cochlear implant is a well accepted treatment to profound sensorineural hearing loss. Imaging provides essential information about anatomical Variants that could be riskyand should be considered by cochlear implant surgeon and the aim of the study:-

• Identify inner ear congenital and acquired abnormalities.
• Identify cochlear nerve anomalies.
• Detect temporal bone abnormalities that require surgical modification by cochlear implant surgeon.

Cochlear implant (CI) is a well-accepted treatment for severe to profound sensorineural hearing loss. Patients who are refractory to conventional hearing augmentation .

(CI) is a surgically implanted device consisting of external and internal components. An external microphone and speech processor worn behind the ear and convert sound into an electrical signal. A magnet held external transmitter sends the signal via electromagnetic induction through the skin to an internal receiver- stimulator which converts the signal into rapid electrical impulses which distributed to multiple electrodes on an electrode array implanted within the cochlea. The electrodes electrically stimulate the spiral ganglion cells along the cochlear turns, which then travel along the auditory nerve axons to the brain for sound perception .

Imaging provides essential information about many of the anatomical variations that could be risky and should be considered by cochlear implant surgeon to avoid complications.

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 .

Both computed tomography (CT) and magnetic resonance imaging(MRI) are complementary to each other. They detect cochlear, middle ear anatomy and the anatomical variants .

The strength of CT is visualization of the bony structures of the middle and inner ear and the strength of MRI is visualization of the fluid content of the membranous labyrinth, visualization of the vestibule-cochlear nerve in the fluid filled internal auditory canal and the cerebello-pontine angle .

Inclusion Criteria:

• Age, any age will included
• Gender, both genders will be included.
• Patient full filled criteria for CI including audiological & phoniatric criteria

Exclusion Criteria:

• • Patient who did not fulfill the criteria for indicating CI surgery.

patients who suffering from deep to profound sensorineural hearing loss( inculde any age,both genders)