Sonography of appendiceal intussusception.

A case in which appendiceal intussusception was diagnosed preoperatively by sonography is described. The sonographic finding of multiple concentric hypoechoic and hyperechoic rings was confirmed at laparotomy to be due to appendiceal intussusception. Demonstration of the sonographic coiled spring sign in the right lower quadrant should raise the possibility of appendiceal intussusception. The differential diagnosis is discussed.