title: Reliability of landmark identification in cephalometric radiography acquired by a storage phosphor imaging system.
abstract: OBJECTIVE
  To compare the cephalometric landmark identification on softcopy and hardcopy of direct digital cephalography acquired by a storage-phosphor (SP) imaging system.
  
  
  METHODS
  Ten digital cephalograms and their conventional counterpart, hardcopy on a transparent blue film, were obtained by a SP imaging system and a dye sublimation printer. Twelve orthodontic residents identified 19 cephalometric landmarks on monitor-displayed SP digital images with computer-aided method and on their hardcopies with conventional method. The x- and y-coordinates for each landmark, indicating the horizontal and vertical positions, were analysed to assess the reliability of landmark identification and evaluate the concordance of the landmark locations in softcopy and hardcopy of SP digital cephalometric radiography.
  
  
  RESULTS
  For each of the 19 landmarks, the location differences as well as the horizontal and vertical components were statistically significant between SP digital cephalometric radiography and its hardcopy. Smaller interobserver errors on SP digital images than those on their hardcopies were noted for all the landmarks, except point Go in vertical direction. The scatter-plots demonstrate the characteristic distribution of the interobserver error in both horizontal and vertical directions. Generally, the dispersion of interobserver error on SP digital cephalometric radiography is less than that on its hardcopy with conventional method.
  
  
  CONCLUSIONS
  The SP digital cephalometric radiography could yield better or comparable level of performance in landmark identification as its hardcopy, except point Go in vertical direction.
authors.affiliation: School of Dentistry, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Chen
authors.forename: S-K
authors.initials: SK
authors.lastname: Chen
authors.forename: H-W
authors.initials: HW
authors.lastname: Huang
authors.forename: C-C
authors.initials: CC
authors.lastname: Yao
authors.forename: H-F
authors.initials: HF
authors.lastname: Chang
mesh_terms: D002508:Cephalometry / Q000379:methods*; D002680:Chin / Q000000981:diagnostic imaging; D003626:Data Display; D005147:Facial Bones / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008334:Mandible / Q000000981:diagnostic imaging; D015588:Observer Variation; D009970:Orthodontics; D019252:Radiography, Dental, Digital / Q000379:methods*; D015203:Reproducibility of Results; D014962:X-Ray Film