title: Quantitative computed tomography measures of emphysema and airway wall thickness are related to respiratory symptoms.
abstract: BACKGROUND
  There is limited knowledge about the relationship between respiratory symptoms and quantitative high-resolution computed tomography measures of emphysema and airway wall thickness.
  
  
  OBJECTIVE
  To describe the ability of these measures of emphysema and airway wall thickness to predict respiratory symptoms in subjects with and without chronic obstructive pulmonary disease (COPD).
  
  
  METHODS
  We included 463 subjects with chronic obstructive pulmonary disease (COPD) (65% men) and 488 subjects without COPD (53% men). All subjects were current or ex-smokers older than 40 years. They underwent spirometry and high-resolution computed tomography examination, and completed an American Thoracic Society questionnaire on respiratory symptoms.
  
  
  RESULTS
  Median (25th percentile, 75th percentile) percent low-attenuation areas less than -950 Hounsfield units (%LAA) was 7.0 (2.2, 17.8) in subjects with COPD and 0.5 (0.2, 1.3) in subjects without COPD. Mean (SD) standardized airway wall thickness (AWT) at an internal perimeter of 10 mm (AWT-Pi10) was 4.94 (0.33) mm in subjects with COPD and 4.77 (0.29) in subjects without COPD. Both %LAA and AWT-Pi10 were independently and significantly related to the level of dyspnea among subjects with COPD, even after adjustments for percent predicted FEV(1). AWT-Pi10 was significantly related to cough and wheezing in subjects with COPD, and to wheezing in subjects without COPD. Odds ratios (95% confidence intervals) for increased dyspnea in subjects with COPD and in subjects without COPD were 1.9 (1.5-2.3) and 1.9 (0.6-6.6) per 10% increase in %LAA, and 1.07 (1.01-1.14) and 1.11 (0.99-1.24) per 0.1-mm increase in AWT-Pi10, respectively.
  
  
  CONCLUSIONS
  Quantitative computed tomography assessment of the lung parenchyma and airways may be used to explain the presence of respiratory symptoms beyond the information offered by spirometry.
authors.affiliation: Department of Thoracic Medicine, Haukeland University Hospital, N-5021 Bergen, Norway. thomas.grydeland@med.uib.no
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Grydeland
authors.forename: Asger
authors.initials: A
authors.lastname: Dirksen
authors.forename: Harvey O
authors.initials: HO
authors.lastname: Coxson
authors.forename: Tomas M L
authors.initials: TM
authors.lastname: Eagan
authors.forename: Einar
authors.initials: E
authors.lastname: Thorsen
authors.forename: Sreekumar G
authors.initials: SG
authors.lastname: Pillai
authors.forename: Sanjay
authors.initials: S
authors.lastname: Sharma
authors.forename: Geir Egil
authors.initials: GE
authors.lastname: Eide
authors.forename: Amund
authors.initials: A
authors.lastname: Gulsvik
authors.forename: Per S
authors.initials: PS
authors.lastname: Bakke
mesh_terms: D000368:Aged; D016001:Confidence Intervals; D003371:Cough / Q000473:pathology / Q000503:physiopathology; D004417:Dyspnea / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D029424:Pulmonary Disease, Chronic Obstructive / Q000473:pathology / Q000503:physiopathology; D011656:Pulmonary Emphysema / Q000473:pathology* / Q000503:physiopathology; D012135:Respiratory Sounds / Q000503:physiopathology; D012737:Sex Factors; D013147:Spirometry; D014057:Tomography, X-Ray Computed