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

Abstract

ObjectiveTo test the feasibility of measuring fine temporal bone structures using a newly established cone-beam computed tomography (CBCT) system.Materials and methodsSix 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.ResultsThe 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).ConclusionThis 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.

Practicable assessment of cochlear size and shape from clinical CT images

“…The next-generation CBCT image in Fig. 2 a is superior to those currently found in clinical practice, but resembles the state-of-the-art research images in Zou et al 32 .

Figure 2 Pseudo-clinical data.

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The radioanatomical assessment of the Körner’s septum

“…Cone-beam CT was introduced in mid 90 s and has been used, especially in dental and maxillofacial radiology. Although high-resolution CT is the gold standard in the imaging of the temporal bone, there is an increasing number of papers that report attempts to use CBCT in otorhinolaryngology [ 8 , 22 ] and imaging of the fine structures inside the temporal bone [ 11 ], particularly when there is need for preoperative assessment of cochlear implantation, or postoperative follow-up. Cone-beam CT technique is still developing and it seems to be a promising method for the diagnostics of chronic otitis media, or traumatic lesions.…”

Ultra-low-dose CBCT scan: rational map for ear surgery

“…The IQ of CBCT images could be further enhanced if the patient were supine during scanning (this would reduce motion artefact) and by adjusting the primary focal area on the ear. In optimal circumstances (in vitro), superb resolution of fine structures (stapes, incudostapedial joint, tendon of the tensor tympani and the stapes footplate, to name a few) is possible with CBCT (tube voltage: 88 kV; tube current: 11 mA; voxel size: 0.1 mm; FOV: 60 × 60 mm) [ 5 , 7 ]. We knew from experience that ULD CBCT with our specifications is not likely to produce clinically sufficient images of these above mentioned structures, hence majority of them were not even included in our list of structures.…”

“…As early as 15 years ago, Peltonen et al [5] demonstrated the substantial potential of CBCT for imaging the middle ear; however, multi-slice computed tomography (MSCT) is still the standard method. The most recent articles rank CBCT as equal or superior to MSCT in terms of image quality (IQ) and resolution [6][7][8]. However, these studies compared images of cadaver heads and are thus free of reallife motion artifacts.…”