You probably know what an MRI is: A very powerful magnetic-field emitting machine used to see your body’s organs and structures. MEGs are not as well-known, but that doesn’t mean they are any less important. These two technologies can be very effective when used together.
Magnetic Resonance Imaging (MRI) is a very widespread technology. An MRI machine uses very strong magnets to create a very strong magnetic field. This magnetic field is used to create a very detailed picture of the part of the patient’s body that is being examined. These pictures are viewed via a computer as a cross-section (layer-by-layer). MRI scans are much safer than CT scans, as no radioactive dye is injected.
Magnetoencephalography. Try to pronounce that. Its abbreviation is MEG. It is basically the opposite of an MRI. An MEG is a machine that is very sensitive to magnetic fields. Your brain emits very small magnetic pulses when you process information or react to it. An MEG needs to be able to detect those very small magnetic fields from your brain, which are about one-billionth of the earth’s magnetic field. MEGs are used in a specially designed room to “block” all incoming magnetic fields so the reading of your brain’s magnetic pulses are clear and without background “noise”. Unlike an MRI, which can be extremely loud, an MEG is silent.
While both of these technologies are very useful on their own, combining their data can be used to create functional maps of brain activity. MRI results create a picture of what the brain looks like. MEG data shows what the brain is doing. Combining the data of these two, called Magnetic Source Imaging (MSI), can show what parts of the brain are doing what, and under what circumstances (relaxing, watching TV, thinking about something scary, etc.). The Surrey Memorial Hospital has both MRI and MEG machines. These two machines are only a few walls apart, which makes this lab very unique in Western Canada.
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