Three-dimensional CT reconstruction of the orbital cavity channel and its clinical significance

Objective To provide anatomical basis for clinical diagnosis of lesion spread between the orbital cavity and its surrounding area. Methods 100 cadaveric heads were selected with no diseases of the orbital cavity and the orbital cavity channel, and scanned in series by spiral CT from canthomeatal line(CML);all original images were transferred to the CT three-dimensional reconstruction workstation, and the orbital cavity channel were reconstructed through its long axis and perpendicular to the long axis. The position, shape and its adjacent structures of orbital cavity channel were observed and measured for diameter.Results The length or longidudinal diameter of bony nasolacrimal duct, infraorbital canal, inferior orbital fissure, superior orbital fissure and optic canal in CT image were(13.72±1.56),(24.62±2.03),(28.16±1.03),(19.02±2.43) and(6.20±0.44) mm respectively. There were significant difference in the length and transverse diameter between bony nasolacrimal duct of the male and female(P0.05), the length and transverse diameter of bony nasolacrimal duct were larger in male than in female. The size of the orbital opening, middle part and cranial opening of the optic canal was(25.22±4.89),(18.72±3.79) and(24.88±4.23) mm2 respectively. It was narrowest in the middle part of optic canal, which was the frequent location of optic canal stenosis.Conclusion CT three-dimensional reconstruction could display micro-structure of the orbital cavity channel intuitively, making it an important tool for diagnosis of the malignant tumor and inflammation of orbital cavity and its surrounding area.