title: Paired maximum inspiratory and expiratory plain chest radiographs for assessment of airflow limitation in chronic obstructive pulmonary disease.
abstract: BACKGROUND
  The usefulness of paired maximum inspiratory and expiratory (I/E) plain chest radiography (pCR) for diagnosis of chronic obstructive pulmonary disease (COPD) is still unclear.
  
  
  OBJECTIVE
  We examined whether measurement of the I/E ratio using paired I/E pCR could be used for detection of airflow limitation in patients with COPD.
  
  
  METHODS
  Eighty patients with COPD (GOLD stage I=23, stage II=32, stage III=15, stage IV=10) and 34 control subjects were enrolled. The I/E ratios of frontal and lateral lung areas, and lung distance between the apex and base on pCR views were analyzed quantitatively. Pulmonary function parameters were measured at the same time.
  
  
  RESULTS
  The I/E ratios for the frontal lung area (1.25±0.01), the lateral lung area (1.29±0.01), and the lung distance (1.18±0.01) were significantly (p<0.05) reduced in COPD patients compared with controls (1.31±0.02 and 1.38±0.02, and 1.22±0.01, respectively). The I/E ratios in frontal and lateral areas, and lung distance were significantly (p<0.05) reduced in severe (GOLD stage III) and very severe (GOLD stage IV) COPD as compared to control subjects, although the I/E ratios did not differ significantly between severe and very severe COPD. Moreover, the I/E ratios were significantly correlated with pulmonary function parameters.
  
  
  CONCLUSIONS
  Measurement of I/E ratios on paired I/E pCR is simple and reproducible, and can detect airflow limitation in patients with severe and very severe COPD.
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. Electronic address: tkino@med.kurume-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kinoshita
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. Electronic address: kawayama_tomotaka@med.kurume-u.ac.jp.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Kawayama
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. Electronic address: mamura_youhei@med.kurume-u.ac.jp.
authors.forename: Youhei
authors.initials: Y
authors.lastname: Imamura
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. Electronic address: sakazaki@med.kurume-u.ac.jp.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Sakazaki
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. Electronic address: hirai_ryou@kurume-u.ac.jp.
authors.forename: Ryo
authors.initials: R
authors.lastname: Hirai
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. Electronic address: shii_hidenobu@med.kurume-u.ac.jp.
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Ishii
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. Electronic address: jin_t_f_c@yahoo.co.jp.
authors.forename: Masashi
authors.initials: M
authors.lastname: Suetomo
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. Electronic address: kmatsunaga@kouhoukai.or.jp.
authors.forename: Kazuko
authors.initials: K
authors.lastname: Matsunaga
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. Electronic address: azuma@med.kurume-u.ac.jp.
authors.forename: Koichi
authors.initials: K
authors.lastname: Azuma
authors.affiliation: Department of Radiology, Kurume University School of Medicine, Kurume, Japan. Electronic address: kimichan@med.kurume-u.ac.jp.
authors.forename: Kiminori
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, Japan. Electronic address: hoshino@med.kurume-u.ac.jp.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Hoshino
mesh_terms: D000368:Aged; D000402:Airway Obstruction / Q000000981:diagnostic imaging; D045853:Exhalation; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging*; D011859:Radiography; D015203:Reproducibility of Results; D012119:Respiration
keywords: Airway obstruction; Chronic obstructive pulmonary disease; Imaging