Significance of Coronary Artery Calcification on CT Scan

Checking for coronary artery calcification (build-up of calcium in the heart’s arteries) is one of the best ways to determine heart health.

It allows doctors to evaluate an individual’s risk for heart disease and can help prompt at-risk patients to make necessary lifestyle changes in order to prevent complications.

Coronary artery calcification can be seen and measured with heart imaging tests, like CT. But understanding the results of such tests can be confusing. To help patients navigate the significance of coronary artery calcification on a CT scan, we spoke with expert Cardiothoracic Radiologist, Dr. Aimee Carswell. From how coronary artery calcification is detected and scored to what it means to have a blockage, Dr. Carswell takes us through what medical imaging can help tell us about our heart health.

DocPanel is committed to making sure every patient receives excellent care. If you would like an expert second opinion on your medical imaging scan from one of our chest & cardiac subspecialists, you can learn more here.

[DocPanel] What is coronary artery calcification?

[Dr. Carswell]

Coronary artery calcification is calcium buildup within the walls of the arteries that supply oxygen-rich blood to the heart. This calcium causes the walls to become more hardened, as seen with atherosclerosis. It may also cause narrowing of the inside of the coronary artery, which can limit blood flow to the heart muscle.

[DocPanel] How is coronary artery calcification detected and diagnosed?

[Dr. Carswell]

Coronary artery calcification may be seen on many different types of radiology exams, including x-ray, CT, and MRI. There is a special CT scan called a Coronary Artery Calcium Scoring CT that is used to measure the amount of calcium, giving a patient their coronary artery calcium score. That score is able to estimate the patient's risk of having a heart attack or stroke in the next 5-10 years.

[DocPanel] Who should get a calcium score CT?

[Dr. Carswell]

A calcium score CT is a screening test. It helps your doctor know how to treat you if you have no symptoms. It’s recommended for patients at medium risk - including those with a personal history of high cholesterol, diabetes, hypertension, obesity, or a family history of coronary artery disease.

If you have already had a heart attack, have a stent, or have had a heart bypass procedure, you are already at high risk - so a calcium score CT would not be beneficial for these types of patients.

[DocPanel] Are there any challenges in accurately scoring coronary artery calcification?

[Dr. Carswell]

As with any CT scan, you must follow directions in terms of holding still and holding your breath for up to 30 seconds. If you are unable to properly follow the directions, part of the artery may be missed or part may be scanned twice, causing the score to be invalid. If your heart rate is too high, this may cause a similar problem. Additionally, if a patient is obese, they may not fit in the scanner.

[DocPanel] What are the benefits of cardiac CT when compared to other imaging tests?

[Dr. Carswell]

Coronary calcium score CTs are fast, painless, and easy but non-invasive ways to give your doctor more information about how to treat you. It is called "noninvasive" because you are not having to go to an operating room or fluoroscopy suite and have dye injected or catheters placed into your veins or arteries.

In terms of providing information about cardiovascular risk, coronary artery calcium scores are most beneficial for women who are 35-70 years old, and men who are 40-60 years old.

[DocPanel] What is considered a high calcium score?

[Dr. Carswell]

A negative test means there is no calcium. A positive test means there is calcium present, and it is graded as shown in the table below.


[DocPanel] What does it mean to have a high calcium score with no blockage?

[Dr. Carswell]

You may have a high calcium score, but if you had dye injected into your coronary arteries, either during a coronary artery CT scan (which differs from a non-contrast coronary calcium score CT) or during coronary angiography procedure under fluoroscopy, there may be no blockage in the arteries or no significant blockage.

This is due to a phenomenon called "positive remodeling" in which the calcium is found on the outer part of the vessel and "grows" outward instead of inward. At any rate, if you are in the age categories listed above and you have a high calcium score, you are at risk for a cardiovascular event. Additionally, some young patients may have no coronary artery calcium, but still have a blockage in the arteries, sometimes due to soft plaque. Soft plaque is atherosclerosis that does not contain calcium. This is why it is important for the referring providers to take other cardiovascular risk factors into account, in addition to the calcium score.

[DocPanel] What other markers are used to determine heart health?

[Dr. Carswell]

Other markers used to determine heart health include high blood cholesterol levels, family history of heart disease, diabetes, high blood pressure, smoking, obesity, and physical inactivity.

[DocPanel] What advice do you have for someone with a high calcium score?

[Dr. Carswell]

If your calcium score is high, you should discuss this with your doctor. They may give you recommendations on lifestyle changes, such as shifting to your diet, stopping smoking, or beginning an exercise program. They may also decide to place you on medications to help with other diseases, such as diabetes, high blood pressure, or high cholesterol.