Table 3 Comparison of Emphysema variables between the carbon dioxide retention and non-carbon dioxide retention COPD

Volume _whole

6106.56 (5113.8–6767.43)

5578.61 (4512.44–6459.67)

0.011

%LAA _whole

23.23 (15.43–29.51)

18.02 (11.83–25.83)

0.007

Mean lung density _whole

−861.37(−878.99--834.07)

−851.21 (−867.76--829.83)

0.043

Volume _{Right lung}

3180.79 (2756.52–3578.41)

3014.42 (2482.47–3488.95)

0.047

%LAA _{Right lung}

23.4 (15.24–30.08)

17.65 (12.28–25.68)

0.006

Mean lung density _Right

−859.2 (− 879.56--835.39)

−851.14 (− 866.61--829.63)

0.032

Volume _{Left lung}

2878.78 (2319.57–3221.92)

2599.85 (2039.45–3039.15)

0.003

%LAA _{Left lung}

23.39 (14.8–29.1)

18.83 (11.65–26.32)

0.008

Mean lung density _Left

− 862.98 (−876.01--837.3)

− 847.85 (− 870.33--826.79)

0.039

HI _whole

0.09 (−0.08–0.29)

0.16 (−0.02–0.32)

0.169

HI _{Right lung}

0.15 (−0.06–0.35)

0.18 (− 0.02–0.38)

0.458

HI _{Right lung}

− 0.17 (− 0.41–0.05)

−0.08 (− 0.28–0.11)

0.079