fMRI
Dr. med. Philipp Nicol is a freelance writer for the medical editorial team.
More about the experts All content is checked by medical journalists.The fMRI (functional magnetic resonance imaging) is a method for displaying brain activity. It is mostly used to prepare for neurosurgical interventions and in brain research. Read everything about fMRI, when to do it and the risks involved in fMRI here.
What is an fMRI?
The fMRI is a special form of magnetic resonance imaging (MRT), with which the metabolic activity in the brain can be displayed.
Basis of the MRI
MRI is a complex imaging procedure that is used in medical diagnostics to show the structure and function of the tissues and organs in the body. It is based on the application of a very strong magnetic field, which initially energizes the hydrogen atoms in the body. The energy released later can be measured and localized with the help of a computer. In this way, anatomical structures can be represented much better than with other imaging methods such as X-rays or computed tomography. Since no harmful (ionizing) radiation is used, the MRI examination is harmless according to the current state of knowledge and can be repeated more often.
Basis of the fMRI
With the help of fMRI, the metabolic activity in the brain can be visualized. This uses the increase in the oxygen content in the blood that occurs when brain areas are activated in these areas. The increased oxygen concentration can be measured, made visible and anatomically assigned with the fMRI. It allows a spatial representation of activated areas of the brain. This mechanism is also known as BOLD (Blood Level Oxygenation Dependent). The fMRI is mainly used for scientific purposes. It has not yet established itself in the standard diagnosis of diseases.
When is an fMRI performed?
An fMRI is used for the scientific investigation of various brain diseases, including:
- Parkinson's Syndrome, Huntington's Disease
- Dystonia (persistent muscle cramps)
- Amnesias (memory problems)
- after a stroke
- Dementia
- schizophrenia
- depression
In addition to the localization of certain areas of the brain, this can be used, for example, to examine the success of a drug therapy.
Since the MRI machine generates a strong magnetic field, prostheses or implants can be damaged and no longer function properly. An fMRI must therefore not be performed on patients with metal implants (e.g. hip or knee prostheses, bone screws) or implanted pacemakers or defibrillators (ICD).
What do you do with an fMRI?
Before starting the measurement, the doctor will explain all aspects of fMRI to you. You must not have any metal objects with you during the examination. Thanks to the strong magnetic field, even loose coins in your pocket can be accelerated to the speed of a pistol bullet!
During the examination, the patient lies in a tube about 70 to 100 centimeters long. He has to lie absolutely still and breathe evenly so that the recording is not disturbed - the head is fixed in a frame for this. The patient is connected to the doctors via an intercom. There is an additional alarm button for emergencies.
What are the risks of fMRI?
As far as we know today, fMRI is not dangerous. The examination can take up to an hour, during which you have to lie very quietly in a narrow tube. Some people find this uncomfortable and do not want to have an MRI scan due to claustrophobia.
What do I have to consider after an fMRI?
After an fMRI, it can be helpful to take a short rest to recover from the long, quiet lying in the tube.
Overall, the fMRI is a safe and painless examination with which new insights into the functional processes of the brain can be gained. The method has not yet established itself as standard diagnostics.
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