title: Acquired tracheomalacia: detection by expiratory CT scan.
abstract: OBJECTIVE
  The purpose of this work was to determine whether cross-sectional area and coronal and sagittal diameter measurements of the trachea between inspiration and end-expiration on CT are significantly different between patients with acquired tracheomalacia and those without this condition.
  
  
  METHODS
  Inspiratory and end-expiratory CT scans of the trachea of 23 normal patients and 10 patients with acquired tracheomalacia were analyzed. Percent changes in cross-sectional area, coronal, and sagittal diameters were calculated.
  
  
  RESULTS
  For patients with tracheomalacia, mean percent changes in the upper and middle trachea between inspiration and expiration were 49 and 44%; mean changes in the coronal and sagittal diameters in the upper and middle tracheal were 4 and 10% and 39 and 54%, respectively. Control group mean percent changes in the upper and middle tracheal area were 12 and 14%, respectively, and mean changes in the coronal and sagittal diameters in the upper and middle trachea were 4 and 4% and 11 and 13%, respectively. Significant differences were calculated for changes in cross-sectional area and sagittal diameter between groups (p < 10-5). Based on receiver operator curve analysis, a > 18% change in the upper trachea and 28% change in the midtrachea between inspiration and expiration were observed; the probability of tracheomalacia was 89-100%. The probability of tracheomalacia was > 89%, especially if the change in sagittal diameter was > 28%.
  
  
  CONCLUSIONS
  By measuring changes in tracheal cross-sectional area and sagittal diameters between inspiratory and end-expiratory CT, a significant difference can be identified between normal patients and those with acquired tracheomalacia.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston 02114, USA. saquino@partners.org
authors.forename: S L
authors.initials: SL
authors.lastname: Aquino
authors.forename: J A
authors.initials: JA
authors.lastname: Shepard
authors.forename: L C
authors.initials: LC
authors.lastname: Ginns
authors.forename: R H
authors.initials: RH
authors.lastname: Moore
authors.forename: E
authors.initials: E
authors.lastname: Halpern
authors.forename: H C
authors.initials: HC
authors.lastname: Grillo
authors.forename: T C
authors.initials: TC
authors.lastname: McLoud
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000402:Airway Obstruction / Q000000981:diagnostic imaging; D001999:Bronchoscopy; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014132:Trachea / Q000000981:diagnostic imaging; D014133:Tracheal Diseases / Q000000981:diagnostic imaging*