Table 2. Degree of structural CT changes (emphysema. airway wall thickening and gas trapping) for the total population and stratified by classification of airflow limitation.
| Total, n = 1,108 | FEV1/FVC >70%, n = 671 | FEV1/FVC <70%, but>LLN, n = 216 | FEV1/FVC <70%, and <LLN, n = 221 | |
| Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | |
| 15th percentile | −908.1 (18.9) | −902.6 (17.9) | −912.4 (15. 5)# | −921.1 (18.6)# |
| log950% | −0.22 (1.14) | −0.61 (0.93) | 0.21 (0.95)# | 0.76 (1.23)# |
| E/I-ratio% | 83.70 (6.2) | 81.67 (5.9) | 85.53 (4.9)# | 88.73 (4.7)# |
| Pi10 [millimeters] | 2.43 (0.51) | 2.28 (0.42) | 2.51 (0.49)# | 2.79 (0.56)# |
Univariate analysis with the group FEV1/FVC >70% as reference. # p<0.001. Log950% = log-transformed percentage of voxels below HU -950. E/I-ratio% = expiratory mean lung density in HU divided by the inspiratory mean lung density in HU expressed as a percentage. Pi10 = the square root of wall area for a theoretical airway with 10mm lumen perimeter.