Vector-field dynamic x-ray (VF-DXR) using optical flow method in patients with chronic obstructive pulmonary disease

European Radiology Experimental

Table 3 Correlation between lung motion velocity in the left lung and demographic data

Variables	Tidal inspiration		Tidal expiration		Forced inspiration		Forced expiration
Variables	r_s [95% CI]	p value	r_s [95% CI]	p value	r_s [95% CI]	p value	r_s [95% CI]	p value
Age	0.14 [-0.08, 0.35]	0.199	-0.17 [-0.37, 0.06]	0.135	-0.02 [-0.24, 0.20]	0.852	-0.19 [-0.40, 0.03]	0.079
Sex	0.27 [0.05, 0.47]	0.013^*	-0.10 [-0.32, 0.12]	0.348	0.18 [-0.05, 0.38]	0.110	-0.27 [-0.46, -0.05]	0.013^*
Height	0.08 [-0.15, 0.29]	0.500	-0.06 [-0.27, 0.17]	0.612	0.17 [-0.05, 0.38]	0.121	-0.31 [-0.50, -0.10]	0.004^**
Weight	0.07 [-0.16, 0.29]	0.544	-0.05 [-0.26, 0.18]	0.681	0.22 [0, 0.42]	0.047^*	-0.30 [-0.49, 0.08]	0.006^**
BMI	0.05 [-0.17, 0.27]	0.628	-0.04 [-0.26, 0.18]	0.695	0.17 [-0.06, 0.38]	0.131	-0.20 [-0.40, 0.02]	0.072
TV	-0.05 [-0.27, 0.18]	0.663	0.05 [-0.18, 0.27]	0.667	0.13 [-0.09, 0.34]	0.232	-0.25 [-0.45, -0.03]	0.023^*
VC	-0.03 [-0.25, 0.20]	0.807	0.06 [-0.17, 0.28]	0.595	0.21 [-0.01, 0.42]	0.053	-0.23 [-0.43, -0.01]	0.038^*
%VC	-0.23 [-0.43, -0.01]	0.038^*	0.12 [-0.10, 0.34]	0.261	0.15 [-0.08, 0.36]	0.186	-0.09 [-0.30, 0.14]	0.436
FEV₁	-0.16 [-0.37, 0.06]	0.137	0.07 [-0.16, 0.28]	0.559	0.20 [-0.20, 0.41]	0.067	-0.06 [-0.28, 0.17]	0.613
FEV₁%	-0.21 [-0.42, 0.01]	0.052	0.02 [-0.20, 0.24]	0.858	0.09 [-0.13, 0.31]	0.405	0.08 [-0.14, 0.30]	0.446
%FEV₁	-0.32 [-0.51, -0.10]	0.003^**	0.11 [-0.11, 0.32]	0.338	0.13 [-0.10, 0.34]	0.245	0.10 [-0.13, 0.31]	0.396

Spearman’s rank correlation coefficient (r_s) was calculated. *p < 0.05; **p < 0.01. BMI Body mass index, CI Confidence interval, FEV₁ Forced expiratory volume in one second, FEV₁% Forced expiratory volume percent in one second divided by forced vital capacity, %FEV₁ Percent predicted forced expiratory volume in one second, GOLD Global initiative for chronic obstructive lung disease, LMV Lung motion velocity, TV Tidal volume, VC Vital capacity; %VC Percent predicted vital capacity