Diagnostic utility of labyrinth capsule bone density in the diagnosis of otosclerosis with high resolution tomography.

OBJECTIVE

The aim of this study is to compare the bone density around the otic capsule in otosclerotic patients with a control group, and find the cut-off values of bone density from which we can diagnose the disease.

MATERIAL AND

METHODS

A retrospective case-control study was performed. Bone densities in Hounsfield units (HU) from 28 otosclerotic ears were compared to the densities of 33 non otosclerotic capsules. These densities were measured in eight regions of interest (ROI) where the otosclerotic foci are usually found. The mean density of these regions (PROMED) was taken. Furthermore, the ROC curves of each ROI and the mean density (PROMED) were calculated.

RESULTS

All radiological densities in HU of each ROI and the mean density in otosclerotic patients were lower compared to non otosclerotic ears. The area under the ROC curve of each ROI and the mean density showed that the areas with greater accuracy for the diagnosis of otosclerosis were mean density, the fissula ante fenestram, and precochlear region, with cut-off values of 1980HU, 1750HU and 2114HU, respectively.

CONCLUSION

The mean density of the otic capsule (PROMED), the density in the fissula ante fenestram (ROI1) and in the precochlear region (ROI3) seem to be the most useful parameters to make a diagnosis of otosclerosis.