Abstract
Purpose::
To determine the orbital volume behind the axis of the globe in normal Chinese adults.
Methods::
The volume of orbit was evaluated in 20 dry, anatomic specimens filled with find sand by 3-dimensional CT measurements (using 2mm, 3mm and 5 mm layer thickness and windows) and compared with the volume obtained by direct measurement using fine sand displacement method. The precision and accuracy of CT measurement was assessed. The orbital volume behind the axis of the globe from 30 normal Chinese adults (15 male, 15 female), 24 to 45 years old, was measured using a 3-dimensional CT method. The volume values from the left and right orbits, between male and female were compared.
Results::
By 3-dimensional CT measurements, the orbital volume behind the axis of the globe from 20 skull specimen was 15.91±1.62ml in 2mm layer thickness, the sand volume by volumetric cylinder is 15.87±1.70ml, which did not show a significant difference between the both methods (p>0.05). By direct measurement with volumetric cylinder, the volume of the left orbit was 16.04±1.84ml, the right orbit was 15.70±1.62ml in skull specimen. There was no significant difference between left and right (p>0.05). In normal Chinese subjects, the orbital volume behind the axis of the globe was 18.58±1.47ml in adult males and 16.84±1.53ml in adult females by 3-dimensional CT measurement, which exhibited a significant difference between males and females (p<0.01). The orbital volume behind the axis of the globe was 17.70±1.74ml in the left orbit and 17.70±1.73ml in the right orbit, there was no significant difference between left and right orbits (p>0.05).
Conclusions::
The 3-dimensional CT measurement of orbital volume behind the axis of the globe is precise and accurate. The orbit volume behind the axis of the globe is larger in male than in female of normal Chinese subjects. Quantitative assessment of orbital volume behind the axis of the globe may provide useful information in clinical management of enophthalmos and other orbital diseases.
Keywords: orbit • imaging/image analysis: clinical • image processing