Incidence of tracheobronchomalacia associated with pulmonary emphysema: Detection with paired inspiratory-expiratory multidetector computed tomography using a low-dose technique

Masanori Inoue, Ichiro Hasegawa, Keiko Nakano, Kazuhiro Yamaguchi, Sachio Kuribayashi

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Purpose: The purpose of this study was to evaluate the frequency of tracheobronchomalacia (TBM) associated with pulmonary emphysema with paired inspiratory-expiratory multidetector computed tomography (MDCT) using a low-dose technique. Materials and methods: This study included 56 consecutive patients (55 men, 1 woman; mean age 68.9 years) with pulmonary emphysema who had undergone paired inspiratory-expiratory CT scanning with a low-dose technique (40 mA). All images were retrospectively examined by two thoracic radiologists in a blinded fashion. The diagnosis of TBM was based on the standard criterion of >50% reduction in the cross-sectional area of the tracheobronchial lumen at the end-expiratory phase. A mild TBM criterion of >30% reduction was also reviewed. All patients underwent pulmonary function tests. The relation between the forced expiratory volume in 1 s (FEV1.0%) and TBM was statistically analyzed. Results: Four (7.1%) and eight (14.3%) patients were diagnosed as TBM based on the standard and mild criteria, respectively. In four patients, the percentages of luminal narrowing were 63.4% and 51.2%, respectively for tracheomalacia and 59.2% and 62.0%, respectively, for bronchomalacia. The FEV1.0% values between patients with and without TBM showed no statistical difference. Conclusion: The incidence of TBM associated with pulmonary emphysema was 7.1% with the standard criterion. It is possible that TBM has been underdiagnosed in a number of patients with pulmonary emphysema.

Original languageEnglish
Pages (from-to)303-308
Number of pages6
JournalJapanese Journal of Radiology
Issue number8
Publication statusPublished - 2009 Oct 1



  • Emphysema
  • Expiratory
  • Inspiratory
  • Multidetector CT
  • Tracheobronchomalacia

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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