MRI sacrum and coccyx: how is the procedure?

Physical examination and laboratory diagnostics are far from always able to give a doctor enough information about the patient's state of health, especially when it comes to the pathological processes occurring inside the body. Externally, these diseases may not manifest. Analyzes allow only to lift the veil on what is happening in the body, but they are unlikely to give full information about spinal anomalies, degenerative processes in it and the surrounding tissues. Fluorography, which is usually aimed at identifying possible pulmonary tuberculosis and tumors in this area, despite the reduced image size, allows an assessment of the condition of the thoracic spine. But for the diagnosis of pathologies of the lower part of the spine, it is more expedient to use X-ray diagnostics or relatively new and at the same time more informative methods. MRI of the sacral spine can certainly be called just such an innovative method.

The benefits of magnetic resonance diagnostics

Since the end of the nineteenth century, mankind has been able to see the processes occurring inside a person on an x-ray film. It was a breakthrough in medicine at that time, but later it turned out that such an examination of a person is unsafe, so it cannot be performed many times. In addition, X-ray diagnostics. Easily identifying pathological processes in the bones, it was not always possible to accurately assess changes in the soft tissues adjacent to the bones (muscles, cartilage tissue, ligaments).

This prompted scientists to further search for more informative and safer methods for diagnosing human health, and in 1971, finally, a description of an innovative technique appeared that made it possible to obtain an image of human internal organs using a magnetic field and reflection processes in it (magnetic resonance). In fact, such an opportunity was mentioned back in 1960, when the Soviet inventor V.A. Ivanov proposed his invention, which allows to look inside material objects, and the phenomenon of nuclear magnetic resonance has been known to mankind since 1938.

From the moment of discovery of such a useful phenomenon to the realization of its capabilities and their introduction into the practice of medical research, many decades passed until the MRI method entered the complex of diagnostic methods on the border of the nineteenth and twentieth centuries as one of the most informative and at the same time safe methods of examining human organism.

The basis of the innovation technique is the phenomenon of nuclear magnetic resonance itself. In our body, every second atom is a hydrogen atom that is able to vibrate (resonate), if it is influenced by a magnetic field large enough, but safe for human strength. At the same time, energy is released, which the tomograph catches and through special programs converts it into an image on the monitor screen. Thus, doctors have the opportunity to get on the screen both a flat and three-dimensional image of those organs and the adjacent tissues in which the alleged malfunction occurred.

As used for a long time X-ray examination, magnetic resonance imaging is among the painless non-invasive techniques, i.e. It allows you to look inside the body without incisions and punctures, and the patient does not feel physical discomfort. But at the same time, it is possible to undergo MRI, unlike radiography, several times a year, without worrying about the consequences of exposure of the organism. The MRI does not use light rays, it is based on the properties of hydrogen atoms to react to a magnetic field, and after the effect of the field ceases, everything returns to normal.

A very important and useful property of magnetic resonance imaging is the ability to assess the condition of not only bone tissue, but also connective, cartilage, muscle, including the spinal cord and blood vessels. Thus, MRI of the sacral spine provides an opportunity to see not only the integrity of the bones in this area, but also to evaluate the degenerative changes occurring in it, the presence of inflammatory processes or tumors, compression of the bone marrow and blood vessels, pinching of nerve fibers, which is often associated with pain syndrome.

Indications for the procedure

In order to understand under what diseases and symptoms a doctor may suggest a magnetic resonance examination of the sacral section, it would be helpful to understand the structure of the lower part of the spine. At the same time, it is not at all necessary to delve into the evidence-based framework, but rather recall the information from the school course of anatomy.

The part of the spine below the rib cage includes 3 sections:

• lumbar, consisting of 5 separate vertebrae,
• sacral, in which there are also 5 vertebrae, the size of which decreases as they approach the coccyx (in adolescence, the sacral vertebrae fuse into one bone),
• coccygeal, which may include from 4 to 5 small vertebrae (they also fuse together)

Of the 3 parts of the lower spine in adults, only the lumbar is mobile. In children and adolescents, the sacral region also has some mobility, whose vertebrae grow together only in adolescence. The tailbone is considered a rudimentary body, inherited from tail ancestors and eventually lost its relevance.

