Emphysema- and airway-dominant COPD phenotypes defined by standardised quantitative computed tomography

Area of Science:

• Pulmonary Medicine
• Radiology
• Biomarker Discovery

Background:

• Chronic obstructive pulmonary disease (COPD) encompasses diverse pathologies, including emphysema and airway disease.
• Accurate phenotyping is crucial for understanding COPD mechanisms and developing targeted therapies.
• Current phenotyping methods may lack objective, quantitative measures for distinguishing emphysema-dominant from airway disease-dominant presentations.

Purpose of the Study:

• To objectively delineate emphysema-dominant and airway disease-dominant phenotypes in COPD using quantitative computed tomography (QCT) indices.
• To standardize QCT measurements across multiple centers using a novel phantom-based approach for improved robustness.
• To correlate imaging-derived phenotypes with clinical and physiological characteristics of COPD patients.

Main Methods:

• A multicenter study involving 441 COPD patients (GOLD stages 1-3).
• Quantitative computed tomography (QCT) was used to assess emphysema and airway wall geometry.
• A novel phantom-based approach standardized QCT indices to minimize scanner variability.
• Clinical, physiological, and laboratory data were collected for correlation.

Main Results:

• Standardization of QCT indices significantly reduced measurement variability (p<0.001).
• Four distinct imaging-derived phenotypes were identified: emphysema-dominant, airway disease-dominant, mixed, and mild disease.
• The emphysema-dominant group exhibited higher lung volumes and distinct gas exchange and hematological profiles compared to the airway disease-dominant group.

Conclusions:

• Standardized QCT is a valuable tool for robust phenotyping in multicenter COPD research.
• QCT can delineate COPD phenotypic groups with distinct clinical features, improving disease characterization.
• This approach enhances the utility of imaging for understanding COPD heterogeneity and guiding clinical management.