 Abdominal ultrasonography, preferably with doppler sonography, is useful to detect appendicitis, especially in children.Ultrasound can show the free fluid collection in the right iliac fossa, along with a visible appendix with increased blood flow when using color Doppler, and noncompressibility of the appendix, as it is essentially walled-off abscess.Other secondary sonographic signs of acute appendicitis include the presence of echogenic mesenteric fat surrounding the appendix and the acoustic shadowing of an appendicolith.