Sonographic assessment of the retroperitoneal position of the third portion of the duodenum: an indicator of normal intestinal rotation

The diagnosis of intestinal malrotation is based on an upper gastrointestinal contrast series (UGI), which is considered the imaging reference standard. It may however be challenging even for experienced paediatric radiologists. The purpose of this study was to demonstrate the agreement between UGI and US in assessing the position of the third portion of the duodenum (D3) and to show that a retroperitoneal duodenum indicates normal forgut rotation. In a prospective study, US assessment of the duodenum and the superior mesenteric vessels was performed in consecutive children who were referred for clinically indicated UGI at a single institution. Eighty-five children, 5 months to 14 years old, were studied. In 82/85 (96%), both US and UGI suggested normal forgut rotation. In three children, US demonstrated a normal position of the D3 whereas UGI showed an abnormal position of the duodeno-jejunal junction. US is a non-invasive, easily performed technique for excluding malrotation. UGI may be reserved for situations where US does not demonstrate a normal position of the D3.