Background MRI is a sensitive method to detect local inflammation in Rheumatoid Arthritis (RA). In addition to synovitis and osteitis it also visualizes tenosynovitis. The prevalence of MRI-detected tenosynovitis and its diagnostic and prognostic value in early arthritis are unclear.

Objectives This study aimed to identify the frequency of MRI-detected tenosynovitis at the metacarpophalangeal (MCP) and wrist joints in early arthritis, the diagnostic value for RA and the association with severity features within RA.

Methods 178 early arthritis patients included in the Leiden EAC underwent unilateral 1.5T extremity-MRI at baseline. MRI-scans were made and scored using the RAMRIS-protocol. Tenosynovitis was scored at the wrist and MCP joints by two readers using the method as described by Haavardsholm et al.[1]During the first year 69 patients fulfilled the 2010-classification criteria for RA; patients with and without RA were compared. Within RA-patients comparisons were made for anti-citrullinated-peptide-antibody (ACPA)-positivity and for radiographic progression (increase in Sharp van der Heijde score) during the first year.

Results 65% of the 178 early arthritis patients had MRI-detected tenosynovitis at any of the studied locations. The flexor tendon at MCP-3 and the tendon of the extensor carpi ulnaris were most frequently affected (22% and 34%). Furthermore, tenosynovitis was more often present in RA than non-RA patients (75% versus 59% p 0.023). More commonly affected locations in RA than in non-RA were the tendons of the flexors at MCP-5 (odds ratio (OR) 2.8 95% CI 1.2-7.0), the extensor at MCP-2 (OR 9.1 95% CI 1.9-42.8) and MCP-4 (OR 14.2 95% CI 1.7-115.9) and extensor compartment I at the wrist 4.0 (95% CI 1.4-11.1). The specificity for these locations ranged between 92-99% and the positive predictive value between 61-89%. The associations between tenosynovitis at these locations and RA were independent of the presence of local synovitis. Within RA-patients, the tenosynovitis scores were not associated with the presence of ACPA or radiographic progression during the first year.

Conclusions MRI-detected tenosynovitis is common in early arthritis and is more common in RA patients than in early arthritis patients with other diagnoses. Locations with a high specificity for RA are the tendons of the flexor at MCP-5, the extensor at MCP-2 and MCP-4 and the first extensor compartment of the wrist.

References

1. Haavardsholm EA, Ostergaard M, Ejbjerg BJ, et al. Introduction of a novel magnetic resonance imaging tenosynovitis score for rheumatoid arthritis: reliability in a multireader longitudinal study. Ann Rheum Dis 2007;66:1216–20. doi:10.1136/ard.2006.068361

Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.2851