Normal trachea during forced expiration: dynamic CT measurements

Radiology. 1993 Apr;187(1):27-31. doi: 10.1148/radiology.187.1.8451427.


The purpose of this study was to define the range of normal intrathoracic tracheal diameters and cross-sectional areas during forced respiration. A report of tracheomalacia is also presented. Ten volunteers were studied in the supine position with dynamic computed tomography (CT), at a level at or between the brachiocephalic vein and the aortic arch, with 3-mm collimation and with image reconstruction by means of a high-spatial-frequency algorithm. Ten 100-msec dynamic scans were obtained at 500-msec intervals during a 6-second period as the patient performed forced inspiration and expiration vital capacity maneuvers. The mean cross-sectional area of the trachea decreased dynamically from 280 mm2 at end inspiration (standard deviation, 50.5; range, 221-388 mm2) to 178 mm2 at end expiration (standard deviation, 40.2; range, 115-236 mm2; P < .001) (mean decrease, 35% between inspiration and expiration; standard deviation, 18%; range, 11%-61%). The percentage decrease in cross-sectional area of the trachea correlates well with the decrease in the anteroposterior and coronal diameters of the trachea from maximum inspiration to maximum expiration (r = .879 and .916 and P = .0018 and .0002, respectively).

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Humans
  • Male
  • Reference Values
  • Respiration*
  • Spirometry
  • Tomography, X-Ray Computed*
  • Trachea / diagnostic imaging*
  • Trachea / physiology
  • Tracheal Diseases / diagnostic imaging
  • Tracheal Diseases / physiopathology