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.
Psoriatic arthritis (PsA) is a chronic inflammatory musculoskeletal disease associated with psoriasis and characterized by peripheral arthritis, axial involvement, dactylitis, and enthesitis. Enthesitis, defined as inflammation at the insertion sites of tendons, ligaments, fascia, or joint capsules into bone, is considered one of the hallmark manifestations of PsA and may contribute substantially to pain, functional impairment, and structural damage. Early and accurate assessment of enthesitis is essential for disease evaluation and management. However, clinical examination alone has limited sensitivity for detecting subclinical or early entheseal inflammation. Musculoskeletal ultrasonography has become an important imaging modality for the evaluation of enthesitis. Grayscale ultrasonography allows assessment of structural abnormalities such as tendon thickening, hypoechogenicity, calcifications, enthesophytes, erosions, and bursitis, while Power Doppler ultrasonography enables the detection of active vascularization associated with ongoing inflammation. In addition, shear wave elastography (SWE) is an ultrasound-based technique that quantitatively measures tissue stiffness and may identify biomechanical changes that are not detectable with conventional ultrasonography. Combining grayscale ultrasonography, Power Doppler ultrasonography, and SWE may provide a more comprehensive evaluation of entheseal involvement in PsA. This is a single-center, observational, cross-sectional study conducted at Marmara University Pendik Education and Research Hospital. The study will include patients with psoriatic arthritis fulfilling the CASPAR classification criteria and age- and sex-matched healthy controls. Bilateral enthesis sites included in the Madrid Sonography Enthesitis Index (MASEI) will be evaluated using grayscale ultrasonography, Power Doppler ultrasonography, and shear wave elastography. Clinical assessments will include disease activity indices, patient-reported outcome measures, functional assessments, and laboratory inflammatory markers. The primary objective of the study is to compare ultrasonographic and elastographic findings between patients with PsA and healthy controls. Secondary objectives are to investigate the relationships between imaging findings and disease activity, disease duration, clinical characteristics, functional status, and laboratory parameters. The study aims to determine the potential contribution of shear wave elastography, in combination with conventional ultrasonography and Power Doppler imaging, to the assessment of enthesitis in patients with psoriatic arthritis.
Study Type
OBSERVATIONAL
Enrollment
60
Participants will undergo standardized musculoskeletal ultrasound evaluation of bilateral enthesis sites, including grayscale ultrasonography, Power Doppler ultrasonography, and shear wave elastography. The imaging protocol will be identical for both the psoriatic arthritis and healthy control groups. No therapeutic intervention will be administered as part of the study.
Total Madrid Sonography Enthesitis Index (MASEI) Score
Comparison of the total Madrid Sonography Enthesitis Index (MASEI) score between patients with psoriatic arthritis and healthy controls. The total MASEI score is calculated by combining the predefined grayscale ultrasonography and Power Doppler findings assessed at six bilateral enthesis sites: the plantar fascia, Achilles tendon, proximal and distal patellar tendon, quadriceps tendon, and triceps tendon insertions. The total score ranges from 0 to 136 points, with higher scores indicating greater entheseal involvement.
Time frame: Baseline
Shear Wave Elastography Young's Modulus of Bilateral Enthesis Sites
Comparison of shear wave elastography measurements between patients with psoriatic arthritis and healthy controls. Young's modulus will be measured in kilopascals (kPa) at the bilateral plantar fascia, Achilles tendon, proximal and distal patellar tendon, quadriceps tendon, and triceps tendon insertions. Three separate SWE images will be acquired at each enthesis site, with two 1-mm circular regions of interest placed on each image, resulting in a total of six measurements per enthesis. The arithmetic mean of the six measurements will be used as the SWE value for that enthesis. Results will be evaluated separately for each enthesis site.
