MRI diagnostics - what is it? Purpose, advantages and contraindications. MRI of the whole body: is there any point in doing it? Medical term mri

Magnetic resonance imaging (MRI), also known as nuclear magnetic resonance imaging, is a scanning technique to create detailed images of the human body.

The scan uses a strong magnetic field and radio waves to generate images of parts of the body that cannot be seen with X-rays, CT scans or ultrasound. For example, it can help doctors see internal joints, cartilage, ligaments, muscles and tendons, making it useful for detecting various sports injuries.

According to the Mayo Clinic, MRI also examines the internal structures of the body and diagnoses various disorders such as strokes, tumors, aneurysms, spinal cord injuries, multiple sclerosis and problems with the eye or inner ear. It is, among other things, widely used in research to measure brain structure and function.

In humans, soft tissue, and anatomical details, the greatest advantage of MRI compared to other imaging methods (such as CT scans and X-rays) is that there is no risk of exposure to radiation.

How is an MRI done?

During an MRI, a person will be asked to lie on a movable table that will slide into a donut-shaped opening to scan a specific part of the body. The machine itself will create a strong magnetic field around the person, and radio waves will be directed toward the body, according to the Mayo Clinic.

The person will not feel the magnetic field or radio waves, so the procedure itself is painless. However, there may be a lot of loud noises during the scan (it can sound like a sledgehammer!). Therefore, people are often given headphones to listen to music or earplugs to block out sound. The technician may also give you instructions during the test.

Some people may receive a contrast injection with an intravenous, liquid dye that can highlight specific problems not usually shown on scans.

Young children and people who feel claustrophobic in enclosed spaces may be given a sedative medication to help them relax or fall asleep during the scan because it is important to remain quiet to get clear images. Movement can blur images.

Some hospitals may have an MRI machine that is open on the sides rather than a tunnel tube. This can be a useful alternative for people who are afraid of tight spaces.

The scan may take 30 to 60 minutes.

The radiologist will look at the images and send a report to your doctor with the test results.

How does MRI work?

The human body is mostly water. Water molecules (H2O) contain hydrogen nuclei (protons) that align in a magnetic field. An MRI scanner uses a very strong magnetic field (about 0.2 to 3 Tesla, or about a thousand times the strength of a typical refrigerator magnet) to align the protons

The scanner also creates a radio frequency current that creates an alternating magnetic field. The proton absorbs energy from the magnetic field and flips them around. When the field is turned off, the protons gradually return to their normal rotation, a process called precession. The return process produces a radio signal that can be measured by receivers in the scanner to produce an image.

MRI scans reveal the gross anatomical structure of the human brain.

Types of MRI

Protons in different tissues of the body return to their normal movements at different rates, so the scanner can distinguish between different types of tissue. Scanner settings can be adjusted to create contrasts between different body tissues. Additional magnetic fields are used to create three-dimensional images that can be viewed from different angles. There are many forms of MRI, but diffusion MRI and functional MRI are the two most common.

Diffusion MRI

This form of MRI measures how water molecules diffuse through body tissue. Some diseases, such as stroke or tumor, can limit this diffusion, so this method is often used to diagnose them. Diffusion MRI has only been around for about 15-20 years.

Functional MRI

In addition to structural imaging, MRI can also be used to visualize functional activity in the brain. Functional MRI measures changes in blood flow to different parts of the brain.

It is used to monitor brain structures and determine which parts of the brain are performing critical functions. Functional MRI can also be used to assess damage from head injury or Alzheimer's disease. fMRI is particularly useful in the field of neuroscience - it has truly revolutionized the way we study the brain.

MRI Safety

Unlike other forms of imaging, such as X-rays or CT scans, MRI does not use ionizing radiation. MRI is increasingly used to image fetuses during pregnancy, and no adverse effects on the fetus have been demonstrated.

However, the procedure may have risks, and medical societies do not recommend using MRI as the first step in diagnosis.

Because MRI uses strong magnets, any kind of metal implant such as artificial joints, artificial heart valves, cochlear implants, or metal plates, screws, or rods is dangerous. The implant may move or heat up in the magnetic field.

Several patients with pacemakers who have had MRI scans have died, patients should always be asked about any implants before they are scanned. Many implants today are MRI safe.

Constantly reversing magnetic fields may cause loud clicking or beeping sounds, so ear protection is required during scanning.

A procedure called magnetic resonance imaging is a modern high-tech method for diagnosing human organs and systems in order to identify dangerous diseases and pathological abnormalities. After a specialist prescribes a procedure for a patient, the question arises: why is an MRI done? The main goal of magnetic resonance imaging is the ability to timely diagnose various types of diseases in humans. The MRI procedure can be performed both for certain indications and for preventive purposes to exclude the presence of various neoplasms in the human body. Timely diagnosis of pathologies increases the likelihood of getting rid of them. Let's look at all the important points about what MRI is, why diagnostics are carried out, as well as its main advantages.

MRI diagnostics: why the study is needed

The MRI procedure is a non-invasive research method that provides the opportunity to obtain the most accurate information about the state of internal organs, systems, tissues, blood vessels, tendons, bone tissue, etc. The study makes it possible to diagnose diseases in all human tissues, for which it has become widespread throughout the world.

