Magnetic resonance imaging (MRI) of joints

Previous Next In diagnostic centers in St. Petersburg, you can examine the knee joint using MRI and ultrasound, but which of them will better show this or that pathology is the topic of this article. Almost a third of the population suffers from joint diseases. Diseases of the musculoskeletal system affect absolutely all age categories, from children to mature and elderly people. Most often, knee joint damage occurs for the following reasons:

• injuries during sports and road accidents;
• degenerative joint diseases.

• MRI
• Ultrasound

MRI tomograph:

Siemens Magnetom C

Type:

Open (expert class)

What's included in the price:

Diagnostics, interpretation of images, written report from a radiologist, recording of tomograms on CD + free consultation with a neurologist or orthopedist after an MRI of the spine or joint

Ultrasound machine

SAMSUNG SONOACE R7

Class:

Expert (installation year 2019)

What's included in the price:

Diagnostics, interpretation of images, written diagnostic report

Ultrasound or MRI of the knee - what to choose?

With injuries and pain in the knee, the patient usually comes to see an orthopedic traumatologist, who issues a referral for an ultrasound or MRI of the knee joint. In most cases, adult patients are prescribed a tomography of the knee rather than an ultrasound or x-ray, since the informative and diagnostic value of an MRI of the knee is higher. Magnetic resonance imaging better and more accurately visualizes bone and soft tissue structures - ligaments, joint capsule, various cartilage discs, menisci and muscles. However, ultrasound of the knee joint also has its advantages:

• this examination allows you to see the joint in motion;
• Ultrasound is a priority method for examining joints in newborns and infants.

The final decision on the advisability of a particular type of diagnosis is usually made by the attending physician, based on the primary diagnosis and the purposes of the scan. If the patient himself has decided on the need to examine the knee for preventive purposes, it is better to start his diagnostic journey with a more comprehensive MRI of the knee joint.

What is the difference between MRI and ultrasound of the knee joint?

Ultrasound and MRI of the knee joint are two fundamentally different examinations. On an ultrasound, the image is visualized by treating the area being diagnosed with ultrasonic waves. Magnetic resonance imaging is a method of in-depth examination of a joint with a detailed display of all muscle-bone tissues using the effect of nuclear magnetic resonance. During an MRI, the patient is placed in a tomograph where a powerful magnetic field is created. Then the radio frequency pulse sensors are turned on. Under the influence of a magnetic field and RF, the protons of hydrogen atoms in the body's cells begin to vibrate, and this resonance is picked up by the device's computer. It processes the received data and converts it into digital three-dimensional images. This is how a series of MRI images of the knee appear on the installation screen. Since soft tissue cells contain a lot of water, MRI of the knee shows the condition of ligaments, menisci, nerve endings, and tendons better than ultrasound. However, both ultrasound and MRI of the joint do not visualize bone well. They are best examined using x-rays or computed tomography.

How long does it take to do an MRI of the knee?

The duration of the diagnostic procedure ranges from 25 to 40 minutes and depends on the characteristics of the unit. Contrasting increases time costs.

The MRI result will be ready within an hour. The patient receives a specialist’s report and a disk with a recording of the scan. You can open the electronic media using a special program that is installed on computers in all major medical centers. Images can be easily sent electronically to any clinic in the world and uploaded to a cloud digital server. At the patient’s request, illustrative photographs are printed onto film for an additional fee.

Cost difference

The affordable price of joint ultrasound allows all patients to undergo examination. You just need to make an appointment for a scan at a time convenient for you. MRI of the knee joint is a more expensive test. However, the information content of MRI of joints is certainly higher than ultrasound examination.

How to sign up for diagnostics?

You can book a time for any type of scanning through the consulting service of the “Unified Recording Center” in St. Petersburg. Choose a procedure, compare medical institutions by ratings, locations and prices, and reserve an appointment. The telephone number for registration is located at the top of each page of the portal. Book a test and receive a special discount from the service for the selected type of screening.

