Clinically relevant human temporal bone measurements using novel high-resolution cone-beam CT

OBJECTIVE: To test the feasibility of measuring fine temporal bone structures using a newly established cone-beam computed tomography (CBCT) system. MATERIALS AND METHODS: Six formalin-fixed human cadaver temporal bones were imaged using a high-resolution CBCT system that has 900 frames and copper + aluminum filtration. Fine temporal bone structures, including those of the facial nerve canal and vestibular structures, were identified and measured. RESULTS: The fine structures of the middle ear, including the tympanic membrane, tendon of the tensor tympani, cochleariform process of the semicanal of the tensor tympani, pyramidal eminence, footplate of the stapes, full path of the facial nerve within the temporal bone, supralabyrinthine space, semicircular canals, pathway of the subarcuate canal, and full path of the vestibular aqueduct, were clearly demonstrated. The vestibular aqueduct has a midpoint width of 0.4 ± 0.0 mm and opercular width of 0.5 ± 0.1 mm (mean ± SD). The length of the internal acoustic meatus was 10.6 ± 1.2 mm (mean ± SD), and the diameter of the internal acoustic meatus was 3.7 ± 0.3 mm (mean ± SD). CONCLUSION: This novel high-resolution CBCT system has potentially broad applications in the diagnosis of inner ear disease and in monitoring associated pathological changes, surgical planning, navigation for the ear surgery, and temporal bone training.