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  • Writer's pictureMannat Barhey

Brain Scan Imaging: A Quick Introduction

When studying neuroscience, it is crucial to have a fundamental understanding of brain scan imaging. The list of applications for this technology is endless and includes detecting electrical activity, abnormalities, aberrant sizes and shapes, and many more. As it provides us with an interior perspective on what is truly happening in someone's body, brain imaging has been a turning point in this field as well as many others. In the field of neuroscience, we examine every aspect of the brain. These are typically used when a patient exhibits abnormal cognitive function or other brain-related problems. In order to diagnose and monitor patients, doctors and scientists carefully study the images or waves that are generated. Since imaging is so important in helping people, it is also important to know the basic types, dangers and decisions to consider about brain scan imaging.


Firstly, there are several ways to scan someone's brain and several questions to ask. Which observation is the focus of this scan? What specific data is required? Which approach will result in more precise findings for this particular patient? What dangers may there be? And finally, which is more crucial: accuracy or speed?


The "speed-accuracy trade-off" is a significant choice that must be taken for the patient's benefit, but the doctor must also give it careful consideration. Electroencephalography (EEG) vs. magnetoencephalography (MEG) is a comparison that exemplifies this trade-off. An EEG offers data on the cerebral cortex's nuclei, which are frequently used to examine and gauge brain activity and postsynaptic potentials. MEG makes use of tiny magnetic fields to examine how various parts of the brain function when performing activities. Although it is challenging to pinpoint the precise site of this activity, EEG is a very valuable tool for observing brain activity in response to stimuli. MEG, however, can offer a higher spatial resolution. Depending on the circumstance, studying the MEG data could take up to an hour. The processing of some EEGs' results, however, can take days. Therefore, what is more important - test speed or accuracy? The response of accuracy seems to be a relatively natural one to give, but there are other considerations when you take into account how serious the patient's situation is.


Here are some common methods of brain scanning:

  • CAT/CT (Computerized Axial Tomography) Scan. A cat scan uses computer analysis x-ray equipment to produce images of several levels of the brain. This process is mainly used to identify brain abnormalities in structure or tissue. It is most commonly used for blood clot and tumor detection in patients.

  • An MRI (Magnetic Resonance imaging) and fMRI (Functional Magnetic Resonance imaging) scan. Both MRI and fMRI use magnetic fields that attract hydrogen protons and once done they emit electromagnetic signals which produce images. An MRI is commonly used to view structural detail and the specifics of size and shape of abnormalities in the brain. An fMRI uses the same process but rather analyzes a different function of the brain which is blood. It shows blood flow, movement and changes for any patients with blood related issues. A method called BOLD contrast is also used to see the deoxygenated and oxygenated blood present in the brain and where exactly it is. It also analyzes how different networks in the brain interact/collaborate with each other to spot any abnormal or absent connections.

  • DTI (Diffusion Tensor imaging) and DTI Tractography are different in terms of the process of how the scanning is performed but look at a similar part of the brain. DTI uses the diffusion of water in a space to produce images of axonal fiber tracts such as the corpus callosum. DTI tractography manipulates the data mathematically to study axonal pathways. These techniques can be useful to spot unusual miscommunication between the hemispheres of the brain, present during certain injuries.

  • A PET (Positron emission tomography) scan. PET scans are radiative and show the blood movement and oxygen levels in the brain. They do this by injecting radioactive substance injections into one's brain. The substance injected emits positrons (particles of an electric charge). These positrons emit gamma rays into the brain. Gamma rays eventually collide with the electrons in the brain and produce images for results.

  • An EEG (Electroencephalography). EEG’s are commonly used to see electrical activity in the brain such as postsynaptic action potentials. Electrodes are placed on the skull and help see the cerebral cortex activity that may be connected to the cognitive function of one's brain. However an EEG is recorded in brain waves making them more time consuming to analyze and read. Alongside the incredible real-time activity accuracy, an EEG has a harder time showing exact and precise brain activity location.

  • Similar to an EEG is an ERP (Event related potential). This test shows how one's brain responds to visual and auditory stimuli. It is commonly used with patients who have epilepsy and monitors their seizures as well as how they respond to their environment and detect any abnormalities. The abnormal responses can help pinpoint any triggers or which parts of the brain are causing intense suffering.


This image shows the comparison of some of the different types of brain imaging scans and how each one has a unique result and usage. Image from https://sdbif.org/whats-the-difference-between-all-the-different-head-scans/


In addition to these brain scanning methods, you can undergo and explore a multitude of other scans. There are many different kinds of scans and tests with various objectives. It is often crucial to consider risks including radiation and long or short-term effects before having a brain scan. Radiation exposure in excess can harm cells and cause other diseases. In order to provide the best care for their patients, doctors should consider as much information as possible and employ the safest techniques. Brain scan Imaging is an incredible tool for aiding patients and we should continue its utilization while also seeking opportunities for further enhancement of new machines.


Resources:

  • Brain imaging: What are the different types?. BrainLine. (2021, October 26). https://www.brainline.org/slideshow/brain-imaging-what-are-different-types

  • Lovering, N. (2021, October 22). What is this brain imaging being used for?. Psych Central. https://psychcentral.com/lib/types-of-brain-imaging-techniques

  • Mayo Foundation for Medical Education and Research. (n.d.). CT scan images of the brain. Mayo Clinic. https://www.mayoclinic.org/tests-procedures/ct-scan/multimedia/ct-scan-images-of-the-bra in/img-20008347

  • MD, J. V. (2023, August 8). Normal brain mri. Kenhub. https://www.kenhub.com/en/library/anatomy/normal-brain-mri

  • professional, C. C. medical. (n.d.). EEG: Tests, what is it & definition. Cleveland Clinic. https://my.clevelandclinic.org/health/diagnostics/9656-electroencephalogram-eeg#:~:text= There%20are%20several%20types%20of,types%20can%20last%20several%20days.


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