Role of Multislice Computed Tomography and Magnetic Resonance Imaging in Preoperative Cochlear Implant Evaluation

Cochlear implant is the treatment of choice for deep sensorineural hearing loss, notably in those patients for whom conventional amplification devices do not provide significant clinical improvement. Imaging plays an important role in the workup of cochlear implant candidates not only to identify inner ear congenital and acquired abnormalities or cochlear nerve anomalies but also to detect temporal bone abnormalities that may be encountered during surgery and may alter surgical approach.

Some variations are potential surgical hazards that may lead to problems during the surgery and may alert the surgeon regarding potential surgical dangers and complications.

The radiologist and surgeon must be familiar with these imaging findings. Both computed tomography and magnetic resonance imaging should be used as they delineate, in different manners, cochlear and middle ear anatomy as well as other anatomical variants.

Mastoid pneumatization is important for planning the surgery. It is classified into pneumatic, diploic, sclerotic, and mixed. Effusion of the middle ear cleft should also be reported.

Korner's septum divides the mastoid process into a superficial squamous portion and a deep petrous portion. It may mislead the surgeon to the mastoid antrum during surgery. Mastoid emissary veins participate in extracranial venous drainage of the posterior fossa dural sinuses. Most of them disappear, however, some persist and enlarge.