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Diseases of the musculoskeletal system include symptoms such as prolonged back pain, spasm of the back muscles, decreased mobility of the spine, swelling of soft tissues in the region of various parts of the spine, lameness, and muscle pain. Some ailments, such as ankylosing spondylitis or ankylosing spondylitis or ankylosing spondylitis, are difficult to treat and can make a person disabled. With osteochondrosis, working capacity usually decreases, but this is a disease that, with adequate therapy, gives a lasting positive effect. True, the prognosis here also depends on how timely the patient went to the hospital, as well as how correctly the diagnosis was made. Computed tomography or plain radiography can suspect inflammatory diseases of the joints of the spinal column – spondyloarthritis. For example, with sacroiliitis (inflammation of the ileosacral joints) only at the second stage of disease progression. While magnetic resonance imaging (MRI) of the sacroiliac joints is able to detect the disease at a very early stage.
The sacroiliac joints are located near the lower spine, below the lumbar spine and above the coccyx. They connect the sacrum to the pelvis. The sacrum is a triangular bone in the lower part of the spine, located in the center under the lumbar spine. While most of the bones of the vertebrae are movable, the sacrum is made up of five vertebrae that are fused together and do not move. The ilium are the two large bones that form the pelvis. As a result, the sacroiliac or ileosacral joints connect the spine to the pelvis. The sacroiliac bone is held together by strong ligaments.
There is relatively little movement in the ileosacral junctions. Typically, these joints have less than 4 degrees of rotation, which is approximately 2 mm. Most of the movement in the pelvis occurs either in the hips or in the lumbar spine. These joints must support the entire weight of the upper torso when the human body is upright, which in turn places enormous stress on them. They also serve as a cushioning structure. Since these joints help to support the upper body of a person on themselves, over time this can lead to wear of the cartilage of these sacroiliac joints with the development of serious diseases.
Dysfunction of the constituent sacroiliac joints is believed to cause pain in the back and legs. Pain in the legs can be especially severe and the person may feel the same way as with a serious illness – a hernia of the lumbar spine. Treatment for sacroiliac joint pain is usually non-surgical and focuses on restoring normal movement of the joint.
What is an MRI of the sacroiliac joints?
Magnetic resonance imaging of the sacroiliac joints is an absolutely painless and safe procedure for diagnosing inflammatory diseases of these joints. Peter Mansfield and Paul Lauterbur invented this method of research, for which they received the Nobel Prize in 2004. Its main difference is the fact that MRI does not contain harmful ionizing radiation for the human body. MRI does not use x-rays, but examines bone tissue, articular processes, adjacent soft tissues using magnetic fields. As a result, we get a high-quality high-contrast image, and with its help the doctor can make an accurate and quick diagnosis for the patient.
Sometimes the study is carried out using the introduction of contrast agents based on gadolinium, in order to conduct, if necessary, a more in-depth diagnosis.
Indications for an MRI study
Your doctor may order magnetic resonance imaging for the following conditions:
- pelvic injuries (suspected fracture) and post-traumatic changes;
- anomalies in the development of the pelvic bones;
- suspicions of the development of tumor neoplasms and in the presence of metastases in the pelvic bones;
- the presence of foreign bodies in the area of the iliac-sacral joints;
- inflammatory diseases of the joints (arthritis), including the joints of the lower extremities, especially the ankles, as well as psoriatic arthritis;
- excessive bone growths (osteophytes, exostoses);
- the presence of ankylosing spondylitis or its predisposition, including the presence of an HLA-B27 antigen in a patient;
- Crohn’s disease and ulcerative colitis with the presence of pain in the pelvic area.
MRI of the ileosacral joints is performed with:
- pain in the lower back, which may be aggravated by physical exertion, while sitting, at night, may radiate to the lower extremities or buttocks;
- the presence of subfebrile temperature, fever;
- sudden or persistent bouts of lameness;
- the presence of inflammatory changes in the pelvic bones or surrounding tissues;
- decreased flexibility of the spine.
MRI plays an important role in the early diagnosis of sacroiliitis – inflammation of the sacroiliac joints. It can also be used to predict the development of new syndesophytes. It is magnetic resonance imaging that is sensitive to assessing activity at relatively early stages of disease development; it is superior to CT scanning in detecting cartilage changes, bone erosion and subchondral bone changes, and in detecting bone marrow edema.
