Emphysema detection by qualitative and quantitative analysis and relationship to spirometric obstruction in an urban comprehensive lung cancer screening programme: the Temple Healthy Chest Initiative (THCI) – a retrospective cohort study

This retrospective study evaluated the relationship between emphysema detection and spirometric obstruction in an urban lung cancer screening cohort from the Temple Healthy Chest Initiative (THCI). A total of 2,111 participants underwent low-dose CT (LDCT), with 629 completing spirometry. In a subcohort of 181 participants, AI-based quantitative CT (QCT) analysis was performed using Aview software (Coreline Soft) to quantify low-attenuation area (%LAA) at −950 HU and −910 HU thresholds. Radiologist-based qualitative assessment showed a sensitivity of 81.3% and specificity of 53.4%. Using a %LAA cutoff of ≥6% at −910 HU yielded a sensitivity of 63%, specificity of 49%, and a positive predictive value of 73%. Median %LAA increased significantly with higher COPD GOLD stage (p<0.001), indicating a strong association between quantitative emphysema burden and disease severity. The findings suggest that spirometry should be considered when %LAA is ≥6%, supporting the clinical utility of AI-based QCT in lung cancer screening populations.