감각 신경성 난청환자에서 좁은 와우신경 골도의 중요성 및 의의: CT와 MRI소견 = The Significance of a Hypoplastic Bony Canal for the Cochlear Nerve in Patients with Sensorineural Hearing Loss: CT and MRI Findings

다국어 초록 (Multilingual Abstract)

Purpose: The purpose of this study is to evaluate the significance of the hypoplastic canal for the cochlear nerve in patients with sensorineural hearing loss (SNHL) and the relationship between the hypoplastic bony canal and aplasia or hypoplasia of the cochlear nerve.
Materials and Methods: A retrospective review of high resolution temporal CT(HRCT) and MRI findings was conducted. The narrow bony canal of the cochlear nerve and the relative size of the internal auditory canal were correlated with the cochlear nerve deficiency on MRI. The comparative size of the component nerves (facial, cochlear, superior vestibular, inferior vestibular nerve), and the relative size of the internal auditory canal and the bony canal of the cochlear nerve were measured. The clinical history and the results of the clinical examination were reviewed for each patient.
Results: High resolution MRI showed aplasia of the common vestibulocochlear nerve in one patient and a deficiency of the cochlear nerve in 9 patients. These abnormalities occurred in association with a prominent narrowing of the canal for the cochlear nerve and a stenosis of the internal auditory canal, which was observed on temporal bone CT in 9 patients with congenital SNHL. Three patients had normal IAC, despite the presence of a hypoplastic cochlear nerve on the side on which they had SNHL. In one patient, the narrowing of the canal for the cochlear nerve and internal auditory canal were not found to be associated with acquired SNHL.
Conclusion: The hypoplastic bony canal for the cochlear nerve might be more highly indicative of congenital cochlear nerve deficiency than that of the narrow internal auditory canal, and the position of the crista falciformis should also be carefully.

국문 초록 (Abstract)

목적: 감각신경성 난청환자에서 와우신경분지의 좁은 골도의 중요성과 와우신경의 부분 형성부전이나 형성부전의 연관성을 알아보고자 하였다.
대상과 방법: 감각신경성 난청인 10예의 환자에서 고해상도 측두골 CT에서 와우신경분지의 골도가 좁아져있는 경우를 자기공명영상 와우신경 형성부전과 비교하였다. 자기공명영상소견상 안면신경, 전정와우신경의 와우분지, 상전정분지, 그리고 하전정분지의 존재와 상대적 크기를 검토하였고, 내이도 및 와우신경분지의 골도의 크기를 측정하였다. 각 환자에 대한 임상소견과 이학적 소견을 검토하였다.
결과: 자기공명영상 결과 1예의 환자에서 전정와우신경의 형성부전을 관찰하였으며 9예에서 와우신경분지의 형성부전이 관찰되었다. 고해상도 측두골 CT에서 선천성 감각신경성 난청환자인 9예에서 와우신경분지가 지나는 골도의 크기가 좁아져 있었고 자기공명영상상 와우신경의 형성부전 또는 부분 형성부전이 관찰되었다. 후천성 감각신경성 난청환자 1예에서는 와우신경분지가 지나는 골도의 크기나 내이도의 협착과의 연관성은 없었다.
결론: 와우신경 분지가 지나는 골도의 크기가 좁아져 있는 경우들은 선천성 와우신경 형성부전을 시사하는 소견이라 할 수 있겠으며, 나사선공열이 와우신경분지의 골관을 감싸는 겸상능선의 아래쪽 전와우부는 고해상도 전산화 단층촬영의 시상면에서 세심한 관찰이 필요하겠다.

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