title: Computed tomography-bronchoscopic simulation for guiding transbronchial fine needle aspiration of extramural targets: a phantom study.
abstract: OBJECTIVE
  Extramural paratracheal/-bronchial tumors of the mediastinum and the hilum that cannot be seen in bronchoscopy constitute a particular challenge for transbronchial fine needle aspiration cytology. A software prototype was developed as a guidance tool to visualize extramural targets on computed tomography (CT)-bronchoscopy. A phantom study was conducted to evaluate this guidance tool.
  
  
  METHODS
  For CT-bronchoscopic simulation extramural targets are visualized behind the semitransparent wall in the endoluminal view. An airway phantom with 16 targets was examined by 3 bronchoscopists. In a first pass the targets were bronchoscopically punctured in the conventional way only with knowledge of axial CT-sections. In a second pass guidance by CT-bronchoscopic simulation was used. A postinterventional CT scan of the phantom was conducted to analyze the spatial relationship between the marked puncture sites and the targets. The punctures were classified in hits and failed punctures due to deviation in distance and angle.
  
  
  RESULTS
  The total hit rate of the 3 operators was significantly higher with CT-bronchoscopic simulation (32 of 48) than with the conventional method (14 of 48; P < 0.01). Concerning the failed punctures the deviation in distance and angle was significantly smaller with CT-bronchoscopic simulation (P < 0.01, P < 0.05, respectively).
  
  
  CONCLUSIONS
  CT-bronchoscopic simulation significantly increased hit rate of bronchoscopic punctures of extramural lesions compared with conventional orientation using axial CT-sections in this phantom study. These results suggest that CT-bronchoscopic simulation might be a valuable tool for increasing yield and accuracy of bronchoscopic transbronchial fine needle aspiration in patients with mediastinal and hilar masses that are invisible for conventional bronchoscopy.
authors.affiliation: Department of Radiology and Nuclear Medicine, Charité Campus Benjamin Franklin, Berlin, Germany. guido.weiner@charite.de
authors.forename: Guido M
authors.initials: GM
authors.lastname: Weiner
authors.forename: Bernhard
authors.initials: B
authors.lastname: Geiger
authors.forename: Karsten
authors.initials: K
authors.lastname: Schulze
authors.forename: Patricia
authors.initials: P
authors.lastname: Hortig
authors.forename: Johannes
authors.initials: J
authors.lastname: Bilger
authors.forename: Stefan
authors.initials: S
authors.lastname: Schaller
authors.forename: Ulrike
authors.initials: U
authors.lastname: Grittner
authors.forename: Karl-Jürgen
authors.initials: KJ
authors.lastname: Wolf
authors.forename: Thomas
authors.initials: T
authors.lastname: Albrecht
mesh_terms: D044963:Biopsy, Fine-Needle / Q000379:methods*; D001984:Bronchial Neoplasms / Q000175:diagnosis*; D001999:Bronchoscopy / Q000379:methods*; D003198:Computer Simulation; D008953:Models, Anatomic; D019047:Phantoms, Imaging; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014584:User-Computer Interface