title: Static end-expiratory and dynamic forced expiratory tracheal collapse in COPD.
abstract: OBJECTIVE
  To determine the range of tracheal collapse at end-expiration among chronic obstructive pulmonary disease (COPD) patients and to compare the extent of tracheal collapse between static end-expiratory and dynamic forced-expiratory multidetector-row computed tomography (MDCT).
  
  
  METHODS
  After institutional review board approval and obtaining informed consent, 67 patients meeting the National Heart, Lung, and Blood Institute (NHLBI)/World Health Organization (WHO) Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD were sequentially imaged using a 64-detector-row CT machine at end-inspiration, during forced expiration, and at end-expiration. Standardized respiratory coaching and spirometric monitoring were employed. Mean percentage tracheal collapse at end-expiration and forced expiration were compared using correlation analysis, and the power of end-expiratory cross-sectional area to predict excessive forced-expiratory tracheal collapse was computed following construction of receiver operating characteristic (ROC) curves.
  
  
  RESULTS
  Mean percentage expiratory collapse among COPD patients was 17 ± 18% at end-expiration compared to 62 ± 16% during forced expiration. Over the observed range of end-expiratory tracheal collapse (approximately 10-50%), the positive predictive value of end-expiratory collapse to predict excessive (≥80%) forced expiratory tracheal collapse was <0.3.
  
  
  CONCLUSIONS
  COPD patients demonstrate a wide range of end-expiratory tracheal collapse. The magnitude of static end-expiratory tracheal collapse does not predict excessive dynamic expiratory tracheal collapse.
authors.affiliation: Department of Pulmonary, Critical Care and Sleep Medicine, Harvard Medical School, Boston, MA, USA. Electronic address: codonne1@bidmc.harvard.edu.
authors.forename: C R
authors.initials: CR
authors.lastname: O'Donnell
authors.affiliation: Department of Radiology, Harvard Medical School, Boston, MA, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Bankier
authors.affiliation: Department of Radiology, Harvard Medical School, Boston, MA, USA.
authors.forename: D H
authors.initials: DH
authors.lastname: O'Donnell
authors.affiliation: Department of Anesthesia, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, MA, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Loring
authors.affiliation: Department of Radiology, Harvard Medical School, Boston, MA, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Boiselle
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D061330:Multidetector Computed Tomography; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000503:physiopathology*; D012372:ROC Curve; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014132:Trachea / Q000000981:diagnostic imaging / Q000503:physiopathology*; D055090:Tracheomalacia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014481:United States / Q000453:epidemiology