The neighbor of the sacral spine on the top is the lumbar, and on the bottom the coccygeal. Therefore, when pain or restriction of spinal mobility in the lower part of the spine is often found, it is very difficult to say in which of the departments lies the cause of the appearance of pathological symptoms. Difficulties of visual diagnostics allow the appointment of a complex examination of 2 sections simultaneously: MRI of the lumbosacral or sacrococcygeal spine.

Doctors give directions for MRI diagnostics of the lumbosacral, if they have:

• Suspected intervertebral hernia or protrusion of vertebrae in the lumbosacral region as a result of damage to the fibrous ring.
• Suspected osteochondrosis of the lumbosacral spine is a degenerative disease characterized by destruction of intervertebral discs.
• The assumption that the cause of the ailment is stenosis of the spinal canal of the spine, or rather of its lower segments, resulting in compression of the spinal cord and roots of the spinal nerves. With this diagnosis, patients usually complain of pain in the back and legs, weakness in the lower extremities, impaired sensitivity in the lower extremities and the pelvic area, cramps in the calf muscles, etc.
• There is reason to suspect tumor processes of the vertebrae and the spinal cord in the lumbar region and the sacrum. Such a diagnosis can also be carried out with the established diagnosis to identify metastases in the vertebrae, spinal cord and pelvic organs.
• Suspected multiple sclerosis is an autoimmune disease with damage to the myelin sheaths of the nervous tissues of the brain and spinal cord, in which, along with memory loss, a complex of neurological symptoms is noted (increased tendon reflexes, weakness and pain in muscles, dysfunction of the pelvic organs, up to incontinence and t.d.)
• Suspicion of the development of syringomyelia is a chronic spinal disease prone to progression with the formation of cavities inside the spinal cord, resulting in reduction or loss of pain and temperature sensitivity, weakness and decrease in muscle volume, decreased sweating, increased muscle fragility.
• Suspected spinal cord inflammation (myelitis) resulting from injury, intoxication, or infection. It is characterized by a decrease in the sensitivity of soft tissues and an increase in muscle tone, enhanced perspiration, impaired urination and a process of defecation, and strong weakness in the limbs.

Instrumental diagnostics of MRI may also be needed when symptoms of circulatory disorders appear in the lower extremities. They can be caused both by vascular pathologies (phlebitis, varicose veins), and deforming changes in the spinal column, as a result of which the blood vessels and tumor processes are compressed.

In general, we can say that MRI of the lumbosacral spine can be prescribed for any pain syndrome in the lumbar region, sacrum, sacroiliac joints, constraint of movements in this area. The same examination can be prescribed in violation of the sensitivity in the pelvis and legs associated with impaired blood flow and tissue innervation due to compression of the nerve fibers and vessels with modified or displaced bones, cartilage, ligaments and muscles.

MRI of the sacral or sacro-coccygeal spine involves the identification of pathological changes in the coccyx, and in the sacrum and sacroiliac joints, where there are multiple blood vessels and nerve roots that provide innervation to the pelvic region and lower extremities. Doctors prescribe a similar examination for symptoms such as:

• pain in the muscles of the buttocks,
• forced posture due to pain in the coccyx or sacrum area and the restriction of intervertebral intervertebral joints,
• the appearance or increase in pain when pressing on the area of the sacrum,
• pains in the coccyx, which are aggravated during movement or sitting
• change in sensitivity in the lower limbs.

The sacrum and the tailbone in adults are fixed organs with accrete vertebrae, so we can speak here about the deformation of the vertebrae rather than their displacement. In addition, the spinal cord in this part of the spine is presented in the form of a thin filament with a lower probability of damage than in other parts. Most of the pathologies of the sacro-coccygeal tract are of a traumatic nature, less often it is a question of inflammatory-degenerative processes or oncological diseases. However, doctors sometimes find it difficult to make a diagnosis without relying on visual information about the internal structures of the body.

For example, injuries of the coccyx, which usually occur when the buttocks fall on a hard surface or during childbirth in women, are often immediately ignored by patients. But pains that increase during walking or pressing on an organ force patients to seek help. At the same time, patients do not always even remember a long-term injury, but MRI images of the coccyx clearly indicate a fracture, dislocation or displacement of the vertebrae that occurred during an impact or strong pressure, with the formation of cicatricial and fibrotic changes, which is the cause of prolonged pain.

