 Magnetoencephalography (MEG)
or
Magnetic Source Imaging (MSI)
Magnetoencephalography (MEG), also known as Magnetic Source Imaging (MSI), is a non-invasive scanning technique which provides information about the structure and function of the brain. It is a safe and painless procedure that detects small biomagnetic signals produced by the brain, recording magnetic fields over the surface of the head. These signals provide information about the location of active brain areas. This technique allows doctors to investigate how different areas of the brain interact with one another.
MEG can help to identify brain zones which emit abnormal electric currents associated with epilepsy; "see" the magnetic fields associated with sensory areas of the brain by stimulating the senses during MEG recording sessions; view the brain zones which control language by having a patient perform linguistic tasks during MEG; and, identify the brain zones associated with learning and memory by having a patient perform cognitive tasks during MEG. It is useful in planning surgical treatment of epilepsy and for pre-surgical functional mapping of the brain. It quickly provides high resolution images of the brain, to compare function in relationship to behaviour.
Before an MEG/MSI
- No special diet is required. Your child can eat and drink as usual.
- Dress your child in comfortable clothing on the day of the test.
- Your child's hair should be shampooed and left loose:
do not use hairspray, gel or other hair products.
- Your child should not wear any metal objects
(jewellery, piercings, belts etc.).
During an MEG/MSI
- Your child will be placed in a shielded room away from fan motors, elevators and other sources of magnetic "noise".
- S/he will either lie down on a bed or sit in a chair.
- An electrical device, known as a neuromagnetometer, will be placed near your child's head. This instrument acts as an antenna to pick up the magnetic fields emerging from the brain, and takes a snapshot every millisecond.
Payment
This test is covered by the Ontario Health Insurance Plan (OHIP).
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