In established disease, MRI can detect pseudarthrosis, diverticulum associated with cauda equina syndrome, and spinal stenosis. MRI is considered mandatory for patients with neurological symptoms, both those who are in remission and those who have a negative trend after establishing the fact of spinal cord injury.
Contraindications for MRI of the sacroiliac joints
MRI is a fairly safe research method, but there are several relative and absolute contraindications to this examination.
Relative contraindications include: pregnancy in the first trimester, the presence of claustrophobia, overweight.
During the procedure, the patient must be in a special long tunnel of equipment, exclusively in an immovable state. For claustrophobic patients who experience fear in confined spaces, such a study may not bring good results, but only provoke an even greater attack of panic and anxiety. Therefore, medical staff may use sedatives or mild tranquilizers to relieve discomfort.
MRI of the sacroiliac joints during pregnancy should only be performed if there is a serious vital indication in the first trimester and if indicated in the second and third, if it is believed that the potential benefit of MRI outweighs the possible risks. Although there have been no large studies of the effect of magnetic tomography on the fetus, since it is forbidden to conduct experiments on embryos.
For obese patients who are overweight, it is not possible to perform an MRI examination for purely technical reasons. After all, the load capacity of the table and the size of the channel of the apparatus have their limitations. Depending on the type of device, patients weighing over 130-150 kilograms will not be able to undergo an MRI.
Absolute contraindications are the presence of metallic foreign bodies and medical devices in the body, the impossibility of MRI with contrast in patients allergic to gadolinium.
MRI of the sacroiliac joints is performed without any prior preparation. It is absolutely contraindicated to perform the procedure with contrast in patients with a history of allergy to gadolinium. This can provoke anaphylactic shock, which has serious consequences, especially with untimely and incorrect first aid.
If patients have metal and electronic objects, they are not allowed into the room with a magnetic tomograph. After all, this affects expensive equipment, the magnetic field and can worsen the state of human health. All jewelry must be left at home or removed immediately before entering the room with a tomograph. It is also forbidden to bring credit cards, hairpins, metal zippers, pocket knives or pens, items containing microchips. It is recommended to remove hearing aids and removable dental work, piercings.
It is forbidden to conduct an MRI study of the ileosacral joints in patients with pacemakers, artificial pacemakers or cardiac defibrillators. If it is not known whether foreign objects are present in the human body (for example, fragments of ammunition), he is advised to take an x-ray for clarification.
MRI technique
An MRI examination is performed in a special room that houses the MRI system or “scanner”. You will be escorted into the room by a medical officer and asked to lie down on a special slide-out table that will slowly slide out of the scanner. A typical scanner is open at both ends.
In general, you may need to use ear plugs or hearing protection when preparing for an MRI exam, because certain scanners may make loud noises when they are used. These loud noises are normal and should not be a concern.
If a study with a contrast agent is required during the examination, the radiologist controls the extension of the table from the scanner to introduce contrast.
The most important thing for the patient to do is to relax and lie still. Most MRI exams take between 15 and 45 minutes. You will be told in advance how long the scan will take. During the examination, the radiographer will be able to talk to you, hear you and observe you at any time. If the patient has any questions or a feeling of fear and anxiety, it is imperative to report this using a special signal bulb. When the procedure is complete, you may be asked to wait while the images are examined to determine if more images are needed for an accurate and correct diagnosis. After the scan, the patient has no restrictions and can safely perform their normal activities.
What does the study show?
Depending on what kind of disease the patient has, how long ago it has been developing, whether the sacroiliac joints are diagnosed with or without contrast, what imaging modes are used, you can see different things. Usually, the doctor sees the presence of edema, fatty bone degeneration, osteosclerotic changes in bone tissue, in the articular cartilage – the presence of subchondral sclerosis, perichondritis, cartilage destruction, the state of the joint space – narrowing, expansion, absence of it, are there signs of inflammation of the ligamentous apparatuses. The doctor will be able to see the joint effusion, foci of inflammation, fatty degeneration, degenerative changes, fusion of the articular surface of the bone – ankylosis.
With sacroiliitis, STIR (“short tau inversion recovery”) mode is often used. This means that when the doctor turns on this mode on the equipment, the scanner suppresses the fat signal, and thus improves the visualization of various pathologies. For example, detection of fatty degenerations of bone and connective tissues.
This helps to detect inflammation at the earliest stages of disease progression.
With the help of MRI of the sacroiliac joints, such an effective early diagnosis, the doctor will be able to make the correct diagnosis and start a complex of therapeutic and preventive procedures as early as possible.