It is important to recognize sonographic features of midgut volvulus because they can help to substantiate the diagnosis in an equivocal UGI study or when US is performed for other indications (eg, evaluation for HPS). Variant 5: Bilious vomiting in an infant older than 2 days (suspected malrotation). Initial imaging. Most congenital intestinal atresia and stenosis will present in the first 2 days of life. Midgut volvulus is the most important diagnosis in older infants presenting with bilious vomiting because this is a medical emergency [15]. Fluoroscopy Contrast Enema There is no relevant literature to support the use of a contrast enema as the initial imaging study for suspected malrotation. In suspected malrotation with midgut volvulus, if the UGI fails to show the etiology or is equivocal, a contrast enema may be performed as a follow-up study in the workup of bilious vomiting. However, up to 15% of individuals may have a normal mobile cecum [29]. More commonly, if the UGI is equivocal, small bowel follow through to the cecum may be pursued. Vomiting in Infants Fluoroscopy Upper GI Series The barium UGI series evaluates the esophagus, stomach, pylorus, and the duodenum to the duodenal jejunal junction, indicating the location of the ligament of Treitz [5,6,15]. Although the UGI series is considered the reference standard for evaluating malrotation, false-positive and false-negative interpretations may occur. In a retrospective review of 229 cases by Sizemore et al [16], UGI had a sensitivity of 96% with two false-positives (abnormal jejunal position with no malrotation) and seven false-negatives (normal jejunal position with malrotation). Retrospective reviews by Hsiao et al [17] and another such study by Long et al [18] noted false- positive rates of 10% and 15%, respectively. The studies concluded that redundant duodenum, bowel distension, and jejunal position can lead to inaccurate UGI interpretation; thus meticulous technique is warranted [16-18].
Vomiting in Infants. It is important to recognize sonographic features of midgut volvulus because they can help to substantiate the diagnosis in an equivocal UGI study or when US is performed for other indications (eg, evaluation for HPS). Variant 5: Bilious vomiting in an infant older than 2 days (suspected malrotation). Initial imaging. Most congenital intestinal atresia and stenosis will present in the first 2 days of life. Midgut volvulus is the most important diagnosis in older infants presenting with bilious vomiting because this is a medical emergency [15]. Fluoroscopy Contrast Enema There is no relevant literature to support the use of a contrast enema as the initial imaging study for suspected malrotation. In suspected malrotation with midgut volvulus, if the UGI fails to show the etiology or is equivocal, a contrast enema may be performed as a follow-up study in the workup of bilious vomiting. However, up to 15% of individuals may have a normal mobile cecum [29]. More commonly, if the UGI is equivocal, small bowel follow through to the cecum may be pursued. Vomiting in Infants Fluoroscopy Upper GI Series The barium UGI series evaluates the esophagus, stomach, pylorus, and the duodenum to the duodenal jejunal junction, indicating the location of the ligament of Treitz [5,6,15]. Although the UGI series is considered the reference standard for evaluating malrotation, false-positive and false-negative interpretations may occur. In a retrospective review of 229 cases by Sizemore et al [16], UGI had a sensitivity of 96% with two false-positives (abnormal jejunal position with no malrotation) and seven false-negatives (normal jejunal position with malrotation). Retrospective reviews by Hsiao et al [17] and another such study by Long et al [18] noted false- positive rates of 10% and 15%, respectively. The studies concluded that redundant duodenum, bowel distension, and jejunal position can lead to inaccurate UGI interpretation; thus meticulous technique is warranted [16-18].