Bilateral MR images of the hand and wrist of a 33-year-old woman with early inflammatory arthritis with a disease duration of 3 months. Source: Radiology (doi: 10.1148/radiol.12112513)

Inflammation of the synovium surrounding a tendon, also known as tenosynovitis, is a common MR imaging finding in early rheumatoid arthritis (RA) and including its presence in a newly developed scoring criterion may offer an improved approach for early identification of RA, according to a study published June 21 online in Radiology.

In 2010, the American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) developed new classification criteria for RA which emphasized the identification of patients with a relatively short duration of symptoms, explained study authors Márcio Navalho, MD, of the Faculty of Medicine of the University of Lisbon, and colleagues.

“However, the new criteria may still lead to substantial over- and underdiagnosis within the first three months after symptom onset,” they wrote. “Therefore, the use of additional tests, namely more sensitive imaging techniques, would be helpful.”

To test whether including tenosynovitis as an MRI parameter for the ACR/EULAR RA classification criteria, Navalho and colleagues studied 32 women and three men with untreated recent-onset inflammatory arthritis. All subjects underwent MR imaging of both wrists and hands, and associations between synovitis for each joint and tendon and RA diagnosis were tested at 12-month follow-up.

Data showed that tenosynovitis is a common imaging finding in early RA, according to the authors. Among patients grouped in the very-early-RA (VERA) cohort (disease duration less than three months), tenosynovitis of the extensor carpi ulnaris and flexor tendons of the second finger were significantly associated with progression to RA. Likewise, tenosynovitis of flexor tendons of the second finger in the early-RA (ERA) cohort (disease duration between three and 12 months) was also associated with RA.

Consideration of tenosynovitis improved the diagnostic performance of the ACR/EULAR criteria. Including it as a scoring criterion improved areas under the receiver operating characteristic curve for diagnosis of RA from 0.942 to 0.972.

“In addition, our study identifies early RA as an asymmetric disease, suggesting the importance of a bilateral acquisition protocol,” wrote the authors, who noted asymmetry was found in 80 percent and 69.3 percent of joint or tendon pairs in the VERA and ERA patients, respectively.

“In view of our results, it seems peculiar that tenosynovitis of the wrists and hands has received so little attention in previous literature,” Navalho et al wrote in the study’s conclusion. They added that MR imaging can help better identify RA patients with a short duration of symptoms, which is important because that is the phase in which treatment makes the greatest difference.