Aim. Determination of the possibility of reliable quantitative assessment of the coronary calcium index based on ultra-low-dose computed tomography (ultra-LDCT) which used in Moscow Lung Cancer Screening project.Material and methods. The study included the results of 254 ultra-LDCT studies conducted as part of the Moscow lung cancer screening project. For compare the parameters of coronary calcium on different images used 16 pairs of ultra-LDCT images with a slice thickness of 1 mm and CT images with a slice thickness of 3 mm, performed without ECG synchronization, performed with an interval of less than 10 days, as well as 18 pairs of ultra-LDCT with a slice thickness of 1 mm and CT with ECG synchronization with a slice thickness of 3 mm, performed on the same day after execution. Analysis of DICOM 3.0 standard images was performed. Quantitative indicators of coronary calcium in patients from lung cancer screening were analyzed, a comparative analysis of the calcium index for Agatstone, Volume, Mass, and using the CAC-DRS scale (assessment of the degree of calcification by scores from 0 to 3 and the number of affected arteries from 0 to 4 points) was performed.Results. Evaluation ultra-LDCT with a slice thickness in 1 mm and with a CT scan with slice thickness in 3 mm with and without ECG-synchronization for the presence of coronary calcium, and subsequent rating according to the index Agatston, Volume, Mass, as the total coronary calcium and for each coronary artery (right, left, left descending, left circumflex) received the complete data correlation (Pearson's - 1), with full correlation (Spearman's >0.9), with good rank correlations (>0,9). Compare qualitative (CAC-DRS V) and quantitative (CAC-DRS A) estimates on ultra-LDCT with CT with ECG synchronization in the same patients show a complete correlation of data was obtained (Pearson's formula - 1), with a complete correlation (Spearman's formula - 1).Conclusion. Coronary calcium which detected in lung cancer screening subjects should be included in the overall decision-making process for further routing of patients (cardiologist, interventional surgeon, pulmonologist, therapist). Ultra-LDCT is a method that has high diagnostic accuracy in detecting and evaluating the prevalence of coronary calcium in comparison with standard CT with and without ECG synchronization, as demonstrated in our study. Evaluation of coronary calcium according to ultra-LDCT without ECG synchronization used in screening, preferably with a 1 mm slice thickness. Despite the fact that the gold standard is CT with ECG synchronization with a 3 mm slice thickness, the diagnostic significance of ultra-LDCT which used in lung cancer screening is high in relation to detecting coronary artery calcification.

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.