Coronary calcium score (CAC scan)

What it is and what it promises

Calcium in the coronary arteries is part of hardening of the arteries, atherosclerosis. For the measurement, an ECG-gated CT scan without contrast agent is taken, that is, an image acquired in time with the heartbeat (Lindholt 2022). The software calculates the Agatston score from the area and density of the calcified spots. Zero means: no measurable calcium. The studies usually compare a score of zero with levels such as above 100, above 300 or 400 and more; the US guideline regards a score of 100 or more, or at or above the 75th percentile for age, sex and ethnicity, as a reason to classify risk higher (Arnett 2019). The ESC advises comparing the score with what would be expected for people of the same age and sex (Visseren 2021).

The promise is obvious: instead of estimating risk from averages, you see whether the disease has already begun in your own body. A high score is meant to prompt more consistent prevention, a score of zero may spare you a long-term medication. Other screening offers can be found under Screenings and in the whole-body MRI; another cardiac risk marker in lipoprotein(a).

What the studies show

MESA 2018 – ten years, 6,814 people

The Multi-Ethnic Study of Atherosclerosis followed 6,814 adults aged 45 to 84 without cardiovascular disease for a median of 11.1 years. During this time, 500 heart attacks, strokes, resuscitated cardiac arrests and cardiac deaths occurred. With a calcium score of zero, the ten-year risk was between 1.3 and 5.6 percent depending on age, sex and ethnicity; with scores above 300, between 13.1 and 25.6 percent. From a score above 100, the estimated risk exceeded 7.5 percent in every subgroup, the threshold from which the US guideline speaks of intermediate risk. Each doubling of the score increased risk by 14 percent, adjusted for the traditional risk factors (Budoff 2018).

CAC Consortium 2020 – mortality over 12.5 years

66,636 people without coronary heart disease from several US centres were followed for a median of 12.5 years; 3,158 died, around one third of them from cardiovascular disease. Those with a score of 400 or more had a 5.4-fold higher risk of dying from coronary heart disease than those with a score of zero (hazard ratio 5.44). Three or more traditional risk factors compared with none roughly doubled this risk (2.09). People without risk factors but with a score of 400 or more died more often than people with three or more risk factors and no calcium. With a score of zero, most deaths were not heart-related (Grandhi 2020).

DANCAVAS 2022 – screening and mortality

The Danish trial invited, by random allocation, 16,736 men aged 65 to 74 to comprehensive cardiovascular screening, while 29,790 formed the control group; 62.6 percent of those invited attended. The screening included the calcium scan, a search for aneurysms and atrial fibrillation, ankle and arm blood pressure measurement and blood tests. After 5.6 years, 12.6 versus 13.1 percent had died, hazard ratio 0.95 (95% CI 0.90 to 1.00; p = 0.06), narrowly not significant. Strokes were somewhat less frequent in the invited group (0.93; 95% CI 0.86 to 0.99); for heart attacks, the difference was not significant (0.91; 0.81 to 1.03). There were no significant differences in safety outcomes. Because the calcium scan was only one part of the package, its own contribution cannot be isolated (Lindholt 2022).

Scheu 2025 – what happens after the result

A systematic review combined seven randomized trials and one cohort study with a total of 51,554 participants. In five studies, people with a calcium scan had somewhat better LDL levels, by 4.9 to 6.0 mg/dl, and in one study with 2,137 participants a more favourable course of blood pressure. Results on prescriptions of cardiovascular medication contradicted each other: sometimes more, sometimes fewer. One study found higher adherence to statin use (63.3 versus 45.6 percent). None of the three studies that recorded heart attacks or deaths found a difference, because of too few events, short duration or small sample size. Most studies had a moderate to high risk of bias (Scheu 2025).

Drysch 2026 – incidental findings in the lungs

A calcium scan also images parts of the lungs. In a US cohort from five hospitals with 9,702 adults who were not eligible for lung cancer screening, nodules requiring further workup were found in 11.7 percent. Only 42.8 percent of them attended the recommended follow-up. Lung cancer was confirmed in 18 people, 83.3 percent of them at stage I. The study was retrospective and shows both sides: a calcium scan can find an early cancer along the way, but triggers follow-up examinations in more than one in ten people (Drysch 2026).

What users report

In the Dutch ROBINSCA trial, 2,687 participants completed questionnaires on quality of life and anxiety before and after screening; they had been randomly allocated to classification either by calcium scan or by a traditional risk calculator. Quality of life and anxiety did not differ between the two approaches. Participants were most strained at invitation and allocation, not after the result. A result indicating increased risk was associated with more anxiety in the calcium group (Moldovanu 2024). In one study of the 2025 review, 94 percent of the calcium group said they were motivated to change their lifestyle, compared with 62.8 percent of the comparison group; in another, 96 versus 59 percent reported sticking to more physical activity (Scheu 2025). These are surveys and self-reports, not proof of fewer heart attacks.

