Understanding Coronary Artery Calcium Scans: A Tool for Assessing Heart Risk  

Heart disease remains the leading cause of death in the U.S. and many of its underlying risk factors are on the rise.¹ Coronary artery disease, the most common cause of heart attacks, often progresses quietly for years before symptoms appear. Traditional risk assessments for heart disease, such as cholesterol levels, blood pressure, and age, can miss early signs of disease. Coronary artery calcium (CAC) scans can help address this gap by identifying risk earlier.  

Here, our experts from Private Health Management (PHM) summarize what you need to know about CAC scans, including how they are used, who may benefit most from testing, what the results mean, and how they can inform personalized strategies for heart disease prevention. 

What is a coronary artery calcium scan? 

Coronary artery disease is caused by plaque buildup (atherosclerosis) in the arteries that supply the heart over time, which can narrow the arteries and reduce blood flow. As this plaque matures, calcium tends to accumulate within it. A CAC scan is a non-invasive CT scan that detects this calcium in these arteries. The results are reported as a calcium score, which reflects underlying plaque buildup in the arteries. CAC scoring can improve cardiovascular risk prediction beyond standard risk factors such as cholesterol and blood pressure.²  

Experts often compare CAC findings to colon polyps on a colonoscopy; it signals increased risk and the need for prevention, but it is not a diagnosis of disease or an emergency. 

When is a coronary artery calcium scan helpful? 

Guidelines from the American Heart Association and American College of Cardiology support the use of CAC scoring in certain adults when standard risk factors leave uncertainty about preventative treatment decisions, such as whether to begin statin therapy.³ CAC scoring is not intended as a routine screening test, but rather as a tool to help refine risk and support more personalized decision-making. In select individuals, repeat CAC testing may be considered over time to reassess risk, particularly if the initial score is low or if clinical circumstances change. 

CAC scanning is most useful for:^3,4 

• Adults (often ages 40–70) with intermediate or uncertain cardiovascular risk 

• People with family history of early heart disease 

• Individuals with borderline or uncertain risk factors (for example, mildly elevated cholesterol or a family history of early heart disease) when overall cardiovascular risk is not clearly high or low. 

• Situations where patients and clinicians are asking questions such as: 

• “What does this mild cholesterol elevation really mean for me?” 

• “Should I be more aggressive about prevention?” 

CAC scanning is not intended for: 

• Individuals who are already at high risk, such as those with elevated cholesterol or diabetes, and for whom preventive treatment decisions are already established. 

• Low-risk, asymptomatic individuals with no risk factors. 

• Those with known coronary artery disease, active chest pain, or symptoms suggesting a heart attack. 

What to expect during the scan 

The coronary calcium scan is quick and straightforward, and most people find it easy to complete: 

• A brief CT scan lasting about 10–15 minutes. 

• No contrast dye or needles. 

• Painless, with minimal preparation required. 

• Radiation exposure is low and comparable to other commonly used medical imaging tests.⁵ 

Coronary calcium score results: what they mean 

CAC scan results are grouped into ranges that correspond to increasing plaque burden and long-term cardiovascular risk. Scores are often interpreted in the context of age and sex, allowing comparison with others in a similar age group. In some cases, the location of calcium within specific vessels, such as the left anterior descending artery (LAD), which supplies a large portion of the heart muscle, may carry greater clinical significance and this information is considered when results are interpreted. 

Coronary Calcium Score Summary 

How the results can influence care decisions 

A CAC score is best understood as one component of cardiovascular risk assessment, similar to a lab test, and is interpreted alongside lipid profiles and other factors such as blood pressure, obesity, family history, smoking, and diabetes.² By reflecting plaque that has accumulated in the coronary arteries over many years, CAC scoring helps estimate long-term or lifetime cardiovascular risk, not just short-term risk. 

In clinical practice, CAC results help guide shared decision-making between patients and clinicians, helping tailor prevention strategies to an individual’s overall risk and preferences. As calcium scores increase, clinicians are more likely to encourage advancement of anti-lipid therapies and lifestyle interventions to prevent further disease progression.⁴ Higher calcium scores often strengthen the case for additional, more invasive diagnostics, such as a cardiac catheterization, to better assess plaque burden and determine whether coronary stenting or revascularization may be needed.  

Common misconceptions about coronary artery calcium scans 

Below are some common misconceptions about coronary calcium scans and how the test is used in clinical practice. 

• “Is a CAC scan the same as a coronary CT angiogram (CTA)?” 
  • No. A CAC scan measures calcium in the coronary arteries to assess long-term cardiovascular risk, while a coronary CT angiogram looks directly at the arteries for narrowing or blockages. Although both use CT technology, they serve different clinical purposes. 

• “Does this test tell me if I need a stent or surgery?”  
  • No. CAC scans do not determine the need for procedures. Tests such as cardiac catheterization are used when there is concern for significant blockages that may require intervention. 

• “Does it diagnose a heart attack?”  
  • No. The test does not evaluate active symptoms or acute events. 

• “If my score is zero, do I never need to worry about heart disease?”  
  • Not necessarily, a score of zero is reassuring, but risk can change over time. 

• “Does a low or zero score mean there are no blockages?”  
  • Not always. CAC scans detect calcified plaque, and some early or soft plaque may not yet be visible on this type of scan. 

Key takeaways 

As part of a comprehensive cardiovascular risk-assessment strategy, CAC scans can help identify hidden risk before symptoms appear and provide additional context beyond traditional measures. At PHM, we help individuals understand whether CAC testing is appropriate and how results fit into a broader, personalized approach to heart health, supporting informed conversations with clinicians and long-term prevention planning. 

References 

1. Martin, S. S. et al. 2025 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association. Circulation 151, e41–e660 (2025). 

2. Greenland, P. & Lloyd-Jones, D. M. Role of Coronary Artery Calcium Testing for Risk Assessment in Primary Prevention of Atherosclerotic Cardiovascular Disease: A Review. JAMA Cardiol. 7, 219–224 (2022). 

3. Arnett, D. K. et al. 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation 140, e596–e646 (2019). 

4. Walter, K. L. What Is a Cardiac CT Calcium Score? JAMA 334, 462 (2025). 

5. Kim, K. P., Einstein, A. J. & Berrington de González, A. Coronary Artery Calcification Screening: Estimated Radiation Dose and Cancer Risk. Arch. Intern. Med. 169, 1188–1194 (2009).