The operating principle of a magnetic resonance imaging scanner is based directly on the creation of a high-power magnetic field. Electromagnetic vibrations are recorded, on the basis of which a corresponding picture of what is happening inside a person appears. A device called a tomograph performs this function. The tomograph is equipped with a high-precision computer that allows you to analyze magnetic vibrations and produce the corresponding results in the form of visualization. The results of the study are displayed on the computer screen in a three-dimensional image, and are also recorded in the form of photographs, which the patient receives in his hands at the end of the diagnosis.

The tomograph is a large capsule with free space inside. This space is intended to accommodate the patient. The capsule shell is equipped with a powerful magnet, through which a constant magnetic field is created. MRI examination is often used when x-rays, ultrasound or computed tomography do not provide accurate results.

It is important to know! MRI diagnostics is also used for preventive purposes, but you need to know that magnetic resonance imaging is one of the most expensive diagnostic techniques.

In what cases does a doctor prescribe an MRI?

An important advantage of MRI diagnostics is the complete safety and harmlessness of the technique. The study does not use X-rays, since the diagnostic process is based on the influence of magnetic fields. The magnetic field is safe for humans, as has been proven by numerous studies conducted by scientists on animals. Every day a person is exposed to the influence of electromagnetic fields that do not harm our body.

It is important to know! The MRI procedure is carried out in order to carry out the most detailed examination. Sometimes, in order to diagnose certain diseases at the stage of their development, they resort to the use of contrast agents.

What is a contrast agent, and why is it necessary during research? The contrast agent is presented in the form of gadolinium salts. This component is injected mainly into a vein in the required quantity. It is immediately worth noting that the contrast is absolutely safe and harmless. The only contraindication to its use is the presence of signs of individual intolerance. After the contrast enters the body, the blood delivers it to all organs and tissues. Staining the organ under study increases the efficiency of diagnostics up to 100%.

Typically, the study is prescribed by the attending physician if he has doubts when making an accurate diagnosis. In this case, the doctor may prescribe an x-ray, computed tomography or ultrasound, but these types of studies have a significant drawback - the impossibility of obtaining the most accurate results. Often, it is on the basis of the preliminary results of these studies that a decision is made to conduct additional MRI diagnostics. Magnetic resonance imaging is used not only as prescribed by a doctor, but also at their own request. In this case, the patient must understand what specific area of ​​the body he wants to examine. The results obtained must be deciphered by the doctor, since the diagnostician writes only a conclusion.

It is important to know! MRI diagnostics can be carried out as many times as necessary, due to the harmlessness of the technique.

The main types of pathologies diagnosed on MRI

Magnetic resonance imaging can be used to diagnose the whole body or individual organs. A complete examination of the body takes a long time, so experts recommend carrying out diagnostics in stages, which increases the likelihood of detecting serious pathologies. Let's look at the main parts of the body that need to be diagnosed using a magnetic resonance imaging scanner.

1. MRI of the brain. One of the most common types of diagnostics, which makes it possible to determine the presence of tumors, identify problems with blood vessels, the presence of aneurysms, as well as various types of neoplasms.
2. MRI of the spine. The procedure is prescribed primarily to identify the causes of pain syndromes. The spine, like the brain, is one of the important parts of the body that are subject to greater trauma. Spinal diagnostics allows you to obtain information about the condition of the intervertebral discs, the presence of hernias and tumors, and also makes it possible to track the speed of movement of the cerebrospinal fluid.
3. MRI of the abdominal cavity. Allows for a complete examination of all organs, as well as visualization of them. The organs of the abdominal cavity are susceptible to negative influences from the food consumed, so timely MRI diagnosis can prevent serious pathological manifestations: tumors, neoplasms, ulcers.
4. MRI of joints. The MRI procedure for joints is prescribed in cases where there is a need to diagnose outdated injuries and deformities. Usually, an x-ray is initially prescribed, but if the correct diagnosis cannot be made against this background, then an in-depth MRI study is resorted to.

MRI diagnostics allows you to study the hands, lower and upper limbs, feet, eyes, ears and other organs and parts of the human body. It is important to note that the MRI procedure is useless if it is necessary to study the intestines and kidneys for urolithiasis. In all other cases, MRI is the leader among research procedures that save hundreds and even thousands of patients every day.

Key benefits of MRI

Why do you need to do an MRI if you have X-rays or an ultrasound report? MRI is prescribed by the attending physician if he has doubts about the preliminary diagnosis. Techniques such as radiography and ultrasound do not provide a complete picture of what is happening inside, so a specialist may prescribe an MRI on an individual basis. If the picture of the disease is clear, then the doctor may prescribe an MRI after therapeutic treatment or surgery.

Like any diagnostic method, the magnetic research technique has its pros and cons. The advantages of the MRI technique include:

1. Harmlessness and safety. The procedure is so safe that it can be performed on children.
2. High information content. After completing the diagnosis, the doctor can make a 100% accurate diagnosis.
3. Non-invasive. To conduct the study, the patient does not need to introduce various devices or objects into the body. During diagnostics, the only drawback is the need to lie motionless on the device table for a long time.
4. Efficiency. Despite the high cost of diagnostics, the results of the study make it possible to obtain accurate information about the presence of pathologies in a person.

