Appendicitis on ultrasound – the first step is to identify the appendix by finding a blind-ending tubular structure arising from the base of the cecum.

The sonographic signs of appendicitis include:

  • dilated appendix > 6mm outer diameter (left image)
  • noncompressible
  • distinct appendiceal wall layers due to edema (left image)
  • target appearance (axial section)
  • appendicolith – an echogenic focus with posterior shadowing
  • periappendiceal fluid collection (right image)
  • echogenic and prominent periappendiceal and pericecal fat
  • surrounding hypervascularity on color Doppler (centre image)