Coronary artery calcium (CAC) score

The coronary artery calcium (CAC) score is a non-contrast cardiac CT measurement reported as an Agatston score that quantifies calcified atherosclerotic plaque as a marker of total atherosclerotic burden; non-calcified (soft) plaque is not detected. A higher CAC score is strongly associated with future myocardial infarction, cardiovascular events, and all-cause mortality, and primary-prevention guidelines (2018 ACC/AHA, 2021 ESC) recommend CAC for risk reclassification in intermediate-risk adults. A score of zero indicates very low short-term event risk but does not fully exclude atherosclerosis, particularly in younger adults or those with elevated Lp(a) or familial hypercholesterolemia. Standard Agatston categories are: 0 (very low), 1–99 (mild), 100–399 (moderate), and ≥400 (severe).