CT Coronary Angiograms - What is It for, Risks & How Long It Take

What is a CT angiogram?

A computed tomography (CT) angiogram, or CT angiogram for short, is a non-invasive imaging test used to visualise your tissues and blood vessels.  A CT angiogram uses a technique that combines X-ray technology with intravenous contrast dye to produce detailed 3D images of blood vessels. It helps detect multiple different medical conditions , including plaque buildup, blockages, or structural abnormalities in blood vessels that may affect the blood flow.

What is a CT coronary angiogram?

A computed tomography (CT) coronary angiogram, or CT angiogram for short, is a non-invasive imaging test used to monitor the coronary arteries, which are the arteries that supply blood to the heart. It’s almost identical to how a CT angiogram is performed, with the only exception being its visualisation being focused on the coronary arteries and structures near the heart.

What are the differences between a CT angiogram, standard coronary angiogram and CT coronary calcium scan?

A CT angiogram, a coronary angiogram, and a CT coronary calcium scan are all diagnostic methods used to assess various medical conditions, particularly heart conditions such as coronary heart disease or the risk of heart attacks. However, these three medical procedures have quite a few differences, such as:

Why do I need a CT angiogram?

There are many reasons why your healthcare provider might suggest you get a CT angiogram, such as:

• To find or measure the size of 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 assess your risk of heart disease by identifying and quantifying plaque buildup in the coronary 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

The information provided from a CT angiogram may help prevent a stroke or a heart attack. This type of test may also help your healthcare provider plan cancer treatments and aftercare or prepare you for a kidney transplant. However, your healthcare provider may have other reasons for ordering this test as well.

If you have any concerns relating to your blood vessels or worry about the possibility of heart disease, request an appointment with Thomson Medical to discuss with a specialist for your next course of action.

What are the risks of a CT angiogram?

The following is a list of the risks associated with a CT angiogram:

1. Allergic reactions to contrast dye:

   • Let your healthcare provider and radiologist know if you have any history of allergies to a contrast material, in this case, contrast dye. While it is rare, it is possible to have an allergic reaction to the contrast dye. Antihistamines may be pre-administered by your doctor to reduce the risk of an allergic reaction before the test.

2. Kidney stress:

   • Contrast dye is often safe for kidneys in people with normal to mildly abnormal renal functions. However, it may affect the renal function in patients with severe kidney disease.

3. Minimal exposure to radiation:

   • There will be radiation used during the CT angiography, but it is minimal, so the radiation exposure is low, as modern machines usually emit lower amounts of radiation. No unnecessary radiation remains in your body after a CT scan.

4. Tissue irritation:

   • If a large amount of contrast dye leaks into the tissues around your IV site, it can irritate your skin or the blood vessels and nerves just under your skin. Inform your radiologist if you have any pain when the contrast dye is injected through your IV.

There may be additional risks depending on your individual condition. If you have any concerns, it’s best to discuss them with your healthcare provider or radiology technologist before the test.

How do I prepare for a CT angiogram?

• Preparation includes avoiding caffeine for at least 12 hours, as it can raise your heart rate, resulting in the loss of image quality.

• You may also need to fast for at least 8 hours before the test. You can still drink water during this fasting period. Please check with your healthcare provider for the specific instructions on fasting.

• You will also need to remove any jewellery or accessories before the procedure. You will be asked to change into a hospital gown before the procedure.

• Remember to inform your doctor about any history of allergy, history of problems with your kidney functions, or medications that you take beforehand, as it may affect the procedure and hinder the possibility of getting an accurate diagnosis. 

• If you are pregnant or breastfeeding, inform your doctors immediately, especially if you are concerned about whether the dye used in the test is safe. Usually, very little dye is introduced into your breast milk, and even less is passed down to the baby. If this is a concern, you can store some of your breast milk ahead of time to use it a few days after the test to be safe.

Your healthcare provider may also give you a medicine called a beta blocker, which slows down your heart rate to help the CT scanner take clearer images. Do let them know if you have experienced any adverse effects when taking beta blockers in the past. Additionally, you may also be given nitroglycerine to widen your coronary arteries to help your doctor see more detailed images of your arteries.

However, these are all based on your personal medical conditions. Discussing with your doctor how to prepare beforehand is the best course of action, as they may request other specific preparation protocols that you may need to adhere to.

What happens during a CT angiogram?

