Objectives Clinically evident tenosynovitis can be seen in established rheumatoid arthritis (RA). Imaging research has recently shown that tenosynovitis at small joints occurs in early RA, contributes to typical RA symptoms (including joint swelling) and is infrequent in healthy controls. Imaging-detectable tenosynovitis is often not recognisable at joint examination, hence its prevalence can therefore be underestimated. We hypothesised that if MRI-detectable tenosynovitis is a true RA feature, the sensitivity for RA is high, in both anti-citrullinated protein antibodies (ACPA)-positive and ACPA-negative RA, and lower in other diseases that are associated with enthesitis (such as spondyloarthritis (SpA) and psoriatic arthritis (PsA)). So far, no large MRI study addressed these questions.
Methods Consecutive patients with early arthritis (n=1211) from one healthcare region underwent contrast-enhanced 1.5T MRI of hand and foot at diagnosis. MRIs were scored for synovitis and tenosynovitis by two readers blinded for clinical data. All included patients with ACPA-positive RA (n=250), ACPA-negative RA (n=282), PsA (n=88), peripheral SpA (n=24), reactive arthritis (n=30) and self-limiting undifferentiated arthritis (UA; n=76) were studied. Sensitivity was calculated.
Results The sensitivity of tenosynovitis in RA was 85%; 88% for ACPA-positive RA and 82% for and ACPA-negative RA (p=0.19). The sensitivity for RA was significantly higher than for PsA (65%; p=0.001), SpA (53%; p<0.001), reactive arthritis (36%; p<0.001) and self-limiting UA (42%; p<0.001). The observed sensitivity of MRI synovitis was 91% in RA and ranged from 83% to 54% in other groups.
Conclusions MRI-detected tenosynovitis has a high sensitivity for early ACPA-positive and ACPA-negative RA. This supports that both juxta-articular (tenosynovitis) and intra-articular synovial involvement is characteristic of RA.
- magnetic resonance imaging
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Handling editor Josef S Smolen
Contributors XMEM and AvdHvM contributed to the conception and study design. XMEM analysed the data. XMEM, EN and AvdHvM contributed to interpretation of the data. XMEM, FW, NS and EN contributed to acquisition of the data. XMEM and AvdHvM wrote the first version of the manuscript and FW, NS and EN revised it critically. All authors read and approved the final version of the document.
Funding The research leading to these results has received funding from the Dutch Arthritis Foundation and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Starting grant, Agreement No 714312).
Disclaimer The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval ‘Commissie Medische Ethiek' of the Leiden University Medical Centre.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request.
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