Figure 4. Classification of structural phenotypes — normal and mixed emphysema/small airway disease.

Classification performance of normal (A) (emphysema <5% and small airway disease <20%) and mixed (B) (emphysema >5% and small airway disease >20%) groups. The results show per-class area under the curve (AUC) of the FCN model versus random forest classifier and logistic regression models with FEV₁/FVC and FEV₁% predicted measurements. Results shown for the hold-out test data set. FEV₁, forced expiratory volume in the first second; FVC, forced vital capacity; FCN, fully convolutional network. Small airway disease was defined by parametric response mapping.