Total Pulmonary Vascular Volume and One Year Progression of CT-Assessed Emphysema in the SPIROMICS Cohort

Methods: SPIROMICS is a prospective cohort study of smokers with COPD and controls age 40-80 years old. We studied the first 973 SPIROMICS subjects with CT images, performed at total lung capacity (TLC), and residual volume (RV), and a one-year follow-up CT. We identified three groups based on change in percent emphysema (EI:% lung voxels<-950HU): rapid progressors (RP) had a whole lung EI difference> 1%; non-progressors (NP) had EI change (±) of≤ 0.5%; normal non-smoking subjects (NL) were included as a control group. To minimize EI change due to mis-matched breath holds at baseline and one year, all groups were limited to CT volume differences between visits< 10%. Of the 973 subjects, 796 met these criteria. Pulmonary vessel masks were extracted (Apollo: VIDA Diagnostics), and refined using a fuzzy distance analysis to smooth and preserve vessel boundaries. From this, whole lung …