The effect of screening sonography on the positive rate of enemas for intussusception

Background: The referring physicians at our institution used the enema as a diagnostic test in children with suspected intussusception. Objective: To determine the change in rate of positive enema findings performed for suspected intussusception with the intervention of screening ultrasound (US). Materials and methods: Since October 1995, 224 children (mean age years) with suspected intussusception were referred for enema examination. In January 2001, US was introduced as a screening test for intussusception. Enemas were performed for all children with positive US findings and were offered for those with negative US findings if clinical suspicion persisted. Results: Before 2001, 184 children underwent enema with intussusception documented in 40 (22%). Since January 2001, 40 children have been seen with suspected intussusception (12/40 positive or 30%). Two directly underwent enema (1/2 positive); 38 children underwent US. In 12 of 38 children, the US finding was positive, and an intussusception was found at enema examination in 11 of 12. In 26 cases, the US finding was negative. Seven of the 26 children with a negative sonogram finding had an enema, which was also negative. Nineteen enemas were canceled. With a screening US, the positive rate for enemas is now 58% (11/19). We know of no case of intussusception missed at US. Conclusion: Screening US has decreased unnecessary enemas for clinically suspected intussusception, increasing positive findings from 22% to 58%. This has in turn reduced children's exposure to radiation.