Functional magnetic resonance imaging is a variation of classical MRI. The difference between these two similar procedures is that the first version is needed to detect hemodynamic parameters. We are talking about checking possible changes in blood flow when special zones located in the brain are activated.
The survey is based on the principle of monitoring the increased activity of the area under study by taking into account the increase or decrease in blood flow to a certain point. With a slowdown or intensification of activity, the parameters of blood movement in the studied vascular bed change.
This approach provides primary information regarding diseases related to neurodegenerative lesions. We are talking about mental disorders, up to schizophrenia, and some specific motor pathologies.
The results of the study are often a guide for the subsequent planning of operations to remove various brain tumors. With the help of a specific “map”, specialists reduce the risks of damage to the motor and speech center during a surgical operation, which eliminates the risks of side effects.
Advantages of fMRI
The development of imaging technologies began to rapidly enter clinical practice approximately thirty years ago. Since then, neuroimaging, which is also called a division of functional magnetic resonance imaging, has been in consistently high demand. One of the most important advantages of the method is non-invasiveness. This means the absence of any pain during the manipulation.
Among other positive aspects, safety for the subject is highlighted. Unlike many other diagnostic formats that involve harmful radiation exposure, it is not provided here.
Clinicians value the study for its ability to provide good spatial and temporal resolution. The data collected with its help can be used in the future for further research in the fields of psychology, psychotherapy, psychoanalysis.
Thanks to psychosomatic information, in recent years we have learned to understand the nature of the formation of memories, the perception of language, the ability to learn, as well as to experience emotions or pain.
If the doctor recommended the passage of such a procedure, it is imperative to choose only the newest models of equipment in order to provide yourself with a number of advantages:
- improved visualization quality;
- increased speed of examination with a more detailed final picture.
The acceleration of the process of collecting the necessary information is ensured by the high voltage of the magnetic field, which reduces the time spent under the scanner. This item may be especially relevant for patients who suffer from neurodegenerative disorders or disorders of the psychological center.
In addition to the fact that the collected information becomes the basis for surgical intervention, it can be useful for a number of other purposes. It is about bringing the results of testing to check the current state of the patient. Using informative markers to control the dynamics and assess the progression of neurodegenerative abnormalities, it is possible to monitor the effectiveness of the prescribed treatment. If necessary, the specialist may decide to correct the previously established course of therapy, for example, when:
- Parkinson’s disease;
- Alzheimer’s disease;
- mental disorders.
All of the above has become possible thanks to technological advances in the field of determining the activation of specific areas of the brain at the stage of their typical functioning. Additionally, the doctor can expand the examination by changing the position of the patient.
How does it work?
Experts call full-fledged neuroimaging not only fMRI, but a whole complex approach aimed at assessing brain activity. This requires a device that allows you to register the features of the intravital functioning of the structure, along with deviations. Instead of classical X-rays, preference is given to studies based on the principles of nuclear magnetic resonance.
Schematically, a device for recording and visualizing an image is a tomograph equipped with a high-powered electromagnet. The average level of scanning is equal to the field strength of about 3T (tesla), which is approximately 50 thousand times greater than the Earth’s magnetic field.
When the device is activated, the effect on the chaotic arrangement of atomic nuclei begins. Under the influence of a magnetic field, they begin to line up in a direction directly proportional to the intensity.
By combining the individual magnetic signals from all the nuclei, the signal becomes more powerful, allowing it to be tracked and measured. The presented method registers the signals of hydrogen nuclei, which provide visualization:
- gray matter;
- white matter;
- cerebrospinal fluid.
From a physiological point of view, the ability to measure brain activity is explained by the reaction of oxygen delivered to neurons by a capillary network with the help of hemoglobin. As soon as the active activity of neurons increases, they require more oxygen. Physiologically, the body responds to the need for an increased dose of oxygen with high nervous activity.
How is a functional MRI performed?
The procedure for functional MRI is somewhat different from the classic version. The patient is placed in the tunnel of the scanner and must follow the instructions of the operator. To do this, the device has a two-way communication to make it easier to contact the medical staff even in unforeseen situations.
Simultaneously with the execution of tasks, the program registers anatomical sections and functional T2-weighted images. Tasks include the alternation of rest with motor and mental activity.
The main reasons for testing are:
- preoperative preparatory measures;
- risk assessment of complications after surgery;
- diagnosing mental anomalies;
- preparation for the invasive stage of studying the brain – mapping the cortex.
Despite the significant benefits, the technique has several important contraindications. Testing is not performed if the victim has implanted electronic devices. We are talking not only about a pacemaker, but also electronic implants to stabilize the activity of the middle ear.
Also, the procedure is contraindicated in patients who have hemostatic clips installed, or there are foreign metal objects. Another contraindication, but of a relative nature, is renal failure.
The study does not require any specific preparation of the patient. It is enough just to follow the rules of the previously stated briefing, following the commands of the laboratory assistant.