title: Computed tomography assessment of airways throughout bronchial tree demonstrates airway narrowing in severe asthma.
abstract: OBJECTIVE
  To analyze airway dimensions throughout the bronchial tree in severe asthmatic patients using multidetector row computed tomography (MDCT) focusing on airway narrowing.
  
  
  METHODS
  Thirty-two patients with severe asthma underwent automated (BronCare software) analysis of their right lung bronchi, with counts of airways >3 mm long arising from the main bronchi (airway count) and bronchial dimension quantification at segmental and subsegmental levels (lumen area [LA], wall area [WA], and WA%). Focal bronchial stenosis was defined as >50% narrowing of maximal LA on contiguous cross-sectional slices. Severe asthmatics were compared to 13 nonsevere asthmatic patients and nonasthmatic (pooled) subjects (Wilcoxon rank tests, then stepwise logistic regression). Finally, cluster analysis of severe asthmatic patients and stepwise logistic regression identified specific imaging subgroups.
  
  
  RESULTS
  The most significant differences between severe asthmatic patients and the pooled subjects were bronchial stenosis (subsegmental and all bronchi: P < .002) and WA% (P < .0003). Stepwise logistic regression retained WA% as the only explanatory covariable (P = .002). Two identified clusters of severe asthmatic patients differed for parameters characterizing airway narrowing (airway count: P = .0002; focal bronchial stenosis: P = .009). Airway count was as discriminant as forced expiratory volume in 1 second/forced vital capacity (P = .01) to identify patients in each cluster, with both variables being correlated (r = 0.59, P = .005).
  
  
  CONCLUSIONS
  Severe asthma-associated morphologic changes were characterized by focal bronchial stenoses and diffuse airway narrowing; the latter was associated with airflow obstruction. WA%, dependent on airway caliber, is the best parameter to identify severe asthmatic patients from pooled subjects.
authors.affiliation: University Paris 13, Sorbonne Paris Cité, Bobigny, France; Department of Radiology, APHP, Hôpital Avicenne, Bobigny, France.
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Brillet
authors.affiliation: Department of Radiology, APHP, Hôpital Bichat, Paris, France.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Debray
authors.affiliation: Department of Biostatistics, APHP, Hôpital Pitié-Salpêtrière, Paris, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Golmard
authors.affiliation: Department of Radiology, APHP, Hôpital Avicenne, Bobigny, France.
authors.forename: Yahya
authors.initials: Y
authors.lastname: Ould Hmeidi
authors.affiliation: Department ARTEMIS, CNRS UMR 8145, Telecom SudParis, Evry, France.
authors.forename: Catalin
authors.initials: C
authors.lastname: Fetita
authors.affiliation: Université Paris Diderot-Paris 7, Paris, France; INSERM U700, Faculté de Médecine Bichat, Paris, France; Department of Pulmonology, APHP, Hôpital Bichat, Paris, France.
authors.forename: Camille
authors.initials: C
authors.lastname: Taillé
authors.affiliation: Université Paris Diderot-Paris 7, Paris, France; INSERM U700, Faculté de Médecine Bichat, Paris, France; Department of Pulmonology, APHP, Hôpital Bichat, Paris, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Aubier
authors.affiliation: Université Pierre et Marie Curie, INSERM U678, Paris, France; Department of Radiology, APHP, Hôpital Pitié-Salpêtrière, Paris, France. Electronic address: philippe.grenier@psl.aphp.fr.
authors.forename: Philippe A
authors.initials: PA
authors.lastname: Grenier
mesh_terms: D000328:Adult; D001249:Asthma / Q000000981:diagnostic imaging*; D001980:Bronchi; D001995:Bronchography; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D012720:Severity of Illness Index
keywords: Asthma; airway remodeling; imaging; multidetector computed tomography; three-dimensional