Ultrasound and Shear Wave Elastography Assessment of Entheses in Psoriatic Arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory disease that frequently involves the entheses, where tendons, ligaments, and fascia insert into bone. Early detection of enthesitis is important for disease assessment and management. Conventional musculoskeletal ultrasonography, including grayscale and Power Doppler ultrasonography, can identify structural and inflammatory changes, while shear wave elastography (SWE) provides quantitative information about tissue stiffness. This observational cross-sectional study aims to evaluate bilateral enthesis sites using grayscale ultrasonography, Power Doppler ultrasonography, and SWE in patients with PsA and age- and sex-matched healthy controls. The study will investigate the relationship between imaging findings and clinical disease characteristics, disease activity, functional status, and laboratory parameters. The findings may improve understanding of enthesis involvement in PsA and clarify the potential role of multimodal ultrasound assessment, including SWE, in disease evaluation.

Inclusion Criteria: * Psoriatic arthritis group: 1. Adults aged 18 years or older. 2. Diagnosis of psoriatic arthritis according to the Classification Criteria for Psoriatic Arthritis (CASPAR). 3. Ability to provide written informed consent. 4. Willingness to undergo clinical assessment, laboratory evaluation, grayscale ultrasonography, Power Doppler ultrasonography, and shear wave elastography. * Healthy control group: 1. Adults aged 18 years or older. 2. No history or diagnosis of inflammatory rheumatic disease. 3. Age- and sex-matched to the psoriatic arthritis group. 4. Ability to provide written informed consent. 5. Willingness to undergo grayscale ultrasonography, Power Doppler ultrasonography, and shear wave elastography. Exclusion Criteria: * Psoriatic arthritis group: 1. Age younger than 18 years. 2. Refusal to participate in the study or inability/unwillingness to provide written informed consent. 3. Inability to complete the clinical or ultrasonographic assessments. 4. History of surgery, fracture, major trauma, or tendon rupture involving the enthesis sites to be evaluated. 5. Local corticosteroid injection, platelet-rich plasma (PRP), prolotherapy, or other local interventional treatment at the enthesis sites to be evaluated within the previous 3 months. 6. Presence of acute traumatic tendinopathy, active soft tissue infection, open wound, or ulcer at the enthesis sites to be evaluated. 7. Diagnosis of another inflammatory rheumatic disease or connective tissue disease other than psoriatic arthritis. 8. Active infection, active malignancy, or severe systemic disease that may interfere with study assessments. * Healthy control group: 1. Age younger than 18 years. 2. Refusal to participate in the study or inability/unwillingness to provide written informed consent. 3. Inability to complete the clinical or ultrasonographic assessments. 4. History or diagnosis of psoriasis, psoriatic arthritis, or any other inflammatory rheumatic disease. 5. History of surgery, fracture, major trauma, or tendon rupture involving the enthesis sites to be evaluated. 6. Local corticosteroid injection, platelet-rich plasma (PRP), prolotherapy, or other local interventional treatment at the enthesis sites to be evaluated within the previous 3 months. 7. Presence of acute traumatic tendinopathy, active soft tissue infection, open wound, or ulcer at the enthesis sites to be evaluated. 8. Active infection, active malignancy, or severe systemic disease that may interfere with study assessments.