Year: 2013
Type: article
Abstract: BACKGROUND: Gas trapping quantified on chest CT scans has been proposed as a surrogate for small airway disease in COPD. We sought to determine if measurements using paired inspiratory and expiratory CT scans may be better able to separate gas trapping due to emphysema from gas trapping due to small airway disease. METHODS: Smokers with and without COPD from the COPDGene Study underwent inspiratory and expiratory chest CT scans. Emphysema was quantified by the percent of lung with attenuation < -950HU on inspiratory CT. Four gas trapping measures were defined: (1) Exp(-856), the percent of lung < -856HU on expiratory imaging; (2) E/I MLA, the ratio of expiratory to inspiratory mean lung attenuation; (3) RVC(856-950), the difference between expiratory and inspiratory lung volumes with attenuation between -856 and -950 HU; and (4) Residuals from the regression of Exp(-856) on percent emphysema. RESULTS: In 8517 subjects with complete data, Exp(-856) was highly correlated with emphysema. The measures based on paired inspiratory and expiratory CT scans were less strongly correlated with emphysema. Exp(-856), E/I MLA and RVC(856-950) were predictive of spirometry, exercise capacity and quality of life in all subjects and in subjects without emphysema. In subjects with severe emphysema, E/I MLA and RVC(856-950) showed the highest correlations with clinical variables. CONCLUSIONS: Quantitative measures based on paired inspiratory and expiratory chest CT scans can be used as markers of small airway disease in smokers with and without COPD, but this will require that future studies acquire both inspiratory and expiratory CT scans.
Source: Respiratory Research
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,490
Funders: Pfizer, AstraZeneca, GlaxoSmithKline, Gilead Sciences, Ikaria, University of Minnesota, Johns Hopkins University, University of Pittsburgh, COPD Foundation, Sunovion, Temple University, National Jewish Health, Morehouse School of Medicine, Astellas Pharma, Grifols, National Institutes of Health, University of California, San Diego, University of Texas Health Science Center at San Antonio, National Heart, Lung, and Blood Institute, National Institute of Nursing Research, National Institute of Environmental Health Sciences, National Center for Advancing Translational Sciences
Awards: LONG-TERM OXYGEN TREATMENT TRIAL (LOTT) PHARMACOGENOMICS ANCILLARY STUDY, PHARMACOGENOMICS OF INHALED CORTICOSTEROIDS TO REDUCE COPD EXACERBATIONS, G2417563097, (2 of 2) Genetic Epidemiology of COPD, University of Pittsburgh Clinical and Translational Science Institute, Th17 inflammation is responsible for mucous metaplasia in COPD, (1 of 2) Genetic Epidemiology of COPD, Graduate Training in Biostatistics, G993448119
OpenAlex ID: W2153997368