Preoperative cochlear implant imaging: is magnetic resonance imaging enough?

Objective: To investigate the accuracy of magnetic resonance imaging (MRI) as a preoperative imaging technique for cochlear implant candidates.

Study design: Retrospective, blinded.

Setting: Tertiary medical center.

Patients: 31 cochlear implant candidates with various causes of hearing loss.

Intervention: Cochlear implant patients received preoperative high-resolution temporal bone computed tomography (CT), and high-resolution T2-weighted fast spin echo MRI (FSE-MRI). The images were read independently of each other and in a blinded manner by two neuroradiologists. The imaging results were also correlated with intraoperative findings.

Main outcome measures: Lack of agreement between the findings for either imaging technique; also, lack of agreement between imaging findings and intraoperative findings.

Results: FSE-MRI is equal to CT imaging in the detection of abnormalities of cochlear patency. It is better than CT imaging in detecting cochlear dysplasia and large vestibular aqueducts, and in determining the presence of the cochlear nerve.

Conclusion: FSE-MRI is accurate in predicting inner ear anomalies and obstruction of the cochlear lumen. It also adds information not gathered from CT imaging, such as the presence and size of the cochlear nerve.