Figure 1

Determination of the optimal airway size. Mean cumulativeassessed perimeter fractions in the total lung, for different groupsof patients at different internal airway lumen diameters. APF wasmeasured on low-dose CT of 20 selected NELSON subjects divided into3 groups: subjects without emphysema and with normal lung function(n = 8, perc15 > −910 and FEV₁/FVC >85 %), with moderate emphysema and normal lung function (n= 4, -940 < perc15 < −960 and FEV₁/FVC> 70 %) and without emphysema and having severeairflow limitation (n = 8, perc15 > −920 andFEV₁/FVC < 50 %), in airways with alumen diameter of 2.5, 3.0, 3.5, 4.0, 4.5 and 5.0 mm (±0.25 mm).