title: "Direct DICOM Slice Landmarking" A Novel Research Technique to Quantify Skeletal Changes in Orthognathic Surgery.
abstract: The limitations of the current methods of quantifying the surgical movements of facial bones inspired this study. The aim of this study was the assessment of the accuracy and reproducibility of directly landmarking of 3D DICOM images (Digital Imaging and Communications in Medicine) to quantify the changes in the jaw bones following surgery. The study was carried out on plastic skull to simulate the surgical movements of the jaw bones. Cone beam CT scans were taken at 3mm, 6mm, and 9mm maxillary advancement; together with a 2mm, 4mm, 6mm and 8mm "down graft" which in total generated 12 different positions of the maxilla for the analysis. The movements of the maxilla were calculated using two methods, the standard approach where distances between surface landmarks on the jaw bones were measured and the novel approach where measurements were taken directly from the internal structures of the corresponding 3D DICOME slices. A one sample t-test showed that there was no statistically significant difference between the two methods of measurements for the y and z directions, however, the x direction showed a significant difference. The mean difference between the two absolute measurements were 0.34±0.20mm, 0.22±0.16mm, 0.18±0.13mm in the y, z and x directions respectively. In conclusion, the direct landmarking of 3D DICOM image slices is a reliable, reproducible and informative method for assessment of the 3D skeletal changes. The method has a clear clinical application which includes the analysis of the jaw movements "orthognathic surgery" for the correction of facial deformities.
authors.affiliation: The Dental School, MVLS College, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Anas
authors.initials: A
authors.lastname: Almukhtar
authors.affiliation: Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong, P R China.
authors.forename: Balvinder
authors.initials: B
authors.lastname: Khambay
authors.affiliation: The Dental School, MVLS College, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Ashraf
authors.initials: A
authors.lastname: Ayoub
authors.affiliation: The Dental School, MVLS College, University of Glasgow, Glasgow, United Kingdom; Medical Device Unit, Department of Clinical Physics and Bioengineering, NHS Greater Glasgow and Clyde, Glasgow, United Kingdom.
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Ju
authors.affiliation: The Dental School, MVLS College, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Ali
authors.initials: A
authors.lastname: Al-Hiyali
authors.affiliation: The Dental School, MVLS College, University of Glasgow, Glasgow, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Macdonald
authors.affiliation: Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong, P R China.
authors.forename: Norhayati
authors.initials: N
authors.lastname: Jabar
authors.affiliation: Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong, P R China.
authors.forename: Tazuko
authors.initials: T
authors.lastname: Goto
mesh_terms: D059925:Anatomic Landmarks; D001842:Bone and Bones / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D057909:Orthognathic Surgery / Q000379:methods*; D010865:Pilot Projects; D012107:Research Design; D012886:Skull / Q000601:surgery