Tendon ultrasound

The ultrasound method competes with MRI in diagnosing tendon pathology. The main advantage of ultrasound is: high spatial resolution when scanning soft tissue structures and the possibility of dynamic research in real time.

Ultrasound technique of tendons.

The choice of 7.5 MHz frequency of the linear sensor is optimal for examining almost all tendons. For superficial tendons, it is recommended to use higher frequencies - 12-15 MHz. The examination should begin with the identification of the bone structure - the area of tendon attachment. To search for small tendons, the examination can begin with cross-sections. Tendon images are obtained in both cross-sections and longitudinal sections. To compare the results, it is necessary to examine the contralateral side as well. Some change in the scanning angle can lead to a change in the echogenicity of the scanned tendon due to the resulting anisotropy effect, so it is important that the tendon under examination is at an angle of 90 degrees to the ultrasound beam. The panoramic scanning mode provides visualization of the tendon along its entire length.

The echo picture of the tendons is normal.

Tendons consist of long collagen fibers. Some tendons have a synovial sheath around them. Between the tendon and the sheath there is a small amount of synovial fluid, which facilitates the sliding of the tendon in the synovial sheath. Such tendons are found in particularly mobile joints (hand, wrist, ankle). The presence of such a sheath makes it possible to conduct a good ultrasound assessment of the tendon. For example, when examining the shoulder, the tendon of the long head of the biceps muscle, which is surrounded by a synovial sheath, is well differentiated. Tendons without a synovial sheath are more difficult to examine using the ultrasound method. They are surrounded by connective tissue - paratenon and always form tendon bags (bursae) at the site of their attachment. Using the ultrasound method, it is possible to examine large tendons: Achilles, plantar, proximal gastrocnemius and semimembranosus. Whereas smaller tendons are difficult to image with ultrasound. In longitudinal ultrasound scanning, tendons appear as linear fibrillar, alternating hyper- and hypoechoic structures. Tissue harmonic mode more clearly outlines the contours and fibrous structure of tendons. Tendons with a synovial sheath are surrounded by a hypoechoic "halo", which normally always contains a small amount of fluid. Tendons without a synovial sheath are surrounded by hyperechoic connective tissue, forming the peritendinous space.

The course of tendon fibers in the attachment area is not always perpendicular to the ultrasound beam and therefore, due to the anisotropy effect, this zone appears hypoechoic. In transverse scanning, some tendons have a rounded shape, for example, the tendon of the long head of the biceps or an oval shape - the Achilles tendon. and also a square shape - the plantar tendon. In MR tomograms, tendons in T1- and T2-weighted images have low intensity.

Ultrasound signs of tendon pathology.

Strains or tears most often occur at the junction of the tendon and muscle or at the attachment of the tendon to the bone.

Stretching. With stretching, there is no violation of the integrity of the tendon fibers. However, at the site of stretching, the tendon may be thickened due to edema. Local soreness is determined by palpation, and sharp pain is detected with passive tension. Discomfort when moving the joint. Often, muscle spasm occurs in response to stretching. Treatment consists of limiting mobility and load, in some cases - immobilization; painkillers, muscle relaxants and anti-inflammatory drugs are used.

Partial tendon rupture. Partial ruptures are characterized by incomplete disruption of the integrity of the tendon fibers with significant loss of function of the corresponding muscle. The echographic picture depends on the type of tendon and the presence or absence of a synovial membrane.

Tendons with a synovial sheath. The tendon of the long head of the biceps is most often damaged. Predisposing factors are rotator cuff tendinitis and inflammation of the tendon of the long head of the biceps. At the site of the rupture, there is a partial disruption of the fibrillar structure of the tendon with the formation of an anechoic defect - synovial effusion around the damaged tendon.

Tendons without a synovial sheath. Partial rupture of tendons without a synovial sheath leads to local thickening of the tendon with disruption of the tendon contours and fibrillar structure at the site of the defect. The rupture site is filled with fluid or fatty tissue. The approach to treatment is differentiated, depending on the type of tendon, its degree of significance and activity. Long-term immobilization is recommended.

