title: CT attenuation of the bronchial wall in patients with asthma: comparison with geometric parameters and correlation with function and histologic characteristics.
abstract: OBJECTIVE
  The purposes of this study were to compare airway wall attenuation in subjects with asthma and subjects without asthma; to correlate this value with pulmonary function test results, standard bronchial CT parameters, and immunohistologic data; and to identify CT parameters that influence obstructive indexes.
  
  
  METHODS
  Bronchial airway wall attenuation was averaged over four bronchi in 27 subjects with asthma and 15 control subjects without asthma. The following five standard bronchial parameters also were assessed: lumen area, wall area, wall thickness, wall-to-lumen area ratio, and wall-to-total area ratio (wall area percentage). These parameters were compared between groups and correlated with functional data. Ability to predict patient group with these parameters was determined by comparison of receiver operating characteristic curves and areas under the curve. The influence of the parameters on obstructive indexes was assessed by multivariate analysis. Correlations between wall attenuation value and histologic data were studied in 11 patients with asthma.
  
  
  RESULTS
  Wall attenuation value was greater in patients with asthma (-322 ± 79 HU) than in control subjects (-463 ± 69 HU). Correlation coefficients of wall attenuation value with functional obstructive parameters were significant and greater than those obtained for any other CT parameter. The area under the curve of wall attenuation value was greater than that of bronchial lumen area and bronchial wall area. In the model of multiple regression that included wall attenuation value and wall-to-total area ratio, wall attenuation value was the only measurement that significantly influenced obstructive indexes (R(2) = 0.39-0.43). Wall attenuation value correlated with mast cell infiltration.
  
  
  CONCLUSIONS
  Compared with the usual bronchial CT parameters, airway wall attenuation better differentiates patients with asthma from control subjects and better correlates with obstruction.
authors.affiliation: Unité d'Imagerie Thoracique et Cardiovasculaire, CHU de Bordeaux, Hopital du Haut-Lévêque, 5 Ave de Magellan, 33604 Pessac, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Lederlin
authors.forename: François
authors.initials: F
authors.lastname: Laurent
authors.forename: Yann
authors.initials: Y
authors.lastname: Portron
authors.forename: Annaïg
authors.initials: A
authors.lastname: Ozier
authors.forename: Hubert
authors.initials: H
authors.lastname: Cochet
authors.forename: Patrick
authors.initials: P
authors.lastname: Berger
authors.forename: Michel
authors.initials: M
authors.lastname: Montaudon
mesh_terms: D019540:Area Under Curve; D001249:Asthma / Q000000981:diagnostic imaging* / Q000473:pathology; D001980:Bronchi / Q000473:pathology*; D001999:Bronchoscopy; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed / Q000379:methods*