Coronary Artery Calcification on Low-Dose Lung Cancer Screening CT in South Korea: Visual and Artificial Intelligence-Based Assessment and Association With Cardiovascular Events.

Background: Coronary artery calcification (CAC) on lung cancer screening low-dose chest CT (LDCT) is a cardiovascular risk marker. South Korea was the first Asian country to initiate a national LDCT lung cancer screening program, although CAC-related outcomes are poorly explored. Objective: To evaluate CAC prevalence and severity using visual analysis and artificial intelligence (AI) methods and to characterize CAC's association with major adverse cardiovascular events (MACEs) in patients undergoing LDCT in Korea's national lung cancer screening program. Methods: This retrospective study included 1002 patients (mean age, 62.4±5.4 years; 994 men, 8 women) who underwent LDCT at two Korean medical centers between April 2017 and May 2023 as part of Korea's national lung cancer screening program. Two radiologists independently assessed CAC presence and severity using visual analysis, consulting a third radiologist to resolve differences. Two AI software applications were also used to assess CAC presence and severity. MACE occurrences were identified by EMR review. Results: Interreader agreement for CAC presence and severity, expressed as kappa, were 0.793 and 0.671, respectively. CAC prevalence was 53.4% by consensus visual assessment, 56.6% by AI software I, and 60.1% by AI software II. CAC severity was mild, moderate, and severe by consensus visual analysis in 28.0%, 10.3% and 15.1%; by AI software I in 39.9%, 14.0%, and 6.2%; and by AI software II in 34.9%, 14.3%, and 7.3%. MACE occurred in 36 of 625 (5.6%) patients with follow-up after LDCT (median, 1108 days). MACE incidence in patients with no, mild, moderate, and severe CAC, for consensus visual analysis was 1.1%, 5.0%, 2.9%, and 8.6% (p<.001); for AI software I was 1.3%, 3.0%, 7.9%, and 11.3% (p<.001); and for AI software II was 1.2%, 5.0%, 7.7%, and 9.6% (p<.001) Conclusion: For Korea's national lung cancer screening program, MACE occurrence increased significantly with increasing CAC severity, whether assessed by visual analysis or AI software. The study is limited by the large sex imbalance for Korea's national lung cancer screening program. Clinical Impact: The findings provide reference data for healthcare practitioners engaged in developing and overseeing national lung cancer screening programs, highlighting the importance of routine CAC evaluation.