Multislice computed tomography in the diagnosis of superior canal dehiscence: how much error, and how to minimize it?

Hypothesis: Multi-slice computed tomography (MSCT) overestimates the size of superior semicircular canal dehiscences (SSCDs) and also can misinterpret thin bone over the superior semicircular canal as dehiscent. A threshold of the radiodensity of the bone over the superior semicircular canal may exist that could optimize prediction of an actual SSCD.

Background: The gold standard for diagnosis of SSCD is MSCT, but there is a higher prevalence of SSCD based on MSCT compared with histologic studies.

Cone-beam volumetric tomography for applications in the temporal bone.

Hypothesis: Cone beam volumetric tomography (CBVT) has better spatial resolution compared with multi slice computed tomography (MSCT) in temporal bone imaging for superior canal dehiscence (SCD).

Background: Imaging of SCD has traditionally used MSCT, but the ability to resolve thin bone next to low-radiodensity brain and inner ear fluids at the interface of the superior canal (SC) with the middle cranial fossa can be adversely affected by partial volume averaging, errors in registration of successive slices, and other factors. CBVT may offer advantages in these regards and may have better spatial resolution for this application.