Researchers in Brazil have developed a simplified ultrasound scoring system for rheumatoid arthritis that relies on just ten joint recesses, selected because they showed the strongest statistical correlations with clinical measures of disease activity. The cross-sectional study, published in Advances in Rheumatology, evaluated 59 patients with rheumatoid arthritis and analyzed 3,540 joint recesses across small, medium, and large joints, generating 14,160 individual ultrasound measurements.
The study assessed joint recesses bilaterally, covering 60 recesses in total per evaluation protocol across the patient group. Upper limb joints examined included the shoulders, elbows, wrists, metacarpophalangeal joints assessed from both dorsal and palmar approaches, and proximal interphalangeal joints. Lower limb joints included the hips, knees, ankles, and metatarsophalangeal joints. For each recess, the team recorded quantitative and semi-quantitative measures of synovitis, power Doppler signals, and bone erosion.
Clinical variables used for correlation included the DAS-28, CDAI, and SDAI disease activity scores, the HAQ functional index, morning stiffness duration, erythrocyte sedimentation rate, and visual analogue scales from 0 to 10 centimeters for pain and swelling. Joint recesses were selected for the score when they showed the highest Pearson correlation coefficients between ultrasonographic findings and these clinical variables, with statistical significance set at p < 0.05.
The correlation analysis identified substantial numbers of significant associations across ultrasound modalities. Quantitative synovitis measurements produced 129 significant correlations, with coefficients ranging from 0.284 to 0.508. Power Doppler yielded 101 correlations ranging from 0.252 to 0.569, the strongest upper range of any modality. Semi-quantitative synovitis produced 86 correlations between 0.256 and 0.460, while bone erosion generated 48 correlations between 0.184 and 0.381, the weakest of the four measures.
Based on these results, the ten recesses with the highest correlations, corresponding to 20 joints assessed per patient when counted bilaterally, were ranked in descending order as follows: wrists, fifth metacarpophalangeal joints (dorsal and palmar), first metatarsophalangeal joints, first metacarpophalangeal joints (dorsal), fourth metacarpophalangeal joints (dorsal), second metacarpophalangeal joints (dorsal), third metacarpophalangeal joints (dorsal and palmar), third proximal interphalangeal joints, ankles, and fifth metatarsophalangeal joints.
Quantitative synovitis and power Doppler were selected for inclusion in the final score because they showed both a higher number and stronger statistical correlations with clinical variables. Semi-quantitative synovitis and bone erosion were excluded on the same statistical grounds, having fewer and weaker correlations. In the concluding statement of the abstract, the authors identified power Doppler as the ultrasonographic variable included in the Brazilian ultrasound-based score, citing its practicality.
The resulting US20BR Score, with BR denoting Brazil, incorporates the following joints: wrists, first through fifth metacarpophalangeals, third proximal interphalangeals, ankles, and first and fifth metatarsophalangeals. The authors state that this score may optimize the ultrasound assessment of patients with rheumatoid arthritis by concentrating imaging on the recesses most closely tied to clinical disease activity.
The patient cohort comprised 59 people with rheumatoid arthritis, of whom 44 were women, representing 74.6 percent of the group, with a mean age of 46.50 years and a standard deviation of 9.28 years. As a cross-sectional study, the design captures a single point in time and establishes associations between ultrasound findings and clinical measures rather than causal effects or predictive performance over follow-up. The authors report the correlation-based selection process as the basis for the score’s joint selection, and the abstract does not include validation data for the score’s performance against outcomes in independent cohorts.
Subject of Research: Development of a Brazilian ultrasound joint score (US20BR) for assessing rheumatoid arthritis based on correlations between ultrasonographic and clinical measures.
Article Title: Development of an ultrasound score (US20BR) with small, medium, and large joints: a cross-sectional study in rheumatoid arthritis
Article References: Silva, K. R., Natour, J., Machado, F. S., Takahashi, R. D., & Furtado, R. N. V. (2026). Development of an ultrasound score (US20BR) with small, medium, and large joints: a cross-sectional study in rheumatoid arthritis. Advances in Rheumatology. https://doi.org/10.1186/s42358-026-00568-6
Image Credits: AI Generated
DOI: 10.1186/s42358-026-00568-6
Keywords: rheumatoid arthritis, ultrasound, power Doppler, synovitis, US20BR score, joint recesses, cross-sectional study, DAS-28, bone erosion, disease activity, Brazil, Development
News Source: Ophelia Keating. (October 29, 2026). New Ultrasound Score for Rheumatoid Arthritis Focuses on Wrists, Hands, Ankles and Toes. Scienmag.
