OBJECTIVES In the ascending aorta, calcification density was independently and inversely associated with cardiovascular disease (CVD) risk prediction. Until now, the density of thoracic aorta calcium (TAC) was estimated as the Agatston score divided by the calcium area (DAG). We thought to analyze TAC density in a full Hounsfield unit (HU) range and to study its association with TAC volume, traditional risk factors, and CVD events. METHODS Non-enhanced CT images of 1426 patients at intermediate risk were retrospectively reviewed. A calcium density score was estimated as the average of the maximum HU attenuation in all calcified plaques of the entire thoracic aorta (DAV). RESULTS During a mean 4.0 years follow-up, there were 26 events for a total of 674 patients with TAC > 0. TAC volume and DAV were positively correlated (R = 0.72). The median DAV value was 457 HU (IQ 323-603 HU) and was exponentially related to DAG (R = 0.86). DAV was inversely associated with systolic pressure (p < 0.05), pulse pressure (p < 0.01), hypertension (p < 0.05), and 10-year FRS (p < 0.001) after adjusting for TAC volume. When TAC volume and DAV were included in a logistic model, a significant improvement was shown in CVD risk estimation beyond coronary artery calcium (CAC) (AUC = 0.768 vs 0.814, p < 0.05). In multivariable Cox models, TAC volume and DAV showed an independent association with CVD. CONCLUSIONS In intermediate risk patients, TAC density was inversely associated with several risk factors after adjustment for TAC volume. A significant improvement was observed over CAC when TAC volume and density were added into the risk prediction model. KEY POINTS • Calcifications in the aorta can be non-invasively assessed using CT images • A higher calcium score is associated with a higher cardiovascular risk • Measuring the calcifications size and the density separately can improve the risk prediction.

中文翻译：

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胸主动脉钙密度与危险因素和临床事件的关系。

目的在升主动脉中，钙化密度与心血管疾病（CVD）风险预测独立且成反比。到目前为止，胸主动脉钙（TAC）的密度估计为阿格斯顿评分除以钙面积（DAG）。我们考虑分析整个Hounsfield单位（HU）范围内的TAC密度，并研究其与TAC量，传统危险因素和CVD事件的关系。方法回顾性分析1426例中危患者的非增强CT图像。钙密度评分被估计为整个胸主动脉（DAV）所有钙化斑块中最大HU衰减的平均值。结果在平均4.0年的随访中，共有674例TAC> 0的患者发生了26例事件。TAC量与DAV呈正相关（R = 0.72）。DAV的中位数为457 HU（IQ 323-603 HU），与DAG呈指数关系（R = 0.86）。在调整TAC量后，DAV与收缩压（p <0.05），脉压（p <0.01），高血压（p <0.05）和10年FRS（p <0.001）呈负相关。当将TAC量和DAV包括在logistic模型中时，CVD风险评估显示出超过冠状动脉钙（CAC）的显着改善（AUC = 0.768 vs 0.814，p <0.05）。在多变量Cox模型中，TAC量和DAV显示与CVD有独立的关联。结论在中危患者中，调整TAC量后，TAC密度与多种危险因素成反比。当将TAC体积和密度添加到风险预测模型中时，与CAC相比，观察到了显着改善。