title: Computer-aided analysis of orbital volume:  a novel technique.
abstract: OBJECTIVE
  : To demonstrate the accuracy and efficiency of a novel software tool designed specifically for volumetric analysis of the orbit.
  
  
  METHODS
  : The software was evaluated for accuracy and speed in analysis of orbital CT data sets. The analysis included: 1) intraoperator error: one operator repeatedly evaluated a single orbit multiple times. The variation in volumes was compared; 2) interoperator error: 3 operators evaluated the same orbits multiple times. The variation in volume measurements among operators was compared; 3) interscan error: one operator evaluated the volume of single orbit scanned on multiple occasions by different CT scanners. The variation in volume measurements among scans performed at different times was compared; and 4) time for analysis: one operator evaluated 52 orbits, recording the time it took to analyze each orbit.
  
  
  RESULTS
  : Intraoperator error was 0.08 cc (95% confidence interval, 0.06-0.10). Interoperator error was 0.18 cc (95% confidence interval, 0.14-0.20). Interscan variability data showed a trend toward increasing error for repeated patient scans using different CT scanners. Average time for analysis of single orbit was 138 seconds (standard deviation = 24; range, 95-217 seconds).
  
  
  CONCLUSIONS
  : Maxillo is an accurate and efficient tool for semiautomatic evaluation of orbital volume in nontraumatized orbits.
authors.affiliation: Department of Otolaryngology, University of California Davis, Sacramento, CA 95817, USA. edward.strong@ucdmc.ucdavis.edu
authors.forename: E Bradley
authors.initials: EB
authors.lastname: Strong
authors.forename: Scott C
authors.initials: SC
authors.lastname: Fuller
authors.forename: Harinder S
authors.initials: HS
authors.lastname: Chahal
mesh_terms: D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D008297:Male; D015588:Observer Variation; D009915:Orbit / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D010865:Pilot Projects; D015203:Reproducibility of Results; D012984:Software; D014057:Tomography, X-Ray Computed