✍️ Written by the MedTestBD Editorial Team · Last reviewed: June 2026
What is an MRI of the Ear / IAC / Mastoid?
An MRI of the ear, internal auditory canal (IAC), and mastoid produces detailed images of the structures involved in hearing and balance — including the cochlea, semicircular canals, auditory nerve (CN VIII), facial nerve (CN VII), and mastoid air cells. It is the investigation of choice for evaluating sensorineural hearing loss, vertigo, and suspected tumours of the auditory nerve. The IAC is the bony canal through which the hearing and facial nerves travel from the brainstem to the inner ear.
Why is an Ear / IAC / Mastoid MRI Done?
- To diagnose acoustic neuroma (vestibular schwannoma) — a benign tumour on the hearing nerve causing unilateral hearing loss and tinnitus
- To investigate sudden sensorineural hearing loss — MRI can detect labyrinthitis, ischaemia, or tumour
- To evaluate unexplained vertigo, balance disturbance, or tinnitus
- To assess facial nerve palsy — MRI can detect facial nerve inflammation, compression, or tumour
- To evaluate cholesteatoma — an abnormal skin growth in the middle ear that can erode bone
- To investigate mastoid disease or chronic otitis media not adequately assessed by CT
MRI vs CT for Ear Problems
| Feature | MRI Ear/IAC | CT Temporal Bone |
|---|---|---|
| Best for | Soft tissue, nerves, cochlea, acoustic neuroma | Bone detail, cholesteatoma, ossicle erosion |
| Acoustic neuroma detection | Excellent — definitive test | Poor — misses small tumours |
| Bone erosion | Limited | Excellent |
| Radiation | None | Yes |
How to Prepare for an Ear / IAC / Mastoid MRI
- No fasting is required for a non-contrast scan — fast for 4 hours if contrast is planned
- Remove all earrings, hearing aids, and metal objects from the head and neck
- Inform staff about any cochlear implants — these are usually a contraindication to MRI
- Do not apply makeup, mascara, or metallic hair products on the day of the scan
- Inform staff about any pacemaker or intracranial metal implants
- Bring previous audiometry results, CT scans, and ENT referral letters for the radiologist
⚠️ This information is for general reference only. Always consult a qualified physician before undergoing any medical test.