The purpose of this study was to evaluate the clinical and abdominal ultrasonogra- phic (US) features of spontaneously reduced transient small bowel intussusception in chlidren.

We retrospectively reviewed the clinical and US findings of 98 children with intussusception who were admitted to the Pediatric Department of Ulsan Dong-Kang General Hospital from Mar. 1999 to Feb. 2000.

1) Among 98 cases, there were 12 cases (12.3%) of transient small bowel intussusception (TSBI) and 86 cases (87.7%) of classic intussusception (CI). 2) The peak incidence of age in TSBI was over 3 years, which was older than that in CI. With regard to sex distribution, male predominated in both type. 3) Clinical symptoms and signs including cyclic irritability, vomiting, bloody stool, and abdominal mass in TSBI group were less common than those in CI group (41.7%, 33.4%, 0.0%, 0.0% vs 91.9%, 59.3%, 41.9%, 26.7%, respectively) but persistent abdominal pain was more common in TSBI group than in CI group (58.5% vs 11.2% ). 4) The size of total target sign and surrounding peripheral hypoechoic rim of TSBI group on US were smaller than those of CI group (11.9±2.61 mm, 2.08±1.15 mm vs 26.91±5.98 mm, 7.86±2.77 mm, respectively). 5) Concomittant illness was found more frequently in TSBI group than in CI group (66.7% vs 26.7%). 6) All case of TSBI group were reduced spontaneouly, which were confirmed by US, but none of CI group.

Transient small bowel intussusception is probably more common than generally thought and its clinical and US findings is quite different from classical obstructing intussus-ception. Because all of our cases resulted in spontaneous reduction, we recommend careful observation and repeat examination rather than an immediate operation in transient small bowel intussusception.