. CTA can be performed to evaluate many of the body’s arterial systems, such as the heart, the brain, or the blood vessels coursing through the chest, abdomen and pelvis.
How Does It Work?
Contrast dye is injected into the blood vessels to make it easier to view them. Radiation is then beamed at the area of the body that is being tested, and a detector opposite the source of the radiation beam translates the radiation into images. These images are taken of different views of the same part of the body and compiled by a computer into three-dimensional (3-D) images.
How Is It Performed?
Before a CTA, you will be asked not to eat or drink for about four hours. You should ask your doctor or nurse practitioner about continuing to take your medications before the examination. If you are not already on medications to slow down your heart rate, your doctor may opt to administer beta blockers, a type of medication, to slow your heart rate to get a better image during the test.
Immediately before the test is performed, you will change into a hospital gown and remove all jewelry and other metal objects from your body. These can interfere with the x-rays. Plan on the procedure taking 20 minutes to one hour to complete.
You will need to lie very still for the best quality images. The technician may ask you to hold your breath for 10 to 25 seconds at a time because any movement, even breathing, can blur the images.
During the test, a contrast dye is injected into a vein in your hand or arm. As the dye flows through your blood stream, x-ray images are taken of the artery system under evaluation, which highlights the blood vessels and any blockages. A computer converts the x-ray images into three-dimensional (3-D) images.
Once the CTA is complete, you can go back to your normal routine immediately. Doctors advise drinking water and other fluids to speed the elimination of the dye from your body.
Is It Safe?
Most reactions to CTA are due to the contrast dye. Most people experience a harmless sensation of warmth that passes quickly. If you have an allergic reaction, you may experience flushing, itching, and, rarely, trouble breathing and swallowing. Redness, swelling and pain may occur if the dye leaks under your skin where it is injected. Depending on various factors, dye can also damage kidney function, though kidney failure is very rare. If you have diabetes, are on medications for diabetes or have known kidney problems, be sure to discuss these factors with your doctor prior to the CTA test. You should mention iodine allergy to your healthcare providers before receiving intravenous contrast dye.
CTA carries some radiation risk, as do all x-ray imaging tests. Operational controls and professional standards are in place in hospitals to reduce the risk of radiation exposure beyond very small doses. Typically, the main concern is to reduce lifetime radiation exposure. That is, CTA should only be ordered when the benefits of gathering the images are clear and cannot be achieved through a method that does not use ionizing radiation. For more about radiation and imaging for cardiovascular disease diagnosis, see SecondsCount Guide to Radiation Safety in Medical Testing.
Questions to Ask Your Doctor About CTA
The following questions can help you talk to your physician about undergoing computerized tomographic angiography (CTA). Consider printing out or writing down these questions and taking them with you to your appointment. Taking notes can help you remember your physician’s response when you get home.
- What will CTA tell us about my cardiovascular health?
- What are the possible benefits of CTA?
- What are my individual risks from having CTA performed?
- How much radiation will I be exposed to during the test?
- What happens next if the CTA test shows something that needs further examination?
- How often is a CTA test incorrect, and what are common reasons for it being incorrect?
Please print this list of questions here. Take them with you to the doctor and share them with friends and loved ones when you are encouraging them to see their doctors.