Intussusception occurs when a segment of bowel “telescopes” onto another segment, or onto itself, because of peristalsis. It is a common cause of acute abdomen in children, the most common cause of intestinal obstruction in children, and has significant complications, such as bowel necrosis, making its timely detection imperative (Edwards).
The classic triad of intussusception is intermittent abdominal pain, vomiting, and the presence of a right upper quadrant mass. When paired with the presence of gross or occult bleeding on rectal exam, this has a high positive predictive value for intussusception.
The most common ultrasound findings for intussusception are:
- Target sign: inflamed bands of hyperechoic mucosa and relatively hypoechoic submucosa are visible.
- Pseudokidney sign: fat-containing mesentery is dragged into the intussusception, resembling the kidney hilum. The resultant longitudinal appearance is of a small kidney.