Figure 5.

Effect of heterogeneity on endobronchial valve (EBV) response at 6 months. Shown is the effect of heterogeneity on change in (A) FEV₁ and (B) 6-minute walk distance (6MWD) at 6 months after EBV implantation. Percent heterogeneity was the difference in quantitative emphysema score (the proportion of pixels less than −910 Hounsfield units) between EBV-treated and ipsilateral nontreated lobes. In (C), sagittal high-resolution chest computed tomography views with density mask views show low (6%, left) and high heterogeneity (25%, right). Darker areas represent pixels less than −910 Hounsfield units, consistent with emphysema. Reprinted by permission from Reference 2.