Comparison of CT measures of emphysema and air trapping.

All values expressed as Mean (standard deviation, SD). LAA950insp = Percent Low attenuation area below −950 HU at end inspiration. LAA856exp = Percent Low attenuation area below −856 HU at end expiration.*significant difference on univariate analysis compared to non smokers at p†significant difference compared to non smokers on multivariate analysis, adjusted for age, gender, height and body mass index, at p¥significant difference compared to non smokers on multivariate analysis, adjusted for age, gender, height and body mass index, at p