EULAR IN LONDON: TOWARDS A STRUCTURAL INFLAMMATORY ACTIVATION MEASURE (SIAM)

The EULAR European Congress of Rheumatology, this year held from 3–6 June 2026 at the ExCeL conference center in London (Carousel pp. 1 & 2), is one of the major international platforms for exchange between clinicians, researchers, patient representatives, industry, and regulatory stakeholders in rheumatic and musculoskeletal diseases. This year’s congress again provided an excellent setting for scientific presentation, discussion, networking across the rheumatology and osteoarthritis communities, and meeting collaborators and friends.

A central focus of our poster contribution was the further development of quantitative imaging markers related to synovial and inflammatory activation in knee osteoarthritis. We presented face-to-face work on effusion synovitis volume (ESV) and Hoffa synovitis radiomics (HSR), both derived from non-contrast-enhanced MRI using AI-based automated image analysis.

Our poster, titled “Is synovitis, as measured by effusion morphometry or Hoffa radiomics, related to OA progression?”, explored the longitudinal and prognostic performance of these imaging markers in the Osteoarthritis Initiative Foundation for the National Institutes of Health OA Biomarkers Consortium progression cohort (see Gallery → Poster).

The findings suggest that the two measures provide complementary information. Hoffa synovitis radiomics appeared to identify knees at risk of combined radiographic and symptomatic progression at an earlier stage, while effusion synovitis volume showed stronger responsiveness to longitudinal structural change concurrent with progression. These observations support the further development of a multivariable framework combining different inflammatory imaging proxies.

This work forms part of a broader concept we refer to as SIAM: Structural Inflammatory Activation Measure. SIAM is being developed as a fully automated, quantitative, multi-component imaging measure that may integrate several MRI-based proxies of inflammatory activation, including effusion synovitis, Hoffa synovitis, and, in future work, bone marrow lesions, osteophytes, and potentially other structural features.

The long-term aim is to provide scalable biomarkers that may support osteoarthritis research and clinical trials by helping to phenotype and subtype patients, assess prognosis, monitor structural disease progression, select patients for targeted therapies, and evaluate response to anti-inflammatory treatment approaches.

Beyond the scientific presentation, EULAR 2026 was also an important opportunity to discuss regulatory and clinical development pathways for imaging biomarkers in osteoarthritis (carousel pp. 2 & 3). We were pleased to exchange views with colleagues from Formation Bio (New York) on the potential role of MRI-based cartilage thickness measures as surrogate endpoint in the development of disease-modifying osteoarthritis drugs.

For Chondrometrics, the congress confirmed the growing interest in automated quantitative MRI analysis as a tool for making structural and inflammatory tissue changes in osteoarthritis more measurable, reproducible, and clinically meaningful. The discussions in London highlighted both the scientific opportunities and the translational challenges ahead: imaging biomarkers must not only be technically accurate, but also clinically meaningful, sensitive to change, and useful in the context of therapeutic decision-making and clinical trial design.

We thank our collaborators and supporting institutions, including PROTO Horizon, the Ludwig Boltzmann Institute Arthritis and Rehabilitation, and Paracelsus Medizinische Privatuniversität, and all colleagues who contributed to the scientific exchange at EULAR 2026 (carousel pp. 2 & 3).

Our poster presented at EULAR is available in the gallery on the Chondrometrics website.