Measurement of orbital volume by a 3-dimensional software program:: An experimental study

Purpose: This study reports a simple method with high accuracy for determining orbital volume from computed tomography (CT) scans. Materials and Methods: The volume of 20 orbits was evaluated in 20 dry skulls by use of a 3-dimensional software program in General Electric High-Speed Advantage CT/I (Milwaukee, WI), and compared with the volume obtained by direct measurement using the water displacement method. Accuracy of volume measurement by this software program was assessed statistically by paired samples t-test, Results: The mean volume was found to be 28.37 mL +/- 2.15 by direct impression and 28.41 mL +/- 2.09 by the software program. Volume difference between the 2 methods averaged 0.93 +/- 1.08 mt for each orbit (P <.01). The correlation between the techniques was found to be high (r = 0.887, P <.01). There was no significant volume discrepancy between the 2 methods. Conclusion: Measurement by the technique described is an easy and accurate method of assessing the volume of the orbit, (C) 2000 American Association of Oral and Maxillofacial Surgeons.