Musculoskeletal Ultrasound for Differentiating Rheumatoid and Gouty Arthritis

Role of Musculoskeletal Ultrasound in Differentiation of Rheumatoid Arthritis and Gouty Arthritis Using Semi-Quantitative Scoring

Rheumatoid arthritis (RA) and gouty arthritis (GA) are two common forms of joint inflammation that can present with very similar physical symptoms, making them difficult to tell apart early in the disease process. Accurate and early differentiation is crucial because the treatment strategies and long-term management for the two conditions are substantially different.

The primary purpose of this observational study is to evaluate the diagnostic performance of musculoskeletal ultrasound (MSUS) in distinguishing between RA and GA. Ultrasound is a safe, radiation-free imaging tool that can visualize joint inflammation and structural changes in real-time. This study utilizes a structured semi-quantitative scoring system (graded on a scale of 0 to 3) to systematically measure the severity of joint lining thickness (synovial hypertrophy) and active blood flow (power Doppler signal). It also checks for crystal-related deposits, such as tophi or the double contour sign, which are highly suggestive of gout.

Participants aged 18 and older with suspected or confirmed RA or GA who are referred for joint assessment at Assiut University Hospitals will undergo a standard clinical evaluation, routine laboratory testing, and an ultrasound examination of specific target joints (such as the wrists, hands, knees, and ankles). By comparing the ultrasound scores and specific structural findings between the two patient groups, the study aims to establish a reliable, standardized imaging approach to help physicians make faster, more confident diagnoses and initiate the correct disease-specific therapies sooner.

Study Overview

• Status: Not yet recruiting
• Conditions: Inflammatory Arthritis; Gout; Rheumatoid Arthritis (RA); Gouty Arthritis (GA)

• Study Type: Observational
• Enrollment (Estimated): 100

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: N/A

• Sampling Method: Non-Probability Sample

Study Population

The study population consists of adult patients, aged 18 years or older, of either sex. It includes individuals presenting with clinically suspected or confirmed rheumatoid arthritis or gouty arthritis. These participants are specifically those referred to the radiology department at Assiut University Hospitals in Assiut, Egypt, for a musculoskeletal ultrasound assessment of painful, swollen, or inflamed joints.

Description

Inclusion Criteria:

• Patients aged 18 years or older.
• Either sex.
• Patients with clinically suspected or confirmed rheumatoid arthritis.
• Patients with clinically suspected or confirmed gouty arthritis.
• Patients referred for musculoskeletal ultrasound assessment of painful, swollen, or inflamed joints.
• Patients able and willing to provide informed consent.
• Patients whose final diagnosis is established by clinical assessment, laboratory testing, and/or relevant imaging or synovial fluid analysis when available.

Exclusion Criteria:

• Patients younger than 18 years.
• Patients with septic arthritis or suspected joint infection.
• Patients with traumatic joint injury involving the target joint.
• Patients with other inflammatory arthropathies such as psoriatic arthritis, reactive arthritis, or systemic lupus erythematosus if they may confound imaging interpretation.
• Patients with advanced osteoarthritis in the scanned joint if it markedly limits Faculty of Medicine Institutional Review Board (IRB) Assiut Medical School Research Proposal Form 5 interpretation.
• Patients with incomplete clinical records or insufficient ultrasound windows.
• Patients who refuse consent.
• Patients whose diagnosis remains uncertain after clinical workup.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Rheumatoid Arthritis Cohort; Patients aged 18 years or older presenting with clinically suspected or confirmed rheumatoid arthritis. Participants undergo standard clinical and laboratory assessment followed by a musculoskeletal ultrasound examination of target joints (including wrists, metacarpophalangeal joints, proximal interphalangeal joints, knees, and ankles). The ultrasound evaluates the presence and severity of gray-scale synovitis, power Doppler vascularity, joint effusion, and bone erosions using a 0-3 semi-quantitative scoring system.
Gouty Arthritis Cohort; Patients aged 18 years or older presenting with clinically suspected or confirmed gouty arthritis. Participants undergo standard clinical and laboratory assessment followed by a musculoskeletal ultrasound examination of target joints, particularly the first metatarsophalangeal joint and other symptomatic areas. The ultrasound applies a semi-quantitative scoring system to evaluate inflammatory changes and specifically targets crystal-related findings, including the double contour sign, tophus formation, hyperechoic aggregates, and erosions with overhanging edges.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Semi-quantitative Gray-Scale Synovitis Score	Synovial hypertrophy evaluated using high-resolution musculoskeletal ultrasound, graded on a 0 to 3 scale where 0 indicates no synovial thickening, 1 indicates mild synovial hypertrophy, 2 indicates moderate synovial hypertrophy, and 3 indicates severe synovial hypertrophy.	Baseline (Single assessment at the time of the cross-sectional ultrasound examination)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Semi-quantitative Power Doppler Synovitis Score	Synovial vascularity evaluated using high-resolution musculoskeletal ultrasound, graded on a 0 to 3 scale where 0 indicates no Doppler signal, 1 indicates a mild signal, 2 indicates a moderate signal, and 3 indicates marked Doppler activity.	Baseline (Single assessment)
Presence of Double Contour Sign	The frequency of the double contour sign, representing urate crystal deposits on the articular cartilage, detected via musculoskeletal ultrasound in the target joints.	Baseline (Single assessment)
Presence of Tophi	The frequency of tophus formation, identified as hyperechoic aggregates, detected via musculoskeletal ultrasound in the target joints.	Baseline (Single assessment)
Frequency of Bone Erosions	The presence and frequency of bone erosions detected via musculoskeletal ultrasound in the target joints.	Baseline (Single assessment)
Frequency of Tenosynovitis	The presence and frequency of tenosynovitis detected via musculoskeletal ultrasound in the target joints.	Baseline (Single assessment)

Collaborators and Investigators

• Sponsor: Assiut University

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): July 1, 2027
• Study Completion (Estimated): August 1, 2027

Study Registration Dates

• First Submitted: June 14, 2026
• First Submitted That Met QC Criteria: June 14, 2026
• First Posted (Actual): June 18, 2026

Study Record Updates

• Last Update Posted (Actual): June 18, 2026
• Last Update Submitted That Met QC Criteria: June 14, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Musculoskeletal Ultrasound; Ultrasonography; Synovitis; Diagnostic Imaging; Tophi; Power Doppler; Semi-quantitative Scoring; Double Contour Sign
• Additional Relevant MeSH Terms: Crystal Arthropathies; Musculoskeletal Diseases; Joint Diseases; Rheumatic Diseases; Purine-Pyrimidine Metabolism, Inborn Errors; Metabolism, Inborn Errors; Genetic Diseases, Inborn; Metabolic Diseases; Connective Tissue Diseases; Autoimmune Diseases; Immune System Diseases; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Nutritional and Metabolic Diseases; Skin and Connective Tissue Diseases; Gout; Arthritis; Arthritis, Rheumatoid; Synovitis; Arthritis, Gouty
• Other Study ID Numbers: US Scoring: RA vs Gout