&nbsp;Imaging and audiological characteristics of patients with cochlear nerve dysplasia

LU Zhao-Yi; PAN Tao; WANG Yu

doi:10.16098/j.issn.0529-1356.2020.05.010

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Acta Anatomica Sinica ›› 2020, Vol. 51 ›› Issue (5) : 693-698. DOI: 10.16098/j.issn.0529-1356.2020.05.010

Imaging and audiological characteristics of patients with cochlear nerve dysplasia

LU Zhao-yi PAN Tao* WANG Yu

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Abstract

Objective To investigate the imaging and audiological characteristics of patients with cochlear nerve dysplasia (CND), and the relationship between them. Methods Seven patients undergoing unilateral cochlear implantation with abnormal cochlear nerve development were studied retrospectively. The patients were examined by audiology, high-resolution CT of temporal bone and MRI of internal auditory canal (IAC). The diameter of IAC and bony cochlear nerve canal (BCNC) were measured in temporal bone CT. The number of nerve bundles in IAC and the stenosis or absence of cochlear nerve were measured in the MRI of IAC, and inner ear　was checked whether there is deformity. The differences of hearing performance in different imaging manifestations were analyzed. Results In the imaging findings, 7 cases all indicated cochlear nerve dysplasia. In temporal bone CT, 3 cases (5 ears) showed abnormal IAC, 6 cases (9 ears) showed stenosis or absence of BCNC. In the MRI findings, 7 cases (12 ears) showed stenosis or absence of the cochlear nerve. The number of nerve bundles in IAC varied from 0 to 3. In addition, 4 cases (8 ears) with different types of inner ear malformations were found by imaging examination. The audiological performance of 7 patients were severe or profound sensorineural hearing loss. There were no significant differences in the pure tone average threshold in different imaging manifestations. (including IAC, BCNC, number of nerve bundles, and whether combined with inner ear malformations) (P>0.05). Conclusion The imaging features of CND include the abnormalities of the IAC and BCNC in temporal bone CT, the number of nerve bundles in IAC and abnormalities of the cochlear nerve in MRI. The audiogram usually shows severe or profound sensorineural hearing loss. There is no significant correlation between the imaging and audiological manifestations. There is a big challenge for cochlear implantation in such cases.

Key words

Cochlear nerve dysplasia / Internal auditory canal / Bony cochlear nerve canal / Cochlear nerve / High resolution computed tomography / Magnetic resonance imaging / Human

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LU Zhao-yi PAN Tao WANG Yu. Imaging and audiological characteristics of patients with cochlear nerve dysplasia[J]. Acta Anatomica Sinica. 2020, 51(5): 693-698 https://doi.org/10.16098/j.issn.0529-1356.2020.05.010

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