Background/Purpose: 2010 ACR–EULAR criteria enable us to make diagnosis of early rheumatoid arhtiritis (RA) with no erosion revealed by X-ray. However, the criteria potentially possess two critical issues. One is that some seronegative patients with polyarthritis may be excluded from RA even if they met 1987 ACR criteria. The other is that seropositive patients with arthralgia may be included in RA even in absence of synovitis, if “no synovitis” is not appropriately proven. In this study we assessed the roles of ultrasonography (US) in the diagnosis of early rheumatoid arthritis when the new criteria were applied clinically.

Methods: We retrospectively examined 122 undiagnosed patients who first visited our hospital from 2009 to 2011 due to joint symptoms without any previous therapies except for NSAIDs. The patients who started to receive anti-rheumatic therapy during the one-year observation period were categorized into the RA group. At the study entry, 10 joints (second proximal interphalangeal, second and third metacarpophalangeal joints, wrists and knees) were assessed by US using gray-scale (GS) and power Doppler (PD) scoring.

Results: Fifty and 72 patients were divided into RA group and non-RA group, respectively. Fulfillment of the 2010 ACR–EULAR criteria in the RA group was 70% at the first visit and 96% at the end of study. When applying US synovitis to �esynovitis’ in the scoring system of the 2010 criteria in addition to routine works, sensitivity of the criteria in RA diagnosis increased from 70% to 82% at the first visit. According to ROC analysis, diagnostic findings of US in early RA are the presence of more than 1 joint with GS score ³a2 and/or PD score ³a1, synovitis in wrists, and tenosynovitis (Table). Abnormal US findings including tenosynovitis were found in all 12 patients who did not satisfied the criteria at the first visit, including 8 patients without swollen joints and 5 with negative RF and ACPA. On the contrary, anti-rheumatic therapy was suspended in a patient having high titers of RF and ACPA, because US proved “no synovitis”, repetitively.

Conclusion: US contributes to making early diagnosis of RA, especially in patients having no clinically apparent arthritis and seronegative patients. It is also useful to determine the optimal initiation of anti-rheumatic therapy.

Table. ROC analysis of each US parameter in differentiation of RA from non-RA.