Evaluation of semicircular canal dehiscence using micro-computed tomography and comparison with cone-beam computed tomography

Semicircular canal dehiscence (SSCD), is a rare bony defect that reveals a third window of semicircular canal except oval and round window. Dizziness, acute vertigo attacks, conductive hearing loss, tinnitus and amplified heartbeat sounds are the symptoms of dehiscence. The aim of this article is to analyze the length and location of semicircular canal dehiscence as superior (anterior), inferior (posterior), or lateral (horizontal) canals using micro-CT and compare it with Cone beam CT. A total of 39 dry temporal bones without visible damage were examined both in Micro CT and Cone beam CT. Measurements were made on these cross-sectional images using the CTAn software. Statistical significance was defined as p < 0.05. When examining Micro-CT images, only 4 canals showed dehiscence among 39 bones. The dehicences were observed in both lateral, superior, and posterior semicircular canals. One dehiscence was in the lateral semicircular canal, two were in the superior semicircular canal, and the last one was in the posterior semicircular canal. In CBCT images, dehiscence was observed in a total of 11 canals among the 39 bones. Two dehiscences were in the lateral semicircular canal, three in the posterior semicircular canal, and six in the superior semicircular canal. There was a significant difference between Micro CT and Cone beam CT in terms of dehiscence detection (p < 0,05). Consequently, this study emphasizes the potential danger of an uncertain diagnosis of canal dehiscence with CT in individuals with minor irregularities in Cone beam CT scans, which could result in potentially inappropriate surgical interventions.