MRI has only one drawback - the high cost of the procedure. If a contrast agent needs to be used during the study, the cost increases several times.

It is important to know! MRI is not used in cases where it is necessary to determine the presence of pathologies in the stomach, lungs, intestines and bone tissues.

How is MRI performed?

The technique is so safe that the patient does not need to prepare for it. Every patient who has signed up for diagnostics wants to know how the magnetic resonance imaging process goes. It all starts with the fact that on the day when the procedure is scheduled, the person must come to the clinic 10-15 minutes earlier than scheduled. This time is allocated so that the patient can initially familiarize himself with the contract, which states that he will not have any claims if something goes wrong. This program is especially often practiced in private clinics.

After this, the patient must take off his clothes that have metal elements. Usually the procedure is carried out in a special medical gown. The patient is warned in advance about the need to purchase such a gown. When everything is ready, the patient lies down on the retractable table of the tomograph, after which the diagnostician fastens him with straps. This is done to ensure that the patient does not move during the examination, as this cannot be done.

It is important to know! If the patient moves during the examination, the results will be blurry and inaccurate.

Once the patient is ready, the diagnostician places the table with the patient in the capsule and then leaves the room. In order to avoid a deterioration in the patient’s well-being, the specialist puts a special device in his hand, which he must press if he feels unwell. The duration of the diagnosis lasts from 20-30 minutes to 2 hours, which depends on the area being examined, as well as the need to use a contrast agent.

During the study, the patient will only feel the hum from the operating tomograph. Sometimes, so that the noise of the tomograph does not disturb, the patient is given headphones to listen to music. The diagnosis made allows us to immediately identify the presence of pathologies. Based on the results obtained, the diagnostician writes a conclusion with which the patient must consult a doctor.

It is important to know! Sometimes the MRI procedure is performed under anesthesia, but not because it can cause pain, but with the aim of immobilizing the patient. Under sedatives, MRI is performed on children and patients who suffer from claustrophobia and other nervous disorders.

Contraindications

The safety of the MRI procedure does not mean that the diagnosis has no contraindications. The main contraindications include:

1. The presence of electronic devices or metal prostheses and other elements in the patient’s body.
2. First trimester of pregnancy. Experts simply do not recommend that women undergo diagnostic tests in the first 12 weeks of pregnancy in order to reduce the risk of pathologies in the baby after birth.
3. Claustrophobia and mental disorders. Decisions are made on an individual basis to conduct the study under anesthesia or open-type MRI machines.
4. If there are tattoos on the patient's body. Tattoo ink contains metal particles that negatively affect diagnostics.

The patient should inform the specialist prematurely about the presence of contraindications. If the patient does not know about the presence of claustrophobia, then the decision to conduct a diagnosis under anesthesia is made during the study. Based on the results obtained and images in the form of sections of the examined organs, the doctor makes a diagnosis and then prescribes treatment.

Effective diagnostic procedures make life better for both doctors and patients. The former receive more information, and therefore can make a diagnosis more accurately, and less time is spent on the process. The other side also benefits - at least the distance a person travels when visiting doctors' offices is shortened. Although this is dominated by the desire not to visit doctors at all, always remaining healthy. However, this is only possible in an ideal world, and we live in an imperfect one.

Somehow we know how capsule endoscopy works, designed for painless diagnostic procedures and examinations of hard-to-reach areas of the gastrointestinal tract. This time we will try to understand how magnetic resonance imaging works - another painless way to obtain data on the state of human internal organs and tissues.

Draw your attention to, that the material is published solely for educational purposes and does not constitute instructions, recommendations, or an official, scientific or medical document.

Simple theory

First, a little simple theory. MRI (MRI in English) is a method of obtaining a layer-by-layer image of the internal structure of an object. Roughly speaking, MRI helps to obtain virtual sections of tissues and organs of a living person without invading his body - this is the so-called non-invasive method.

It is based on a phenomenon called nuclear magnetic resonance (NMR), and in the past the abbreviation MRI was prefixed with the letter "I" (in English, MRI was said to be NMR). But they decided to get rid of the word “nuclear” for a simple reason - so as not to irritate people, although there is nothing in common with bombs or radioactive elements of the periodic table.

If this somehow helps to understand the processes underlying the phenomenon, in this case we are talking about measuring the electromagnetic response of atomic nuclei excited by electromagnetic waves of different combinations (which is why, by the way, a rhythmic sound of different tones is heard) in a constant magnetic field of high intensity, indicated in Tesla.

The field strength affects the quality of the resulting picture. The lower the power, the narrower the range of applicability of tomographs, which, in turn, are divided into several main types - from low-field to ultra-high-field (from the word “field”, not “floor”).

We won’t say that the more powerful the better. Let's put it this way: the more powerful, the more versatile and accurate the system. But the more universal it is, the higher its price, which can amount to hundreds of thousands of dollars and even exceed a million.

