Brain scans are imaging tests of the head that are used to diagnose possible injury or disease.
The most common rain scan technologies are computed axial tomography (CAT), position emission tomography (PET), magnetic resonance imaging (MRI), Functional MRI (fMRI), Electroencephalography (EEG), and Magnetoencephalography (MEG).
Brain scans are usually painless and minimally invasive. After one has been performed, a radiologist will analyze the images to produce a report for the patient and the patient’ physician.
Here’s a summary of how the most common brain scans work.
Computed Axial Tomography (CAT)
A revolving x-ray generator scans the brain in this technology. As the x-rays pass through tissue, the beams hit sensors that constructs a visual image of the brain.
Positron-Emission Tomography (PET) Scans are similar to CAT scans, except that radioactive dyes are first injected into the blood stream. As these dyes flow through the brain, the brain cells use the dyes in different amounts. Thus doctors can see which portions of the brain are having problems or working properly. The dyes also help to show structures within the head such as blood vessels, bones, brain, and nerve tissue.
Magnetic Resonance Imaging (MRI)
This is a safer alternative to CAT and PET scans. This method aligns atomic particles in the body tissues by magnetism then bombards them with radio waves, with the information being sent to a computer to create a three-dimensional image. Thee scans look grayish in nature, but have much more detail and thus can detect smaller injuries and abnormalities.
Functional MRI (fMRI)
This technique measures the areas of the brain that are working the hardest by looking at glucose and oxygen intake. When an area of the brain is working, these substances flow towards it. fMRI is a rapid scanning technique that easily shows the ebb and flow of brain activity. Its drawback, however, is that it is prohibitively expensive.
Electroencephalography (EEG)
EEGs measures brainwaves or the electrical patterns of the brain. These waves are measured via electrodes placed on the skull. Change will occur according to the type of neuron activity that is occurring. This is the type of scanning used to produce brain mapping which delineates how fast or slow the brain is firing.
Magnetoencephalography (MEG)
Similar to EEGs in that it measures brainwaves, but differs in that it does so by picking up the magnetic pulses hose waves produce. It s faster that other scanning techniques and can therefore pick up brain activity more accurately. Its drawback, however, is that the magnetic signals are usually weak and contain a lot of interference.
