title: Thin-section CT imaging that correlates with pulmonary function tests in obstructive airway disease.
abstract: OBJECTIVE
  The purpose of this study was to identify independent CT findings that correlated with pulmonary function tests (PFTs) in patients with obstructive airway diseases.
  
  
  METHODS
  Sixty-eight patients with obstructive airway disease and 29 normal subjects (mean age, 52 years; 36 men and 61 women) underwent inspiratory and expiratory thin-section CT and PFTs. Patient with obvious emphysema was excluded. Two radiologists independently reviewed the images and semi-quantitatively evaluated lung attenuation (mosaic perfusion, air trapping) and airway abnormalities (extent and severity of bronchial wall thickening and bronchiectasis, bronchiolectasis or centrilobular nodules, mucous plugging). Univariate, multivariate and receiver operating characteristic (ROC) analyses were performed with CT findings and PFTs.
  
  
  RESULTS
  Forty-two patients showed obstructive PFTs, 26 symptomatic patients showed near-normal PFTs. On univariate analysis, air trapping and bronchial wall thickening showed highest correlation with obstructive PFTs such as FEV1.0/FVC, MMEF and FEF75 (r ranged from -0.712 to -0.782; p<0.001), while mosaic perfusion and mucous plugging showed moderate correlation, and bronchiectasis, bronchiolectasis and nodules showed the least, but significant, correlation. Multiple logistic analyses revealed air trapping and bronchial wall thickening as the only significant independent determinants of obstructive PFTs. ROC analysis revealed the cut-off value of air trapping for obstructive PFTs to be one-third of whole lung (area under curve, 0.847).
  
  
  CONCLUSIONS
  Our study confirmed air trapping and bronchial wall thickening are the most important observations when imaging obstructive PFTs. The cut-off value of air trapping for identifying obstructive PFTs was one-third of lung irrespective of inspiratory CT findings.
authors.affiliation: Department of Radiology, Dokkyo Medical University, 880 Kita-Kobayashi, Mibu, Tochigi 321-0293, Japan. arakawa@dokkyomed.ac.jp
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Arakawa
authors.forename: Kiminori
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Yasutugu
authors.initials: Y
authors.lastname: Fukushima
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kaji
mesh_terms: D000328:Adult; D019540:Area Under Curve; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012044:Regression Analysis; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*