Fig. 3From: Principal component analysis of flow-volume curves in COPDGene to link spirometry with phenotypes of COPDPercentage emphysema (PRMemph), percentage gas trapping (PRMfSAD) and bronchial wall thickening (Pi10) per group (never-smoked normal control subjects; mild COPD (GOLD I); moderate-severe COPD (GOLD II-III-IV)). The cut-offs (dashed lines) are determined by using the 95th percentile (upper limit of normal) on the control subjectsBack to article page