Can MRI replace CT in evaluating semicircular canal dehiscence?

Area of Science:

• Radiology
• Neuroimaging
• Otolaryngology

Background:

• Semicircular canal (SCC) dehiscence diagnosis often involves both CT and MR imaging.
• Evaluating the utility of FIESTA-sequence MR imaging as a replacement for CT in diagnosing SCC dehiscence.

Purpose of the Study:

• To assess if FIESTA MR imaging can replace temporal bone CT for SCC dehiscence evaluation.
• To compare the diagnostic performance of FIESTA MR imaging against CT for SCC dehiscence.

Main Methods:

• Retrospective review of 112 patients (224 ears) with vestibulocochlear symptoms.
• Concurrent MR imaging (FIESTA sequence) and CT of the temporal bones were analyzed.
• Two neuroradiologists evaluated for superior and posterior SCC dehiscence, with CT as the reference standard.

Main Results:

• MR imaging demonstrated 100% sensitivity and 100% negative predictive value for both SSC and PSC dehiscence compared to CT.
• Specificity for SSC dehiscence was 96.5%, and for PSC dehiscence was 99.1%.

Conclusions:

• MR imaging with FIESTA sequences has high sensitivity and NPV, effectively excluding SCC dehiscence.
• Negative MR imaging findings negate the need for CT in SCC dehiscence detection.
• CT should be reserved for patients with positive MR imaging findings for SCC dehiscence.