MRI of the jaws (TMJ): what are the indications for tomography, what does it show and how to decipher it? When should a CT scan of the maxillofacial joint be performed? Can children do

An MRI of the maxillofacial joint is indicated if pain occurs in this area or if an injury is suspected, tumor lesion or degenerative-dystrophic disorder. With its help, various anatomical or structural changes in the area under study are determined.

When are they assigned?

MRI of the jaw with functional tests carried out if a person has such symptoms that disrupt normal life:

• severe pain;
• violation of the chewing process;
• diction disorder;
• blocking the movable part of the jaw in a certain state;
• clicking sound when moving the lower jaw;
• pain in the temples;
• decrease in the amplitude of the opening of the mouth;
• swelling of the face;
• tumor growths;
• jaw injuries;
• preparation for surgery;
• TMJ arthritis.

On CT, the body tissues of the examined area of ​​a person are visualized in layers.

Preparation for the event

Before computed tomography of the temporomandibular lower jaw joint the patient is examined and questioned about the presence in his body of various metal objects and structures. If the introduction of a contrast agent is necessary, then it should be determined whether the patient is allergic. It is also important that the patient does not eat anything for 6 hours before the introduction of contrast. Immediately before the start of the study, it is important to remove all metal objects, hairpins and jewelry from yourself. It is also necessary to find out if the person suffers from fear closed space or claustrophobia, because this is a contraindication to manipulation.

How is an MRI of the maxillofacial joints done?

MRI of the temporomandibular joints lasts from 15 to 40 minutes. Before starting the procedure, the patient is recommended to place earplugs in his ears, as there is high level noise. A person changes into a special dressing gown and lies down on a pull-out table. After that, the couch smoothly enters the tunnel of the apparatus. In this case, the patient's body is outside it. For about 5 minutes, the person is asked to keep their mouth open, sometimes by placing a filled tube of toothpaste in it, which allows them to keep static and no trembling in the open state. This position shows disc displacement and abnormalities. ligamentous apparatus. After the study, the decoding of the results lasts for an hour.

What does the contrast show?

When performing an MRI of the mandibular joint, special staining preparations are sometimes used. With the help of the introduction of a contrast agent into the vascular bed, it is possible to thoroughly see the state and direction of the vessels. Through this, it is possible to discover various diseases caused by circulatory disorders. To do this, a special drug is injected using a catheter into the systemic circulation and can be fed into the vessels during the procedure. This is ensured by its execution of plastic without the use of metal components. After instrumental research the substance is independently excreted from the body without causing any adverse reactions.

The contrast functions due to a special substance called gadolinium.

Deciphering the results

During an MRI or CT scan of the temporomandibular joint, a series of images is taken. They reveal the maxillofacial joint and all its structures in section. The doctor interprets the results of the analysis. It is he who can detect all anatomical defects upper jaw and diseases of the maxillary joint. Research reveals infection and degenerative-dystrophic pathologies of soft tissues and bones.

Contraindications

MRI of the jaw joint cannot be performed in such cases:

• interruptions in the work of the heart and the presence of a pacemaker in the body;
• braces on teeth;
• presence hearing aid or ear implants;
• the period after prosthetic heart valves;
• childhood;
• mental illness;
• claustrophobia or fear of closed spaces;
• tattoos.

A study using a contrast agent cannot be performed if the patient is allergic to the injected substance. In addition, this type of diagnosis affects a person through X-rays, so conduct magnetic resonance imaging too often not recommended.

CT scan(CT) - a 3D volumetric image of the jaw, made in digital format. This is the most objective method diagnostics in dentistry and maxillofacial surgery.

The examination is carried out with minimal radiation exposure and provides a more detailed image compared to a traditional x-ray.

Diagnosis principle

Computed tomography of the teeth allows you to see the jaw "in section" with all the nuances and details. It is carried out using a cone beam tomograph, which is considered the gold standard of R-equipment.

The basis of such diagnostics is a layered image of an object. The received information (scans) is processed computer program, resulting in a digital model dental system person in 3D format (three-dimensional panorama).

On a computer monitor, the doctor can zoom in on the image and examine the desired area in detail from various angles (literally millimeter by millimeter).

With the help of CT, you can examine 2 jaws at once, one of them, or a specific problem area, which will be cheaper.

Building a 3D model of the jaw

Why is CT needed in dentistry?

The method of computed tomography of the teeth is indispensable for the study of hard-to-reach areas of the jaw and deep tissues. It allows you to scan the jawbone, teeth, maxillary sinuses, temporomandibular joint and put the maximum accurate diagnosis.

