The role of Power Doppler ultrasonography in comparison with biological markers in the evaluation of disease activity in Juvenile Idiopathic Arthritis.

OBJECTIVE

To evaluate the performance of Power Doppler Ultrasonography (PDUS) compared with biological markers, in the assessment of disease activity in children with Juvenile Idiopathic Arthritis (JIA).

METHODS

Forty hospital visits were studied comprising 32 patients with JIA, during one year of follow-up. Each patient underwent clinical, laboratory and ultrasound (PDUS) evaluation. The physician global assessment score on the visual analog scale (PhGA) was used as a standard for assessing disease activity, based on previous studies. The PDUS signal was scored according to a semiquantitative four grade scale (0-3).

RESULTS

PDUS assessment of synovial vascularisation was more sensitive than erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) in identification of the active disease: 90.4% vs. 57% and 28.5% respectively. CRP had a higher specificity (94%) in comparison with PDUS (89.5%). A significant association between clinical examination (PhGA) and PDUS score or ESR was found. Kappa statistics revealed a high level of agreement between PhGA and PDUS score (k=0.799) and a low level of agreement between PhGA and biological markers (k=0.356 and k=0.225 respectively). Patients with higher PDUS score (>or=2), ESR>or=30 mm/h or CRP>or=2 mg/dl were more likely to have active disease.

CONCLUSION

Laboratory tests used today are not sufficiently sensitive for the prediction of active disease. PDUS assessment of synovial vascularisation is a technique with good sensitivity and specificity, thus it may be a beneficial criteria for evaluating disease activity in JIA, completing conventional clinical examination.