title: Image quality of two different mobile cone beam computed tomographs for maxillofacial surgery.
abstract: OBJECTIVE
  We evaluated two mobile cone beam computed tomographs (mCBCT) comparing image quality with respect to radiation dosage. Image quality was analyzed by using different scanning modes.
  
  
  METHODS
  The skulls of three human cadavers were scanned by use of conventional Computed Tomography (CT) as well as with two mobile cone beam computed tomographs (Siemens Arcadis Orbic 3D and Ziehm Vision Vario 3D). Six different acquisition modes with different radiation dosages were used. The axial views of all scans were evaluated by five medical doctors regarding image quality by identifying predefined anatomical structures of the skull. A five-point ranking scale was used. The inter-rater reliability was statistically depicted by Cohen's Kappa coefficient. A Wilcoxon signed rank test was used to evaluate the rater's results. For evaluating the signal-to-noise ratio (SNR) a Catphan 600 reference body with two different inlays was used.
  
  
  RESULTS
  Comparing the mCBCTs, the image quality of the Siemens Arcadis Orbic 3D in high-dosage mode received the best score (median: 2.27). The inter-rater reliability was fair (Kappa=-0.030 to 0.328). The Wilcoxon test showed significant (p<0.05) different median rating values in 18 out of 21 imaging modes. The SNR was higher (better) in the high-dosage modes.
  
  
  CONCLUSIONS
  Intra-operative 3D imaging by using mCBCT for maxillofacial surgery in low-dose mode acquisition is adequate in terms of signal-to-noise ratio and image quality. The image quality does not correlate in a linear manner with a higher radiation dosage. Surgeons using this technique should gather their own experience with the different acquisition modes.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospital Heidelberg, Germany. robin.seeberger@med.uni-heidelberg.de
authors.forename: Robin
authors.initials: R
authors.lastname: Seeberger
authors.forename: Markus
authors.initials: M
authors.lastname: Buchgeister
authors.forename: Andreas C
authors.initials: AC
authors.lastname: Seethaler
authors.forename: Thomas
authors.initials: T
authors.lastname: Shiozawa
authors.forename: Juergen
authors.initials: J
authors.lastname: Hoffmann
mesh_terms: D002102:Cadaver; D054893:Cone-Beam Computed Tomography / Q000295:instrumentation / Q000706:statistics & numerical data*; D005004:Ethmoid Bone / Q000000981:diagnostic imaging; D057918:Fiducial Markers; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data; D007430:Intraoperative Care; D008334:Mandible / Q000000981:diagnostic imaging; D008443:Maxillary Sinus / Q000000981:diagnostic imaging; D061330:Multidetector Computed Tomography / Q000706:statistics & numerical data; D009300:Nasal Septum / Q000000981:diagnostic imaging; D015588:Observer Variation; D019647:Oral Surgical Procedures / Q000379:methods*; D009915:Orbit / Q000000981:diagnostic imaging; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D012886:Skull / Q000000981:diagnostic imaging* / Q000601:surgery