Contents
The paranasal sinuses act as a kind of filter to protect the human body from infections, dust and other external factors. They are prone to a variety of diseases, from birth defects to cysts and polyps. For quick and effective diagnosis, doctors prescribe magnetic resonance imaging. Why is the method good, in what cases is an MRI prescribed and what to expect from the procedure?
What you need to know about the scanned area
There are only 4 types of paranasal sinuses: maxillary, frontal, sphenoid and ethmoid labyrinth. Their names indicate the localization and structural features of the sinus. Sinuses begin to form even in utero. The final period of development of the body falls on the period of pubertydevelopment. From the inside, the sinuses are lined with a specific epithelium, which is able to produce mucus and have a bactericidal effect.
Normally, the sinuses are filled with air, and under certain conditions or during illness, accumulations of mucus / pus / bloody elements are possible.
Protection against pathogenic environmental influences is not the only function of the sinuses. The scientific community still cannot come to a consensus on this issue.
The most likely functions of the organ include humidifying and warming the inhaled air, isolating sensitive structures (eyeballs/tooth roots), and additional protection against injury.
It is also popularly believed that the paranasal sinuses increase vocal resonance, respond to atmospheric pressure and harmonize the shape of the skull. In any case, defects and pathologies of the paranasal sinuses can significantly affect the patient’s quality of life.
The specifics of the operation of a magnetic resonance tomograph
The human body mostly consists of water, and water contains elementary particles called protons. In fact, the human body is a source of protons. Elementary particles have one interesting feature – spin.
This is the angular momentum of the proton, which is equal to ½. If you place a proton in a strong magnetic field, it will emit radio waves at a certain frequency and intensity (depending on location). This strong magnetic field is the MRI equipment. A whole software and hardware complex is built into it, which not only creates a magnetic field, but also captures information, processes it and turns it into a high-quality three-dimensional image.
The computer catches radio waves, determines their frequency / intensity. Through complex mathematical algorithms, the system locates the proton that emits radio waves.
As soon as all the protons are found, the tomograph makes up a complete picture of the scanned area with all kinds of cuts, the possibility of magnification, and so on. Diagnostics (taking into account scanning and processing of results) takes an average of 20-40 minutes.
Contrast MRI
Contrast agents are used to improve the visualization of the scanned area. The substance literally illuminates the cavities of the human body, which helps to make the final image as informative, clear and detailed as possible.
Most MRI contrast agents contain gadolinium. Substance injected intravenously after the first (native) scan, after which, quite often, the need for an additional stage of contrast is determined. After the injection of the contrast agent, a rescan is started. The contrast penetrates, interacts with the hydrogen protons, amplifies the signal coming from them and increases the contrast of the image.
When to Scan
MRI has no age restrictions. Scientists believe that the magnetic field does not adversely affect the human body. That is why diagnostics are allowed for the most vulnerable categories of patients – infants, toddlers, adolescents, pregnant/nursing mothers and the elderly.
Magnetic resonance imaging is completely painless, and side effects occur in extremely rare cases.
Diagnosis using a magnetic field can replace x-rays or computed tomography. Both methods involve radiation exposure, which means additional stress and exposure of the body, which is associated with certain health risks. The only caveat is contrast diagnostics.
It is with contrast that most of the side effects after diagnosis are associated. Among them are nausea / vomiting, general deterioration in condition, etc., which occur very rarely. Be sure to consult with your doctor about the need for a contrast injection and take an allergy test. This will help predict the reaction of the body and reduce possible risks.
Features of MRI of the paranasal sinuses
A separate study of the sinuses is extremely rare. Why? Most diseases in this area (for example, sinusitis or frontal sinusitis) can be easily tracked using x-rays, computed tomography or ENT endoscopy.
These methods allow you to get the result much faster and cheaper than magnetic resonance imaging.
Endoscopy is a technique for examining internal organs using an endoscope. This is a special tool in the form of an elongated tube. Various optical devices and video cameras are built into endoscopes for greater information content of the procedure.
Magnetic resonance imaging is necessary to study pathological changes in the nasopharynx (in this case, conventional x-rays will not be enough).
Diagnostics will reveal the pathology, establish the current state of the body and provide several sections of the area under study for further medical manipulations.
