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

Objectives: 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). Materials and 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.