Additional ultra-low-dose protocols in coronary computed tomography angiography scans to early detection of lung cancer

Background Chest CT screening improves lung cancer detection at early stages for high-risk populations, such as heavy-smokers. However, CT screening also has some considerable disadvantages as radiation exposure, patient distress and overdiagnosis. Tobacco is also a major risk factor for coronary heart disease. Purpose To assess whether an additional chest ultra-low-dose CT scan to the coronary CT angiography protocol can be used for lung cancer screening among patients with suspected coronary artery disease. Methods 980 patients underwent coronary CT angiography for assessment of coronary artery disease, additionally undergoing ultra-low-dose CT screening to early diagnosis of lung cancer in the same scanner (80kVp and 15mAs). Patients presenting pulmonary nodules were followed-up for two years, repeating low-dose CTs in intervals of 3, 6, or 12 months based on nodule size and growth rate in accordance with National Comprehensive Cancer Network guidelines. Results Ultra-low-dose CT identified 437 patients with solitary pulmonary nodules (45%), with a mean diameter of 5.40±4.10mm. One hundred fifty two were >6mm, and in 83% (n=126) of these cases they were false positive findings, further confirmed by follow-up (n=114), resection (n=3), or biopsy (n=9). Lung cancer was detected in twenty nine patients due to CT screening (diagnostic yield: 2.9%). Among these, 20 cases could not be detected in the cardiac field of view. Most patients were in early stages of the disease, and eight patients diagnosed at advanced stages (IIIB and IV). The addition of the ultra-low-dose CT scan represented a radiation dose increment of 1.32±0.29% (effective dose, 0.12±0.04mSv). Conclusions Lung cancer might be detected using additional ultra-low-dose protocols in coronary CT angiography scans among patients with suspected coronary artery disease. FUNDunding Acknowledgement Type of funding sources: None.