Ultrasonography in Early Rheumatoid Arthritis of Hand and Wrist Joints: Comparison with Magnetic Resonance Imaging.

BACKGROUND: The aim of the study was to evaluate the use of ultrasonography (USG) including power Doppler in detecting hand and wrist joint changes in early rheumatoid arthritis (RA) and to compare USG findings with magnetic resonance imaging (MRI). MATERIALS AND METHODS: Thirty-four patients diagnosed as RA by 2010 ACR/EULAR criteria; with the onset of symptoms within last one year, were included in the study after institute ethical clearance and informed consent to undergo USG and contrast-enhanced MRI of the dominant affected hand. Second to fifth metacarpophalangeal (MCP) joints, second to fifth proximal interphalangeal (PIP) joints and wrist joints (total nine joints) were evaluated for synovitis, erosions along with tenosynovitis. USG and MRI features were compared; agreement on the two imaging modalities as well as sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy of ultrasonography compared to MRI (gold standard) was calculated. RESULTS: One hundred thirty-six MCP, 136 PIP and 34 wrist joints (total 306 joints) and 136 flexor tendons were evaluated. The sensitivity, specificity, PPV, NPV and diagnostic accuracy of USG for diagnosing synovitis was 78.6%, 91.1%, 86.1%, 85.8%, 86.3%; for erosions 67.2%, 97.5%, 84.8%, 90.5%, 91.5%; for tenosynovitis 86.5%, 100%, 100%, 92.3% and 94.8% respectively. The overall agreement between USG and MRI for detection of synovitis was achieved in 83% joints and for erosions in 89.5% joints. CONCLUSION: In early RA, USG was nearly as effective in diagnosing features of joint and tendon sheath involvement, with relatively better performance of USG for tenosynovitis. The performance of USG in diagnosing erosions was limited likely due to difficult access of three-dimensional joint structure.