Quantifying the extent of emphysema: factors associated with radiologists' estimations and quantitative indices of emphysema severity using the ECLIPSE cohort

RATIONALE AND OBJECTIVES: This study investigated what factors radiologists take into account when estimating emphysema severity and assessed quantitative computed tomography (CT) measurements of low attenuation areas. MATERIALS AND METHODS: CT scans and spirometry were obtained on 1519 chronic obstructive pulmonary disease (COPD) subjects, 269 smoker controls, and 184 nonsmoker controls from the Evaluation of COPD Longitudinally to Indentify Surrogate Endpoints (ECLIPSE) study. CT scans were analyzed using the threshold technique (%<-950HU) and a low attenuation cluster analysis. Two radiologists scored emphysema severity (0 to 5 scale), described the predominant type and distribution of emphysema, and the presence of suspected small airways disease. RESULTS: The percent low attenuation area (%LAA) and visual scores of emphysema severity correlated well (r = 0.77, P < .001). %LAA, low attenuation cluster analysis, and absence of radiologist described gas trapping, distribution, and predominant type of emphysema were predictors of visual scores of emphysema severity (all P < .001). CT scans scored as showing regions of gas trapping had smaller lesions for a similar %LAA than those without (P < .001). CONCLUSIONS: Visual estimates of emphysema are not only determined by the extent of LAA, but also by lesion size, predominant type, and distribution of emphysema and presence/absence of areas of small airways disease. A computer analysis of low attenuation cluster size helps quantitative algorithms discriminate low attenuation areas from gas trapping, image noise, and emphysema

Potential cardiovascular and total mortality benefits of air pollution control in Urban China.

Background -Outdoor air pollution ranks fourth among preventable causes of China&#39;s burden of disease. We hypothesized that the magnitude of health gains from air quality improvement in urban China could compare with achieving recommended blood pressure or smoking control goals. Methods -The Cardiovascular Disease Policy Model-China projected coronary heart disease, stroke, and all-cause deaths in urban Chinese adults aged 35-84 years from 2017 to 2030 if recent air quality (particulate matter with aerodynamic diameter &le; 2.5 &mu;m, PM2.5) and traditional cardiovascular risk factor trends continue. We projected life years gained if urban China were to reach one of three air quality goals: Beijing Olympic Games level (mean PM2.5, 55 &mu;g/m(3)), China Class II standard (35 &mu;g/m(3)), or World Health Organization (WHO) standard (10 &mu;g/m(3)). We compared projected air pollution reduction control benefits with potential benefits of reaching WHO hypertension and tobacco control goals. Results -Mean PM2.5 reduction to Beijing Olympic levels by 2030 would gain about 241,000 (95% uncertainty interval, 189,000-293,000) life-years annually. Achieving either the China Class II standard or WHO PM2.5 standard would yield greater health benefits [992,000 (95% uncertainty interval, 790,000-1,180,000) or 1,827,000 (95% uncertainty interval, 1,481,000-2,129,000) annual life years gained, respectively] than WHO-recommended goals of 25% improvement in systolic hypertension control and 30% reduction in smoking combined [928,000 (95% uncertainty interval, 830,000-1,033,000) life years]. Conclusions -Air quality improvement at different scenarios could lead to graded health benefits ranging from 241,000 life-years gained to much greater benefits are equal to or greater than the combined benefits of 25% improvement in systolic hypertension control and 30% smoking reduction