Where the data stop

The decisive question has not been answered: do people without symptoms who have themselves screened for calcium live longer? The largest trial, DANCAVAS, narrowly missed significance, and it tested a package of several examinations in men aged 65 to 74. Such data are lacking for women and younger people. The 2025 review found insufficient evidence on whether calcium screening affects cardiac events or mortality (Scheu 2025). Results from ROBINSCA on heart attacks and deaths were not yet available at the time of our research in October 2026.

The score itself also has limits. It measures calcified deposits, not the total amount of plaque and not how severely a vessel is narrowed. In middle-aged people it can be low or zero even though soft, not yet calcified plaques are present (Visseren 2021). A score of zero is therefore a good sign, but not a free pass. And the guidelines see the scan as a decision aid for people close to a treatment threshold; they contain no recommendation for it as screening for everyone.

Status, approval and legal

Guidelines: the European Society of Cardiology (ESC) wrote in 2021 that calcium scoring may be considered to improve risk classification around treatment thresholds (class of recommendation IIb, level of evidence B); the availability and cost-effectiveness of widespread use should be weighed regionally (Visseren 2021). The US societies ACC and AHA considered the measurement reasonable in 2019 for intermediate ten-year risk (7.5 to under 20 percent) and in selected people with borderline risk when the decision about prevention such as a statin remains uncertain (class of recommendation IIa). A score of zero moves risk down, a score of 100 or more or at or above the 75th percentile moves it up (Arnett 2019).

Law in Germany: early detection using X-rays in people without symptoms and without a concrete suspicion of disease is only permitted under § 84 of the Radiation Protection Act (Strahlenschutzgesetz) if a statutory ordinance expressly provides for it. No such ordinance exists for coronary calcium measurement. In 2019, experts from the Federal Office for Radiation Protection evaluated 50 internet offers each for CT early detection of lung and colon cancer and coronary heart disease, classified such offers as not permitted and found the information mostly inadequate, with overemphasized benefits (Brix 2020). This must be distinguished from an examination based on a medical question: for this, a physician with specialist knowledge in radiation protection must determine in the individual case that the health benefit outweighs the radiation risk, the so-called justifying indication under § 83 of the Radiation Protection Act. A scan purely on request does not meet this.

Costs: statutory health insurance does not cover calcium measurement in people without symptoms; it is offered as a self-pay service.

Safety

The examination itself is short and requires neither contrast agent nor catheter. The radiation dose was determined in 3,442 MESA participants on four modern CT scanners: a mean of 1.05 millisievert, a median of 0.95, between 0.74 and 1.26 depending on the centre; with severe obesity (BMI over 40), a mean of 1.47 (Messenger 2016). Repeated scans add up.

The real consequences come afterwards: lung nodules and other incidental findings lead to follow-up CT scans and sometimes procedures, in the US cohort in more than one in ten people (Drysch 2026). A result indicating increased risk can cause anxiety (Moldovanu 2024). Which prevention follows from a high score belongs in a conversation with a physician; there are separate pages on statins and aspirin for prevention.

If you decide to have it, clarify beforehand: is there a medical question, who reports on the entire scan including the lungs, and who takes care of working up an incidental finding.

Sources

• Budoff MJ et al., Eur Heart J 2018 – MESA, 6,814 people, ten years of coronary calcium and cardiovascular events (PMID 29688297)
• Grandhi GR et al., JACC Cardiovasc Imaging 2020 – CAC Consortium, 66,636 people, calcium score, risk factors and mortality (PMID 31734198)
• Lindholt JS et al., N Engl J Med 2022 – DANCAVAS, randomized cardiovascular screening in 46,611 men (PMID 36027560)
• Scheu V et al., BMJ Open 2025 – systematic review, calcium screening, risk factors, behaviour and events (PMID 40617605)
• Moldovanu D et al., Eur Heart J Open 2024 – ROBINSCA, quality of life and anxiety after calcium screening (PMID 39421139)
• Drysch A et al., J Am Coll Surg 2026 – lung nodules and lung cancer as incidental findings in 9,702 calcium scans (PMID 42566001)
• Messenger B et al., Int J Cardiovasc Imaging 2016 – MESA, radiation dose of calcium scoring in 3,442 participants (PMID 26515964)
• Visseren FLJ et al., Eur Heart J 2021 – ESC guideline on cardiovascular disease prevention (PMID 34458905)
• Arnett DK et al., Circulation 2019 – ACC/AHA guideline on the primary prevention of cardiovascular disease (PMID 30879355)
• Brix G, Nekolla EA, Griebel J, Fortschr Röntgenstr 2020 – early detection with X-rays: new legal situation and evaluation of CT offers (PMID 31514212)