title: The impact of different cone beam computed tomography and multi-slice computed tomography scan parameters on virtual three-dimensional model accuracy using a highly precise ex vivo evaluation method.
abstract: OBJECTIVE
  Multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT) are indispensable imaging techniques in advanced medicine. The possibility of creating virtual and corporal three-dimensional (3D) models enables detailed planning in craniofacial and oral surgery. The objective of this study was to evaluate the impact of different scan protocols for CBCT and MSCT on virtual 3D model accuracy using a software-based evaluation method that excludes human measurement errors.
  
  
  METHODS
  MSCT and CBCT scans with different manufacturers' predefined scan protocols were obtained from a human lower jaw and were superimposed with a master model generated by an optical scan of an industrial noncontact scanner. To determine the accuracy, the mean and standard deviations were calculated, and t-tests were used for comparisons between the different settings.
  
  
  RESULTS
  Averaged over 10 repeated X-ray scans per method and 19 measurement points per scan (n = 190), it was found that the MSCT scan protocol 140 kV delivered the most accurate virtual 3D model, with a mean deviation of 0.106 mm compared to the master model. Only the CBCT scans with 0.2-voxel resolution delivered a similar accurate 3D model (mean deviation 0.119 mm).
  
  
  CONCLUSIONS
  Within the limitations of this study, it was demonstrated that the accuracy of a 3D model of the lower jaw depends on the protocol used for MSCT and CBCT scans.
authors.affiliation: Department of Prosthodontics (Head: Prof. Dr. M. Wichmann), Erlangen University Hospital, Glückstrasse 11, 91054 Erlangen, Germany.
authors.forename: Ragai-Edward
authors.initials: RE
authors.lastname: Matta
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Dr. h.c. F.W. Neukam), Erlangen University Hospital, Glückstrasse 11, 91054 Erlangen, Germany.
authors.forename: Cornelius
authors.initials: C
authors.lastname: von Wilmowsky
authors.affiliation: Department I (Head: Prof. Dr. W. Neuhuber), Institute of Anatomy, Friedrich-Alexander-University of Erlangen-Nuremberg, Krankenhausstraße 9, 91054 Erlangen, Germany.
authors.forename: Winfried
authors.initials: W
authors.lastname: Neuhuber
authors.affiliation: Institute of Radiology (Head: Prof. Dr. M. Uder), Erlangen University Hospital, Maximiliansplatz 1, 91054 Erlangen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Lell
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Dr. h.c. F.W. Neukam), Erlangen University Hospital, Glückstrasse 11, 91054 Erlangen, Germany.
authors.forename: Friedrich W
authors.initials: FW
authors.lastname: Neukam
authors.affiliation: Department of Medical Informatics, Biometry and Epidemiology (Head: Prof. Dr. O. Gefeller), Friedrich-Alexander-University of Erlangen-Nuremberg, Universitätsstraße 22, 91054 Erlangen, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Adler
authors.affiliation: Department of Prosthodontics (Head: Prof. Dr. M. Wichmann), Erlangen University Hospital, Glückstrasse 11, 91054 Erlangen, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Wichmann
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Dr. h.c. F.W. Neukam), Erlangen University Hospital, Glückstrasse 11, 91054 Erlangen, Germany. Electronic address: bastian.bergauer@uk-erlangen.de.
authors.forename: Bastian
authors.initials: B
authors.lastname: Bergauer
mesh_terms: D003198:Computer Simulation; D054893:Cone-Beam Computed Tomography; D006801:Humans; D021621:Imaging, Three-Dimensional; D008334:Mandible / Q000000981:diagnostic imaging*; D061330:Multidetector Computed Tomography; D012984:Software
keywords: CBCT; Digital imaging; MSCT; Virtual 3D model; X-ray scan parameters