A CT angiogram procedure is an imaging test to diagnose several vascular conditions, such as aneurysms, atherosclerosis, and blood clots1. Here, we’ll discuss how a CT angiogram works and when (and why) someone would get one. We'll also discuss what a CT angiogram can show and how it compares to a low-dose CT coronary artery calcium test.
What Is a CT Angiogram and What Can It Find?
What Is a CT Angiogram?
A computed tomography angiogram (CTA, or computed tomography angiography) is an imaging test that creates detailed pictures of various blood vessels and tissues in your body. This imaging technique uses computed tomography, which is thousands of X-rays taken at one time to produce detailed pictures of a particular area of your body1. CTA also uses a type of contrast dye injection that helps visualize the blood vessels and surrounding tissues2.
The CT scanner itself is a donut-shaped machine with a tunnel that the exam table slides into. Once the scan begins, X-ray beams will examine the particular area of the body. A nearby computer translates that information into pictures, and the images are then read by a radiologist3.
Why Would Someone Need a CT Angiogram?
Medical providers order a CT angiogram procedure when they’re looking for an abnormality involving the blood vessels of a specific area. Depending on the area of concern, a CTA can be done on different body regions, such as the heart, brain, and kidneys4–6.
What Can a CT Angiogram Test Find?
Some conditions it can diagnose include:
Aneurysms: This is a bulge in a blood vessel wall that can grow over time and can ultimately rupture or bleed. Aneurysms can be found throughout the body but major areas of concern are in the brain, coronary arteries (vessels that supply the heart), and the aorta, which is the largest artery in the body7,8.
Atherosclerosis: Atherosclerosis is cholesterol deposits or plaque build-up in the blood vessels that can cause blood vessel narrowing over time. This increases the risk of high blood pressure and vascular disease9,10.
Arteriovenous malformations: AVMs are abnormal connections between veins and arteries that have the potential to rupture or bleed11.
Blood clots: Blood clots can be seen on a CT angiogram test. These can include pulmonary embolisms, which are blood clots in the lungs that usually have traveled from veins in the legs12.
Blood flow to tumors: A CT angiogram test can also be used to evaluate the blood flow or supply to tumors, which can be helpful when planning for tumor removal surgery13.
How Is a CT Angiogram Performed and How Can I Prepare?
For safety purposes, you will complete a questionnaire before undergoing the procedure. You will be asked if you have any medical conditions, including kidney disease, diabetes, or thyroid problems. You will also have to inform the doctor of all medications that you are taking and whether you have any allergies – this is particularly important if you have previously reacted to contrast material3. People with a history of contrast dye allergy may be pre-medicated with steroids to decrease their risk of an allergic reaction3.
You may have to stop eating for 3-4 hours before your scan but should continue drinking water14. If undergoing a chest CTA then you should not have any caffeine for 3 hours before your scan14. All metal objects must be removed, including jewelry and dentures, as metal can affect the CT images. Once you arrive at the imaging center, you'll change into a hospital gown and lie on the exam table. The technologist may use straps and pillows to ensure that you remain in the correct position for the duration of the scan3.
You’ll then have an IV (intravenous) line placed for the contrast dye to be injected. When injected, you may feel a quick sensation of warmth as it flows throughout your body. You may also experience a brief metallic taste in your mouth3. Once the contrast dye is in your body, you will be moved into the scanner, which will start taking images. Within the scanner you may hear quiet sounds of the scanner taking the images – these will involve clicking and whirring sounds3. You must remain very still and may be asked to briefly hold your breath if requested3.
After the scan is complete, the technologist will remove the IV line and cover the needle puncture wound with a small dressing. Unless told otherwise, you can immediately carry on with your day as normal3.
How Safe Is Contrast
The contrast used in a CT angiogram test is safe for the majority of people. Risks include:
- Allergic reactions to the contrast dye – ranging from vomiting and hives to anaphylactic reactions15.
- Kidney damage (contrast-induced nephropathy) – those with pre-existing kidney problems or diabetes are more at risk15.
- Thyroid dysfunction – contrast media containing iodide can affect thyroid function15.
How Long Does a CT Angiogram Take?
Generally, a CT angiogram is quick and can gather the necessary images in as little as 15 minutes, depending on which body area is being scanned16. However, it can take longer if more images are needed. For instance, during a coronary angiogram procedure, a person’s heart rate can affect the quality of the CT images. As a result, medications such as beta-blockers may be needed to slow the heart rate down to improve the image quality. These will take about an hour to have the desired effect16.
What’s the Difference Between a CT Scan and a CT Angiogram?
Both CT scans and CT angiograms use X-rays to produce images of the body, however, they focus on different structures17. A CT scan creates images of organs, bones, and soft tissues to diagnose conditions such as bone fractures or tumor growth. CT scans can be done with or without contrast, depending on the structure being examined18. A CT angiogram specifically focuses on blood vessels. Contrast dye is always used as it is necessary to highlight the blood vessels. CT angiograms assess vascular structures and issues, including aneurysms and blockages17.
How Does a Coronary Calcium Scan Compare to a CT Coronary Angiogram?
While coronary CT angiography can diagnose a wide range of conditions, it can also be beneficial in preventing life-threatening episodes such as a heart attack or stroke14. For example, if a CT coronary angiography reveals narrowing in certain blood vessels supplying the heart, preventive action can be taken that can be potentially lifesaving. Such measures could include lifestyle changes, medications, and surgical procedures19.
On the other hand, a coronary calcium scan, or CT with CAC scoring, can detect calcium deposits in the blood vessels of the heart, which may help predict the future risk of a heart attack20. It can also help you and your cardiologist decide if medications such as statins would significantly decrease your risk of heart disease20. It is a preventive action that can be potentially lifesaving.
CAC scoring has repeatedly been shown to be beneficial in identifying those who are at high risk of heart disease and who don’t yet have any signs or symptoms21. Another key difference is that a CT with CAC scoring usually only has a fraction of the radiation exposure of a CT angiography22.
Can You Get a Coronary Calcium Score Plus a Full Body MRI?
Yes, with Ezra’s Full Body Plus scan, you can get a low-dose chest CT with CAC scoring to assess your heart disease risk, plus an MRI scan of the entire body, which can detect a wide range of conditions. The Full Body MRI only takes one hour of your time and the low-dose CT can take just five minutes.
Summary: What Is a CT Angiogram and What Can It Find?
A CT angiogram is an imaging test that creates detailed pictures of blood vessels and tissues using computed tomography and contrast dye. It's used to diagnose various vascular conditions such as aneurysms, atherosclerosis, and blood clots. The procedure involves injecting contrast dye through an IV, then using a CT scanner to capture images. CT angiograms can examine different body regions, including the heart, brain, and kidneys. The test is generally quick, taking about 15 minutes, though it may be longer depending on the area scanned. While generally safe, there are some risks associated with the contrast dye, including allergic reactions and potential kidney damage.
Take charge of your health and get your scans done with Ezra — we can catch over 500 conditions in up to 13 organs, and it may be your key to better outcomes.
References
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