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). Among 2,111 participants undergoing low-dose CT (LDCT), a subset received spirometry, and 181 participants underwent AI-based quantitative CT (QCT) analysis using Aview software (Coreline, Seoul, South Korea). QCT was used 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%, while a %LAA threshold of ≥6% at −910 HU demonstrated a sensitivity of 63%, specificity of 49%, and positive predictive value of 73%. Median %LAA increased significantly with higher COPD GOLD stages (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 analysis for COPD risk stratification in lung cancer screening populations.