Coronary Artery Calcium Score

Non-contrast cardiac CT measuring calcified atherosclerotic plaque in the coronary arteries to produce an Agatston score — a direct, independent measure of coronary artery disease burden that predicts future cardiovascular event risk with high accuracy. No contrast injection, no fasting, brief appointment.

The coronary artery calcium (CAC) score at Claraspital Basel is performed using ECG-gated CT on the Dual-Layer Spectral CT scanner. Unlike blood tests such as cholesterol or C-reactive protein, which estimate cardiovascular risk through surrogate markers, the CAC score directly measures atherosclerotic calcification in the coronary arterial walls — the physical disease process itself. This makes it one of the most powerful independent predictors of future myocardial infarction available in clinical practice, performing better than most traditional risk calculators in reclassifying patients at intermediate risk. The cardiac CT is acquired with ECG gating to freeze cardiac motion and isolate the coronary arteries from surrounding structures. No intravenous contrast is required; the scan relies solely on the natural density difference between calcified plaque and soft tissue. The raw images are processed to calculate the Agatston score — a standardised, weighted sum of calcium deposits across the left main, left anterior descending, left circumflex, and right coronary arteries. Risk tiers are: 0 (no detectable calcification — extremely low 10-year event risk regardless of other risk factors); 1–99 (mild); 100–399 (moderate); 400+ (severe, with substantially elevated risk). A score of zero is particularly clinically powerful: large prospective studies including the MESA cohort demonstrate a cardiovascular event rate below 1% over 10 years in zero-CAC patients even when standard risk scores suggest intermediate risk, supporting evidence-based deferral of statin therapy in appropriate individuals. Conversely, a high score — especially above the 75th percentile for age and sex — justifies intensifying preventive therapy even when LDL cholesterol appears well-controlled. The examination requires no fasting, no intravenous access, and no preparation beyond avoiding stimulants. Total appointment time is approximately 20 to 30 minutes. The cardiologically reviewed written report from Claraspital includes the total Agatston score, per-vessel calcium distribution, age- and sex-specific risk percentile, and a clinical recommendation for follow-up or further investigation.