Preoperative dual imaging evaluation of profound sensorineural hearing loss in patients for cochlear implantation

Abstract

Background: Profound sensorineural hearing loss (SNHL) may be the result of major inner ear structural malformations, and cochlear implantation remains the only viable treatment option. High-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) are indispensable for optimum preoperative implant workup and thus play a vital role in patient selection, pre-implantation counseling, and surgical management. Aim and Objectives: The aim of this study is to evaluate patients with profound SNHL for cochlear implantation preoperatively on both HRCT and MRI and to compare imaging findings in both modalities. Materials and Methods: This longitudinal prospective study was conducted in the Department of Radiology of a tertiary care-based hospital in North India. A total of 45 patients (90 temporal bones) with clinically diagnosed bilateral profound SNHL were included in the study. Patients with a previous history of temporal bone injury were excluded from the study. All cases were evaluated on both 128 slice Philips computed tomography (CT) machine and 1.5 Tesla Siemens Magnetom MRI scanner. Each temporal bone was systematically analyzed for anatomical and structural abnormalities. Results: Both high-resolution CT and MRI played vital roles in the workup of patients with profound SNHL for cochlear implantation and allowed accurate assessment of critical inner ear abnormalities. Cochlear malformations (30%) were responsible for the majority of structural abnormalities in this study with Type II incomplete partition (8.9%) being the most common. Cochlear nerve deficiency was seen in 20 cases (22.2%) and was diagnosed only on MRI. Similarly, early fibrosis and abnormal signal intensity were also detected only on MRI, which were missed on CT. Conclusions: Both high-resolution CT and high magnet MRI complement each other and reduce the chances of missing critical findings, which are crucial for surgical management and planning. Thus, it is advisable to perform dual imaging with both modalities wherever and whenever possible, to offer maximum information to treating surgeon preoperatively.