Diffusion tensor imaging and auditory tractography to evaluate cochlear implant candidacy: a pilot study

Background: Conventional radiological evaluation does not evaluate the functional status of the auditory pathway in patients scheduled for cochlear implantation (CI).

Objectives: Determine the value of diffusion tensor imaging [DTI] in the preoperative evaluation of some patients scheduled for CI.

Material and methods: Patients with profound SNHL and inner ear and/or cochlear nerve anomalies or long standing SNHL were selected. They underwent conventional MRI images of the brain in three orthogonal planes, MR arterial spin labelling (ASL), perfusion, and DTI auditory tractography to determine functional status of the auditory pathways.

Results: Ten patients were included. Seven with bilateral SNHL, one with fluctuating hearing loss and one with long standing single sided deafness. In 8 patients the auditory pathway could be traced and functional maps could determine the side of possible better function. In the patient with progressive hearing loss DTI revealed major central pathway problems and CI was discouraged. In the patient with SSD, DTI revealed a robust intact pathway and CI was advised.

Conclusions: DTI and auditory tractography can help in outlining the functional integrity of the 33auditory pathway and assist in decision making before CI.