Table 2.

Preliminary definitions for the sonographic features of synovitis in children.

Overarching principle: Synovitis detection by ultrasound in children includes the assessment of B-mode and Doppler mode (color or power Doppler) findings.
Synovitis can be detected on the basis of B-mode findings alone. Synovitis cannot be detected based on color/power Doppler findings alone.

  • B-mode findings comprise synovial effusion and synovial hypertrophy.

  • Synovial effusion is defined as an abnormal, intraarticular, anechoic, or hypoechoic material that is displaceable.

  • Synovial hypertrophy is defined as an abnormal, intraarticular, hypoechoic material that is nondisplaceable.

  • Color/power Doppler signals must be detected within synovial hypertrophy to be considered as a sign of synovitis.