Have you ever wondered how the different parts of our brain work and how they respond to each other? Sometimes, especially before doing something like brain surgery, doctors want to know exactly which parts of the brain are doing the most important work and which parts could be at risk if damaged. Today, we're going to talk about a special scan that's used at times like these and can reveal some of the secrets inside the brain.
What is fMRI? Simply put...
Simply put, Functional Magnetic Resonance Imaging (fMRI) is a scan that shows the activity of specific parts of our brain, that is, how much those parts are working at a given time. You've probably heard of an MRI (Magnetic Resonance Imaging) scan. It involves going inside a big, round machine. It uses a very strong magnetic field, radio waves, and computer technology to take very clear 3D pictures of the inside of our body. The best part is that it doesn't use radiation like an X-ray. So there's no need to worry about radiation exposure.
Now, this fMRI scan is done with the same regular MRI machine. But what's special about this one is that it can monitor the blood flow to different parts of your brain. Think about it, when our brain cells are working, they need more oxygen. Then that oxygen is carried by the blood. So, the areas where there is more blood flow are the areas of the brain that are most active. Those areas appear brighter in the fMRI scan. Do you understand how that happens?
What is an fMRI scan used for?
By mapping the blood flow and activity in different parts of your brain, doctors can tell which part of your brain controls a specific function or ability. This is very useful when planning brain surgery or other medical procedures that may affect the brain. Imagine that you need to have surgery on a certain part of your brain. Then the neurosurgeon can use this fMRI to plan the surgery. It can also see exactly which parts of the brain are performing essential functions and should be left undisturbed . This fMRI scan can be done on adults as well as young children.
For example, muscle movements are controlled by a specific area in the frontal lobe of our brain. If you ask someone to tap your fingers during an fMRI scan, the scan will show which parts of the brain are involved in that action. The neurosurgeon then knows to operate without damaging them.
Here are some situations or medical procedures that may require this type of planning:
- Epilepsy: If epilepsy is not controlled by medication or other treatments, you may need to undergo brain surgery (epilepsy surgery) .
- Brain tumors: Surgery may be required to remove all types of tumors, both cancerous and benign.
- Radiation therapy to the brain: Precision radiation therapies can be used for many brain diseases, such as cancer and circulatory problems.
- Post-treatment scans: This scan also helps to see if there are any changes in brain function after a certain medical treatment.
In addition, researchers are exploring other uses for fMRI. For example, there is evidence that it may be useful in things like biofeedback therapy .
How common are fMRI scans?
Because the medical benefits of fMRI scans are limited, they are not very common in healthcare settings. Small hospitals or health centers may not have the facilities to perform an fMRI scan. If you want one, you may need to go to a larger medical center.
How do I prepare for this scan?
On the day of your fMRI scan, you should not drink anything containing caffeine , as it can affect the fMRI results. If you are taking any medications, your doctor will advise you on how to take them (and when to stop taking them) before the scan.
Like a regular MRI scan, an fMRI scan uses a very strong magnet. This magnet is so strong that it can damage some objects and can quickly attract magnetic objects. Even ordinary metal objects can be dangerous near an MRI machine.
Therefore, the clothes you wear, the jewelry you use, and the hairpins you use should not have any metal parts. This applies not only to metals that have magnetic properties, but also to all other types of metals. Because even non-magnetic metals can affect the clarity of the scan.
Things you should not bring or wear to an MRI machine
- Jewelry, watches, credit cards and hearing aids .
- Pins, metal hairpins, underwired brassieres, and metal zippers (these can distort MRI images).
- Removable dentures .
- Pens, pocket knives or multitools .
- Body piercings .
- Mobile phones, electronic watches and tracking devices .
Definitely something to tell the doctor !
If you have any of the following conditions, you should definitely inform your doctor before having an MRI:
- A heart pacemaker or defibrillator .
- Electronic or implanted stimulators or devices. Examples include: deep brain stimulators , vagus nerve stimulators , bladder stimulators, spine stimulators, neurostimulators , and implanted electrodes or wires.
- Replacement joints .
- Cochlear implants or other ear implants.
- Implanted drug pumps . Examples: those that deliver painkillers, those that deliver drugs that reduce muscle stiffness (spasticity) .
- Programmable shunts .
- Aneurysm clips and coils .
- Stents that are not in the heart.
- Filters, for example blood clot filters.
- Metal fragments stuck in your body or eyes. Examples: bullets, shrapnel , metal fragments or powder.
- A continuous glucose monitor (CGM) .
- An insulin pump .
- A medication patch that you stick somewhere on your body.
Also, you should tell your doctor about these things before the fMRI:
- If you are pregnant or think you might be.
