Fig 4. The ratio of mucus-occluded bronchial compartments in 13 subjects by airway generation during asthma exacerbation and the stable phase.

Mucus occlusion (mucus plug) was measured by HRCT using curved MPR software. Mucus plugs are defined as the complete occlusion of a bronchus, contiguous with patent airway lumen on longitudinal airway image. Mucus occlusions are counted per airway generation in all segments of the lung for each subject. Each point represents the ratio of mucus-occluded compartments in 13 patients for each segment.