For low-field ones, the field strength is up to 0.5 T. It is believed that such tomographs without contrast allow one to obtain basic information. This is followed by mid-field (1 T), high-field (1.5 T) and ultra-high-field (3 T). There are more powerful ones, but ordinary medical institutions do not need them.

“Many people ask what is the difference between 3 T and 1.5 T? The fundamental difference is in the detail and clarity of the picture,”- explained Vesta Korolenok, head of the MRI room at the Tomography Center. As an example, she talked about a patient with a small tumor: the device with 1.5 T did not notice it, but at 3 T they saw the pathology, sending the person to one of the Republican Scientific and Practical Centers.

There are also closed and open type tomographs. One of the features of the former, which is more common, is the limitations on the patient’s size - a very overweight person simply will not fit into the “tube”. In addition, those suffering from claustrophobia may feel uncomfortable in a confined space where they cannot move. Open tomographs allow examination of individual joints, the spine and even the head. The weakness of open-type tomographs is their lower resolution: they are all low-field and have a magnetic field strength of no more than 0.35 T.

What not to do

You can get inside the tomograph, but not everyone. First of all, owners of various types of implants are not allowed there: from pacemakers to hearing aids. There are several reasons: firstly, the magnetic field can damage and/or disrupt the operation of the implant, secondly, there is a chance of causing thermal or other injury to the patient, and thirdly, the presence of the implant will negatively affect the scanning results.

The same applies to metal in the body - “spokes” and pins, shot and fragments, surgical clamps and similar elements (titanium is an exception).

In some cases, contrast agents are used during scanning to further increase image clarity. Their components can cause allergies; they are usually contraindicated for pregnant women, as well as during lactation.

Tested for myself

Tomography is equipped with an ultra-high-field Siemens Magnetom Spectra 3 T. The unit cannot be called lightweight: its weight in running order is about 7.3 tons with a tunnel length of 173 cm. The system allows the use of up to 120 coil elements to cover the entire anatomical zone (for example, throughout the central nervous system). Siemens proprietary software is used, which primarily affects the quality of the scan and the final image with slices 0.5-1 mm thick.

The subject is dressed in a disposable, dimensionless suit, in which he is sent into the mouth of the tomograph. The person is placed on a table (this is the name of the structure, which is then hidden in the tunnel). In order to somehow protect the ears from loud sound, headphones are put on the head, from which light music sounds. If you wish, you can arm yourself with your own track list or audiobook.

This surprised me: what kind of headphones if there should be no metals? It's simple - sound is transmitted into funnel headphones not through wires, but through tubes made of elastic plastic, so the compositions sound like they come from a well. It is worth noting that the accessory is not completely capable of drowning out the “tunes” of the tomograph.

It is impossible to jump out of the device, so just in case, a bulb is placed in the patient's hand (that's right - a signaling device). During panic attacks or for any other reason, it is enough to squeeze it, and an extremely loud alarm will go off for the X-ray technician monitoring the process in the room nearby (in the so-called control room).

“It would seem that everything is fine, the patient was put to bed, but they had only just managed to close the door when the pear was already pressed,”- Vesta tells us. According to her, there are people who get tired during the process, and it can last up to two hours. Therefore, sometimes a break is taken so that the patient can rest. This primarily applies to studies such as whole body MRI.

People with claustrophobia and panic disorders are also quite common. In this case, it is recommended to ask a specialist about all stages of the study and look at the device itself.

Scanning can take some time, in our case it lasted about 20 minutes. The second 10 (or all 19) dragged on for an infinitely long time - after all, you can’t move, but you really want to. "Houston, we have problems"- stuck in my head at the moment when my nose began to itch more and more (and this happened when I thought: “The main thing is not to itch your nose”). But a light breeze from a fan somewhere overhead helped me hold still until the end of the procedure.

There is absolutely nothing to do in the tunnel - there is nowhere to look, since almost in front of the nose there is a coil (?) similar to a holding device. All you have to do is close your eyes and listen to “magnetic resonance music”: the system, collecting data, hums and “sings” in different tones, but always rhythmically (in fact, these are ultra-fast vibrations). Sometimes she goes silent and you think: "It's over." But the pause required to fine-tune the system passes, and the rhythm starts anew. They say that some manage to fall asleep during the process - one can only envy such people.

By the way, the sound of the tomograph depends on the types of coils used and the current program.

Having “left” the tunnel, you want to jump up and walk - due to the motionless position and loud sound, a short feeling of disorientation arises. The main thing is not to rush (and they won’t let you).

After everything I had experienced, I had a desire to do something like in the movies - approach the tomograph with a pistol (this is shown regularly in action films). But there was no weapon at hand, so the experiment remained a dream - it was not possible to check whether the pistol would be magnetized.

How long can a scan take?

- At the Tomography Center - up to two hours. This is a full body MRI with contrast. As mentioned above, in such cases we break the study into parts.

The least amount of time is spent examining common joints, such as the knee. In a standard situation[no pathologies] it lasts no more than 15 minutes for one joint. But this is the time the patient is directly in the tomograph without taking into account data analysis.