Time frame: Baseline
Shear Wave Elastography Shear Wave Velocity of Bilateral Enthesis Sites
Comparison of shear wave velocity measurements between patients with psoriatic arthritis and healthy controls. Shear wave velocity will be measured in meters per second (m/s) at the bilateral plantar fascia, Achilles tendon, proximal and distal patellar tendon, quadriceps tendon, and triceps tendon insertions. Three separate SWE images will be acquired at each enthesis site, with two 1-mm circular regions of interest placed on each image, resulting in a total of six measurements per enthesis. The arithmetic mean of the six measurements will be used as the shear wave velocity value for that enthesis. Results will be evaluated separately for each enthesis site.
Time frame: Baseline
Health Assessment Questionnaire Disability Index (HAQ-DI) Score
Physical function in patients with psoriatic arthritis will be assessed using the Health Assessment Questionnaire Disability Index (HAQ-DI), which consists of 20 items covering eight domains of daily functioning. Each domain is scored from 0 to 3, and the overall HAQ-DI score ranges from 0 to 3 points. Higher scores indicate greater functional disability.
Time frame: Baseline
Duruöz Hand Index (DHI) Score
Hand-related functional disability in patients with psoriatic arthritis will be assessed using the Duruöz Hand Index (DHI), which consists of 18 items evaluating activities of daily living. Each item is scored from 0 to 5, resulting in a total score ranging from 0 to 90 points. Higher scores indicate greater hand-related functional disability.
Time frame: Baseline
12-Item Short Form Health Survey Physical Component Summary (PCS-12) Score
Physical health-related quality of life in patients with psoriatic arthritis will be assessed using the Physical Component Summary of the 12-Item Short Form Health Survey (PCS-12). The score ranges from 0 to 100 points, with higher scores indicating better physical health-related quality of life.
Time frame: Baseline
12-Item Short Form Health Survey Mental Component Summary (MCS-12) Score
Mental health-related quality of life in patients with psoriatic arthritis will be assessed using the Mental Component Summary of the 12-Item Short Form Health Survey (MCS-12). The score ranges from 0 to 100 points, with higher scores indicating better mental health-related quality of life.
Time frame: Baseline
Fibromyalgia Rapid Screening Tool (FiRST) Score
Fibromyalgia-related symptoms in patients with psoriatic arthritis will be assessed using the Fibromyalgia Rapid Screening Tool (FiRST). The questionnaire consists of six yes-or-no items. Each affirmative response is scored as 1 point, resulting in a total score ranging from 0 to 6 points. Higher scores indicate a greater likelihood of fibromyalgia, and a score of 5 or 6 is considered a positive screening result.
Time frame: Baseline
Serum C-Reactive Protein (CRP) Level
Systemic inflammation in patients with psoriatic arthritis will be assessed by measuring the serum C-reactive protein (CRP) level. CRP will be reported in milligrams per liter (mg/L), with higher values indicating greater systemic inflammation.
Time frame: Baseline
Erythrocyte Sedimentation Rate (ESR)
Systemic inflammation in patients with psoriatic arthritis will be assessed using the erythrocyte sedimentation rate (ESR). ESR will be reported in millimeters per hour (mm/hour), with higher values indicating greater systemic inflammation.
Time frame: Baseline
Disease Activity Index for Psoriatic Arthritis (DAPSA) Score
Peripheral joint disease activity in patients with psoriatic arthritis will be assessed using the Disease Activity Index for Psoriatic Arthritis (DAPSA). The score is calculated as the sum of the 68-joint tender joint count, 66-joint swollen joint count, patient global assessment measured on a 0-to-10 scale, patient pain assessment measured on a 0-to-10 scale, and C-reactive protein level expressed in mg/dL. The minimum possible score is 0, and there is no fixed maximum because C-reactive protein is included as a continuous variable. Higher scores indicate greater disease activity. Scores of 4 or lower indicate remission; scores above 4 and up to 14 indicate low disease activity; scores above 14 and up to 28 indicate moderate disease activity; and scores above 28 indicate high disease activity.
