Table 3.
Changes in CT lung density (n = 56)
| Scan 1 | Scan 2 | Median change/yr | Z statistic | |
| Upper zone | -916.45 | -926.7 | -1.11 | -3.59 (p ≤ 0.001) |
| Perc15 (HU) | (-952.3 to -902.2) | (-960.1 to -912.9) | (-4.05 to -0.12) | |
| Upper zone | 4.58 | 7.20 | 0.29 | -4.05 (p ≤ 0.001) |
| VI -950HU (%) | (2.31 to 15.98) | (3.74 to 19.32) | (0.02 to 0.90) | |
| Lower zone | -919.23 | -923.24 | -0.82 | -2.20 (p < 0.05) |
| Perc15 (HU) | (-947.0 to -895.6) | (-948.4 to -906.1) | (-3.05 to 1.37) | |
| Lower zone | 4.79 | 6.46 | 0.20 | -3.43 (p ≤ 0.001) |
| VI -950HU (%) | (1.89 to 11.35) | (3.25 to 14.62) | (-0.12 to 0.73) | |
The data was not normally distributed and therefore is presented as median with interquartile range in parentheses. The Z-statistic derived from the Wilcoxon signed rank test is shown for the change in all CT parameters with p values in parentheses. VI = voxel index, Perc15 = 15th percentile point, HU = Hounsfield Units.