High-pitch dual-source CT for coronary artery calcium scoring: A head-to-head comparison of non-triggered chest versus triggered cardiac acquisition

Background: To determine the effect of low-dose, high-pitch non-electrocardiographic (ECG)-triggered chest CT on coronary artery calcium (CAC) detection, quantification and risk stratification, compared to ECG-triggered cardiac CT. Methods: We selected 1,000 participants from the ImaLife study, 50% with coronary calcification on cardiac CT. All participants underwent non-contrast cardiac CT followed by chest CT using third-generation dual-source technology. Reconstruction settings were equal for both acquisitions. CAC scores were determined by Agatston's method, and divided dichotomously (0, > 0), and into risk categories (0, 1-99, 100-399, >_400). We investigated the influence of heart rate and body mass index (BMI) on risk reclassification. Results: Positive CAC scores on cardiac CT ranged from 1 to 6926 (median 39). Compared to cardiac CT, chest CT had sensitivity of 0.96 (95%CI 0.94-0.98) and specificity of 0.99 (95%CI 0.97-0.99) for CAC detection (kappa = 0.95). In participants with coronary calcification on cardiac CT, CAC score on chest CT was lower than on cardiac CT (median 30 versus 40, p<0.001). Agreement in CAC-based risk strata was excellent (weighted kappa = 0.95). Sixty-five cases (6.5%) were reclassified by one risk category in chest CT, with fifty-five (84.6%) shifting downward. Higher BMI resulted in higher reclassification rate (13% for BMI >= 30 versus 5.2% for BMI < 30, p = 0.001), but there was no effect of heart rate. Conclusion: Low-dose, high-pitch chest CT, using third-generation dual-source technology shows almost perfect agreement with cardiac CT in CAC detection and risk stratification. However, low-dose chest CT mainly underestimates the CAC score as compared to cardiac CT, and results in inaccurate risk categorization in BMI >= 30.

Automated summary

The study found that low-dose, high-pitch chest CT using third-generation dual-source technology demonstrates nearly perfect agreement with cardiac CT in CAC detection and risk stratification. However, chest CT tends to underestimate the CAC score compared to cardiac CT, especially in cases with BMI >= 30, resulting in inaccurate risk categorization.