title: Ratios of peripheral-to-central airway lumen area and percentage wall area as predictors of severity of chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  The purpose of this study was to assess the ability of the ratios of peripheral-to-central airway lumen area (hereafter referred to as LA) and percentage wall area (hereafter referred to as %WA) to predict the severity of chronic obstructive pulmonary disease (COPD) according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines.
  
  
  METHODS
  We examined 32 patients (27 men and five women; mean age ± SD, 70.0 ± 6.8 years; seven GOLD stage 0 [at risk for COPD], 19 GOLD stage 1-2 [mild to moderate airflow limitation], and six GOLD stage 3-4 [severe to very severe airflow limitation]) using inspiratory CT. Mean LA and %WA were measured for the first (main bronchi), third, and fifth generations of five bronchi in each lobe and the ratios of peripheral to central airways were calculated (third to first, fifth to first, and fifth to third) and statistically compared.
  
  
  RESULTS
  The fifth-generation LA, LA fifth to first, and LA fifth to third significantly decreased and fifth %WA, %WA fifth to first, and %WA fifth to third also increased with progression of GOLD stage (p < 0.05), but central measurements, including first and third generations, did not. There were significant differences between GOLD 0 and GOLD 1-2 for %WA fifth to third and LA fifth to third and between GOLD 0 and GOLD 3-4 for all six parameters (p < 0.05); %WA fifth to third had the best cutoff value of 1.02 (sensitivity, 92%; specificity, 86%) for diagnosis of COPD (GOLD 1-4). The %WA fifth to first of 1.51 (sensitivity, 83%; specificity, 89%) was best for diagnosis of GOLD 3-4.
  
  
  CONCLUSIONS
  Ratios of peripheral-to-central airway LA and %WA show improved correlation with COPD severity.
authors.affiliation: 1 Department of Radiology, Asahikawa Medical University, 2-1-1-1 Midorigaoka-higashi, Asahikawa, Hokkaido 078-8510, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Sasaki
authors.forename: Koji
authors.initials: K
authors.lastname: Takahashi
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Takada
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Ohsaki
mesh_terms: D000368:Aged; D001980:Bronchi / Q000503:physiopathology*; D001995:Bronchography; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D011857:Radiographic Image Interpretation, Computer-Assisted; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed
keywords: chronic obstructive pulmonary disease(COPD); quantitative airway measurement