Siemens is constantly developing new software. It allows you to reduce the time for some types of diagnostics. For example, you can speed up scanning of joints - up to 8 minutes, and the brain - up to 6-10. However, new software options require careful study, development and optimization of existing research protocols before implementation.

Are there any tasks that are frankly difficult for a tomograph?

- When examining the abdominal cavity, for example, and if we work in automatic mode, the device adapts to the movement of the diaphragm, reading data at a certain position. This significantly increases the research time. The process can be sped up, but the patient will have to hold their breath for 20 seconds many times. Physically it's not easy.

There are no restrictions for the device when it is fully equipped with coils. For example, we do not yet look at the heart or conduct examinations of the mammary glands. But this year the necessary components will be purchased.

Why can't you move?

- When a person moves, the picture turns out blurry. In some cases, in order to obtain a high-quality image, it is necessary to adjust the tomograph’s operating program. We need to clearly see the walls of the same vertebrae, the structure - this allows us to determine the presence of pathology. When a person moves, even the contours are lost, making diagnosis seriously difficult.

With some types of scans, small and infrequent movements will not be a problem, but in certain cases - when blurry scans are found in a place with a hernia or other changes - we are forced to repeat this or that series to obtain clear images.

Do you have to clench your teeth to prevent fillings from falling out?

- As for dental issues, there are no contraindications. Rather, technical nuances arise. If this is a brain study, an artifact[seal, pin] may fall into the study area. We then build the program to bypass such places and obtain an image of the desired area.

Patients with tattoos done about 20 years ago, when the ink had a high metal content, may experience subtle heating. There are extremely sensitive patients, and they usually talk about such things.

Concerns usually arise among those who undergo a similar procedure for the first time, as well as among older patients.

Software, coils

According to Vesta, MRI allows you to see what remains behind the scenes of X-rays. At the same time, a picture with fractures of the vertebra and sacrum is displayed on the screen of the doctor’s workstation. “This injury is not visible on an x-ray taken at the clinic,”- our interlocutor explains.

In addition to the technical part, a set of programs for research and data analysis has a direct impact on the diagnostic process.

Lumbar

Lumbar

Hip joints

Cervical spine. In the second image the patient was moving

In automatic mode, after receiving the data, the information is transferred to the doctor’s workstation. He, “armed” with his software, views the results, corrects them if necessary and works with an image that allows him to see the whole picture as a whole or its details, that is, the specialist has an accurate virtual model (or map) of the area or organ under study.

There are highly specialized sets of programs, which include, for example, a perfusion algorithm. More often it is used in the occurrence of tumors, particularly in the brain, providing information that allows one to determine the degree of malignancy.

Of course, not all software will be in equal demand. “For example, studies such as tractography (building connections between neurons in the brain down to the smallest cells - a beautiful color three-dimensional image is obtained) or functional MRI, which highlights areas of the brain involved in certain movements, are interesting, but are used mainly for diagnosing complex and rare diseases of the central nervous system",- Vesta explains.

It is believed that MRI can replace some painful or harmful diagnostic testing procedures. A specific example is mammography, which has to be resorted to when ultrasound cannot be done due to a number of factors, including age. The method is highly informative, but extremely uncomfortable, as it requires serious compression of the mammary gland, and in the presence of pathology, this can be very painful. “An alternative could be MRI. Currently, in Europe, MRI scanning of the mammary glands is replacing mammography from the practice of mammologists. This method has enormous advantages and great prospects,”- notes the interlocutor.

“Previously, computed tomography with contrast was mainly used - this is a colossal dose of radiation. And if it is necessary to do such an examination several times during the year... Moreover, all x-ray contrast agents are quite allergenic,”- says Vesta.

Beautiful picture

A beautiful picture, as emphasized in the Tomography center, remains a picture without qualified employees. MRI training is provided in Belarus, but in very limited quantities: you can’t get into such courses; doctors come from all over the republic. They last a month, which, according to experts, is not enough for such a wide field of medicine. Therefore, doctors interested in improving their qualifications use all possible sources of information: from specialized scientific and medical sites and communities to industry exhibitions and conferences.

“Doctors, when referring patients for MRI, often do not indicate the purpose of the study, which they should set before another doctor - an MRI diagnostician. They write “MRI of the brain”... And for what? What do they want to see?- says Emilia Mezina, head physician of the Tomography Center. According to her, training of doctors should have a positive impact on the situation, making the study valuable for the patient in terms of obtaining information, because this procedure is not cheap.

We thank the Tomography Medical Center for their assistance in preparing the material.

Modern medicine has many opportunities for a detailed examination of all organs and tissues of the human body. One of the reliable and reliable methods is magnetic resonance imaging, which has long moved from the category of high-tech assistance to the category of routine, accessible diagnostics. The article will provide answers to the most frequently asked questions about MRI – what it is, how it is performed and in what cases it is prescribed.

How MRI works

What is MRI in medicine? This is a research technique that is based on the physical phenomenon of magnetic resonance. The “resonator” in this case is the patient himself, or rather his tissues and organs. Despite the fact that MRI examination is called “nuclear”, it has nothing to do with radiation.

