The role of sonography in differentiating congenital intrinsic duodenal anomalies from midgut malrotation: emphasizing the new signs of duodenal and gastric wall thickening and hyperechogenicity.

BACKGROUND: The clinical and plain radiographic differentiation of congenital intrinsic duodenal anomalies (atresia, web, stenosis) from intestinal malrotation is not always clear. Although sonography has been documented as an important diagnostic tool in the differentiation of these two entities, its role is still not widely appreciated and it is still not universally utilized in this clinical setting.

OBJECTIVE: To assess the usefulness of sonographic features of the duodenal and gastric wall in the differentiation of congenital intrinsic duodenal anomalies from midgut malrotation in a large series of neonates and to compare them with other features on abdominal radiographs, ultrasound and upper gastrointestinal series.

MATERIALS AND METHODS: Using the surgical database at our tertiary pediatric hospital, we identified neonates who had surgically proven congenital intrinsic duodenal anomalies or malrotation over a period of 15 years (2000-2015). We reviewed imaging findings in both groups of neonates (blinded to the final diagnosis) with attention to the echogenicity and thickness of the wall of the duodenum and stomach, the relationship between the superior mesenteric artery and vein, the position of the third portion of the duodenum and the presence of the whirlpool sign. Findings were compared between the groups using the unpaired t-test and Fisher exact test.

RESULTS: We included 107 neonates in the study, 40 with a congenital intrinsic duodenal anomaly, 49 with malrotation (36 with volvulus) and 18 with a combination of both. Duodenal and gastric wall thickening and hyperechogenicity were significantly more common in the group with a congenital intrinsic duodenal anomaly compared to those with malrotation (P<0.0001). Conversely, an abnormal relationship between the superior mesenteric artery and vein, abnormal position of the third part of the duodenum, and the whirlpool sign were significantly more common in neonates with malrotation than in those with congenital intrinsic duodenal anomalies (P<0.0001).

CONCLUSION: Duodenal or gastric wall thickening, and increased wall echogenicity are helpful sonographic features in the differentiation of congenital intrinsic duodenal anomalies from malrotation. Evaluation of the duodenal and gastric wall should thus be added to the features routinely assessed on ultrasound examinations in the clinical setting of suspected duodenal obstruction in the neonate.