But the reason may be different. Coccyx pain, for example, can be associated with pathologies of internal organs: proctitis, hemorrhoids, anal fissures, prostate pathologies in men, inflammatory diseases of the female reproductive sphere. And given that magnetic resonance imaging allows us to assess the condition of both bone (solid) and soft tissue structures, its value as a method of instrumental diagnostics that helps in differentiating diseases and diagnoses remains beyond doubt.

MRI diagnostics is used not only to detect pathological changes in organs, but also to detect congenital developmental abnormalities that adversely affect the well-being of patients. True, in some cases they are detected by chance, which is also not bad for the prevention of possible health problems.

Some diseases and developmental abnormalities are amenable to surgical treatment or correction. In this case, MRI may be useful not only at the stage of preparation for the operation (its results give the doctor a clear understanding of the location of organs and deformed structures, help determine the localization and depth of incisions, the size of tumors and the spread of metastases), but also in the postoperative period. Using a simple and safe procedure, you can evaluate the quality of the operation performed and follow the healing process, during which corrective procedures may also be needed.

[1], [2], [3]

Preparation

MRI of the sacral spine is a fairly simple procedure. The results of the study do not have a decisive effect neither the foodstuffs or drugs used the day before, nor physical or mental loads, nor the physiological needs of the human body. Under such conditions, doctors do not see the point in limiting patients in some way, i.e. Special preparation for the procedure, as such, is not required.

It is clear that an MRI of the sacral, lumbosacral or coccygeal spine does not come empty-handed and complains of well-being. First, he will have to go to a general practitioner, pediatrician or family doctor, who will either give a referral to the examination after hearing the patient's complaints, studying the history and preliminary examination results (for example, laboratory diagnostics), if any, or refer the person to a specialist. (traumatologist, neuropathologist, rheumatologist, orthopedist). But neither generalists nor highly specialized doctors will not make a final diagnosis without an instrumental study of the relevant department (or departments) of the spine.

The direction given by the doctors will gently present the equipment that conducts magnetic resonance imaging in a specialized hospital room or at a clinic reception specialized in such studies.

Some of the requirements are for clothing and jewelry on the body of the subject. Immediately before the examination procedure, the patient is invited to a separate booth, where he will need to remove outer clothing, all items of clothing and jewelry containing metal components, leave ordinary and electronic keys, bank cards, monetary change, watches, etc. We are talking about any items that can interact with the magnetic field, distorting the information or harming the patient's body.

In many clinics, patients are given special clothes, a robe for examination or a sheet.

It is advisable for women to go for the procedure without cosmetics and some body care products (creams, antiperspirants, etc.), because some of their types may contain metal particles that interact with the magnetic field.

MRI of various parts of the spinal column can be carried out both without contrast and with its use (most often gadolinium salts, safe for humans, play the role of a contrast agent). In this case, the contrast is usually administered intravenously or intraarticularly. Contrasting substances can rarely cause mild symptoms. They do not interact with different substances in the blood or intraarticular fluid, so the preparation of MRI with contrast is no different from that for examination without the use of a contrast agent that improves the visibility of the studied structures, which is especially valuable when diagnosing tumor processes and tumor metastasis.

Regardless of whether the patient underwent an MRI earlier or came for the first time for the examination, the technician who performs the procedure tells how it will be performed, what requirements are imposed on the patient's behavior and what are the possibilities of communication with the medical staff (the procedure is carried out in a separate room, and the technician is in another room).

Technique MRI of the sacral spine

If a person has never had to undergo a magnetic resonance examination, naturally, he immediately has a question about how an MRI of the lumbar, sacral, and coccygeal spine is done. Even in the absence of special training, the procedure may look frightening because of the large size of the installation itself for MRI diagnostics.

Despite the large size of the device itself for the magnetic resonance examination is generally harmless. For the procedure, the patient is placed on a special sliding table, which subsequently moves into the tomograph's chamber, which resembles a large tube.

Lying on the table, you need to take the appropriate comfortable posture, while the patient's arms and legs can be additionally fixed with straps. This is necessary to maintain a fixed posture during the examination, because any movements will affect the clarity of the resulting image, with the result that it will be unsuitable for diagnosis.

