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Computed Tomography Angiography (CTA)

(CTA)

What is a CTA?

CT angiography is a type of medical exam that combines a CT scan with an injection of a contrast media to produce pictures of blood vessels and tissues in a part of your body. The contrast is injected through an intravenous (IV) line started in your arm or hand.

A computerized tomography scan, or CT scan, is a type of X-ray that uses a computer to make cross-sectional images of your body. The media injected to perform CT angiography is called a contrast material because it "lights up" blood vessels and tissues that are being studied.

What are the reasons for a CTA?

You may need this medical test if you have an abnormality that involves the blood vessels of your brain, heart, lungs, kidneys, or other parts of your body. Doctors may use the information from this test to learn more about your condition and to decide the best way to treat you. Some reasons to have a CT angiogram include:

  • To find an aneurysm (a blood vessel that has become enlarged and may be in danger of rupturing)

  • To find blood vessels that have become narrowed by atherosclerosis (fatty material that forms plaques in the walls of arteries)

  • To find abnormal blood vessel formations inside your brain

  • To identify blood vessels damaged by injury

  • To find blood clots that may have formed in your leg veins and traveled into your lungs.

  • To evaluate a tumor that is fed by blood vessels

Information from CT angiography may help prevent a stroke or a heart attack. This type of test may also help your doctor plan cancer treatment or prepare you for a kidney transplant. Your doctor may have other reasons for ordering this test.

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What are the risks of a CTA?

There is always a slight risk for cancer from repeated exposure to radiation, but the benefits of getting an accurate diagnosis generally outweigh the risks. The amount of radiation used during CT angiography is considered minimal, so the risk for radiation exposure is low. No radiation remains in your body after a CT scan.

Other risks include:

  • Allergic reactions. Always let your radiologist know if you have any history of allergies or an allergy to contrast material. Reactions to contrast are uncommon. If you have any history of allergic reactions, you may be given medication to lessen the risk for an allergic reaction before the test.

  • Tissue damage. If a large amount of contrast material leaks around your IV site, it can irritate your skin or the blood vessels and nerves just under your skin. It is important to tell your radiologist or radiology technician if you have any pain when the contrast material is injected through your IV.

Angiography contrast material can damage your kidneys, so you may not be able to have this test if you have severe kidney disease or diabetes.

If you are breastfeeding, you may want to wait for 12 to 24 hours after this test before nursing your baby. If you are pregnant or suspect that you may be pregnant, you should notify your doctor or radiology technician.

There may be other risks, depending on your specific medical condition. Be sure to discuss any concerns with your doctor or radiology technician before the procedure.

How do I prepare for a CTA?

PRECAUTIONS: If you are pregnant or think you may be pregnant, please check with your doctor before scheduling the exam. Other options will be discussed with you and your doctor.

CLOTHING: You may be asked to change into a patient gown. If so, a gown will be provided for you. A lock will be provided to secure all personal belongings. Please remove all piercings and leave all jewelry and valuables at home.

CONTRAST MEDIA: CT scans are most frequently done with and without a contrast media. The contrast media improves the radiologist's ability to find structures that are abnormal.

  • Some patients should not have an iodine-based contrast media. If you have problems with your kidney function, please inform us in advance. We may be able to perform the scan without the contrast media or may be able to find an alternate imaging exam.

  • You will be asked to sign a consent form that will detail the risks and side-effects associated with contrast media injected through an intravenous (IV) line (small tube placed in a vein).

ALLERGY: Please inform the access center representative when you schedule your scan if you have had an allergic reaction to any contrast media. IV contrast will not be administered if you have had a severe or anaphylactic reaction to any contrast media in the past. Mild to moderate reactions warrant a plan that includes taking medication prior to the CT examination. These plans will be discussed with you in detail when you schedule your exam. Any known reactions to a contrast media should be discussed with your personal physician.

EAT/DRINK: If your study was ordered without contrast, you can eat, drink and take your prescribed medications prior to your exam. If your doctor orders a CT scan with contrast, do not eat anything three hours before your CT scan. You are encouraged to drink clear liquids. You may also take your prescribed medications prior to your exam.

  • If you are undergoing a chest CTA, do not consume any caffeine or exercise three hours prior to your appointment.

DIABETICS: Diabetics should eat a light breakfast or lunch three hours prior to the scan time. Depending on your oral medication for diabetes, you may be asked to discontinue use of the medication for 48 hours after the CT examination. Detailed instructions will be given following your examination.

MEDICATION: All patients can take their prescribed medications as usual.

Based on your medical condition, your doctor may request other specific preparation. 

What happens during a CTA?

You may have this exam done at the hospital or at another outpatient facility. The CT scanner is a large machine with a tunnel that the examining table passes in and out of. Procedures may vary depending on your condition and your doctor's practices.

  • You may be asked to change into a patient gown If so, a gown will be provided for you. A locker will be provided to secure all personal belongings. Please remove all piercings and leave all jewelry and valuables at home.

  • You will lie on a scan table that slides into a large, circular opening of the scanning machine. Pillows and straps may be used to prevent movement during the procedure.

  • The technologist will be in another room where the scanner controls are located. However, you will be in constant sight of the technologist through a window. Speakers inside the scanner will enable the technologist to communicate with and hear you. You may have a call button so that you can let the technologist know if you have any problems during the procedure. The technologist will be watching you at all times and will be in constant communication.

  • As the scanner begins to rotate around you, X-rays will pass through the body for short amounts of time. You will hear clicking sounds, which are normal.

  • The X-rays absorbed by the body's tissues will be detected by the scanner and transmitted to the computer. The computer will transform the information into an image to be interpreted by the radiologist.

  • It will be important that you remain very still during the procedure. You may be asked to hold your breath at various times during the procedure.

  • If contrast media is used for your procedure, you may feel some effects when the contrast is injected into the IV line. These effects include a flushing sensation, a salty or metallic taste in the mouth, a brief headache, or nausea and/or vomiting. These effects usually last for a few moments.

  • You should notify the technologist if you feel any breathing difficulties, sweating, numbness or heart palpitations.

  • When the procedure is complete, you will be removed from the scanner.

  • If an IV line was inserted for contrast media, the line will be removed.

While the CTA exam itself causes no pain, having to lie still for the length of the procedure mgiht cause some discomfort or pain, particularly in the case of a recent injury or invasive procedure such as surgery. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.

What happens after a CTA?

If contrast media was used during your procedure, you may be monitored for a period of time for any side effects or reactions to the contrast, such as itching, swelling, rash or difficulty breathing.

If you notice any pain, redness, and/or swelling at the IV site after you return home following your CTA scan, you should notify your doctor as this could indicate an infection or other type of reaction.

Otherwise, there is no special type of care required after a CTA scan. You may resume your usual diet and activities unless your doctor advises you differently. Your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.

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