“Nuclearity” in this case means that the nuclei of hydrogen atoms, present in all tissues, respond to a combination of a constant magnetic field and electromagnetic waves, the source of which is a special scanner. These responses are recorded and organized by a device that combines them into a high-quality, clear image.

Types of magnetic resonance imaging (MRI)=

Diagnosis using MRI is carried out using various types of devices.

Diagnosis using MRI is carried out using various types of devices. The classification that is important for the patient is open and closed devices.

1. Open. What is open MRI? The space in which the patient is located during the examination remains open. The device itself consists of two parts - the upper one, hanging over the patient, and the lower one, on which he rests. Both parts are equipped with magnets. Open MRI examination is indicated for those who suffer from clautrophobia, are obese or have physical limitations.
2. Closed. Traditional devices consisting of a tunnel and a moving table.

Some types of MRI examinations are carried out only in closed machines. For example, if you need to take an MRI of the head, it is important to ensure that it is completely still. To do this, the head is fixed, but in open-type devices, fixation is not provided.

Another difference between MRI machines is the power, measured in Tesla. Depending on this parameter they are divided into:

• Low-floor (0.5 T).
• Mid-field (up to 1 T).
• High-field (up to 1.5 T).

The scanning time of a specific MRI area, the quality of visualization and the cost of the study will depend on the power. The higher the power of the equipment installed in the clinic, the higher the speed and higher the price.

Having understood what MRI diagnostics are, it is worth taking time to study the equipment of the selected medical center. Low-field devices produce images with less accurate visualization than high-field ones.

What does an MRI show?

The study is completely non-invasive and non-contact.

MRI is a unique study because it allows you to see a wide range of pathologies of different organs.

• Inflammatory diseases.
• Infections.
• Tumors.
• Pathologies of blood vessels and heart.
• Injuries and their consequences.

Tissue structure, organ configuration, blood supply, biochemical processes - all these phenomena can be assessed using a magnetic resonance imaging scanner.

Advantages of examination with an MRI scanner

Magnetic resonance imaging has many advantages over other types of medical research:

• Obtaining a very high quality, detailed image.
• The principle of operation of MRI does not involve radiation, and therefore it can also be used in childhood.
• Allows you to visualize structures that are difficult to study, such as the spinal cord and brain.
• You can obtain images in several projections. Thanks to this, the diagnosis of some diseases is carried out earlier than is possible with computed tomography (for example, cerebral ischemia).

Compared to other methods of studying health status, this diagnostic method has both advantages and disadvantages:

1. CT is a more dangerous test because it involves x-rays. However, if it is necessary to diagnose the condition of the musculoskeletal system, it is more advisable to conduct a computed tomography scan.
2. Ultrasound. There are no contraindications for ultrasound examination, so it can be performed on any patient. However, ultrasound cannot cope with such tasks as assessing the condition of bones, stomach, and lungs. In addition, MRI images are more accurate.
3. EEG (electroencephalography) – diagnosis of diseases. It is very difficult to diagnose the presence of tumors and other organic diseases using an encephalogram. In addition, the method cannot be called accurate, since the result is influenced by the emotions that the patient experiences.

How is an MRI done?

The study is completely non-invasive and non-contact. The only unpleasant sensation during scanning can be caused by the sounds produced by the device. To prevent the patient from hearing them, he is offered headphones with pleasant music. How is an MRI performed? The algorithm is as follows:

• The patient removes all metal jewelry and watches.
• The subject lies down on the table. , legs, and sometimes the head are comfortably secured with straps.
• The table moves into a tunnel, where scanning is carried out for the required time (from 15 to 60 minutes).
• Read also: about.

If you have claustrophobia, you should definitely tell your doctor about this. How is an MRI done in this case? Most likely, you will be asked to undergo diagnostics on an open device.

Types of diagnostics

MR angiography can be done without the use of contrast material.

The MRI procedure has several types:

1. MR diffusion. This is a type of magnetic tomography that records the speed of movement of water molecules. The method allows you to determine cerebral circulation disorders and identify oncological formations.
2. MR perfusion visualizes the characteristics of blood passage through tissue, the speed of this process, and vascular permeability. Due to this, it is possible to differentiate healthy tissues from pathological ones.
3. MR spectroscopy to detect biochemical changes in tissues. The value of such an MRI analysis lies in the fact that biochemical changes occur even when there are no clinical manifestations of the disease. This means that it can be detected at a very early stage.
4. Angiography is a study that allows you to see the lumens of blood vessels and evaluate blood flow.

MR angiography can be done without the use of contrast material. But most often, contrast is used to improve the visibility of blood vessels. MRI with contrast is a method that allows you to see what is happening with the vessels that penetrate each organ. So-called paramagnetic substances are used as a contrast agent - primarily gadolinium.

How does MRI with contrast work? Most often it is introduced after photographs without contrast have been taken. The substance is injected intravenously, then repeated images are taken. In what cases and why is it recommended to do such a study?

• Suspicion of an aneurysm.
• There is reason to suspect the presence of tumors.
• Stroke.
• Diagnosis after certain operations (for example, prostate surgery).
• Head injuries.
• To detect metastases.

An allergy to gadolinium is rare, unlike an allergic reaction to iodine, which is used as a contrast agent in CT scans.

