Sonographic features indicative of hydrostatic reducibility of intestinal intussusception in infancy and early childhood.

The aim of the study was to investigate the various sonographic patterns of intussusception, which may be indicative of its reducibility by hydrostatic reduction. Seventy-one infants and children clinically suspected of having intussusception were studied sonographically and given barium enemas. Sonographic patterns of intussusception were correlated with its reducibility. When the head of intussusception appeared as a target-like mass the hydrostatic reduction rate was 100%. When demonstrated as a doughnut-like mass, the intussusception reducibility depended on the thickness of the hypoechoic external ring of the "doughnut". With a thickness equal to, or less than, 7.2 mm the reduction rate was 100%, with a thickness ranged between 7.5 and 11.2 mm the reduction rate was 68.9% and with a thickness measured 14 to 14.2 mm a surgical resection of bowel was required. When a small amount of fluid appeared within the head of intussusception, like a crescent hypoechoic area, the hydrostatic reduction was unsuccessful, regardless of the sonographic pattern of intussusception (target- or doughnut-like mass). The presence of a small amount of free peritoneal fluid did not affect the reducibility of intussusception. In conclusion, sonographic patterns of intussusception identify good and poor prognostic features for the success of hydrostatic reduction.