Table 2.

CT quantitative densitometric data, airway wall thickness, inspiratory–expiratory volume variation, and tracheal collapsibility in 69 patients with COPD subdivided according to the predominant mechanism of air flow limitation and sex

	All patients (n=69)	Predominant airway phenotype (n=28)	Predominant emphysema phenotype (n=41)	P	Males (n=42)	Females (n=27)	P
%LAA−950insp	11.7±13	5±5	16.3±15	<0.001	15±15	7±8	<0.05
%LAA−910exp	12.7±15	4±0.1	16.9±16	<0.01	16±16	7±11	<0.05
AWTPi10 (mm)	3.84±0.11	3.85±0.12	3.83±0.08	NS	3.87±0.09	3.80±0.09	<0.05
Delta volume	0.30±0.13	0.36±0.10	0.26±0.13	0.001	0.29±0.14	0.32±0.10	NS
Tracheal collapsibility (%)	14.4±12	19±13	11.4±10	<0.01	12±10	18±14	<0.05

Notes: Data are mean ± SD. Delta volume is ([inspiratory CT volume – expiratory CT volume]/inspiratory CT volume). Intrathoracic tracheal collapsibility (%) is ([inspiratory tracheal volume – expiratory tracheal volume]/inspiratory tracheal volume) ×100.

Abbreviations: AWTPi10 (mm), average wall thickness of an extrapolated airway with an internal perimeter of 10 mm; COPD, chronic obstructive pulmonary disease; CT, computed tomography; %LAA_−910exp, percentage of total lung area with attenuation values below −910 Hounsfield units at maximal expiration; %LAA_−950insp, percentage of total lung area with attenuation values below −950 Hounsfield units at maximal inspiration; NS, not significant; SD, standard deviation.