title: Bronchoarterial ratio in never-smokers adults: Implications for bronchial dilation definition.
abstract: Bronchiectasis manifests as recurrent respiratory infections and reduced lung function. Airway dilation, which is measured as the ratio of the diameters of the bronchial lumen (B) and adjacent pulmonary artery (A), is a defining radiological feature of bronchiectasis. A challenge to equating the bronchoarterial (BA) ratio to disease severity is that the diameters of airway and vessel in health are not established. We sought to explore the variability of BA ratio in never-smokers without pulmonary disease and its associations with lung function.
  
  
  
  Objective measurements of the BA ratio on volumetric computed tomography (CT) scans and pulmonary function data were collected in 106 never-smokers. The BA ratio was measured in the right upper lobe apical bronchus (RB1) and the right lower lobe basal posterior bronchus. The association between the BA ratio and forced expiratory volume in 1 s (FEV1) was assessed using regression analysis.
  
  
  
  The BA ratio was 0.79 ± 0.16 and was smaller in more peripheral RB1 bronchi (P < 0.0001). The BA ratio was >1, a typical threshold for bronchiectasis, in 10 (8.5%) subjects. Subjects with a BA ratio >1 versus ≤1 had smaller artery diameters (P < 0.0001) but not significantly larger bronchial lumens. After adjusting for age, gender, race and height, the BA ratio was directly related to FEV1(P = 0.0007).
  
  
  
  In never-smokers, the BA ratio varies by airway generation and is associated with lung function. A BA ratio >1 is driven by small arteries. Using artery diameter as reference to define bronchial dilation seems inappropriate.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Alejandro A
authors.initials: AA
authors.lastname: Diaz
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Young
authors.affiliation: Division of Pulmonary Diseases & Critical Care, University of Texas Health Science Center, San Antonio, Texas, USA.
authors.forename: Diego J
authors.initials: DJ
authors.lastname: Maselli
authors.affiliation: Division of Pulmonary & Critical Care Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA.
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Martinez
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Erick S
authors.initials: ES
authors.lastname: Maclean
authors.affiliation: Department of Radiology, University of California, San Diego, California, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Yen
authors.affiliation: Department of Radiology, Temple University Hospital, Philadelphia, Pennsylvania, USA.
authors.forename: Chandra
authors.initials: C
authors.lastname: Dass
authors.affiliation: Department of Radiology, Temple University Hospital, Philadelphia, Pennsylvania, USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Simpson
authors.affiliation: Department of Radiology, National Jewish Health, Denver, Colorado, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Lynch
authors.affiliation: Colorado School of Public Health, University of Colorado Denver, Aurora, Colorado, USA.
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Kinney
authors.affiliation: Colorado School of Public Health, University of Colorado Denver, Aurora, Colorado, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Hokanson
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: George R
authors.initials: GR
authors.lastname: Washko
authors.affiliation: Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Raul
authors.initials: R
authors.lastname: San José Estépar
mesh_terms: D000368:Aged; D001980:Bronchi / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D001987:Bronchiectasis / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000473:pathology; D012044:Regression Analysis; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000379:methods; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: bronchiectasis; bronchoarterial ratio; non-smoking; normal; volumetric computed tomography