Morphometric and Volumetric Measurements of Orbit With Cone-Beam Computed Tomography

The purpose of this study was to determine cone-beam computed tomography (CBCT) as a tool for measuring morphometric and volumetric measurements of the orbit. Also, to assess gender and age variations and compare traditional methods of measurements in dry-skull, cadaveric, and other imaging modalities.

Morphometric and volumetric values of 98 orbits (49 subjects, 21 men/28 women) were measured using CBCT. Their mean and standard deviation were measured and analyzed. The gender and age variability older and younger than 40 years were evaluated. They were compared with other dry-skull and imaging studies done among different populations.

CBCT could accurately measure the various morphometric and volumetric parameters of the orbit. From the reference point infraorbital foramen (I) to lacrimal fossa (F1), inferior orbital fissure (F2), inferior orbital rim (F3), and the optic canal (F4) were (in mm) (mean ± SD) 22.88 ± 1.08, 32.53 ± 0.88, 7.44 ± 0.71, and 51.45 ± 1.28, respectively. From the reference point, superior orbital notch/foramen (S) to superior orbital fissure (S1), lacrimal fossa (S2), and the optic canal (S3) were 49.29 ± 2.1, 26.39 ± 1.58, and 46.82 ± 0.88, respectively. From the reference point frontozygomatic suture (L) to lacrimal fossa (L1), superior orbital fissure (L2), the optic canal (L3), and inferior orbital fissure (L4) were 18.19 ± 0.88, 39.91 ± 1.44, 47.63 ± 1.11, and 35.19 ± 1.02, respectively. Orbital volume was found to show a significant difference between older and younger than 40 years of age, though not significant compared between men and women.

CBCT is a viable tool for morphometric and volumetric measurements of the orbit and other orocraniofacial structures. It can also assess age and gender variability. The low cost, high accuracy, low radiation, and ease of use can help in reproducibility among the different living populations.