Abnormal ultrasound findings in rheumatological diseases (definitions)

The OMERACT ultrasound group published a consensus in 2005 of widely accepted definitions of abnormal ultrasound findings in rheumatological diseases:

• erosion: an intra-articular discontinuity of the bone surface that is visible in two orthogonal planes
• joint effusion: abnormal hypoechoic or an anechoic (relative to subdermal fat, but sometimes isoechoic or hyperechoic) intra-articular material that is displaceable and compressible, but does not exhibit Doppler signal
• synovitis: abnormal hypoechoic (relative to subdermal fat, but sometimes isoechoic or hyperechoic) intra-articular tissue that is non-displaceable, poorly compressible, and may exhibit Doppler signal
• tenosynovitis: abnormal anechoic and/or hypoechoic (relative to tendon fibers) tendon sheath widening or distention, which can be related to the presence of both abnormal tenosynovial fluid and/or synovial hypertrophy
• enthesitis: entheseal thickening, hypoechogenicity, and the presence of a Doppler signal as a marker of active inflammation