Ultrasonographic assessment of inflammatory activity in rheumatoid arthritis: comparison of extended versus reduced joint evaluation.
OBJECTIVE
To investigate the validity of reduced joint counts for ultrasonographic (US) assessment of joint inflammatory activity in patients with rheumatoid arthritis (RA).


METHODS
Ninety-four patients with RA were included. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels were recorded for each patient. The presence of tenderness, swelling and a subjective swelling score from 0 to 3 were assessed by two rheumatologists who reached consensus in 60 joints examined in each patient. All patients underwent an US examination by a third blinded rheumatologist, using power Doppler (PD). US joint effusion, synovitis and PD signal were graded from 0 to 3 in the 60 joints. A 60-joint count and index for effusion, synovitis and PD signal were recorded. A 6-, 10-, 16-, 18-, and two 12-joint counts and indices for US parameters that included the most frequently US involved joints were calculated for each patient.


RESULTS
A 12-joint assessment for effusion, synovitis and PD signal, including bilateral wrist, second and third MCP, second and third PIP of hands and knee joints highly correlated with corresponding 60-joint US counts and indices. This reduced-joint US evaluation showed a similar correlation with clinical and laboratory parameters of disease activity to corresponding 60-joint assessment.


CONCLUSION
We propose that a 12-joint evaluation may be a useful tool for US assessment of overall joint inflammatory activity in RA.