Time frame: Baseline
Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) Score
Axial and related disease activity in patients with psoriatic arthritis will be assessed using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The index consists of six questions evaluating fatigue, spinal pain, peripheral joint pain or swelling, enthesitis, morning stiffness severity, and morning stiffness duration. Each question is scored from 0 to 10. The mean of the two morning stiffness item scores is calculated. This mean and the scores of the remaining four items are summed and divided by five, resulting in an overall score ranging from 0 to 10 points. Higher scores indicate greater disease activity.
Time frame: Baseline
Ankylosing Spondylitis Disease Activity Score Using C-Reactive Protein (ASDAS-CRP)
Axial disease activity in patients with psoriatic arthritis will be assessed using the Ankylosing Spondylitis Disease Activity Score using C-reactive protein (ASDAS-CRP). The score combines back pain, duration of morning stiffness, patient global assessment, and peripheral joint pain or swelling, each assessed on a 0-to-10 scale, with the C-reactive protein level expressed in mg/L. The minimum possible score is 0, and there is no fixed maximum because C-reactive protein is included as a continuous variable. Higher scores indicate greater disease activity. Scores below 1.3 indicate inactive disease, scores from 1.3 to below 2.1 indicate low disease activity, scores from 2.1 to 3.5 indicate high disease activity, and scores above 3.5 indicate very high disease activity.
Time frame: Baseline
Minimal Disease Activity (MDA) Status
Minimal disease activity in patients with psoriatic arthritis will be assessed using the established MDA criteria. A patient will be classified as achieving MDA when at least five of the following seven criteria are met: tender joint count of 1 or lower; swollen joint count of 1 or lower; Psoriasis Area and Severity Index score of 1 or lower or affected body surface area of 3% or lower; patient pain visual analogue scale score of 15 mm or lower; patient global disease activity visual analogue scale score of 20 mm or lower; Health Assessment Questionnaire Disability Index score of 0.5 or lower; and tender entheseal point count of 1 or lower. MDA status will be recorded as a binary categorical outcome: achieved or not achieved.
Time frame: Baseline
Psoriasis Area and Severity Index (PASI) Score
Psoriasis severity in patients with psoriatic arthritis will be assessed using the Psoriasis Area and Severity Index (PASI). The index combines the extent of affected body surface area with the severity of erythema, induration, and scaling across four body regions: the head, upper extremities, trunk, and lower extremities. The total score ranges from 0 to 72 points, with higher scores indicating more severe psoriasis.
Time frame: Baseline
Leeds Enthesitis Index (LEI) Score
Clinical enthesitis in patients with psoriatic arthritis will be assessed using the Leeds Enthesitis Index (LEI). Tenderness will be evaluated at six entheseal sites: the bilateral lateral epicondyles, bilateral medial femoral condyles, and bilateral Achilles tendon insertions. Each tender site is scored as 1 point and each non-tender site as 0 points, resulting in a total score ranging from 0 to 6 points. Higher scores indicate a greater burden of clinical enthesitis.
Time frame: Baseline
Patient Pain Visual Analogue Scale (VAS) Score
Pain severity in patients with psoriatic arthritis will be assessed using a 10-cm visual analogue scale (VAS). The score ranges from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. Higher scores indicate greater pain severity.
Time frame: Baseline
Patient Global Assessment of Disease Activity (PtGA) Score
Overall disease activity from the patient's perspective will be assessed using a 10-cm visual analogue scale. The score ranges from 0 to 10, where 0 indicates no disease activity and 10 indicates the highest possible disease activity. Higher scores indicate greater patient-perceived disease activity.
Time frame: Baseline
Physician Global Assessment of Disease Activity (PhGA) Score
Overall disease activity from the physician's perspective will be assessed using a 10-cm visual analogue scale. The score ranges from 0 to 10, where 0 indicates no disease activity and 10 indicates the highest possible disease activity. Higher scores indicate greater physician-assessed disease activity.
Time frame: Baseline
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