title: Contribution of CT quantified emphysema, air trapping and airway wall thickness on pulmonary function in male smokers with and without COPD.
abstract: Emphysema, airway wall thickening and air trapping are associated with chronic obstructive pulmonary disease (COPD). All three can be quantified by computed tomography (CT) of the chest. The goal of the current study is to determine the relative contribution of CT derived parameters on spirometry, lung volume and lung diffusion testing. Emphysema, airway wall thickening and air trapping were quantified automatically on CT in 1,138 male smokers with and without COPD. Emphysema was quantified by the percentage of voxels below -950 Hounsfield Units (HU), airway wall thickness by the square root of wall area for a theoretical airway with 10 mm lumen perimeter (Pi10) and air trapping by the ratio of mean lung density at expiration and inspiration (E/I-ratio). Spirometry, residual volume to total lung capacity (RV/TLC) and diffusion capacity (Kco) were obtained. Standardized regression coefficients (β) were used to analyze the relative contribution of CT changes to pulmonary function measures. The independent contribution of the three CT measures differed per lung function parameter. For the FEV1 airway wall thickness was the most contributing structural lung change (β = -0.46), while for the FEV1/FVC this was emphysema (β = -0.55). For the residual volume (RV) air trapping was most contributing (β = -0.35). Lung diffusion capacity was most influenced by emphysema (β = -0.42). In a cohort of smokers with and without COPD the effect of different CT changes varies per lung function measure and therefore emphysema, airway wall thickness and air trapping need to be taken in account.
authors.affiliation: 1Department of Respiratory Medicine, Division of Heart & Lungs, University Medical Center Utrecht , Utrecht , the Netherlands.
authors.forename: Firdaus A A
authors.initials: FA
authors.lastname: Mohamed Hoesein
authors.forename: Pim A
authors.initials: PA
authors.lastname: de Jong
authors.forename: Jan-Willem J
authors.initials: JW
authors.lastname: Lammers
authors.forename: Willem P Th M
authors.initials: WP
authors.lastname: Mali
authors.forename: Onno M
authors.initials: OM
authors.lastname: Mets
authors.forename: Michael
authors.initials: M
authors.lastname: Schmidt
authors.forename: Harry J
authors.initials: HJ
authors.lastname: de Koning
authors.forename: Carlijn van der
authors.initials: Cv
authors.lastname: Aalst
authors.forename: Matthijs
authors.initials: M
authors.lastname: Oudkerk
authors.forename: Rozemarijn
authors.initials: R
authors.lastname: Vliegenthart
authors.forename: Bram van
authors.initials: Bv
authors.lastname: Ginneken
authors.forename: Eva M
authors.initials: EM
authors.lastname: van Rikxoort
authors.forename: Pieter
authors.initials: P
authors.lastname: Zanen
mesh_terms: D000368:Aged; D056151:Airway Remodeling; D016022:Case-Control Studies; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011653:Pulmonary Diffusing Capacity; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011656:Pulmonary Emphysema / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012115:Residual Volume; D012907:Smoking; D013147:Spirometry; D014057:Tomography, X-Ray Computed; D014109:Total Lung Capacity
keywords: air trapping; airway wall thickness; chronic obstructive pulmonary disease; computed tomography; emphysema; quantitative