Comparability of coronary risk assessment methods with chest ultra-LDCT and CT coronography with ECG synchronization

Purpose. To assess the comparability of coronary calcium values measured on ultralow-dose computed tomography studies without ECG-synchronization versus a) non-contrast computed tomography with ECG synchronization, b) CT coronography with ECG synchronization.Materials and methods. The study comprised 283 studies: 68 patients who underwent contrast-free ultra-LDCT without ECG synchronization and contrast-free CT with ECG synchronization performed in a single visit, and 49 patients with contrast-free ultra-LDCT without ECG synchronization, non-contrast CT with ECG synchronization, and CT coronography with ECG synchronization and intravenous injection of contrast agent, also carried out in one visit, meeting all inclusion and exclusion criteria of the study.Quantitative coronary calcium values were calculated with the Agatston score and the CAC-DRS scale (score of calcification degree from 0 to 3 and the number of affected arteries from 0 to 4 points). The degree of coronary artery stenosis was analyzed with CAD-RADS scale (0-5).The above parameters were compared using visual/quantitative assessment of coronary calcium on ultra-LDCT without ECG synchronization and visual/quantitative assessment for CT with ECG synchronization, as well as the degree of stenosis on CT coronography in the same patients.Results. Based on the results of accuracy indices comparison, the possibility to use quantitative scale (Agatston score, CAC-DRS quantitative scale) to assess coronary calcification in the lung cancer screening in comparison with ECG-synchronized CT was determined during interpretation of ultra-LDCT without ECG synchronization. The correlation matrix to assess correlation between visual, quantitative scales of coronary artery changes and calcification at ultra-LDCT without ECG synchronization and quantitative scale at CT with ECG synchronization vs. CT coronography identifies very strong positive statistically significant correlations.Conclusion. Methods of coronary calcinosis assessment with chest ultra-LDCT and CT with ECG synchronization are comparable, therefore it is possible to assess coronary calcium in lung cancer screening by ultra-LDCT data at a reliable-high level using both quantitative and visual CAC-DRS scales.