Quantitative Computed Tomography assessment of pulmonary emphysema: Current applications, clinical correlations, and environmental influences with insights from Northeastern China

Abstract

Emphysema is the primary cause of chronic obstructive pulmonary disease (COPD), defined as having an irreversible loss of alveolar walls, expansion of distal airspaces, worsening airflow obstruction, and progressively worsening complaints of shortness of breath (dyspnea). COPD is a leading cause of death and morbidity globally and is associated with air pollutants, tobacco cigarettes, exposure to particulate matter from biomass fuels, dust from work settings, and some genetic factors. Pulmonary function tests (PFTs) determine the level of COPD; FEV1 is a marker used to assess disease severity. However, these tests do not directly assess loss of structural parenchymal integrity. Advances in High-Resolution Computed Tomography (HRCT) and Quantitative CT (QCT) now allow objective assessment of emphysema using biomarkers such as Low Attenuation Area (LAA) percentage, lung density, emphysema index, and percentile density, which strongly correlate with the degree of pulmonary dysfunction, dyspnea severity, disease progression, and mortality. Recent automated Artificial Intelligence (AI) lung segmentation technology has further improved the accuracy and reproducibility of emphysema quantification. Prolonged winters, coal-based heating, factory pollution, and exposure to environmental particles in Northeast China are likely contributing factors to the burden of chronic respiratory diseases. This review summarizes the pathophysiology, clinical manifestations, pulmonary function testing, and QCT measurements of emphysema. It emphasizes the clinical-radiographic correlation and environmental factors associated with emphysema, highlights current research gaps in quantitative emphysema assessment among dyspneic patients in northeastern China, and emphasizes the need for additional radiographic and epidemiologic data from the region.