Spearman correlation coefficients (rho) for the relationship between high-resolution computed tomography (HRCT) and lung function
| HRCT pixel index | ||||
| Upper zone | lower zone | |||
| Inspiratory | Expiratory | Inspiratory | Expiratory | |
| FEV1 | −0.60 | −0.72 | −0.64 | −0.75 |
| FEV1/VC | −0.72 | −0.79 | −0.70 | −0.78 |
| FEF25%–75% | −0.60 | −0.69 | −0.70 | −0.76 |
| sGaw | −0.67 | −0.76 | −0.68 | −0.76 |
| TLC | 0.63 | 0.70 | 0.54 | 0.61 |
| RV | 0.61 | 0.58 | 0.43 | 0.41 |
| RV/TLC | 0.47 | 0.58 | 0.46 | 0.56 |
| T L,CO | −0.76 | −0.81 | −0.64 | −0.72 |
| K CO | −0.79 | −0.77 | −0.61 | −0.62 |
FEV1: forced expiratory volume in one second
VC: vital capacity
FEF25%–75%: forced midexpiratory flows
sGaw: Specific airways conductance
TLC: total lung capacity
RV: residual volume
TL,CO: transfer factor of the lung for carbor monoxide
KCO: carbor monoxide transfer coefficient
expressed as % predicted
percentage of pixels <−910 HU
All correlations are highly significant (p<0.001)