Bone ultrasound

It is impossible to study the bone structure using ultrasound. However, ultrasound can be used to evaluate the bone surface and cortex. Targeted examination of the bone surface is performed in rheumatoid arthritis, trauma, and various infections. Marginal erosions and synovial ulcers are best detected by ultrasound.

Methodology for performing ultrasound examination of bones.

Longitudinal and transverse scanning should be performed perpendicular to the bone surface. Tissue Harmonic mode helps to visualize bone structure contours more clearly, identify bone fragments, protrusions and depressions. Panoramic scanning mode allows for large-scale bone structure imaging. These images are easier for clinicians to interpret, MRI-compatible slices can be obtained, and muscles and tendons can be assessed simultaneously.

Bone echo is normal.

Bone structures reflect the ultrasound beam, so only the bone surface is displayed, which looks like a bright hyperechoic line. Visualization of the periosteum is possible only if there are pathological changes.

Pathology of bone and periosteum.

Fractures. Small fractures or cracks can also be detected by ultrasound. The fracture zone looks like a discontinuity in the contours of the bone surface. Ultrasound angiography shows hypervascularization in the area of forming bone tissue. Ultrasound can be used to monitor fracture consolidation. Granulation tissue with abundant vascular reaction forms 2 weeks after the fracture. Then fibrous tissue with hyperechoic areas forms at this site. The hyperechoic zone gradually increases in size, the acoustic shadow intensifies. The absence of hypervascularization in the fracture zone, hypoechoic tissue in the fracture zone, and fluid are signs of poor fracture healing. This can lead to the formation of a false joint.

Degenerative changes. Degenerative changes are characterized by changes in bone tissue. In this case, the articular surface of the bone becomes uneven due to the appearance of marginal bone growths on it.

False joints. They are formed after incorrectly fused bone fractures. False joints of the hip are observed after osteosynthesis of closed fractures of the femoral diaphysis, if the operation was complicated by suppuration, osteomyelitis, if bone fragments were removed or sequestered, resulting in a bone defect. They look like a discontinuity in the contour along the bone with uneven contours and a distal acoustic shadow.

Erosions in osteomyelitis. In osteomyelitis, fluid contents can be detected in the periosteum as a hypoechoic strip on the cortical surface of the bone. In chronic osteomyelitis, the reaction from the periosteum is defined as a thickening of the periosteal plate.

Prostheses. Ultrasound examination after prosthetics with metal structures is the leading one in identifying periarticular complications due to the fact that MRI is impossible for most of these patients.

Acute complications after prosthetics include the occurrence of hematomas. The main complications - occurring in the late period of prosthetics - are infection and loosening of the joint. In an ultrasound examination, a specific sign of infection is the appearance of fluid around the artificial joint. Another sign can be considered stretching of the pseudocapsule of the joint.

Tumors. Radiography, CT, MRI and bone scintigraphy are methods widely used for diagnostics and staging of bone and cartilage tumors. Radiography is used for primary prediction of the histological form of the tumor (bone-forming, cartilage-forming, etc.). In turn, CT is most often used to diagnose tumors that are not detectable by radiography. MRI is the method of choice for staging sarcomas, lymphomas and benign tumors characterized by rapid growth. In some benign tumors accompanied by soft tissue edema, such as osteoblastoma, osteoid osteoma, chondroblastoma and eosinophilic granuloma, due to the complexity of the picture, it is difficult to assess the changes. Therefore, it is advisable to supplement MRI data with ultrasound examination. Tumor lesions of various structures of the musculoskeletal system are characterized by the presence of a soft tissue component, which is clearly visible on ultrasound as an additional formation "plus tissue"; a violation of the integrity of the bone structure and the presence of a large number of additional tumor vessels are also determined.

Osteogenic sarcoma. Osteogenic sarcoma is one of the most malignant primary bone tumors. The incidence of this tumor among primary skeletal tumors reaches 85%. Children and young adults are more susceptible to the disease. Clinically, it manifests itself as pain that increases as the tumor grows. Limitation of joint mobility also increases rapidly. The metaphyseal sections of long tubular bones (mainly the femur and tibia) are predominantly affected. Radiologically, the tumor is manifested by the presence of a "visor" at the border of the external defect of the cortical bone layer and the extraosseous component of the tumor in the form of an osteophyte. The symptom of "needle spicules" characterizes the spread of the tumor beyond the bone. In an ultrasound examination, the tumor is manifested by a local thickening of the bone with a violation of the cortical layer and the presence of hyperechoic inclusions in the central parts of the tumor with a pronounced distal acoustic effect. Deformed tumor vessels are usually detected along the periphery of the formation.

Chondrosarcoma. The frequency of chondrosarcomas among primary malignant bone tumors is up to 16% and ranks second in frequency after osteosarcoma. The disease occurs most often at the age of 40-50 years. The most common localizations are the pelvic bones, ribs, sternum, scapula, proximal femur. Clinically manifested by moderate pain with significant tumor sizes. They are characterized by slow growth. Radiologically difficult to diagnose in the early stages, later detected due to calcification in the central parts of the tumor.

Ultrasound examination reveals it as a large formation with lumpy contours, decreased echogenicity, with microcalcifications in the central sections and feeding deformed tumor vessels. Treatment of chondrosarcomas is surgical.

Fibrosarcoma. The incidence of fibrosarcomas is up to 6%. The age of patients ranges from 20 to 40 years. Almost a quarter of all tumors are localized in the distal metaphysis of the femur, less often in the proximal part of the tibia.

Clinically manifested by low-intensity intermittent pain. As a rule, the tumor is painful to palpation, immobile in relation to the bone, and tuberous. Radiologically, it is characterized by the presence of an eccentrically located lesion with unclear contours, the absence of a zone of sclerosis and calcareous deposits. Sometimes there is a periosteal reaction. Ultrasound characteristics are similar to chondrosarcoma.

Due to the large extent of the tumor, it is recommended to use panoramic scanning mode for a more accurate assessment of its localization and relationship with underlying structures.

Unlike malignant tumors, benign tumors have clear, fairly even contours, the preservation of the cortical bone layer and an organized nature of the vessels. The most typical benign tumors include osteoma, osteoid osteoma, osteoblastoma, chondroma, chondroblastoma, chondromyxoid fibroma, osteoblastoclastoma, desmoid fibroma, etc.