title: [3D cross section of the laryngotracheal tract. A new method for visualization and quantification of tracheal stenoses].
abstract: OBJECTIVE
  Demonstration of a technique for 3D assessment of tracheal stenoses, regarding site, length and degree, based on spiral computed tomography (S-CT).
  
  
  METHODS
  S-CT scanning and automated segmentation of the laryngo-tracheal tract (LTT) was followed by the extraction of the LTT medial axis using a skeletonisation algorithm. Orthogonal to the medial axis the LTT 3D cross sectional profile was computed and presented as line charts, where degree and length were obtained. Values for both parameters were compared between 36 patients and 18 normal controls separately. Accuracy and precision was derived from 17 phantom studies.
  
  
  RESULTS
  Average degree and length of tracheal stenoses were found to be 60.5% and 4.32 cm in patients compared to minor caliber changes of 8.8% and 2.31 cm in normal controls (p <0.005). For the phantoms an excellent correlation between the true and computed 3D cross sectional profile was found (p <0.005) and an accuracy for length and degree measurements of 2.14 mm and 2.53% respectively could be determined. The corresponding figures for the precision were found to be 0.92 mm and 2.56%.
  
  
  CONCLUSIONS
  LTT 3D cross sectional profiles permit objective, accurate and precise assessment of LTT caliber changes. Minor LTT caliber changes can be observed even in normals and, in case of an otherwise normal S-CT study, can be regarded as artefacts.
authors.affiliation: Abteilung für Digitale Information und Bildverarbeitung, Univ.-Klinik für Radiologie Graz, Austria. erich.sorantin@kfunigraz.ac.at
authors.forename: E
authors.initials: E
authors.lastname: Sorantin
authors.forename: C
authors.initials: C
authors.lastname: Halmai
authors.forename: B
authors.initials: B
authors.lastname: Erdohelyi
authors.forename: K
authors.initials: K
authors.lastname: Palágyi
authors.forename: L G
authors.initials: LG
authors.lastname: Nyúl
authors.forename: K
authors.initials: K
authors.lastname: Ollé
authors.forename: B
authors.initials: B
authors.lastname: Geiger
authors.forename: F
authors.initials: F
authors.lastname: Lindbichler
authors.forename: G
authors.initials: G
authors.lastname: Friedrich
authors.forename: K
authors.initials: K
authors.lastname: Kiesler
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007223:Infant; D007828:Laryngoscopy; D007829:Laryngostenosis / Q000151:congenital / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed; D014135:Tracheal Stenosis / Q000151:congenital / Q000000981:diagnostic imaging*