Fig. 3From: Local heterogeneity of normal lung parenchyma and small airways disease are associated with COPD severity and progressionScatter plots of all study sample participants for (A) VNorm versus VfSAD and (B) χNorm versus χfSAD. Individual points are color coded based on COPD classifications. The size of the points indicates the amount of emphysema as measured by the volume density of PRMEmph (VEmph)Back to article page