[Invagination in adults]

Intussusceptions in adults are rare. With the increasing use of sonography, CT and improved methods for examining the small bowel, they are now diagnosed more frequently before operation. If one considers the possibility, acute invaginations can be readily diagnosed by sonography or barium examination; the CT appearances are pathognomonic. In long-standing cases it may be difficult to separate the oedematous small bowel walls from each other. The "duck bill" narrowing is a sign of chronic invagination.