title: Measurements from conventional, digital and CT-derived cephalograms: a comparative study.
abstract: OBJECTIVE
  The purpose of this retrospective radiographic study was to determine the reliability and reproducibility of skeletal and dental measurements of lateral cephalograms created from a computerised tomography (CT) scan compared with conventional and digital lateral cephalograms.
  
  
  METHODS
  CT and conventional lateral cephalograms of the same patients were obtained from university archives. The lateral cephalometric radiographs of 30 patients were manually traced. The radiographs were subsequently scanned and traced using Dolphin Imaging software version 11 (Dolphin Imaging, Chatsworth, CA, USA). The CT-created lateral cephalograms were also traced using the same software. Sixteen (10 angular and 6 linear) measurements were performed. Cephalometric measurements obtained from conventional, digital and CT-created cephalograms were statistically compared using repeated measures analysis of variance (ANOVA). Statistical significance was set at the p < 0.05 level of confidence.
  
  
  RESULTS
  The intra-rater reliability test for each method showed high values (r > 0.90) except for mandibular length which had a correlation of 0.82 for the CT-created cephalogram. Five measurements (N-A-Pog, N-S, ANS-PNS, Co-ANS and CoGn) were found to be significantly different between the CT-created and conventional cephalograms and three measurements (SNB, ANB, and/1-MP) were found to be significantly different between the CT-created and digital cephalograms.
  
  
  CONCLUSIONS
  There are statistically-significant differences in measurements produced using a traditional manual analysis, a direct digital analysis or a 3D CT-derived cephalometric analysis of orthodontic patients. These differences are, on average, small but because of individual variation, may be of considerable clinical significance in some patients.
authors.affiliation: Department of Orthodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt. aghoneim@iupui.edu
authors.forename: Ahmed
authors.initials: A
authors.lastname: Ghoneima
authors.forename: Sahar
authors.initials: S
authors.lastname: Albarakati
authors.forename: Asli
authors.initials: A
authors.lastname: Baysal
authors.forename: Tancan
authors.initials: T
authors.lastname: Uysal
authors.forename: Katherine
authors.initials: K
authors.lastname: Kula
mesh_terms: D000293:Adolescent; D002508:Cephalometry / Q000379:methods* / Q000706:statistics & numerical data; D002648:Child; D002680:Chin / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000706:statistics & numerical data; D021621:Imaging, Three-Dimensional / Q000379:methods / Q000706:statistics & numerical data; D007180:Incisor / Q000000981:diagnostic imaging; D008334:Mandible / Q000000981:diagnostic imaging; D008335:Mandibular Condyle / Q000000981:diagnostic imaging; D008437:Maxilla / Q000000981:diagnostic imaging; D009295:Nasal Bone / Q000000981:diagnostic imaging; D015588:Observer Variation; D010159:Palate / Q000000981:diagnostic imaging; D019252:Radiography, Dental, Digital / Q000379:methods* / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012658:Sella Turcica / Q000000981:diagnostic imaging; D012984:Software; D036542:Tomography, Spiral Computed / Q000379:methods* / Q000706:statistics & numerical data