Musculoskeletal ultrasonography assists the diagnostic performance of the 2010 classification criteria for rheumatoid arthritis.

Objective: We investigated whether musculoskeletal ultrasonography (MSKUS) assists the diagnostic performance of the 2010 rheumatoid arthritis (RA) classification criteria.

Methods: Sixty-nine early arthritis patients were consecutively enrolled. None of the patients had been treated. In MSKUS of bilateral wrist and finger joints from 22 sites, the findings obtained by gray-scale and power Doppler (PD) assessment were graded on a semiquantitative scale from 0 to 3. Plain magnetic resonance imaging (MRI) of both wrist and finger joints was also examined. Diagnosis of RA was defined by the initiation of disease-modifying antirheumatic drugs within the first 3 months. The diagnostic performance of the patients was evaluated at entry using 2010 RA classification criteria in conjunction with MSKUS.

Results: The indispensable MSKUS finding for differentiating RA was the presence of a PD grade 2 or 3 that was superior to 2010 RA classification criteria or MRI-proven bone edema. We propose that the decision tree algorithm of 2010 RA classification criteria with PD grade 2 or 3 reveals the best discriminative ability.

Conclusion: MSKUS, especially with a strong PD signal, is very useful to assist the diagnostic performance of the 2010 RA classification criteria in the early recognition of RA.