Indications and contraindications

After undergoing an MRI, interpretation of the results usually takes 1-2 days.

Indications for MRI vary depending on the area of ​​the body that needs to be examined. Here are some indications sufficient for MRI:

• The brain is subject to examination in case of neurological symptoms, visual or hearing impairment, or after injury. What is the brain?
• The abdominal organs are examined for pain, jaundice, and severe dyspeptic symptoms.
• The heart is subject to study in case of coronary artery disease, pain and arrhythmias, after a heart attack.
• The genitourinary system is examined for urination disorders, pain, and the appearance of blood.

Modern medicine has various diagnostic methods that can be used to accurately identify a disease that has affected any organ. To make a correct diagnosis, special equipment and equipment is used. Among them, the most modern is the magnetic resonance machine. With its help, you can obtain the most accurate information about the condition of a certain part of the spine, brain, heart, liver, kidneys and others. Today, this research method is the most informative for diagnosing cancer.

MRI - what is it? First of all, this is a safe research method, which is based on the properties of the interaction of the electromagnetic field and hydrogen atoms that are located in the human body. After all, the human body is almost 70% water, and hydrogen atoms change under the influence of the field created by an MRI machine (interventional magnetic resonance imaging method).

Tomography literally means “section” in Greek. A magnetic resonance imaging scanner allows you to obtain layer-by-layer images of sections of a specific area of ​​the body or organ.

The device “photographs” the area under study with a given step width and from different angles, and then transmits the data to the computer. A special program converts this data into a three-dimensional image, which allows you to accurately determine the presence of the disease and select the correct treatment.

Types of magnetic resonance imaging (MRI) To carry out MRI diagnostics, two types of devices are used: open and closed.

This is important for patients who suffer from claustrophobia (fear of closed spaces), have any contraindications, or if the examination requires fixing any part of the body in a motionless state.

1. The power of an MRI machine is defined in Tesla. Depending on the power they are divided into the following types:
2. Low-floor. Up to 0.5 T;
3. Mid-field. Up to 1.0 T;

High-floor. Up to 1.5 T.

The power of the device determines the time it takes to scan a given area, the quality of the resulting image and the final cost of the procedure.

Open type devices. They consist of two parts: the lower one, on which the patient lies during the procedure, and the upper one, which hangs directly over the patient.

Both parts of the device are equipped with a magnet.

When using the device, the patient is in an open space during the procedure and does not experience discomfort, which is very important for those who have mental disabilities, physical problems or are overweight. As a rule, they belong to low-field or mid-field. Their power does not allow obtaining high-quality images of the abdominal and pelvic organs. However, it gives good results in diagnosing joints, spine, and head. Devices of this type are high-field and allow you to obtain the most accurate data. In some cases, to conduct research in this device, the patient must first take sedatives or be given anesthesia.

What does an MRI show?

Magnetic resonance imaging is a unique research method, since it can reliably identify abnormalities that are not always possible to determine by other methods: tumor formations at an early stage, internal bleeding, injuries, consequences of infectious diseases, etc.

In some cases, MRI is performed to obtain clarifying information about the results obtained as a result of ultrasound, CT, x-ray or other examinations.

The tomograph accurately and layer by layer shows the structure of tissues, the contours of internal organs and biochemical processes.

• Unlike other informative studies, MRI has a number of advantages:
• the image of the surveyed area is high-quality and detailed;
• with MRI, the patient does not receive radiation, which means it can be performed on children and pregnant women;
• allows you to accurately examine complex structures such as the brain and spinal cord;

an image in several projections makes it possible to detect the disease at an earlier stage than with other types of studies.

In some cases, MRI requires the administration of a contrast agent to obtain an accurate result.

The principle of operation of the tomograph

MRI is a non-contact and non-invasive study. It is not based on radiation, as in the case of CT or X-ray, but on a powerful magnetic field, frequently changing magnetic fields and radio frequency energy.

To carry out the research, a special apparatus and a powerful computer are used, which make it possible to obtain accurate and clear images of the desired parts of the body or certain organs.

During the procedure, the patient is in the “scanner”. Under the influence of a constant magnetic field in the tissues of the body, a small number of subatomic particles - protons - are aligned. Radio frequencies affect protons, causing them to produce certain signals that are transmitted to the receiver of the “scanner”. A large number of different signals and a local magnetic field, after processing by a computer program, “recreate” accurate images of the studied parts of the body. He makes sure to minimize possible discomfort during the procedure and obtain accurate images of exactly the areas that need to be examined.

In order to save the patient from unpleasant sounds that can be irritating, he is given headphones with calm music or offered earplugs. This will relieve the patient from extraneous sounds and clicks that occur during diagnostics.

The images obtained as a result of the study are described by a radiologist or other medical specialists.

Indications for MRI are:

• Brain. For hearing impairment, visual field impairment, previous TBI, or other neurological symptoms.
• Abdominal organs. For severe pain, jaundice, dyspeptic symptoms.
• Heart. For pain and arrhythmia, ischemic heart disease, after a heart attack.
• Genitourinary system. With painful urination with blood, frequent pain.
• Spine and joints. For constant pain.
• Diseases of the liver and gall bladder.
• Problems with blood vessels and impaired venous flow.
• Hemorrhages.
• Tumors (benign, malignant), with metastases.

