Feasibility of CBCT in Diagnosing Otosclerosis by Measuring CBCT Bone Density: A Preliminary Study

The aim of this study was to measure cone beam computed tomography (CBCT) derived bone density of 6 anatomic points around the otic capsule in preoperative assessment of patients with clinically suspected otosclerosis, and to compare these densities with control group. CBCT images of 21 patients (34 ears, the otosclerosis group) with surgically confirmed otosclerosis and 26 patients (52 normal ears, the control group) were evaluated in this prospective study. Six regions of interest (ROI) were set manually around the otic capsule with the slice thickness of 0.3 mm. The mean CBCT bone density these regions were measured and compared in the case and control groups. In the case group, the mean CBCT bone density at the fissula ante fenestram (FAF) was significantly lower than the control group. Moreover, at the 4 points of the other ROIs (3-6) CBCT bone densities were significantly lower in the case group compared to the control group (p < 0.01). In this group, among 13 bilateral otosclerosis, 22 ears had conductive hearing loss (CHL), 4 ears had mixed hearing loss (MHL) and among 8 unilateral otosclerosis, 5 ears had CHL, 3 ears had MHL. Our study showed the mean CBCT bone density of ROIs 1 and 6 were correlated with the average air-bone gap in the bilateral and unilateral otosclerosis group, respectively. Quantitative evaluation of CBCT with a slice thickness of 0.3 mm can be used as a suitable tool for diagnosis and follow-up of otosclerosis in temporal bone.