During the operation of the tomograph inside it there is a specific sound (noisy tapping) emanating from a working magnetic field generator, which can irritate the subject. To make a person comfortable, he is given earplugs or special headphones for listening to music before the procedure.

Many people are frightened by the very need for isolation during a survey, and those who suffer from claustrophobia (fear of confined space) may experience panic altogether. With phobias, the use of high doses of sedatives is indicated; the remaining patients can always contact the medical staff in case of unpleasant sensations or severe discomfort. The tomograph device provides for two-way communication with the doctor conducting the study and being in the next room during the procedure. If necessary, relatives of the patient can also be there, especially if they are examining a child.

It must be said that unlike radiography, which takes only a couple of minutes to complete, magnetic resonance imaging is a technique that requires much more time. At the same time, the patient should lie motionless while in the device chamber. The procedure without contrast takes about 20-30 minutes, and with the introduction of a contrast agent for 10 minutes longer, which is necessary for the contrast to penetrate into the test organ.

To reduce anxiety and ensure the safety of a static posture during the entire time of the procedure, too excitable patients and those who are afraid of the device are given sedatives. In case of severe back pain, which do not allow you to lie still for a long time, painkillers are offered before the procedure. If the procedure is assigned to a child with back pain, then the best option would be to give a light anesthetic or local anesthesia.

As you can see, the apparatus for MRI of the sacral spine and other human organs, as well as the examination methodology, are designed to ensure maximum patient safety, eliminate panic among them and, if possible, ensure their comfort.

[4]

Contraindications to the procedure

Despite the fact that MRI of the sacral spine is considered absolutely safe procedure, it has its own contraindications. It should be noted that the absolute contraindications of the procedure is not so much. These include:

• Connection to portable devices that affect the heart rhythm (pacemakers), without which a person cannot be present during the procedure. The magnetic field can affect the operation of the device and provoke an exacerbation of heart disease.
• The presence of ferromagnetic implants, various electronic devices embedded in the patient's body (again, due to the danger of interaction with the magnetic field)
• Yelizarov devices used for severe violations of bone integrity.
• Ferromagnetic fragments in the body, which under the influence of a magnetic field can change their position.

Metallic hemostatic clips previously applied to the vessels will also cause failure to perform an MRI scan for safety purposes for the patient's health.

The relative contraindications include:

• The presence in the body or on its surface of metal fragments, metal-ceramic dentures and crowns, tattoos, implants of materials unknown to the patient, insulin pumps, nerve stimulants, prostheses simulating heart valves.
• Claustrophobia, in which examination is recommended in devices with an open circuit, in the presence of the patient's relatives and, if necessary, with the use of drugs that provide sedation or drug sleep.
• States in which a person can not be in a static position for a long time.
• Mental diseases, especially in the acute stage, convulsive syndrome, inadequate condition of the patient (for example, alcohol intoxication, fever, etc.).
• Severe heart failure.
• Severe condition of the patient and the condition requiring constant monitoring of the physiological systems.
• Severe renal and hepatic failure, hemolytic anemia, pregnancy (in the case of the introduction of contrast). The contrast agent is also not administered in case of hypersensitivity of the patient’s body to it.

Pregnancy is not a direct contraindication to an MRI of the sacral spine. However, many doctors do not recommend, unless absolutely necessary, undergo the procedure in the first trimester of pregnancy. This is due to the lack of information about the effect of the magnetic field on the emerging fetus.

Children's age is also not an obstacle for the survey. MRI is prescribed even for babies. If necessary, they even prescribe MRI with contrast, accurately calculating safe doses of contrast agents, depending on the age and weight of the child.

[5], [6]

Normal performance

A useful and important feature of magnetic resonance imaging is the rapid receipt of examination results, which are either sent to the attending physician or given to the patient in his hands. The latter provides further visits to a specialist who will help to correctly interpret the results of the study.

In the absence of spinal abnormalities, MRI images can be seen smooth vertebrae of the correct shape and size, intervertebral discs located in their place and having a standard height, joints without roughness and growths. The spinal cord is characterized by a clear structure, has no pathological distortions and neoplasms, which are clearly visible with the introduction of contrast.

