The Role of Computed Tomography in the Diagnosis of Congenital Sensorineural Hearing Loss

Introduction One of the paths in the investigation of congenital sensorineural hearing loss (CSNHL) is to try to characterize its etiology through the inner ear evaluation using high resolution computer tomography (CT) scans. With minor malformation, it is not always possible for a simple visual inspection to recognize if the structure in the inner ear is normal or not. Objective To verify if measurements of the inner ear are predictive of sensorineural hearing loss (SNHL) and suggest cutoff points of size limits. Methods Retrospective cross-sectional study of inner ear CT scan measurements of 214 patients, 50 with congenital SNHL (CSNHL) and 164 acquired SNHL (ASNHL) (control group). Results In the CSNHL group, central bony island (CBI) were 0.48mm smaller ( p <0.001), cochlear nerve aperture was (CNA) 0.10mm smaller ( p <0.001), and cochlea height was (CH) 0.15mm smaller ( p <0.001). Vestibular aqueduct (VA) and cochlea width (CW) were similar between groups (0.70 vs 0.72, p =0.19, and 7.20 vs 7.15 p =0.23). The predictive cutoff points for CSNHL were CBI=3.6mm, CAN=1.4mm, CH=3.4mm, CW=7.0mm, and VA=0.9mm. Conclusion Congenital sensorineural hearing loss determined a decrease in CBI, opening of the cochlear nerve (OCN), and CW. Thus, these measures, at the cutoff points indicated, should make us aware of the diagnosis of congenital hearing loss.