title: Sources of registration error with image guidance systems during endoscopic anterior cranial base surgery.
abstract: OBJECTIVE
  The goal of this study was to evaluate the accuracy of the registration process and to identify potential sources of error during anterior cranial base surgery.
  
  
  METHODS
  The registration accuracy of image guidance and the location of excluded fiducials were recorded prospectively from 50 endoscopic, anterior cranial base procedures in an academic university setting.
  
  
  RESULTS
  The mean error of initial registration was 2.8 mm (range, 1.4 to 7.1 mm). Following the exclusion of fiducials the mean error of registration was 1.6 mm (range, 0.6 to 3.7 mm). There was a significant improvement in the mean error rate from initial to final registration following the exclusion of fiducials (P < 0.0001). Posterior fiducials were excluded most often and anterior fiducials were excluded the least. Registration accuracy was similar for CT and MRI (P = 0.64).
  
  
  CONCLUSIONS
  The accuracy of the Stryker Image Guidance System is enhanced by the exclusion of individual fiducials with high registration errors.
  
  
  CONCLUSIONS
  The exclusion of fiducials with high registration errors increases the accuracy of image guidance in anterior cranial base surgery.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University of Pittsburg Medical Center, Pittsburg, Pennsylvania, USA. snydermanch@upmc.edu
authors.forename: Carl
authors.initials: C
authors.lastname: Snyderman
authors.forename: Lee A
authors.initials: LA
authors.lastname: Zimmer
authors.forename: Amin
authors.initials: A
authors.lastname: Kassam
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003951:Diagnostic Errors; D004724:Endoscopy; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007430:Intraoperative Care; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D019291:Skull Base / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D025321:Surgery, Computer-Assisted; D014057:Tomography, X-Ray Computed