Main indications:

• planning surgical operations on the jaw;
• selection of dentures in complex clinical cases;
• abnormal development and position of the teeth - the doctor will be able to assess the strength of the teeth before installing braces;
• mechanical injury, fracture of the jaw;
• pain of unknown etiology;
• abnormal growth of wisdom teeth;
• neoplasms of bone and soft tissue of the oral cavity;
• quality control of endodontic procedures (intracanal tooth treatment).

AT emergency cases the doctor prescribes MSCT of the brain (multispiral computed tomography), which is performed by rotating the x-ray emitter along the spiral path.

It is necessary to assess the damage to the bones of the skull, cerebral circulation, diagnosis of diseases of the paranasal sinuses. The method also provides more information for planning the most complex reconstructive plastic surgeries.

CT for dental implants

Having "on hand" a computer model of the jaw, the implantologist will be able to choose correct form and the size of the dental implant. The success of the operation depends on this, as well as the degree of engraftment and the duration of the life of your new tooth.

In addition, an assessment is made bone tissue jaws: height, volume, density. For example, when the height is less than 1 cm, implantation is simply impossible. The picture will also show if bone resorption (resorption) has occurred. Then a sinus lift is prescribed, that is, an increase in bone material.

How is a CT scan of the jaw done?

Diagnosis is carried out in a standing position. You should approach the device and place your chin on a special stand. It will fix the head in the correct position. After that, you need to stand still.

When the doctor starts the device, the jaw is irradiated with an X-ray cone-shaped beam. A special sensor moves around the head, reading information. In this case, the dentist regulates the strength of the radiation and fully controls the process.

For guard internal organs You will be given a special lead vest. It is also necessary to remove all metal jewelry. Scanning lasts 20-50 seconds, it takes a couple of minutes to prepare.

Benefits for the patient

The undeniable advantages of jaw CT over traditional film imaging:

• takes little time;
• perfectly clear picture in HD-quality;
• eliminates the possibility of a "blurred" image;
• comprehensive examination the entire dental system;
• health safety;
• all data can be saved on a “flash drive” and shown to another doctor.

Frequently asked questions about 3D dental tomography

How often can a CT scan of the jaw be done?

The radiation dose for 1 session of computed tomography of the teeth is only 40-60 microsieverts, which is several times less than that of film radiography. Therefore, even 2-3 procedures a day can be carried out, this will not cause significant harm to the body. Maximum allowable dose– 3500 µZ per year.

Does it hurt to do?

CT of the jaw - simple and fast procedure, during the operation of the device, the patient does not feel anything - neither pain nor discomfort. The device emits only a low sound.

Can CT be done during pregnancy?

The CT method of teeth is officially approved for pregnant women, children and nursing mothers. However, the influence x-ray exposure on the fetus has not been fully studied. Therefore, the examination is performed only in case of emergency and only with a cone beam tomograph.

Most safe period for the procedure during childbearing - the second trimester.

Prices

The cost of diagnostics depends on the novelty of the equipment, as well as the required examination area.

• Tomography of both jaws costs about 2000 rubles,
• CT of one jaw - about 1500 rubles,
• scanning a specific segment (50 by 50 mm) - 800–1000 rubles.

On our website there are many clinics where you can do a CT scan of the teeth or

Magnetic resonance imaging is a universal medical diagnostic tool. Using it, doctors get exact images internal structure person. The procedure is used to visualize the brain, spine, soft tissues, joints, internal structure bones. MRI of the jaw is a popular type of diagnostics used in orthodontics, maxillofacial surgery.

What is studied during the diagnosis

Magnetic resonance imaging is carried out on devices of two types: screw and cone-beam apparatus.

Tomography of the jaw shows potential pathologies in this area:

1. arthritis and arthrosis;
2. effusion in the joint bag;
3. joint displacement and its asymmetric position;
4. dislocation;
5. tumor processes.

With arthrosis, a decrease in the height of the upper articular structures or their thickening is determined. In addition, cartilage degeneration and bone growths are visible.

With a dislocation of the lower jaw, a displacement of its head into the region of the tubercle can be traced. Beginning osteomyelitis ( dangerous disease) can be seen on the scanner. It is characterized by enlightenment with uneven edges that do not have clear boundaries.

The scanning method identifies the cyst and tumors. They have the same structure round shape. If the formation has malignant signs, then there are foci of destruction that extend to soft tissues and adjacent bones.

Examination of the jaw on a tomograph is reliable and informative method dental diagnostics. It allows you to visualize the upper and lower jaws, the facial skeleton.

