Table 3.

HRCT in 59 patients with COPD

Variables	Mean	SD
HRCT total volume (L)	6.05	1.26
HRCT tissue volume (L)	0.71	0.16
HRCT air volume (L)	5.34	1.20
HRCT density (HU)	−873.15	29.47
Emphysema less than −950 (%)	27.74	14.9
Emphysema less than −910 (%)	50.54	16.23

Abbreviations: Emphysema less than −950, percent of voxels with Hounsfield units less than −950; emphysema less than −910, percent of voxels with Hounsfield units less than −910; HRCT, high-resolution computed tomography; HU, Hounsfield units; SD, standard deviation.