Table 1– Descriptive statistics of change in Hounsfield units values and change in specific gas volume#
ΔHUΔSVg mL·g−1
HealthyEmphysemaHealthyEmphysema
AACTDAACTDAACTDAACTD
Median176±50168±46192±3812.5±7.6***12±6***19±9***4.7±1.04.7±1.04.9±0.91.3±0.6***1.3±0.6***1.5±0.5***
IQR80±1697±24118±2533.3±9.1***34±10***43±8***2.2±0.42.3±0.42.5±0.44.0±0.8***4.1±1.2***4.1±1.5***
Skewness-0.2±0.4-0.0±0.3-0.1±0.20.0±0.7-0.1±1.1-0.1±0.5-0.2±0.4-0.1±0.4-0.003±0.30.5±0.5***0.6±0.5**0.6±0.3***
QCV0.2±0.030.3±0.040.3±0.01.5±0.6***1.7±1.0***1.2±0.5***0.2±0.040.3±0.040.3±0.031.5±0.6***1.6±0.9***1.2±0.5***

  • Data are presented as mean±sem. ΔHU: ΔHU=HUwarped residual volume-HUtotal lung capacity; ΔSVg: ΔSVg=SVgtotal lung capacity-SVgwarped residual volume; AA: aortic arch; C: carina; TD: top diaphragm; IQR: interquartile range; QVC: quartile variation coefficient. #: shown as average values. **: p<0.01, versus corresponding healthy average; ***: p<0.001, versus corresponding healthy average.