The device helps to identify and show the resonant tomography of the jaw before implantation of teeth. Using a three-dimensional image, the anatomical features of the jaw are evaluated: the structure of the teeth, roots and root canals, which makes it possible correct selection dental implant. The condition of the jawbone is also assessed: height, volume and density. With the help of the device, you can detect gingivitis, periodontitis, pulpitis.

Dental examination with MRI can be done in children from 5 years of age. For this, there are special programs with a reduced effect of radiation. Children's diagnostics last no more than 1 minute and do not require special training.

What is the difference between computed tomography and magnetic resonance imaging

The main difference between MRI and CT diagnostics lies in the physical phenomena used in the devices. CT scan - x-rays, which evaluates physical state internal organs.

MRI machines create a constant and pulsating magnetic field. Radio frequency radiation emitted during the study provides information about the distribution of hydrogen atoms in the body. Thus, it is estimated chemical structure fabrics.

During the procedure, tissues are clearly visible, while bones may not be visible. This type of diagnosis is effective in diffuse and focal lesion brain, spinal, more informative in case of violation cartilage tissue. With the help of diagnostics of the magnetic lower jaw, articular surfaces in her.

The MRI machine detects the slightest changes in the mouth, displacements and injuries received during the injury. Beginning diseases can be seen with an MRI. The procedure helps the doctor to establish an accurate diagnosis and prescribe treatment for the following pathologies:

• tumors in bones and soft tissues;
• liquid cystic formations;
• complex gum disease;
• inflammatory processes;
• recurrent sinusitis;
• the presence of foreign bodies, polyps;
• benign and malignant tumors in the lower and upper jaw;
• osteomyelitis;
• pain in the jaw when opening and closing;
• spasms of the jaw muscles;
• damage to the dentition;
• decrease in the amplitude of movement of the lower and upper jaws;
• chewing difficulties.

In dentistry, an examination of the jaw on an MRI tomograph is prescribed before the installation of prostheses, orthodontic treatment.

Often, an otolaryngologist prescribes a scan of the jaw joint if there is a risk of developing ENT diseases.

Diagnostic MRI is a safe method, but may not be used in all cases. There are some contraindications to the study:

1. It is impossible to carry out the procedure if metal implants are installed, there are foreign elements from ferromagnets. Otherwise, metal objects in a strong magnetic field heat up and give a distorted picture of structural changes.
2. In patients with heart failure, procedures are prescribed with caution.
3. It is not possible to perform an examination of the teeth and jaw if there are fixed metal dentures and electronic implants in the middle ear.
4. If you plan to introduce a contrast agent, then you need to make sure that the patient is not pregnant.

Patients who have allergies should tell their doctor before scanning with contrast.

When scanning the maxillary and mandibular joint, attention should be paid to the metal from which dental posts for implants are made, if any.

Implants are made from materials that can be divided into 3 groups:

• paramagnets;
• diamagnets;
• ferromagnets.

Paramagnets are titanium products, ferromagnets are steel products. Titanium structures do not respond to a magnetic field, unlike ferromagnets, which heat up under the influence of waves and can move. Longer designs of ferromagnetic dental implants heat up more. Under the influence magnetic field MR tomograph only unfixed particles are displaced. Fixed implants cannot move.

With implants, MRI can be done. But for scanning the head, it is not practical to use this method. Metal elements create interference, change the image and thereby distort the picture of the disease. There are no obstacles for scanning during MRI of other parts of the body.

The doctor should also be told what metal the dental crowns are made of. Metal-ceramic and metal crowns distort the results of MRI of the head, jaw.

There are many myths among patients about the effects of MRI on those with braces. But the magnetic field does not affect the properties of the braces, they are not deformed, and the patient does not experience any pain during the examination. However, the doctor should know what metal the bracket system is made of.

Different types of metals react differently to a magnetic field. If metals that react to magnetic radiation were used, then braces can distort the result of an MRI of the head and jaw. Most often they are made from polymer materials that do not react in any way to radiation during the session.

Sometimes during the examination, patients with braces note discomfort in the mouth.

No special preparation for an MRI is required. In a special room, the patient will be asked to remove jewelry, leave metal objects, and a telephone.

If an examination is planned using a contrast agent, then the last meal should be no later than 6 hours before the procedure.

The subject lies on a special table on his back. The head is fixed with special fasteners so that during the diagnosis the patient does not sudden movements. The center of the scanned machine is set above the area to be viewed.

The procedure lasts 15-40 minutes, during which time the scanner takes several pictures in different projections.