When is MRI of the knee better than ultrasound?

Any pathology of the structures of the knee joint can be clearly seen on MRI, which in its diagnostic value is superior to both radiography and ultrasound. X-rays do not show soft tissues, and very often a knee injury is associated with damage to these tissues. Tomography visualizes occult stress fractures much better than CT, since swelling is clearly visible, which does not appear at all on x-rays. An ultrasound of the knee cannot show the ligaments and cartilaginous structures with the same level of detail and does not show the bones very well. If you have any pain in your knee or have suffered an injury, it is better to immediately go to an orthopedist or emergency room for a magnetic resonance imaging scan without wasting time. It will help you accurately and quickly identify:

• all hidden fractures, dislocation and subluxation;
• ruptures of ligaments, tendons and muscles;
• damage to soft tissues, which are characterized by inflammation;
• some systemic diseases.

The tomography procedure does not require any special preparation. You just need to choose a diagnostic center and sign up for an examination in advance. The procedure itself will take 20-30 minutes of your time, and another 30-40 minutes of waiting will be required to receive the results of the study - a series of images and an expert opinion from the doctor. Unfortunately, if you do not have medical knowledge, it will be difficult for you to understand what exactly the radiologist wrote in the conclusion, so the RIORIT clinic offers a free express consultation after an MRI of the joints with an orthopedist who will explain what was revealed during the examination in a simple way, in a language that the patient can understand and recommend therapy if necessary.

Examination of a patient with arthrosis of the knee joint - gonarthrosis

What examinations should a patient undergo with arthrosis of the knee joint - gonarthrosis?

Nowadays, to clarify the diagnosis of gonarthrosis, they most often resort to blood tests, radiography and magnetic resonance or computed tomography.

Clinical blood test

For this test, blood is taken from a finger prick. With arthrosis, a clinical blood test, as a rule, does not show any specific changes. Only in some cases may there be a very slight increase in the erythrocyte sedimentation rate (ESR or ROE): up to 20 mm.

On the contrary, a significant increase in ESR (higher) in combination with night pain in the joint should prompt us to think about the possible rheumatic, inflammatory origin of these pains.

If the patient also has an increased number of leukocytes, then this circumstance confirms the presence of some kind of infectious-inflammatory process in the body, which affects the joints in particular. However, in any case, a clinical blood test does not give clear answers; it only indicates trends and narrows the circle of diagnostic search.

Blood test for inflammatory indicators

When performing this test, blood is taken from a vein, and always on an empty stomach. Such a blood test can provide significant assistance to the doctor in making a differential diagnosis of joint damage: arthrosis or arthritis?

Thus, with rheumatic diseases (arthritis), the level of so-called inflammatory markers in the blood significantly increases: C-reactive protein, seromucoid, ACCP. With arthrosis, these indicators, on the contrary, remain normal.

True, there are cases when certain types of arthritis also do not lead to a significant change in indicators. But still, such an analysis, as a rule, helps to make a clear distinction between inflammatory and metabolic-dystrophic diseases of the joints (between arthritis and arthrosis).

Attention! In cases where we detect “inflammatory” changes in blood parameters taken from a finger or from a vein in a patient with arthrosis, we should be wary - after all, arthrosis does not cause any changes in the tests.

And if inflammation indicators are elevated, there is a high probability that we are dealing not with arthrosis, but with arthritis. Then it is necessary to continue examining the patient until the diagnosis is finally confirmed or refuted.

Another indicator that you need to pay attention to is the level of uric acid in the blood. If uric acid levels are elevated, this may indicate that the knee inflammation is caused by gouty arthritis.

X-ray of joints

Radiography is the most common and one of the most important methods for diagnosing arthrosis. In most cases, even the stage of arthrosis is established solely on the basis of an x-ray: after all, x-rays clearly show changes in the shape of the joint and bone deformations; compaction of the bones under the damaged cartilage is noticeable and osteophytes (“spikes”) are clearly visible. In addition, an x-ray can be used to judge the width of the joint space, that is, the distance between the articulating bones.