In some pathologies, one doesn’t even need to be a specialist to understand what the MRI scan of the sacral spine shows. Here are some examples:

• fractures in the RT image will clearly show the fracture line, you can also note the deformation of the bones or the displacement of its parts relative to each other,
• if we are talking about a compression fracture, there will be no displacement, which means we are talking about the destruction of bones (a decrease in their strength observed in osteoporosis) or the spread of tumor processes into the bone structures (for example, metastases in a tumor diagnosed nearby),
• the tumors themselves are defined as separate spots of a light color (in contrast, they acquire a contrast color) in the area of soft tissues or spinal cord,
• It is possible to diagnose hernia of the spine if there are visible changes in the intervertebral disks in the picture: their displacement and protrusion, unequal height over the entire disk or reduction of the height of one of the intervertebral disks, rupture of the disc sheath (fibrous ring), narrowing of the spinal canal at the displacement of the disk.
• With osteochondrosis or weakness of the spinal muscles, there is a shift in the vertebrae themselves, in the first case their deformity (flattening) can also be seen.
• The cyst in the MRI images of the sacral spine has the appearance of a gray spot with clear edges and is often localized on the marginal segments of the tailbone.
• The spinal canal stenosis can be judged by the state of the spinal cord, which in the images is presented as a light band, which lies inside the spinal column. Crowding and curvature of the spinal cord are clearly visible against the background of the surrounding darker areas. But the bulging bright areas can talk about the development of tumor processes.

Despite the amount of information that can be obtained only by careful examination of MRI images of the sacral spine, a specialist should be engaged in deciphering the results of the examination. This will help to avoid not only unreasonable panic in case of misinterpretation of the results of an MRI scan, but also a risk of delaying treatment if it is dangerous for the patient if the patient ignores the warning signs and does not turn to a doctor. The human brain has such a feature that allows us to overlook what we don’t want to see and recognize. So often we ignore serious diseases only from the unwillingness to admit that we have them, and to be treated. But some diseases of the spine in the absence of treatment - this is a direct path to disability.

[7], [8], [9]

Complications after the procedure

Doctors say that the MRI procedure is absolutely safe, given the above contraindications, do not hide the presence of electronic devices and ferromagnetic implants in the body, and most importantly, listen to the requirements and advice of doctors. Doctors create all the conditions for the patient to be as comfortable as possible during the procedure, ranging from headphones with pleasant, relaxing music and ending with sedatives and painkillers.

With epilepsy and claustrophobia, the patient can be examined in an open-circuit apparatus, which helps to avoid complications of the existing disorders of the nervous system. The same examination can be offered to children. Relatives are allowed to attend the procedure as support.

The most unpleasant consequence after the MRI procedure without the use of contrast is fuzzy images, if a person moved while in a magnetic field. This happens when the proposed drugs are abandoned, which help to calm down or relieve pain, and also in those cases where the patient did not bother to visit the toilet or drank a lot of water the day before.

The side effects of MRI of the sacral spine are usually discussed in connection with the introduction of contrast. These substances, although considered safe, can cause allergic symptoms in some people (skin rashes, tissue swelling, itching, flushing, etc.). Sometimes patients may complain of dizziness and headaches, but this is usually the case when examining the brain or if not all metal objects were left outside the room (for example, it can be ordinary metal buttons).

The occurrence of side effects can be triggered by the concealment of renal failure during the examination with contrast. In this case, the contrast remains in the body longer and may cause a deterioration in the patient's well-being.

About the most dangerous complication usually occurs not after the procedure, but in cases where the patient ignores the pathological symptoms, refuses to be examined or for a long time delays the visit to the doctor, turning only when the treatment does not give positive results. This can be not only the cause of disability, but also the death of the patient (as is usually the case with oncology, if it is not treated at an early stage).

The disadvantage of magnetic resonance imaging is considered to be high cost compared to radiography. But then the harm from it is much less, despite the fact that the research itself is more informative and allows you to get a three-dimensional image of the organs.

The positive side of the MRI of the sacral spine or other departments or organs can also be considered the lack of need for special care after passing the examination. However, this is not a reason to give up on his results with the hand and no longer go to the doctor, if suddenly it seemed that everything was normal in the picture, or to self-medicate by self-diagnosing the picture. Only a specialist can correctly interpret the results of the examination and, if necessary, prescribe an effective treatment. Care after the MRI procedure consists in further professional care of your health.

[10], [11], [12], [13]