- If there is a reason why you cannot lie on your back throughout the entire test.
- If you have claustrophobia (that is, the fear of confined spaces). Imagine that you are afraid of being in a small room. If you have that kind of fear, you may feel a little uncomfortable when you go inside that machine. That is why you should tell the doctor in advance.
If you have claustrophobia, your doctor may recommend that you take anti-anxiety medication during or shortly before the scan. This can vary from person to person, so if you feel anxious during the fMRI, ask your doctor if you can take medication for it.
Even young children can have an fMRI, but they may need to be given medication to relax them. Your child's doctor can explain to you what the options are and what they recommend.
What happens during an fMRI scan?
An fMRI scan is done in the same way as a regular MRI scan. During the scan, you lie on a bed and the bed is moved toward the MRI machine. Most often, fMRI uses a traditional ring-shaped MRI scanner. This is because the magnet in an open MRI machine is usually not as strong.
During an fMRI, your head is placed inside a special helmet-like device called a head coil . This coil helps to get clearer images. You also need to wear a pair of special sound-canceling headphones to block out the noise from the MRI machine. These headphones have another benefit. Healthcare workers, such as MRI technologists or radiologists, can talk to you and give you instructions during the scan.
The main difference between a regular MRI and an fMRI is activity . During an fMRI scan, healthcare workers ask you to talk, wiggle your finger, or do something simple like that. While you do that, the fMRI monitors your blood flow to see which parts of your brain are most active. Then it compares that to what you were doing at that time. That's how they "map" the parts of your brain, figuring out what's going on.
These tasks can be performed in two ways:
- Block system: In this system, you are given a short period of time to do a task, followed by a short period of rest. These periods are called blocks.
- Event system: This involves doing several tasks in a row without a break.
Your doctor may want to do part of the fMRI as a "resting state" scan. During this time, you simply lie down in the scanner (your doctor may ask you to keep your eyes open or closed). This allows the doctor to see and measure the difference in your brain activity between when you are at rest and when you are awake.
Do you do fMRI with contrast material? (Functional MRI with contrast)
Like a regular MRI scan, fMRI scans can sometimes use a contrast material containing gadolinium . This gadolinium is injected into a vein (IV) (that is, through one of your veins) to help with some tests. It allows you to see certain structures inside your body or brain more clearly.
How long does an fMRI scan take?
An fMRI scan usually takes about an hour. It may take a little longer if the doctor needs more data to analyze, or if he needs to do another type of MRI scan along with the fMRI.
What happens after this test?
You can go home as soon as the fMRI scan is done. However, if you were given medication for anxiety during the fMRI, someone will need to drive you home. A radiologist will review the scan, analyze it, and tell you the results, as well as the doctor who referred you for the scan (for example , a neurologist or neurosurgeon) .
What are the advantages of fMRI?
fMRI is particularly useful for pre-surgery planning . It allows neurosurgeons to gain a better understanding of how different brain structures work. This allows them to perform surgery without damaging vital parts of the brain, reducing the risk of losing the functions that those parts control.
There are other tests that can help with planning, but fMRI is usually a better choice. Because other tests are often more invasive , require drugs that are more likely to cause side effects, or are not as accurate at mapping the brain regions involved.
Are there any disadvantages or risks to fMRI?
Compared to other tests, fMRI has several disadvantages. The biggest disadvantage is the relationship between the timing of the fMRI scan and the speed of our brain activity. Imagine taking a photo of someone running really fast. Compared to the speed of the brain, the speed at which fMRI collects data is a bit slow. That is, brain activity can change by tens of milliseconds in a second, but fMRI can only capture what happens second by second. Therefore, very subtle, instantaneous changes may be missed.
The risks of fMRI are very low. They are similar to those of a regular MRI. The side effects of the gadolinium contrast are also very low. The main concern is metal safety. You should follow all the instructions given by your doctor and clinical staff about metal safety. If you have any questions, don't be afraid to ask them.
What is the difference between an EEG and an fMRI?
An electroencephalogram (EEG) is a test that measures and records your brain activity. An EEG machine displays your brain activity as a series of waves on paper or a digital screen. While both record the same data, an fMRI displays it as an image.
So, what is the message we should remember from this?
fMRI is a relatively new technology. Although it has been around for a little over 30 years, it has opened up new insights into how the brain works. Today, it is very useful for mapping brain activity and showing which parts of the brain are active during certain tasks or events. Whether it is an fMRI scan for you or your child, this scanning method helps neurosurgeons plan their operations without damaging as many vital parts as possible. So, if you are going to have this test, don't be afraid and follow the doctor's instructions.
` functional mri, fmri, brain scan, brain function, neurosurgery, brain mapping, mri scan
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