Scanning and hearing implants
An MRI scanner uses strong magnetic fields in order to take very detailed pictures of your head and body. Your consultant will explain why an MRI scan is needed in your case.
If you have a cochlear implant (CI) or an auditory brainstem implant (ABI), the procedure for scans is slightly different, because the implant contains a magnet. This internal magnet can be affected by the magnetic field of the scanner.
Scanning with a magnet in place can create an artefact or visual anomaly which can make it harder to view any tumours.
On occasion it will be necessary to remove the magnet before scanning. Your consultant will discuss this with you. For most cases scanning will proceed with the magnet in place.
It is not expected that scanning will affect the sound from your hearing implant. During the scan we will give you a call bell so that if you are feeling unwell and need assistance you can call the bell and we will stop the scan.
In order to secure the magnet in position for safe MRI scanning, we apply a plastic card over the magnet, keeping it in place with a tight head bandage.
Possible complications of scanning with an implant
- Magnet dislocation or rotation is a serious but rare complication which would require review
- Headache following head bandaging
- Pain during MRI scan if no local anaesthetic is given.
Most patients will be offered a local anaesthetic to reduce any discomfort during scanning. This requires an injection around the magnet area. Some patients are able to tolerate scanning without any need for analgesia (pain killers).
Possible complications of having a local anaesthetic injection
- Allergic reaction, including anaphylaxis
- Potential for developing temporary numbness or tingling of the face including lips and tongue
- ABI/CI magnet may not stick for a short period after local anaesthetic being injected.
- Light headedness, dizziness or drowsiness
- Slurred speech
- Muscle tremor
- Nausea or vomiting
- Cardiac arrhythmias
- Hypotension or hypertension
If you have any questions, please ask your consultant who will be happy to discuss this with you.
We are smoke-free
Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.
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Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge
Telephone +44 (0)1223 245151