title: Multi-detector CT evaluation in patients suspected of tracheobronchomalacia: comparison of end-expiratory with dynamic expiratory volumetric acquisitions.
abstract: OBJECTIVE
  The aim of this study was to compare dynamic expiratory imaging and end-expiratory imaging using multi-detector CT (MDCT) of the central airways in patients suspected of tracheobronchomalacia (TBM).
  
  
  METHODS
  This study had local ethical committee approval. Seventy patients suspected of TBM were prospectively included. All patients underwent evaluation of central airways by three different low-dose MDCT acquisitions: end inspiration, end expiration, and dynamic expiration. Degree of airway collapse was measured by calculating the percentage change in the area and diameter of the airways between inspiratory and the two expiratory techniques at three levels of the trachea and in the sagittal diameter of the right and left main bronchi. Three threshold levels of percentage reduction in diameter or area (30%, 50%, and 70%) for defining TBM were evaluated.
  
  
  RESULTS
  In the entire population, the mean percentage of airway collapse was significantly greater with dynamic expiratory imaging than with the end-expiratory imaging at three different levels: lower thoracic trachea (26% vs. 16.6%, p<0.009), right (25.2% vs. 14%, p<0.01) and left main (24.7% vs. 13.3%, p<0.01) bronchus. Whatever the threshold value for defining TBM, dynamic expiratory imaging always resulted in diagnosing TBM in more patients than end-expiratory imaging.
  
  
  CONCLUSIONS
  Dynamic expiratory imaging shows a significantly greater degree and a significantly greater extent of airway collapse than standard end-expiratory imaging in patients suspected of TBM. Further evaluation of the clinical relevance of such findings is warranted.
authors.affiliation: Department of Radiology, France. gferretti@chu-grenoble.fr
authors.forename: Gilbert R
authors.initials: GR
authors.lastname: Ferretti
authors.forename: Adrien
authors.initials: A
authors.lastname: Jankowski
authors.forename: Marie Amélie
authors.initials: MA
authors.lastname: Perrin
authors.forename: Nathalie
authors.initials: N
authors.lastname: Chouri
authors.forename: Nathalie
authors.initials: N
authors.lastname: Arnol
authors.forename: Laurent
authors.initials: L
authors.lastname: Aubaud
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Pepin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012119:Respiration; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055089:Tracheobronchomalacia / Q000000981:diagnostic imaging*