Synovial fluid | Abnormal hypoechoic or anechoic (relative to subdermal fat, but may be isoechoic or hyperechoic) intraarticular material that is displaceable and compressible, but does not exhibit Doppler signal |
Synovial hypertrophy | Abnormal hypoechoic (relative to subdermal fat, but may be isoechoic or hyperechoic) intraarticular tissue that is nondisplaceable and poorly compressible and may exhibit Doppler signal |
Tenosynovitis | Hypoechoic or anechoic thickened tissue with or without fluid within the tendon sheath, which is seen in 2 perpendicular planes and that may exhibit Doppler signal |
Bone erosion | An intraarticular discontinuity of the bone surface that is visible in 2 perpendicular planes |
Enthesopathy | Abnormally hypoechoic (loss of normal fibrillar architecture) and/or thickened tendon or ligament at its bony attachment (may occasionally contain hyperechoic foci consistent with calcification), seen in 2 perpendicular planes that may exhibit Doppler signal and/or bony changes including enthesophytes, erosions, or irregularity |