title: Marker-free registration for the accurate integration of CT images and the subject's anatomy during navigation surgery of the maxillary sinus.
abstract: OBJECTIVE
  This study compared three marker-free registration methods that are applicable to a navigation system that can be used for maxillary sinus surgery, and evaluated the associated errors, with the aim of determining which registration method is the most applicable for operations that require accurate navigation.
  
  
  METHODS
  The CT digital imaging and communications in medicine (DICOM) data of ten maxillary models in DICOM files were converted into stereolithography file format. All of the ten maxillofacial models were scanned three dimensionally using a light-based three-dimensional scanner. The methods applied for registration of the maxillofacial models utilized the tooth cusp, bony landmarks and maxillary sinus anterior wall area. The errors during registration were compared between the groups.
  
  
  RESULTS
  There were differences between the three registration methods in the zygoma, sinus posterior wall, molar alveolar, premolar alveolar, lateral nasal aperture and the infraorbital areas. The error was smallest using the overlay method for the anterior wall of the maxillary sinus, and the difference was statistically significant.
  
  
  CONCLUSIONS
  The navigation error can be minimized by conducting registration using the anterior wall of the maxillary sinus during image-guided surgery of the maxillary sinus.
authors.affiliation: Department of Oral and Maxillofacial Surgery, National Health Insurance Corporation Ilsan Hospital, Gyeonggi-do, Republic of Korea.
authors.forename: S-H
authors.initials: SH
authors.lastname: Kang
authors.forename: M-K
authors.initials: MK
authors.lastname: Kim
authors.forename: J-H
authors.initials: JH
authors.lastname: Kim
authors.forename: H-K
authors.initials: HK
authors.lastname: Park
authors.forename: W
authors.initials: W
authors.lastname: Park
mesh_terms: D000539:Alveolar Process / Q000000981:diagnostic imaging; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D001641:Bicuspid / Q000000981:diagnostic imaging; D003724:Dental Arch / Q000000981:diagnostic imaging; D057918:Fiducial Markers; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008443:Maxillary Sinus / Q000000981:diagnostic imaging* / Q000601:surgery; D008953:Models, Anatomic; D008963:Molar / Q000000981:diagnostic imaging; D009296:Nasal Cavity / Q000000981:diagnostic imaging; D009915:Orbit / Q000000981:diagnostic imaging; D012984:Software; D012986:Software Validation; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D019228:Tooth Crown / Q000000981:diagnostic imaging; D015050:Zygoma / Q000000981:diagnostic imaging