A calcium score CT is a simple, non-contrast examination that measures the amount of calcified plaque in the coronary arteries. Its main advantages are that it does not require contrast and the scan itself is very quick. The calcium score can also help estimate future cardiovascular risk and may be useful when deciding how aggressively risk factors should be managed, including whether preventive medication should be considered.
However, calcium scoring also has important limitations. Because no contrast is used, it does not directly show the degree of coronary artery narrowing, and it cannot adequately evaluate non-calcified plaque. For this reason, some patients may still need coronary CT angiography after a calcium score CT.
This is particularly relevant in people who already have multiple cardiovascular risk factors. Hypertension, diabetes, dyslipidemia, smoking, and a strong family history all increase the likelihood of underlying coronary artery disease. In someone who is already expected to be at relatively high risk, a calcium score may simply come back elevated and lead to an additional coronary CT angiography examination.
In that situation, performing both studies can increase cost and result in additional radiation exposure. Depending on the individual, going directly to coronary CT angiography may sometimes be a more efficient approach because it provides much more detailed information about the coronary arteries, including stenosis and non-calcified plaque.
Personally, in people with a high cardiovascular risk profile, I think it can be reasonable to consider coronary CT angiography at least once from the 40s onward, depending on the overall clinical situation. This is not something I would recommend automatically for every asymptomatic adult, but cardiovascular disease is no longer limited to older patients. Obesity and metabolic risk factors are increasingly common, and acute myocardial infarction requiring PCI can occasionally occur even in people in their 30s and 40s.
For younger adults or people with a lower to intermediate risk profile, I think calcium score CT can still be useful as a relatively simple way to estimate coronary atherosclerotic burden and help guide future risk management.
My take: Calcium score CT is a useful first-line risk assessment tool in many asymptomatic adults, particularly when the expected cardiovascular risk is not very high. However, in someone with multiple major risk factors, I would consider whether going directly to coronary CT angiography might provide more useful information while avoiding the need for two separate CT examinations.