title: Reproducibility of the sella turcica landmark in three dimensions using a sella turcica-specific reference system.
abstract: OBJECTIVE
  This study was performed to assess the reproducibility of identifying the sella turcica landmark in a three-dimensional (3D) model by using a new sella-specific landmark reference system.
  
  
  METHODS
  Thirty-two cone-beam computed tomographic scans (3D Accuitomo® 170, J. Morita, Kyoto, Japan) were retrospectively collected. The 3D data were exported into the Digital Imaging and Communications in Medicine standard and then imported into the Maxilim® software (Medicim NV, Sint-Niklaas, Belgium) to create 3D surface models. Five observers identified four osseous landmarks in order to create the reference frame and then identified two sella landmarks. The x, y, and z coordinates of each landmark were exported. The observations were repeated after four weeks. Statistical analysis was performed using the multiple paired t-test with Bonferroni correction (intraobserver precision: p<0.005, interobserver precision: p<0.0011).
  
  
  RESULTS
  The intraobserver mean precision of all landmarks was <1 mm. Significant differences were found when comparing the intraobserver precision of each observer (p<0.005). For the sella landmarks, the intraobserver mean precision ranged from 0.43±0.34 mm to 0.51±0.46 mm. The intraobserver reproducibility was generally good. The overall interobserver mean precision was <1 mm. Significant differences between each pair of observers for all anatomical landmarks were found (p<0.0011). The interobserver reproducibility of sella landmarks was good, with >50% precision in locating the landmark within 1 mm.
  
  
  CONCLUSIONS
  A newly developed reference system offers high precision and reproducibility for sella turcica identification in a 3D model without being based on two-dimensional images derived from 3D data.
authors: OIC, OMFS-IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, University of Leuven and Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium. ; Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
authors: Pisha
authors: P
authors: Pittayapat
authors: OIC, OMFS-IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, University of Leuven and Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium.
authors: Reinhilde
authors: R
authors: Jacobs
authors: Service de Chirurgie Orthopédique et Traumatologique, Centre Hospitalier Régional d'Orléans, Orléans Cedex 2, France.
authors: Guillaume A
authors: GA
authors: Odri
authors: Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, Brazil.
authors: Karla de Faria
authors: Kde F
authors: Vasconcelos
authors: Orthodontics, Department of Oral Health Sciences, KU Leuven and Dentistry, University Hospitals Leuven, University of Leuven, Leuven, Belgium.
authors: Guy
authors: G
authors: Willems
authors: Department of Oral and Maxillofacial Surgery, Cliniques Universitaires Saint Luc, Université Catholique de Louvain, Brussels, Belgium.
authors: Raphaël
authors: R
authors: Olszewski
keywords: Cephalometry; Cone-Beam Computed Tomography; Imaging, Three-Dimensional; Orthodontics; Sella Turcica