title: Normal trachea during forced expiration: dynamic CT measurements.
abstract: 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).
authors.affiliation: Department of Radiology, University of California San Francisco.
authors.forename: E J
authors.initials: EJ
authors.lastname: Stern
authors.forename: C M
authors.initials: CM
authors.lastname: Graham
authors.forename: W R
authors.initials: WR
authors.lastname: Webb
authors.forename: G
authors.initials: G
authors.lastname: Gamsu
mesh_terms: D000328:Adult; D006801:Humans; D008297:Male; D012016:Reference Values; D012119:Respiration; D013147:Spirometry; D014057:Tomography, X-Ray Computed; D014132:Trachea / Q000000981:diagnostic imaging* / Q000502:physiology; D014133:Tracheal Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology