Let's simply learn about the fMRI scan (Functional MRI), which looks at the working areas inside the brain.

Imagine that you or someone you know needs brain surgery. The first thing we think is, "Oh, doctors, how do you know to operate without damaging the areas that are important for speech, movement, and memory?" That's a big question. Today we're talking about a special scan that helps with that, one that shows a 'live' map of the inside of the brain. This is called an fMRI, or Functional MRI scan.

Simply put, what is fMRI?

You may have heard of an MRI scan. It takes very clear three-dimensional (3D) pictures of the organs inside our bodies. It doesn't use X-rays or radiation like CT scans. So there's nothing to be afraid of.

Now, fMRI is a special scan that uses the same MRI machine. But what's special about this one is that, in addition to taking a picture of the brain, it also shows which parts of the brain are active at that time.

It works like this: When a part of our brain is working, like when we talk, think, or move our hand, the brain cells in that part need more oxygen. More oxygen means more blood flow. The fMRI machine can detect that increased blood flow. Then the areas that are active appear brighter on the scan.

What are the uses of this scan?

Mapping brain activity in this way is very important, especially for planning brain surgery. If you need to perform surgery, the neurosurgeon can look at this fMRI map and plan the surgery without damaging the areas that control your vital functions, such as speech and movement. This can be done on adults as well as children.

For example, imagine that you have a tumor in your brain. The tumor is located near the part of your brain that controls how you move your fingers. During the scan, you are asked to move your fingers. The fMRI image shows the exact area where you are doing that action, which lights up. Then the surgeon knows to carefully remove the tumor without touching that area.

The main situations where this type of planning is needed are:

• Epilepsy: In cases of epilepsy that is not controlled by medication, if surgery is required, brain function should be monitored prior to surgery.
• Brain tumors: Before surgery to remove cancerous or benign tumors.
• Radiation therapy: When giving radiation therapy to the brain, minimize damage to healthy parts.
• After treatment: See if there is a change in brain function after a certain treatment.

How should I prepare before the scan?

Preparing for an fMRI scan is very important because the machine uses a very strong magnet, so you need to be very careful about your safety.

Your doctor will explain this to you, but you usually have to pay attention to these things.

• Do not drink anything containing caffeine (coffee, tea, some soft drinks) on the day of the scan, as it may affect the scan results.
• Tell your doctor about any medications you are taking. He or she will advise you whether or not to take them before the scan.
• Do not wear or carry anything metallic . Not only metal that is magnetic, but also metal that is not magnetic can affect the clarity of the scan.

Things you should definitely tell your doctor

This is the most important part. If you have any metal or electronic devices inside your body, you must inform your doctor and the staff performing the scan about it before the scan.

Also, if you have claustrophobia (fear of small, enclosed spaces), tell your doctor in advance. If necessary, the doctor can give you a small amount of medicine to calm you down.

What happens during the scan?

Performing the scan is a very simple process.

You will be made to lie down on a bed, and the bed attendant will carefully guide you into a large, circular machine. A special device (head coil) will be placed on your head, like a helmet. This will help to make the images of your brain clearer. You will also be given headphones to help you hear the noise from the machine. The staff will be able to talk to you and give you instructions through these headphones.

As I said before, in a regular MRI, you're just told to stay still. But in an fMRI, you're asked to do small tasks while the scan is being done.

For example, you will be told:

• Wiggle your fingers a little.
• Say a short sentence.
• Look at a picture on the screen.

As you do this task, the fMRI machine records the areas of your brain that are active. You can do this task in two ways.

1. Block system: In this, you are told to do something for a few seconds, then wait a few seconds and then do it again.

2. Event system: This allows you to do several different tasks at once.

Sometimes you're asked to do nothing, just sit there with your eyes closed or open. This is called a "resting state" scan. It measures brain activity when you're at rest.

Sometimes, a contrast agent called gadolinium may be injected into a vein in your arm to make the scan clearer.

The entire fMRI scan usually takes about an hour .

What are the advantages and disadvantages of the scan?

Like any medical test, fMRI has its advantages and some considerations.

What is the difference between fMRI and EEG?

An EEG (Electroencephalogram) is also a test that measures brain activity. But there is a big difference between the two.

• fMRI shows brain activity as a picture . We can see exactly which areas of the brain are working.
• EEG shows brain activity as waves drawn on paper or a screen.

Simply put, while fMRI answers the question "where?", EEG is more sensitive to the question "when?", that is, to rapid changes in activity.

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