Usually, the procedure is carried out in a hospital or at an outpatient imaging facility. 

1. A healthcare professional will place an IV into your hand or arm, and contrast dye will flow through this IV to help your blood vessels show up better in the images. Sticky patches called electrodes will also be attached to your chest to record your heart rate.

2. You’ll lie on a long exam table that slides through the CT scanner while the machine captures images. 

   • If you suffer from claustrophobia or face discomfort when in enclosed spaces, inform your healthcare provider a day before your test. They may provide you with some medicine to help you relax.

3. The healthcare professional will control the CT machine from a separate room, and an intercom system will allow you to communicate with one another. 

   • During the scan, you will need to stay still and hold your breath as directed by the healthcare professional, as movement may cause blurry images.

   • You may hear some whirring and buzzing sounds as the scanner rotates around you. However, the CT angiogram process itself is usually painless. If at any time you experience any pain, do let your doctor know.

Overall, the actual time taken for a CT angiogram may take only a few seconds to a few minutes, but the whole procedure (including the setup time) may take around an hour. You may also have to wait a little longer for the healthcare professional doing the scan to check the images to ensure that they are acceptable.

Afterwards, the IV will be removed, and you will need to drink plenty of water to flush out the contrast dye from your body. The CT scan usually does not cause any complications, and most patients are able to resume normal activities immediately.

CT angiogram results

A radiologist will analyse the images and send an official report to the doctor who ordered the exam. Results of a CT angiogram are usually ready for your doctor within 1 to 2 days. Based on the results, your doctor will advise you if you need a follow-up exam or any necessary treatment options.

Normal results

Normal results typically indicate no narrowing, significant blockages, bulging (aneurysm), or large buildup of plaque is detected. Hence, the blood vessels, heart and heart valves all look normal, and the blood flow is not reduced. Thus, if you receive normal results, you should have no cause for concern or worries.

Abnormal results

Abnormalities like the buildup of plaque or narrowing may require further follow-up exams (e.g., invasive angiogram) to further evaluate a potential issue with more views or a special imaging technique or recommended lifestyle adjustments to keep the heart healthy.

Examples of abnormal results are:

• One or more blood vessels are partially or completely blocked.

• The heart and heart valves look abnormal.

• An aneurysm or tear (dissection) in the aorta is present.

• A narrow spot on the artery may suggest a blood clot or a deposit of fat and calcium is reducing blood flow through the blood vessel.

• An abnormal pattern of blood vessels may be a sign that a tumour is present.

Should any of these abnormalities appear in your results, your doctor will further discuss potential treatment plans that are suitable for your needs.

Overall, CT angiograms offer a safe, efficient way to diagnose heart and vascular conditions. While potential risks exist, modern technology minimises radiation and enhances accuracy, aiding timely treatment decisions, and the benefits of diagnosing heart conditions such as coronary artery disease outweigh such risks.

Get in touch with our doctors at Thomson Medical for personalised recommendations and tailored advice. Request an appointment with Thomson Medical today.

FAQ

What are the benefits and risks of a CT angiogram?

Benefits include its non-invasive nature and ability to provide detailed images of major blood vessels, helping to diagnose potential health conditions and enabling early intervention. Risks are minimal but may include rare allergic reactions to the dye, kidney strain in those with severe kidney disease, and a low risk of radiation exposure.

Are you sedated for a CT angiogram?

No sedation is required for a CT angiogram. Antihistamines may be provided to help calm down those with claustrophobia or face discomfort in enclosed spaces to calm them down during the imaging process in the CT.

Why would a doctor order a CT angiogram?

To evaluate chest pain, buildups of plaque on the heart arteries, other potential diseases of blood vessels, diagnosing other types of heart conditions or surgical planning.

How long is bed rest after an angiogram?

CT angiograms require no recovery time and bed rest. After the procedure, you will just need to be drinking water to flush out the dye from your body. Otherwise, you can resume normal activities.

Is an angiogram painful?

There will be minimal discomfort during IV insertion; however, the scan itself is painless. At any time you feel any pain, please sound out to your doctor.

What happens if an angiogram shows a blockage?

Your doctor may recommend medication, lifestyle changes, or a more invasive procedure such as a standard coronary angiogram to further evaluate the blockage.

The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations and tailored advice, please consult a specialist at Thomson Medical. Request an appointment with Thomson Medical today.