FIGURE 2.

Representative images showing early‐breath ¹⁹F (A), max‐vent ¹⁹F (B), low‐resolution ¹²⁹Xe (C), and high‐resolution ¹²⁹Xe (D) images in three subjects. A threshold was applied to define regions of ventilation defects (red masks). VDPs were calculated as the percentage of lung with a ventilation defect compared with total lung volume calculated by the anatomic mask. VDPs in early‐breath ¹⁹F images were higher than in max‐vent images, likely due to lack of sufficient signal. High‐resolution ¹²⁹Xe images typically displayed higher VDPs than low‐res images