MRI in the jaw area can be performed with kinematics, when the patient gradually opens his mouth and during this, pictures are taken. Thus, a change in the mobility of the joints can be traced.

The first images are obtained in the frontal and sagittal planes, while the mouth must be closed. An oblique-sagittal scan is then performed with the mouth slightly open. The last pictures are taken in a position where the mouth is open as much as possible. If necessary, a foreign object is placed in the mouth to prevent involuntary trembling of the jaw.

During the procedure, you should lie still and do everything that the doctor says. After receiving the images, the radiologist will make a conclusion

Prices for magnetic resonance imaging

The price of a jaw scan on an MRI tomograph depends on the apparatus on which the procedure is performed, on the elite of the clinic, and on the location of the pathology. The cost varies from 2700 to 8000 rubles. Scanning with contrast increases the cost of the procedure. The amount of contrast agent is calculated depending on the weight of the patient.

The cost of a dental examination is slightly lower. Both jaws can be scanned for 2000 rubles. Inspection of the upper or lower teeth will cost 1200 rubles. For contrast, they will charge an additional fee of 800 to 1000 rubles.

There are quite a few different physical ways reliable diagnosis of the state of the jaw joints. When you can't get by alone visual inspection, the doctor can use a wide range of scanning methods. The most widespread in dentistry is radiography and.

MRI diagnostician

The method of irradiation with short-wavelength rays appeared relatively long ago. To this day, X-rays are actively used where it is necessary to clearly visualize hard tissues e.g. dental bone. However, for more professional and complete visualization, a method is needed that supports the universal display of any kind of cells.

MRI has become just such a method. Scanning with radio waves in a magnetic field allows you to accurately differentiate, in theory, any tissue containing hydrogen in various physiological conditions. In practice, this means that a visual separation of the main histological cell types can be easily obtained. At the same time, the use of contrast agents for tinting a specific selective type of tissue makes it possible to further enhance the visualization effect. Thus, MRI has such advantages as:

• Sensitivity to cell heterogeneity.
• The ability to regulate the display of any tissue by adding contrast.
• The ability to display not only the bones, but also the accompanying soft areas.

Tomography, moreover, is much safer for humans, since the magnetic field is absolutely harmless. MRI of the jaw is actively used by dentists to solve various diagnostic problems.

Reason for appointment

As a rule, the reason for the appointment of magnetic resonance imaging in dentistry is the need to diagnose diseases associated with inflammatory processes in tissues adjacent to the teeth. In addition, MRI can easily detect the presence of cystic formations. Direct indications for tomography are the following symptoms:

• Spasms of the jaw muscles.
• Pain and discomfort when opening or closing the mouth.
• Decreased amplitude of jaw movement.
• The presence of any visual pathological abnormalities.

After holding the jaw, the doctor will be able to examine in detail the picture, which can determine the cause of the symptoms. If inflammatory processes are suspected, secondary tomography with contrast is sometimes performed, which makes it possible to highlight areas with inflammation.

Contraindications and safety of the method

Tomography of the facial zone is absolutely harmless for a wide range of patients. In general, as a rule, MRI is not performed on pregnant women - it is believed that the magnetic field can adversely affect the fetus. But due to localization, tomography of the jaw is safe for everyone. Even for children there are no real contraindications.

Difficulties can arise only under two circumstances, and even then not always. Firstly, there are many nuances in the use of additional contrast agents. A similar tomography method is used in only 20% of cases, but, nevertheless, occasionally there are cases of development allergic reaction in contrast. This nuisance is easily prevented by conducting a preliminary allergy test. If the patient is prone to developing a hypersensitivity reaction, then he should definitely inform the attending physician about this.

The second circumstance is connected with people who have implants, a bracket system, or in general any foreign bodies in oral cavity. As you know, metal objects in a strong magnetic field heat up and are attracted to the working tool. However, modern dental alloys, as a rule, are completely devoid of ferromagnetic inclusions. Therefore, the only difficulty that arises when tomography of the jaw with foreign inserts is the presence of distorting interference in the resulting image, which must be taken into account.

Magnetic resonance imaging is recognized by many experts as the most informative diagnostic method. This procedure has long been used by doctors to diagnose various diseases. Magnetic resonance imaging of the face and jaw is prescribed in the presence of any pathologies.

MRI of the jaw in the smallest detail will provide the doctor with all the necessary information about the state of the organs and systems being examined. The method is based on the phenomenon of magnetic resonance, it appears during the action of magnetic fields on tissues. MRI was recognized as the most safe method research of organs, systems.

The entire scanning process takes an average of 15-40 minutes.

