Coronary Artery Calcium Score

A coronary artery calcium scan is a fast, non-contrast CT scan of your heart. It takes about 10 minutes — most of which is positioning. The scan itself is a few seconds, gated to your heartbeat.

The CT detects calcium deposits in the walls of your coronary arteries. Calcium accumulates inside atherosclerotic plaque as it matures, so the amount of calcium present is a direct readout of how much established plaque you've built up over your lifetime.

The result is a single number — your Agatston score — along with a percentile ranking against people your age and sex.

Traditional cardiovascular risk calculators like Framingham or the ASCVD score estimate your risk from population averages — your blood pressure, cholesterol, age, and a few other inputs. They're useful but blunt. Two patients with identical risk-calculator inputs can have wildly different actual plaque burdens.

A CAC scan replaces estimation with measurement. A score of zero in a middle-aged adult is one of the most powerful negative predictors in medicine — very low cardiovascular event risk over the following 10 years. A high score in someone whose risk calculator looked benign reframes the entire prevention conversation.

Major societies including the American College of Cardiology and American Heart Association now recommend CAC scoring to refine risk and guide statin decisions in intermediate-risk adults. We use it more proactively — to give patients in their 40s and 50s a clear picture of where they actually stand.

• Agatston score — the total amount of calcified plaque across all coronary arteries
• Score by individual artery (LAD, LCx, RCA) — useful for understanding which territory is involved
• Age- and sex-adjusted percentile ranking
• 10-year cardiovascular event risk category, based on validated cohort data

• Adults in their 40s, 50s, and early 60s who want a real measurement of their cardiovascular risk rather than an estimate.
• Patients with a family history of early heart disease who want to know whether they share that trajectory.
• Anyone weighing whether to start, continue, or intensify lipid-lowering therapy and wants the data to make that decision well.
• Patients with elevated lipoprotein(a), high LDL, or other concerning markers who want to know if disease has actually started.

• Plan on about 30 minutes at the imaging facility. The scan itself is over in seconds.
• You'll lie on your back inside an open CT scanner. The technician applies a few EKG leads to time the scan to your heartbeat.
• No contrast injection, no fasting required, no IV.
• Radiation exposure is roughly 1 mSv — comparable to a mammogram and a small fraction of a typical chest CT.

We talk through the absolute score, the percentile, and the implications. A score of zero usually means we're focused on prevention rather than treatment. A score above zero shifts the conversation toward how aggressively to lower LDL and other modifiable risk factors.

We look at the score in the context of the rest of your evaluation — lipids, lipoprotein(a), apoB, blood pressure, glucose, family history, and lifestyle. CAC is one input, not the entire picture.

For most patients, a CAC scan is a once-every-5-years test. If treatment changes meaningfully or new risk factors emerge, we may rescan sooner.

1. Detrano R, Guerci AD, Carr JJ, et al. Coronary Calcium as a Predictor of Coronary Events in Four Racial or Ethnic Groups. N Engl J Med. 2008;358(13):1336-1345.The foundational Multi-Ethnic Study of Atherosclerosis (MESA) validation, 6,722 patients.
2. Warranty Period of a Calcium Score of Zero: Comprehensive Analysis From MESA. JACC Cardiovasc Imaging. 2021.Followed 3,116 patients with a baseline score of zero for up to 10 years; the protective window ranges 3–7 years depending on sex, ethnicity, and diabetes status.
3. Biavati F, et al. Prognostic value of coronary artery calcium scoring in the DISCHARGE trial. Radiology. 2024.1,749 patients with stable chest pain — a CAC score of 400+ carried a 6.8% event rate vs. 1.9% for lower scores.