Quantitative Computed Tomography Biomarkers of Emphysema Severity in Chronic Obstructive Pulmonary Disease: Insights from Muscle Mass, Fat Volume, and Vascular Dimensions

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a progressive respiratory condition characterized by airflow limitation and systemic effects. Computed tomography (CT) imaging offers valuable insights into structural changes beyond spirometry, particularly for assessing emphysema severity. This study examines the relationship between CT-derived measures of pectoralis muscle area (PMA), subcutaneous fat volume (SFV), and vascular dimensions with emphysema progression in COPD patients. Materials and Methods: This cross-sectional study included 220 male COPD patients aged 40-75 who underwent CT scans. The associations between SFV, PMA, pulmonary artery diameter (PAD), ascending aortic diameter (AaD), and their ratio (PAD/AaD) with emphysema severity were analyzed. Emphysema was graded using the Fleischner Society classification system, and statistical analyses were performed to assess these associations. Results: Significant differences were observed in all imaging variables across emphysema severity groups (P < 0.05). Patients with advanced emphysema exhibited higher PAD (29.9 +/- 3.1 mm), AaD (36.1 +/- 2.3 mm), and PAD/AaD ratio (0.84 +/- 0.10). PMA showed a weak negative correlation with disease severity (rho = -0.16, P = 0.028), while both PAD and AaD exhibited moderate positive correlations (rho =0.37, P < 0.001). No significant correlation was found for SFV (rho = -0.05, P = 0.46). Conclusions: Quantitative CT-derived metrics, particularly PAD, AaD, and PMA, are significantly associated with emphysema severity, providing valuable insights into COPD progression. These metrics can serve as potential biomarkers for assessing disease severity, supporting a more personalized approach to patient management.