P1555Agreement of coronary calcium scoring on chest CT and ECG triggered cardiac CT: a population-based study

Abstract

Abstract Background Low-dose chest computed tomography (CT) is increasingly used in lung cancer screening. The heart is inherently visualized on chest CT. Coronary artery calcium (CAC) identified on chest scans has predictive value for risk of cardiovascular disease. There is discussion whether non-ECG-triggered chest CT is reliable for CAC scoring. Purpose To investigate the agreement between chest CT and ECG-triggered cardiac CT in CAC identification and risk classification. Methods We included 1000 ImaLife participants who underwent a cardiac scan immediately followed by a non-ECG triggered chest scan. Third-generation dual-source CT and dedicated software were used for scan acquisition and CAC measurement. Chest scans were analyzed after cardiac scans with an interval of at least a month and in a different order. To ensure a comparable prevalence of CAC with previous studies and adequate samples in CAC strata, after the inclusion of the 500th consecutive participants with zero CAC, only participants with >0 CAC based on dedicated cardiac CT were included. CAC scores were divided into four risk strata: 0, 1–99, 100–399, 400. Kappa was used to assess agreement in CAC identification (0 versus >0) and risk classification. Results The mean age was 54 years (range 45–77), 42.5% were women, average body mass index (BMI) was 26.1kg/m2. Compared with dedicated cardiac CT, non-ECG triggered chest CT had an accuracy of 0.97, sensitivity of 0.96 and specificity of 0.99 for identifying CAC, and agreement between scans was very high (kappa 0.95) for CAC presence. In terms of CAC risk strata, chest CT had a very high agreement with cardiac CT (kappa 0.95). Total misclassification rate of CAC strata was 6.5%, with most misclassified cases shifting one risk category downward (55/65, 85%). BMI of discordant pairs was significantly higher than concordant pairs, while no difference in heart rate was found. Conclusion Non-ECG triggered chest CT may be reliably used for CAC identification and risk classification since chest CT has very high agreement with dedicated cardiac CT results.