Is ultrasonography a good screening test for intestinal malrotation?

BACKGROUND: Early diagnosis of malrotation can prevent fatal midgut volvulus. Abnormal orientation of the superior mesenteric artery (SMA) and vein (SMV) on ultrasonography (US) has been described in malrotation. We aimed to determine the accuracy of this technique.

METHODS: All children undergoing both upper gastrointestinal series (UGI) and US for possible malrotation over a 3-year period were reviewed. Patients were excluded if US did not include SMV/SMA orientation or if the duodenojejunal flexure was not visualized on UGI.

RESULTS: Of 211 eligible patients, UGI and US were both normal in 62% and both abnormal in 15%. Forty-four had abnormal US and normal UGI (false positive, 21%), and 5 patients had normal US and abnormal UGI (false negative, 2%). Of these 5, none were found to have a short mesenteric base, which put them at risk for volvulus. Among abnormal ultrasounds, inversion of SMV/SMA and a "whirlpool" sign were more predictive for malrotation and volvulus than anterior/posterior orientation.

CONCLUSIONS: Ultrasonography is a good screening tool that effectively rules out malrotation at risk for volvulus. Children with an abnormal ultrasound should have an UGI or go to the operating room, depending on clinical findings.