But X-ray examination has a serious disadvantage: only bones are captured on the X-ray image. But we will not be able to see the soft tissues of the joint (cartilage, meniscus, joint capsule, etc.) on an x-ray. Therefore, using only X-rays, we will not be able to assess with absolute accuracy the degree of damage to the articular cartilage, meniscus and joint capsule.

Fortunately, in recent years, magnetic tomography has become increasingly widespread.

Magnetic resonance imaging - MRI

The research uses, as the name implies, magnetic waves. They are able to reflect the smallest details of the joint in the resulting image. The magnetic resonance imaging method is very accurate: it helps to detect the earliest changes in cartilage tissue (which are not yet visible on a regular x-ray), and also allows you to see damage to the menisci and ligaments of the knee.

Therefore, I often recommend that my patients, in addition to X-rays, carry out magnetic resonance imaging of the joint to clarify the diagnosis.

Although here one thing must be kept in mind. Usually, having received tomographic examination data, doctors are so confident in their infallibility that they do not consider it necessary to double-check the research results and conduct a personal examination of the patient. It is not right.

Firstly, the specialist in the tomography department who interprets the images is also a person and can make mistakes. In particular, I have repeatedly encountered situations where ordinary age-related changes or other diseases similar in picture to arthrosis were mistaken for arthrosis. This happens very often.

Secondly, arthrosis detected on a tomogram may not be the patient’s only disease. And the main cause of pain, even in the presence of arthrosis, may be another disease: for example, arthritis or meniscus damage. And these diseases will need to be treated first (in parallel with the treatment of arthrosis).

In general, even after receiving a “full package” of patient examinations (X-rays, tests, tomogram), the doctor must still first conduct a personal examination of the patient and only then prescribe treatment.

Computed tomography - CT

In addition to magnetic resonance imaging, some hospitals still use computed tomography. In essence, computed tomography is the most advanced version of x-ray: computed tomography uses the same x-rays as in a conventional x-ray examination. The only difference is that with computed tomography, the tomograph “shreds” the joint with a series of x-rays, and as a result, the image is more voluminous and detailed than with x-rays. But it is still an order of magnitude inferior in terms of information content to a magnetic resonance imaging scan. Therefore, CT should be used only in cases where for some reason we cannot perform magnetic resonance imaging on the patient (for example, if the patient has a pacemaker, a pacemaker, and magnetic waves can disrupt its operation).

Ultrasound of joints (ultrasound examination)

In recent years, ultrasound has been actively used to diagnose joint diseases. After all, ultrasound, like magnetic resonance imaging, allows you to see changes in the soft tissues of the joint - for example, using ultrasound you can detect thinning of cartilage tissue in arthrosis or an increase in the amount of joint fluid in arthritis; it is possible to detect damage to the menisci in the knee, etc. However, the method has a significant drawback - it is very subjective, and the data obtained depend entirely on the qualifications of the specialist conducting the study.

Of course, this does not mean that joint ultrasound specialists are always wrong. But even if such an accurate method as tomography leaves room for discrepancies in the interpretation of the data obtained and disagreements in the diagnosis, then the data from ultrasound examination of joints raises questions especially often.

Therefore, I am not inclined to blindly trust the diagnosis obtained by ultrasound of the joints, and I always double-check such conclusions (through a personal examination of the patient, as well as using X-rays or magnetic resonance imaging).

***

Article by Dr. Evdokimenko© for the book “Pain in the Legs”, published in 2004. Edited 2011. All rights reserved.

