Imaging Evaluation of Pediatric Sensorineural Hearing Loss in Potential Candidates for Cochlear Implantation.

Abstract

Computerized tomography (CT) and magnetic resonance (MR) are complementary in the imaging of the labyrinth, the internal auditory canal and the brain in children with sensorineural hearing loss who are being evaluated for cochlear implantation. An accurate anatomical description of the inner ear is essential in the preoperative work up. Computerized tomography visualizes the bony structures, whereas MR can discern soft-tissue components including intra labyrinthine fluid, cerebrospinal fluid (CSF), nerves, and vessels within the IAC. This prospective study was conducted in the Department of Otorhinolaryngology, Head & Neck Surgery, Government Medical College, Srinagar. 40 children in the age group of 1-16years with unidentified causes of bilateral SNHL were analysed radiologically over the period of 2years from Dec 2011 to Jan 2014. Each patient underwent MRI and high resolution CT scanning of temporal bone in axial and coronal planes. Out of the 40 patients 22 were males (55%) and 18 were females (45%). 30 patients (72.5%)in our study had normal radiological scans. Five patients (12.5%) had B/L large vestibular aqueduct and two patients (5%) had internal auditory canal stenosis with cochlear nerve hypoplasia on CT and MR imaging. Cochlear dysplasia was present in two patients (5%) and semicircular canal dysplasia was present in one patient (2.5%) as an isolated finding on HRCT. In addition isolated cochlear nerve hypoplasia was present in one patient (2.5%). Hyperintense basal ganglia lesion suggestive of kernicterus was present in one patient (2.5%) and hyperintense posterior parietal and occipital white matter lesions suggestive of congenital CMV infection was present in one patient (2.5%) on MR imaging. Arachnoid cysts of middle cranial fossa was an incidental finding present in one patient. Radiological abnormalities of the inner ear are not uncommon. Computerized tomography and MRI are important modalities to analyze the inner ear in children with unexplained SNHL. MRI with an extremely small field of view should be used to study possible abnormalities of the vestibulocochlear nerves.