During this time, the tomograph performs a series of layer-by-layer images of the examined tissues in different projections.

MRI of the jaw is prescribed in the presence of such factors:

• pain when chewing;
• difficulty chewing;
• swelling on any side of the face;
• clarification of the condition of the maxillary sinuses;
• jaw injury;
• pain that manifests itself while touching the chin, ears, temples;
• limitation of muscle movements in the process of opening the mouth;
• pain, clicks that are heard in the area of ​​the jaw joints when opening / closing the mouth;
• preparation for prosthetics, implantation of teeth.

There are very few contraindications for MRI of the jaw. These include:

• the presence of metal implants;
• electronic implants;
• ferromagnetic apparatus of Ilizarov;
• pacemaker;
• people with heart failure;
• pregnant.

MRI of the TMJ is a very important procedure that shows the structure of bone tissue, periarticular soft tissues, cartilage elements.

What can be seen through the survey?

MRI of the jaw is performed to determine a number of dangerous pathologies:

• arthritis;
• ankliosis (immobility of the joint);
• arthrosis;
• the presence of fibrous, bone, cartilage fusion of the joint;
• jaw fracture;
• dislocation.

The price of an MRI of the temporomandibular joint is approximately 5,800 rubles. The cost of the procedure may vary slightly depending on certain factors (qualification medical institution, tomograph model, city, procedure features).

MRI of the temporomandibular joint allows the doctor to examine in detail the structure of this paired joint. This joint is difficult to examine because of its anatomical features. Magnetic resonance imaging provided doctors with the opportunity to carefully examine the state of the joint, the tissues located around it. This procedure is necessary in such areas of medicine as:

• traumatology;
• dentistry.

Thanks to its data, doctors can make best option patient therapy.

MRI of the maxillofacial joint provides comprehensive information, thanks to which the radiologist examines the dysfunction of the TMJ, which manifests itself in the limitation of the mobility of this joint. Also, MRI of the maxillofacial joint will provide information on such conditions of the joints and muscles:

• change in bite;
• pain that appeared in the face, neck, jaw;
• pain in the jaw joint;
• headache when clenching the jaws;
• rigidity jaw muscles, which is usually accompanied by spasms around the jaw;
• clicks, crunch, manifested during chewing.

Examination of the jaw joint is prescribed for the following reasons:

• inflammatory diseases of the jaws;
• jaw injury;
• bruxism (teeth grinding);
• complication after diseases such as: rheumatoid arthritis, gout);
• wear articular cartilage, disk.

Separately, data may be needed after an MRI of the upper jaw or lower jaw. Doctors may need the most accurate information about the state of the dentition, bone tissue, and teeth when planning operations. Diagnosis of patients is prescribed before:

• installation of implants;
• dental prosthetics;
• plastic surgery.

How is the diagnosis carried out?

No diagnostics special training need not. An MRI scan can be done with the mouth wide open/partially open/closed. Since it takes 3-5 minutes to obtain an image of one joint (a picture in one projection), it is inconvenient to keep your mouth open. To relieve the feeling of discomfort, a non-magnetic plastic retainer is used.

Magnetic resonance imaging in the jaw area can be performed with kinematics. This means that the pictures are taken with a gradual opening of the mouth. This is how the mobility of the joint structures is traced. Perform the procedure in the following sequence:

1. Before scanning, the patient lies on the MRI table on their back. During the examination, a standard radiofrequency coil is used, which is used in brain diagnostics.
2. The TMJ research center is installed over the area to be diagnosed.
3. The first pictures are taken in oblique sagittal, oblique frontal planes. The patient's mouth is closed. The picture is taken in 1 minute. Another minute is needed to take a picture of the second joint.
4. Scanning of one joint is performed with slightly open mouth in oblique sagittal projection. When opening the mouth, the patient should not push lower jaw forward. The picture is taken in 1 minute. Another minute is needed to take a picture of the second joint.
5. The scan is performed with the mouth as open as possible. The patient lowers the lower jaw down, pushes it forward. This position should be maintained for a minute. The picture is taken in an oblique sagittal projection. Another minute is needed to take a picture of the second joint.

MRI can be performed with contrast ("Omniksan", "Magnevist", "Tomovist", "Gadovist"). It is carried out if necessary to obtain more information about the pathology.

In order for the specialist to receive the most accurate information about the state of the joints, soft tissues, and bone tissues, you need to remain calm during magnetic resonance imaging. If your doctor ordered an MRI with contrast after your usual procedure, go ahead. This method will provide more accurate information about the pathology under study.