READ MORE:

• Arthrosis of the knee joint (gonarthrosis). Symptoms, stages.
• What is arthrosis of the knee joint (gonarthrosis) often confused with?
• Causes of arthrosis of the knee joint (gonarthrosis)
• Changes in the knee joint with gonarthrosis
• Treatment of arthrosis of the knee joint (gonarthrosis)
• The best exercises for the treatment of gonarthrosis

Chapters from other books by Dr. Evdokimenko

Disadvantages of MRI of the knee joint

• MRI of the knee joint has a number of severe limitations. Tomography is contraindicated if the patient’s body has metal-containing implants, for example: a steel prosthesis, electronic pacemakers - neuro- or cardiac pacemakers.
• Disadvantages of MRI of the knee include the length of the procedure. It can last 30 minutes, and if the pathology is serious and contrast enhancement is required, then the scanning duration reaches 40-60 minutes.
• During the tomography of the knee joint, any movement is prohibited, as this will negatively affect the clarity and accuracy of the MRI images. Therefore, young children have to undergo MRI of the knee under anesthesia.
• MRI of the knee joint using a closed tomograph can be difficult for people suffering from claustrophobia, epileptic seizures and panic attacks.

MRI or ultrasound of the knee: advantages and disadvantages

The main advantage of the first type of scanning is its maximum information content. As a result of the procedure, numerous high-resolution images are obtained that can be zoomed in, rotated at the desired angle, or arranged into a multidimensional projection. Bone structures do not interfere with the examination and do not block hard-to-reach areas. The safety of the study is based on the use of a magnetic field, which has nothing to do with X-rays.

The disadvantage of the tomographic method is the presence of such a contraindication as metal objects implanted into the body. If the body contains ferromagnetic objects of artificial origin (implants, prostheses, electronic stimulators), examination using an MRI device is impossible due to the high probability of damage to both the device itself and harm to the patient’s health. Under the influence of a powerful field, the metal is greatly deformed, heated and displaced in living tissues.

Sound waves are absolutely safe for humans, but do not penetrate well through dense, bone formations or fatty layers. The study will be of little information if the joint area is completely immobilized, and the stiffness of the lower limb does not allow examining the pathological area from different sides. A high degree of obesity also reduces the accuracy of diagnosis. In this case, research methods are designed to complement each other, so they are often prescribed together or one after another.

When is a knee ultrasound better than an MRI?

For a doctor, the main diagnostic advantage of knee ultrasound is the ability to view the knee as it moves. During an ultrasound scan, the diagnostician may ask the patient to change the position of the knee and evaluate how the anatomical features of the knee joint change in a person in motion. Another significant advantage of this technique is that scanning and tracking of the cause of the disease takes place in real time. This means that the doctor can examine the problem area in more detail, spending more time on it, or in case of a unclear image, try to approach the problem from the other side. Unlike an x-ray, where the image may turn out unclear and therefore it will be difficult for the doctor to make a correct diagnosis and additional examination of the body will be required, ultrasound diagnosis of the knee can be quickly corrected during the scan. Ultrasound is the preferred method for examining the knee joint in young children. The fact is that MRI requires complete immobility of the patient, which is difficult to achieve in newborns and children under 5 years of age. Therefore, MRI of the knee in young children has to be performed under deep sedation, which is an undesirable burden on the child’s body. But an ultrasound of a child’s knee does not require any anesthesia and is very informative. Unlike MRI, ultrasound can be done on people with implants, prostheses, pacemakers and other metal-containing components of the body. The cost of joint ultrasound can also be counted as an advantage, since it is not high compared to MRI. Ultrasound of the knee joint does not require special preparation, except for the recommendation to remove hair from the area being examined for a smoother glide of the sensor. The knee scanning procedure takes place in a lying position. The patient lies on his back on a couch previously covered with a disposable diaper. The doctor applies a special gel to the sensor, and the same gel is applied to the patient’s knee joint. Next, the doctor moves the sensor sequentially in different directions along the front, side, and back sides of the knee. The back of the knee joint is examined while lying on the stomach. The procedure lasts approximately 15 minutes. In complex cases, the examination time may increase to 30 minutes. Ultrasound data of the knee joint are given to the patient with a doctor’s report immediately after the scan.

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