title: Bronchoarterial ratio and bronchial wall thickness on high-resolution CT in asymptomatic subjects: correlation with age and smoking.
abstract: OBJECTIVE
  The purpose of this study was to determine whether the values of the bronchoarterial ratio and bronchial wall thickness, as viewed during high-resolution CT, relate to age and smoking status in asymptomatic healthy subjects.
  
  
  METHODS
  High-resolution CT was performed prospectively in 85 subjects without cardiopulmonary disease. The subjects were divided into three groups according to age: 29 subjects were 21-40 years old; 29 subjects, 41-64 years old; and 27 subjects, 65 years or older. Both bronchoarterial ratios, defined as the diameter of the bronchial lumen divided by the diameter of its accompanying artery, and the T/D ratio, defined as wall thickness (T) divided by the total diameter of the bronchus (D), were measured at the segmental and subsegmental levels of the apical and posterior basal segments. Each calculated ratio was evaluated according to age and smoking status.
  
  
  RESULTS
  Significant correlation was found between the bronchoarterial ratio and age (r = 0.768, p < 0.0001), with the bronchoarterial ratio increasing with age and exceeding 1 in 41% of subjects older than 65 years. No significant correlation was seen between the T/D ratio and age. No significant differences in bronchoarterial ratio and T/D ratio were seen between smokers and nonsmokers in subjects overall; but in the elderly group, the T/D ratio was significantly higher in smokers than in nonsmokers (p = 0.021).
  
  
  CONCLUSIONS
  The bronchoarterial ratio is influenced by aging. The normal bronchoarterial ratio in a substantial number of subjects older than 65 years overlaps with the ratio considered to represent bronchiectasis. Thus, when this ratio is used for the quantitative analysis of pulmonary and cardiovascular disease, the influence of age should be considered.
authors.affiliation: Department of Radiology, Teikyo University School of Medicine, Ichihara Hospital, 3426-3 Anesaki, Ichihara, Chiba 299-0111, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Matsuoka
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Uchiyama
authors.forename: Hideki
authors.initials: H
authors.lastname: Shima
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Ueno
authors.forename: Sonomi
authors.initials: S
authors.lastname: Oish
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nojiri
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology*; D000792:Angiography; D001980:Bronchi / Q000033:anatomy & histology / Q000098:blood supply* / Q000473:pathology; D001995:Bronchography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012907:Smoking / Q000473:pathology*; D014057:Tomography, X-Ray Computed / Q000379:methods