Contraindications for MRI

When performing MRI, there are a number of absolute contraindications in which the procedure cannot be performed under any circumstances, as well as contraindications in which the examination is possible, but under certain conditions.

MRI is absolutely prohibited if:

1. The patient has a pacemaker installed. The magnetic field of the tomograph will damage the device.
2. The patient has metal implants or an electronic hearing aid.
3. First trimester of pregnancy. There are not enough studies to prove safety for the fetus.

Conditional contraindications include:

• Epilepsy or mental illness that causes convulsions or seizures (the procedure may be performed under anesthesia).
• Stenting of cardiac vessels. After installation of the clips, MRI is performed no earlier than 6 months later.
• Endoprosthetics of hip joints. Depends on the material from which the prosthesis is made. The doctor must know about the operation performed.
• Metal powder tattoos made many years ago. Modern tattoo artists do not use such compositions.
• Allergy to contrast agent. It happens quite rarely, and can be easily treated after examination.
• Artificial limbs and prostheses containing metal.
• Therapeutic plasters. Some types can cause skin burns, so it is better to warn your doctor about their presence.
• Navy. Some types of intrauterine devices contain metal.
• Dental prostheses. It is important to notify your doctor during an MRI of the brain.

Preparing for an adult study

Electromagnetic field research does not require special preparation for an adult: there is no need to follow a diet or adhere to a special regime. Depending on which organ will be examined, your doctor may recommend coming to the procedure with a full bladder.

Be sure to first test for a contrast agent if there is a possibility of its use. Even modern hypoallergenic drugs can cause individual intolerance.

When visiting the MRI procedure room, choose clothing that does not have metal zippers, buttons, hooks or fasteners. Lurex fabric also contains metallic thread, so choose clothes made from natural fabrics. Some centers offer special disposable medical clothing.

Before the procedure, you should remove dentures, watches, glasses, and jewelry. Crutches, metal canes, etc. are left outside the office.

If you have previously had an MRI of the organ being examined, you need to take the results of the examination with you. This will allow the doctor to compare the results and report on the dynamics of treatment or the speed of the disease (remission, progress, etc.).

Preparing children for magnetic tomography examination

MRI is extremely rarely prescribed for children under 1 year of age. Children under 6 years of age are first given sedatives or given short-term general anesthesia, since it is almost impossible for a child to lie still for 15 minutes.

An inhalation mask is most often used for anesthesia.

Otherwise, preparation for the procedure is the same as for adults - exclusion of metal objects in clothing and hairstyle, according to indications - a full bladder.

The main difference in preparation is protection from psychological trauma. Children over 6 years old need to have the essence of the procedure clearly explained, explain and agree that it is not scary and will not cause harm and will be beneficial.

If an MRI with contrast is to be performed, the child must clearly understand why it is being done and be warned that an injection will be given.

It is important to correctly explain to him that everything is being done only so that the baby recovers faster.

If the MRI was performed under anesthesia, after the procedure the mother should be next to the baby when he wakes up. There should be no fear that will be deposited in the subconscious.

The better the child is tuned to the procedure and prepared for it, the less the consequences will be for his psyche.

How does a magnetic resonance imaging session work?

During the procedure, the patient lies down on a sliding table. Depending on the area being examined, the specialist may secure the head, chest and arms with special belts - this will help maintain stillness during the examination. Heartbeat or breathing monitoring devices may additionally be attached to the body, and the area being examined may be wrapped in a coil.

At the request of the patient, he may first be offered to take a sedative to relieve anxiety or nervous tension. The patient is alone in the MRI room during the procedure. The technologist or doctor is in the next room, separated by a window. Two-way speakerphone is provided for negotiations.

The table gradually moves into the apparatus tunnel. All this time it is important to remain completely still in order to get an accurate result. In some cases, the specialist may ask you to hold your breath for a while. The procedure takes 30-60 minutes, but in rare cases it can last up to 2 hours.

During this period, the patient does not experience pain, but there may be numbness in the limbs due to prolonged stay in one position, or discomfort from prolonged stay on a hard surface.

Magnetic resonance imaging with contrast MRI with contrast is performed immediately after the main study performed without contrast agent. This method is used to improve the visibility of the vessels that permeate each organ.

In most cases, gadolinium or other paramagnetic agents are used - Magnevist, Tomovist, Omniscan, Gadovist, etc.

• The drug is administered intravenously, and repeated images are taken after 2-3 minutes. Typically, MRI with contrast is done in the following cases:
• At ;
• If the presence of a tumor is suspected;
• Suspicion of an aneurysm;
• Clarifying diagnostics after surgery;
• Head trauma;

When metastases are detected.

When the MRI contrast agent is injected, you may feel a cold sensation, but this is a short-term condition.

The doctor gives the first preliminary results immediately after the procedure. A complete and comparative conclusion will take 1-2 days.

In some cases, during MRI, the diagnosis of tumors at the initial stage occurs by chance when the study was carried out for a different purpose.