Relationship between CT densitometry with a slice thickness of 0.5 mm and audiometry in otosclerosis

Abstract

The appropriate cutoff Hounsfield unit (HU) value for the diagnosis of otosclerosis was determined and the correlation between the bone conduction threshold and the findings of computed tomography (CT) densitometry investigated. CT images, 0.5-mm thick, were evaluated in 24 ears with otosclerosis and 19 control ears. Eight regions of interest were set around the otic capsule. The mean HU values in the area anterior to the oval window (A-OW) and anterior to the internal auditory canal (A-IAC) were significantly lower in otosclerosis than in controls. Based on receiver operating characteristic (ROC) analysis, the cutoff HU value in A-OW was determined to be 2,187.3 HU. The mean HU value in retrofenestral otosclerosis was significantly lower in the area A-OW, A-IAC and around the cochlea than in controls. Based on ROC analysis, the cutoff HU value in the latter was determined to be 2,045 HU. A statistically significant correlation was found between the density of the area A-OW and the hearing level at 500 and 1,000 Hz, and between the density of the area around the cochlea and the hearing level at most frequencies. These results suggest the semi-automated diagnosis of otosclerosis may be possible.

Correlation between the Size, CT Density of Otosclerotic Foci, and Audiological Tests in Cases of Otosclerosis

“…This result does not agree with Kawase et al [22] , who found a significant correlation between the density in the area anterior to the oval window and hearing thresholds (both AC and BC).…”

Superior Semicircular Canal Dehiscence: Congenital or Acquired Condition?

“…Certainly, the utility of CT bone attenuation measurement in the diagnosis of otosclerosis has been investigated, with some but not all groups showing focal diminished bone attenuation in patients with otosclerosis compared with controls. [8][9][10][11] Change in bone attenuation with age in the inner ear is of great interest to the authors and is currently under investigation by our group. Alternatively, we conjecture that the condition may be the cumulative result of repetitive microtrauma, which would increase in number throughout the course of life, but this is yet to be proved.…”

Imaging Features and Progression of Hyperostosis Cranialis Interna

“…8 The attenuation degradation can be compared with the process that is visible in otosclerosis, where attenuated (D1) cortical bone of the otic pit is transformed into porous cortical bone containing more fibrous and less calcified tissue. 9,10 There is not yet a definite explanation why some particular areas are involved and others not. Given the fact that only the craniofacial area is involved, there must be a local factor that causes bone metabolic disturbance.…”