Neuropsychology is a specialized branch of psychology. She is involved in the study of brain function and its relation to human behavior.In other words, it looks for correlations between brain function and behavior. For this, she uses different methods. These are computer-calculated axial tomography, better known by the acronym TACO (scanner) and magnetic resonance imaging (MRI).
Both representthe most used neuroimage exams in the news.This is due to the quality of the images they record and their accessibility or ease of use. But do we really know what are their similarities and their differences? What are they for ? We will explain it to you now!
Similarities between the two exams
CT and MRIare used to locate, measure and accurately describe body structures that have been affected by an injury.Moreover, they make it possible to quantify lesions shortly after they have occurred. Thanks to them, we know the volume of the tissue that has been involved.
One of their strengths is their spatial resolution, excellent from a macroscopic point of view.In microscopic terms, the resolution is more modest.
By the way, and even if it does not happen in all cases,to perform a CT scan or an MRI, it is recommended to eat nothing between 4 and 6 hours before the exam.If the person suffers from claustrophobia or does not support closed spaces, it is best that they consult their doctor for solutions. He may, for example, advise him to use anesthesia.
Main differences between CT and MRI
Axial computed tomography (TACO or scanner)
The scanner is the first neuroimage technique that has appeared on the market.It began to sell in 1972. This date marks a before and after in neuropsychology. Until then, there was practically onlypost mortem.
TACO is a type of tube-shaped scanner. It can rotate between 180 and 360 degrees around the area one wishes to examine.The device emits X-rays simultaneously and from different angles.Its purpose is to detect those parts of the body that absorb these X-rays abnormally.
These detectors are sensitive to the density variation of the white fabric at 1%(instead of 10-15% of conventional X-rays). After this emission and this capture of density variations, a computer gives the result under a series of images. These are axial and perpendicular to the cephalocaudal axis (head-to-feet).Hypodense areas are obscure(for example, cerebrospinal fluid and fat). Hyperdense areas, such as bone or haemorrhages, have a lighter tone.
Unlike light, X-rays penetrate the body. This assumes a great advantage when observing the internal structures of the body.Axial tomography is a very useful technique for detecting tumors, edema or cerebral infarction.It also serves to locate bone and internal lesions, intestinal diseases such as diverticulitis and appendicitis. Finally, it allows to visualize the liver, the spleen, the pancreas and the kidneys.
Magnetic resonance imaging (MRI)
For its part,MRI is the technique that allows greater contrast between soft tissues,that is to say those that are not composed of bone, such as muscles, ligaments, menisci, tendons … His discovery in 1946 has considerably improved the anatomical visualization. Especially at the level of the difference between gray matter and white brain.
One of the biggest differences between CT and MRI is that the latter has a high sensitivity to the movement of liquids. This makes it possible to obtain angiographies (images of the blood vessels) without using contrast medium. Nevertheless, the scanner is a faster exam. But its spatial resolution is worse than that of the MRI.
Unlike the scanner,MRI provides images on the three planes of space (horizontal, coronal and sagittal).This favors the use of stereotactic atlases, for which it is necessary to have these three spatial coordinates. In this way, it is possible to identify damaged structures that are not easy to notice visibly.
Adverse effects of CT and MRI
MRI, as its name suggests, operates through a magnetic field and radio frequency waves. Unlike the scanner, which emits X-rays, the MRI emits no radiation. However, MRI examination can be somewhat inconvenient for the patient.Why? Because of the unpleasant noise produced by the machine and the need to remain still for the duration of the examination.
MRI, just like the scanner,can not be performed if the patient has a metal object in the body. The latter may indeed interfere during the examination.It is contraindicated for patients who have cochlear implants (ears), heart valves, vascular clips …
MRI does not produce iatrogenicity either. It does not affect the health of the patient, as it could be the case of an operation during which the surgeon must open to operate. An evil is done to heal another.
As you can see, neither of these two exams is better than the other. They are more or less adequate depending on the purpose and type of structure to be examined.CT and MRI are two methods that highlight the great advances in medicine.Progress that impacts on discoveries made in other fields, such as psychology.