The purposes of this study were: to describe chest CT findings in normal non-smoking controls and cigarette smokers with and without COPD; to compare the prevalence of CT abnormalities with severity of COPD; and to evaluate concordance between visual and quantitative chest CT (QCT) scoring Methods Volumetric inspiratory and expiratory CT scans of 294 subjects, including normal non-smokers, smokers without COPD, and smokers with GOLD Stage I-IV COPD, were scored at a multi-reader workshop using a standardized worksheet. There were fifty-eight observers (33 pulmonologists, 25 radiologists); each scan was scored by 9–11 observers. Interobserver agreement was calculated using kappa statistic. Median score of visual observations was compared with QCT measurements. Results Interobserver agreement was moderate for the presence or absence of emphysema and for the presence of panlobular emphysema; fair for the presence of centrilobular, paraseptal, and bullous emphysema subtypes and for the presence of bronchial wall thickening; and poor for gas trapping, centrilobular nodularity, mosaic attenuation, and bronchial dilation. Agreement was similar for radiologists and pulmonologists. The prevalence on CT readings of most abnormalities (e.g. emphysema, bronchial wall thickening, mosaic attenuation, expiratory gas trapping) increased significantly with greater COPD severity, while the prevalence of centrilobular nodularity decreased. Concordances between visual scoring and quantitative scoring of emphysema, gas trapping and airway wall thickening were 75%, 87% and 65%, respectively. Conclusions Despite substantial inter-observer variation, visual assessment of chest CT scans in cigarette smokers provides information regarding lung disease severity; visual scoring may be complementary to quantitative evaluation.

No abstract

No abstract

A B S T R A C T We measured the response to breathing a mixture of 80% helium and 20% oxygen (He) during a maximum expiratory flow-volume (MEFV) maneuver in 66 nonsmokers and 48 smokers, aged 17-67. All of the subjects studied had (forced expiratory volume in 1 s/forced vital capacity [FEV,.o/FVC]) X 100 of greater than 70%. While the flow rates of the smokers were within ±2 SD of those of the nonsmokers at 50% VC (Vmaxwo), both groups showed a reduction in flow with age (nonsmokers: r = -0.34, P < 0.01; smokers r = -0.52, P < 0.001). Nonsmokers showed no significant reduction with age in response to breathing He, while smokers showed a marked reduction with age (r = -0.63, P < 0.001 at Vmaxw). We also measured the lung volume at which maximum expiratory flow (Vmax) while the subject was breathing He became equal to Vmax while he was breathing air, and expressed it as a percent of the VC. This was the most sensitive method of separating smokers from nonsmokers. These results indicate that the use of He during an MEFV maneuver affords sufficient sensitivity to enable detection of functional abnormalities in smokers at a stage when Vmax while they are breathing air is normal.

Static volume-pressure characteristics of the human lung, closing capacity (CC), closing pressure, and subdivisions of lung volumes were measured in 66 adult nonsmokers, aged 24-58 yr. There were systemic differences between the sexes as well as with age. Young females had less elastic recoil at any lung volume than young males. However, males lost elastic recoil with age faster than females so that in the older age groups the recoil was similar. There were no significant changes in compliance over the volume range containing most values of CC in either males or females. By comparing the age regression of CC and of elastic recoil pressures at 40 and 50% TLC we conclude that the increase in CC with age in males was attributable almost entirely to loss of recoil. In females none of the increase in closing capacity with age was attributable to loss of recoil. By exclusion, it is probably attributable to a change in the intrinsic properties of small airways or an increase in the pleural pressure gradient with age.