Fig. 6.

Representative image of patterns B and D for structural abnormalities in 72-year-old male with Gold stage II emphysema.

Small subpleural bulla in right upper lobe on CT (A; arrowheads) shows high attenuation on wash-in (B) and wash-out xenon-enhanced images (C), which is compatible with pattern B shown in CAC map in sky blue (D). Large subpleural bulla in right lower lobe on CT (A; arrows) shows low attenuation on wash-in (B) and wash-out xenon-enhanced images (C). This ventilation pattern is in agreement with pattern D and is correctly visualized on CAC map in yellow (D). CAC = computer-aided classification