title: Bronchoscope-induced displacement of lung targets: first in vivo demonstration of effect from wedging maneuver in navigated bronchoscopy.
abstract: BACKGROUND
  The accuracy of navigated bronchoscopy relies on a best possible correlation between the preoperative computed tomography images used for planning and the actual tumor position during bronchoscopy. Change in lung structure during the procedure may reduce success rate. The size of the lung changes during breathing, which may be predicted and at least partly compensated by a navigation system. We have studied the effect of the bronchoscopy itself, to see if and how the procedure causes further distortions, which might be harder to predict and compensate.
  
  
  METHODS
  Using newly developed lung tracking sensors, we have measured the movement of individual lung segments during a bronchoscopy session in pigs. The bronchoscope was moved stepwise forward, ending in a wedge position, where it is often positioned when collecting peripheral biopsy specimens during conventional bronchoscopy.
  
  
  RESULTS
  The influence of the bronchoscope on lung segment movement was minimal while positioned in the trachea, main bronchus, or lobe bronchus. However, in the wedge position, it displaced the lung targets and reduced the natural respiratory motion.
  
  
  CONCLUSIONS
  A bronchoscope placed in a wedge position displaces lung targets and affects their respiratory behavior. As an image navigation system guides the operator towards a position dictated by the preoperative computed tomography, the displacement found in this study may cause the operator to miss the target. This may be part of the explanation for the limited success rates reported in the literature for navigated bronchoscopy.
authors.affiliation: Department of Thoracic Medicine, St. Olavs Hospital/Trondheim University Hospital, Trondheim, Norway. hakon.o.leira@ntnu.no
authors.forename: Håkon O
authors.initials: HO
authors.lastname: Leira
authors.forename: Thomas
authors.initials: T
authors.lastname: Langø
authors.forename: Hanne
authors.initials: H
authors.lastname: Sorger
authors.forename: Erlend F
authors.initials: EF
authors.lastname: Hofstad
authors.forename: Tore
authors.initials: T
authors.lastname: Amundsen
mesh_terms: D000818:Animals; D001999:Bronchoscopy / Q000295:instrumentation / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging / Q000502:physiology*; D009038:Motion; D013552:Swine; D014057:Tomography, X-Ray Computed