title: Assessment of COPD severity by combining pulmonary function tests and chest CT images.
abstract: OBJECTIVE
  Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitations. Physicians frequently assess the stage using pulmonary function tests and chest CT images. This paper describes a novel method to assess COPD severity by combining measurements of pulmonary function tests (PFT) and the results of chest CT image analysis.
  
  
  METHODS
  The proposed method utilizes measurements from PFTs and chest CT scans to assess COPD severity. This method automatically classifies COPD severity into five stages, described in GOLD guidelines, by a multi-class AdaBoost classifier. The classifier utilizes 24 measurements as feature values, which include 18 measurements from PFTs and six measurements based on chest CT image analysis. A total of 3 normal and 46 abnormal (COPD) examinations performed in adults were evaluated using the proposed method to test its diagnostic capability.
  
  
  RESULTS
  The experimental results revealed that its accuracy rates were 100.0 % (resubstitution scheme) and 53.1 % (leave-one-out scheme). A total of 95.7 % of missed classifications were assigned in the neighboring severities.
  
  
  CONCLUSIONS
  These results demonstrate that the proposed method is a feasible means to assess COPD severity. A much larger sample size will be required to establish the limits of the method and provide clinical validation.
authors.affiliation: Information and Communications Headquarters, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan. ynimura@mori.m.is.nagoya-u.ac.jp
authors.forename: Yukitaka
authors.initials: Y
authors.lastname: Nimura
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kitasaka
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Honma
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Takabatake
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Natori
authors.forename: Kensaku
authors.initials: K
authors.lastname: Mori
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000145:classification* / Q000175:diagnosis* / Q000503:physiopathology; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed