Differences in airway lumen area between supine and upright computed tomography in patients with chronic obstructive pulmonary disease

Table 4 Correlations of airway lumen area on expiratory CT in the supine and standing positions with the results of the pulmonary function test

Generation	Supine	Standing	Generation	Supine	Standing
FEV₁			RV
Trachea	0.24	0.26	Trachea	0.19	0.24
Main bronchus	0.29*	0.05	Main bronchus	0.31*	0.20
3rd	0.35*	0.31*	3rd	0.37**	0.37**
4th	0.29*	0.34*	4th	0.29*	0.32*
5th	0.28	0.19	5th	0.28*	0.30*
6th	0.24	0.15	6th	0.33*	0.39*
%FEV₁			%RV
Trachea	0.05	0.12	Trachea	– 0.01	– 0.06
Main bronchus	0.02	– 0.04	Main bronchus	0.04	0.10
3rd	0.11	0.07	3rd	0.07	0.12
4th	0.07	0.17	4th	0.08	0.12
5th	0.10	0.12	5th	0.11	0.21
6th	0.10	0.03	6th	0.19	0.31*
			IC/TLC
			Trachea	0.02	0.02
			Main bronchus	– 0.02	– 0.08
			3rd	– 0.09	– 0.16
			4th	– 0.15	– 0.23
			5th	– 0.14	– 0.37*
			6th	– 0.22	– 0.43*

* and ** indicate p < 0.05 and p < 0.01, respectively. FEV₁, forced expiratory volume in 1 s; %FEV₁, forced expiratory volume in 1 s as a percentage of predicted forced expiratory volume in 1 s; RV, residual volume; %RV, residual volume as a percentage of predicted residual volume; IC/TLC; inspiratory capacity/total lung capacity ratio

ISSN: 1465-993X