Indications and contraindications for the procedure
| Показания | Relative contraindications | Absolute contraindications |
|---|---|---|
| Headache, tinnitus, discomfort when swallowing without established etiology | Insulin pumps, nerve stimulators, prosthetic heart valves | Pacemaker |
| Cystic formation | Decompensated heart failure | Metal implants |
| Cancer neoplasms, regardless of the nature of the tumor | First trimester of pregnancy (doctors still cannot determine the degree of exposure to the magnetic field on the fetus) | Ilizarov ferromagnetic apparatus |
| Congenital or acquired defects of the paranasal sinuses | tattoo | Ferromagnetic or electronic implants |
| Abnormal growth of tissue over the mucosa | Claustrophobia or severe mental illness | |
| Internal infectious/inflammatory processes | The general serious condition of the patient (the decision on the diagnosis is made by the attending physician) | |
| General diagnostics of the organ before or after surgery, evaluation of the effectiveness of the established therapeutic course | Dental prostheses and braces | |
| Allergic or non-allergic rhinitis |
Preparation and methodology
No specific preparation before an MRI is required. The only exception is contrast diagnostics. Contrast administration, if planned in advance, is best done on an empty stomach to minimize side effects such as nausea/vomiting and general deterioration.
Before and after the administration of the contrast agent, follow the instructions carefully roentgendiagnostic laboratory technician. If you feel pain, discomfort or any other negative symptoms, be sure to report it.
Often, a contrast MRI is prescribed for suspected cancerous growths. For other indications, standard magnetic resonance imaging will suffice, and in some cases, CT or X-rays. Undergo diagnostics only as prescribed by a doctor to avoid side effects and waste of money.
MRI of the paranasal sinuses is performed according to the standard scheme, but using special programs that help detect defects and pathologies in this area. What is the rationale for this? A lot of mucous, cartilaginous and bone tissues are concentrated near the nose. The equipment may simply not recognize the necessary areas, reducing the information content of the diagnosis. The tomograph itself is a massive closed chamber in the shape of a cylinder. In the middle of this cylinder is a retractable table on which the patient is placed for the duration of therapy.
X-raythe assistant helps the patient to climb onto the retractable table and take a comfortable position. Then the medical officer sets up the operation of the tomograph, correctly installs the scanning ring, reports the location of the call button for communication, and retires to the next room.
Since then, the interaction between roentgenthe laboratory assistant and the patient is carried out through a speakerphone built into equipment.
The patient must be prepared for the fact that the MRI machine makes a lot of noise during operation. If he feels pain/discomfort or wants to stop the diagnostics for any other reason, he must press the call button or a special signal bulb, which is issued before the study, and the patient holds it in his handinstead of screaming for help.
During the procedure, the patient must lie still. Even the slightest careless movement will distort Image, which will affect the final result and reduce the overall information content. The duration of an MRI scan is 10-25 minutes. When using a contrast medium, the procedure time increases.
Upon completion of the scan, the patient can return to the usual rhythm of life. No adaptation or special preventive measures are required. Remember that the MRI machine uses a magnetic field that is completely harmless to the human body.
You can pick up the results on the day of the scan. The patient is asked to wait outside the door while the machine processes the information and the doctorThe radiologist makes a conclusion based on the data obtained..
This usually takes 30-60 minutes, but the time may vary depending on the workload of the medical staff.
Evaluation of results
The tomograph provides a holistic three-dimensional image of the sinuses. The resolution and clarity of differentiation of the picture makes it possible to consider each section of the sinuses, their norms and deviations. It remains for the doctor to separate healthy tissues from those that have undergone a pathological process, compare the results with the anamnesis and make a diagnosis.
The tomograph scans absolutely all areas of the human body – from bones to adipose tissue. The specialist will be able to track changes even in the mucous membrane of the organ and individual areas of the paranasal sinuses. For comparison, X-rays will not be able to accurately convey the state of soft tissues, which complicates diagnosis and prescription of therapy.
The finished image is evaluated by at least two medical staff. It does this first radiologist, which is carried outt generalization of the obtained data and displays them in conclusion, explains to the patient the nuances of his condition, gives the results and sends them to the attending physician.
The attending physician approaches the MRI results more thoroughly, makes a final diagnosis and forms a further therapeutic course.
Magnetic resonance imaging is a standard diagnostic procedure in medical practice. It is suitable not only for the study of pathological changes in the body, but also for regular preventive examinations. The method is based on the study of the magnetic field, which is absolutely harmless for most categories of patients. The only drawback of MRI is the high cost. It is associated with the price of the equipment itself and the need for constant maintenance tomograph. Find the best methods to control your own body and be healthy.