Complete rupture of tendons. Complete rupture of a tendon is accompanied by a complete loss of function of the corresponding muscle and a complete disruption of the integrity of the fibers with retraction of the proximal part, which is manifested by a local bulge on the surface and a depression at the site of the rupture. Treatment consists of urgent restoration of the integrity of the tendon.

Tendons with a synovial sheath. In the case of a complete rupture, the fibrillar structure of the tendon is disrupted, and tendon fibers are completely absent at the site of the rupture. The tendon sheath at the site of the rupture is filled with hypoechoic synovial fluid and blood, which in the distal sections surround the contracted fibers of the ruptured tendon.

Tendons without a synovial sheath. The torn ends of tendons without a synovial sheath contract, their fibrillar structure is completely disrupted, the defect is filled with blood in the case of a rotator cuff rupture or with fatty tissue in the case of an Achilles tendon rupture.

Treatment consists of urgent restoration of the tendon integrity, before the development of spasm and shortening of the tendon-muscle part. After surgical correction, immobilization is performed. The most typical and frequent injuries are considered to be ruptures of the rotator cuff and Achilles tendons.

Acute tendinitis and tenosynovitis.

Tendons with a synovial sheath. Tendons with a synovial sheath may thicken, but their echogenicity does not change. Tendinitis is usually accompanied by tenosynovitis - an increase in the amount of synovial fluid surrounding the tendon. Fluid in the tendon sheath is better detected on cross-sections, since compression of the tendon during longitudinal scanning can displace the synovial fluid to the lateral sections. In the energy mapping mode, an increase in the number of vessels is noted along the fibers of the inflamed tendon. Ultrasound examination helps visualize the tendon when injecting corticosteroids into the synovial sheath.

Tendons without synovial sheath. Tendons without synovial sheath in acute tendinitis look thickened, their echogenicity decreases focally or diffusely. Contours may be unclear. Echostructure is non-uniform, with small hypoechoic areas simulating micro-tears. Blood flow along the tendon fibers in the acute phase increases sharply. Tendinitis at the site of tendon attachment to bone is one of the most common pathologies. The most typical include: "tennis elbow", "jumper's knee", "golfer's elbow". Accordingly, the following are affected: the tendon of the radial extensor of the wrist, the tendon of the patella, the tendons of the flexors of the wrist.

Chronic tendonitis.

Tendons with a synovial sheath. Chronic tendinitis usually shows a thickening of the synovial sheath, which can be either hypo- or hyperechoic. There may be a small amount of fluid in the tendon sheath.

Tendons without synovial sheath. Tendons without synovial sheath appear thickened, usually with heterogeneous echostructure. Calcifications may appear at the tendon attachment site, which are also found along the tendon fibers. Calcifications most often occur in the rotator cuff tendons, patellar tendon, and Achilles tendon.

Calcific tendinitis.

Metabolic and systemic diseases can induce the development of calcific tendinitis. It most often occurs in the tendons of the upper limb. Echographically, the appearance of small hyperechoic point inclusions along the tendon fibers is noted, which may also appear thickened.

Tendon subluxation.

Subluxation of the long head of the biceps tendon is a rare finding that is easy to diagnose using ultrasound.

The absence of the tendon in the intertubercular groove is easily detected by transverse scanning in the neutral position of the shoulder. The tendon is displaced under the tendon of the subscapularis muscle. Subluxation most often accompanies rotator cuff ruptures. This pathology is best manifested during examination from a position for assessing the tendon of the subscapularis muscle. Subluxation of the peroneal tendons is most often associated with chronic ankle trauma in athletes, football players, gymnasts, dancers. Passive flexion of the foot and its inward rotation provoke subluxation of the tendons. As a rule, this is associated with a rupture or ruptures of the retainer of the lateral group of the peroneal tendons.

Ganglion cysts.

One of the common pathologies of the synovial membrane of tendons is a hernia-like bulge due to a defect in the fibrous membrane of the tendon. In most cases, ganglia are found on the hands. The resulting ganglion on the tendon is filled with fluid produced by the synovial membrane. Due to this, the ganglion can increase in volume. A characteristic ultrasound sign of a ganglion is a direct connection with the tendon. Ganglia have an oval or round shape, enclosed in a capsule. The contents may have different consistencies depending on the duration of the disease. Treatment involves excision of the ganglia.