Coronary artery calcium (CAC) is a specific marker of coronary atherosclerosis that can be used to measure calcified subclinical atherosclerotic burden. The Agatston method is the most widely used scoring algorithm for quantifying CAC and is expressed as the product of total calcium area and a quantized peak calcium density weighting factor defined by the calcification attenuation in HU on noncontrast computed tomography. Calcium density has emerged as an important area of inquiry because the Agatston score is upweighted based on the assumption that peak calcium density and atherosclerotic cardiovascular disease (ASCVD) risk are positively correlated. However, recent evidence demonstrates that calcium density is inversely associated with lesion vulnerability and ASCVD risk in population-based cohorts when accounting for age and plaque area. Here, we review calcium density by focusing on 3 main areas: 1) CAC scan acquisition parameters; 2) pathophysiology of calcified plaques; and 3) epidemiologic evidence relating calcium density to ASCVD outcomes. Through this process, we hope to provide further insight into the evolution of CAC scoring on noncontrast computed tomography.

冠状动脉钙（CAC）是冠状动脉粥样硬化的特异性标志物，可用于测量钙化的亚临床动脉粥样硬化负荷。Agatston 方法是最广泛使用的量化 CAC 的评分算法，表示为总钙面积与量化峰值钙密度加权因子的乘积，该加权因子由非对比计算机断层扫描 HU 中的钙化衰减定义。钙密度已成为一个重要的研究领域，因为 Agatston 评分的权重基于峰值钙密度和动脉粥样硬化性心血管疾病 (ASCVD) 风险呈正相关的假设。然而，最近的证据表明，在考虑年龄和斑块面积时，钙密度与基于人群的病变脆弱性和 ASCVD 风险呈负相关。在这里，我们重点关注 3 个主要领域来回顾钙密度：1）CAC 扫描采集参数；2）钙化斑块的病理生理学；3) 钙密度与 ASCVD 结果相关的流行病学证据。通过这个过程，我们希望进一步深入了解非造影计算机断层扫描 CAC 评分的演变。