Diagnostic imaging of joints

Infectious and neuropathic joint lesions

Contrast-enhanced MRI with fat suppression is the gold standard in the early diagnosis of septic arthritis. Delaying diagnosis leads to cartilage destruction by bacterial and neutrophil enzymes.

• Radiography is uninformative in the early stages. Late stages are characterized by joint space narrowing and bone destruction.
• Ultrasound is well-suited for superficial joints: it visualizes effusion, thickening, and hypervascularization of the synovial membrane.
• MRI findings: the key criterion is intense contrast enhancement of the thickened synovium (synovial enhancement) combined with effusion.

In diabetic osteoarthropathy, the pathology is most frequently localized in the tarsometatarsal joints. Radiographs show multiple bone fragmentation, while MRI (in PD fat-sat and STIR sequences) reveals destruction and bone marrow edema without signs of abscess formation.

Ankylosing spondylitis (Bekhterev's disease)

Specific spinal changes in ankylosing spondylitis (AS) directly depend on the stage of the process:

1. Early manifestations (MRI): bone marrow edema in the corners of the vertebral bodies and costovertebral joints (costovertebral joints). Unlike degenerative diseases, edema in AS is oriented craniocaudally and is not accompanied by dehydration or a decrease in intervertebral disc height.
2. Proliferation (CT and X-ray): formation of syndesmophytes — thin vertical bone bridges developing at the sites of vertebral corner sclerosis (Romanus lesions, Romanus lesions).
3. Ankylosis: fusion of the facet joints, anterior parts of the vertebral bodies, and sacroiliac joints, forming the radiographic pattern of a «bamboo spine» (bamboo spine).

A rigid spine is vulnerable to fractures against the background of concurrent osteopenia. Inflammatory foci (Andersson lesion, Andersson lesion) can occur at sites of preserved local mobility, which, due to irregular contours, are easily confused with spondylodiscitis.

Injuries and pathologies of the upper extremity joints

Diagnostic imaging of peripheral joints requires a deep understanding of ligamentous anatomy.

• In the wrist joint, MR arthrography or digital subtraction arthrography is often used to detect ligament tears. Contrast leakage through the lunotriquetral joint (lunotriquetral joint) directly indicates a tear. Damage to the scapholunate ligament (scapholunate ligament) leads to diastasis, subchondral cyst formation, and early osteoarthritis.
• Extensor tendons are divided into 6 groups with separate synovial sheaths. Involvement of group I causes de Quervain's tenosynovitis (de Quervain's tenosynovitis), and inflammation of the extensor carpi ulnaris causes erosion of the ulnar styloid process.
• In the elbow joint, MRI helps evaluate acute and chronic injuries of the ulnar collateral ligament. In osteochondritis dissecans of the humeral capitellum, the absence of contrast extravasation beneath the affected area confirms that the cartilage is intact and the lesion is stable. Early osteoarthritis is manifested on CT by olecranon osteophytes and radiolucent loose bodies.

Class and exam questions

What else to study on this topic

• Anatomy of the triangular fibrocartilage complex (TFC complex) and its role in distal radioulnar joint stabilization.
• Specifics of septic arthritis in intravenous drug users (typical involvement of the sternoclavicular joint).
• Structure of the carpal tunnel, flexor and extensor retinacula (Retinacula).
• Technique and features of CT and MR arthrography of large joints.
• Biomechanics of the intercalated segment of the hand.

Other topics in the "Musculoskeletal System" section

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