Purpose To evaluate the feasibility, diagnostic yield, and radiation impact of additional ultra-low-dose CT (ULDCT) covering the entire thorax during coronary CT angiography (CCTA) and coronary artery calcium scoring (CACS) for lung cancer screening. Materials and Methods This prospective multicenter cohort study enrolled asymptomatic participants undergoing either CACS alone or CACS with CCTA between August 2018 and January 2024. Participants with contraindications to iodinated contrast material or who were pregnant were excluded. All participants underwent additional ULDCT for lung cancer screening. Pulmonary nodules were monitored for 2 years with follow-up low-dose CT. Primary outcomes were lung cancer detection rate, radiation exposure, and detection rate of noncancerous findings. Descriptive and multivariable analyses evaluated predictors of lung cancer, assessing calibration, discrimination, and significance. Results Among 2750 participants (mean age, 57 years ± 9.5 [SD]; 2090 men) who underwent coronary assessment, 1353 (49.2%) met U.S. Preventive Services Task Force lung cancer screening eligibility. ULDCT depicted pulmonary nodules in 1045 (38%) participants, with an average diameter of 4.57 mm ± 4.00. A total of 222 of 254 (87%) nodules larger than 6 mm were noncancerous lesions. Lung cancer was ultimately diagnosed in 32 of 2750 (1.16%) participants, including 12 participants with lung cancer that was undetectable within the cardiac field of view. Early-stage disease was identified in 23 of 32 (72%) participants. Additional ULDCT increased radiation dose by 2.03% ± 0.31 for CCTA and 17.12% ± 0.65 for CACS. Conclusion Additional full-chest ULDCT with CCTA and CACS enabled early lung cancer detection with modest radiation dose increase. Keywords: CT, Coronary CT Angiography, Cardiac, Thorax, Lung, Primary Neoplasms, Epidemiology Supplemental material is available for this article. © RSNA, 2025.
Keywords: CT; Cardiac; Coronary CT Angiography; Epidemiology; Lung; Primary Neoplasms; Thorax.