Gray Scale and Power Doppler Ultrasonographic Findings in the Assessment of Disease Activity and Their Correlation with Disease Activity Parameters in Rheumatoid Arthritis.

Objective: To study the utility of gray scale and power Doppler ultrasonography in assessing the disease activity and correlation of ultrasonographic findings with disease activity parameters in Rheumatoid Arthritis (RA).

Methods: This cross-sectional study was conducted on 100 RA patients diagnosed as per 2010 classification criteria. Rheumatoid Factor (RF), serum Anti-cyclic Citrullinated Peptide Antibodies (ACPA), Erythrocyte Sedimentation Rate (ESR), C-reactive Protein (CRP), disease activity score with 28-joint counts and ESR (DAS28-ESR), Visual Analogue Scale (VAS) for global disease activity and Gray Scale Ultrasonography (GSUS) and Power Doppler Ultrsonography (PDUS) scores in hands and wrists were determined.

Results: Of 100 RA patients with clinically active arthritis, GSUS detected disease activity in all and PDUS in 95 (95%) patients. Of total 2200 joints assessed, disease activity was seen by clinical assessment in 51.31% (1116/2200), GSUS in 57.36% (1262/2200) and PDUS in 48.36% (1064/2200) joints. For detecting active arthritis, clinical assessment showed 79.5% sensitivity and 76.2% specificity while GSUS showed 100% sensitivity and 82.5% specificity using PDUS as a gold standard. GSUS findings of synovitis, joint effusion and bone erosions and PDUS score showed significant correlations with the swollen joint count, tender joint count, ESR and DAS28- ESR (p<0.05 each) but not with VAS, CRP, RF and ACPA (p>0.05 each). Multivariate analysis showed that swollen joint count was independently associated with synovitis (p=0.029) and tender joint count with PDUS score (p=0.036).

Conclusions: GSUS and PDUS findings are useful in ascertaining the disease activity and correlate with clinical disease activity in joints in RA.