Assessment of retromesenteric position of the third portion of the duodenum: an US feasibility study in 33 newborns

US can be used to assess bowel and does not require ionizing radiation or the administration of contrast material. Prior studies of the duodenum with US are limited. This study assesses the success rate of US demonstration of the third portion of the duodenum (D3) between the superior mesenteric artery (SMA) and the aorta in newborns to exclude malrotation based on embryologic and anatomic principles. Thirty-three newborns underwent US studies. The structures between the SMA and the aorta, including D3, were evaluated in axial and longitudinal planes. The length of time to acquire diagnostic images was recorded. In both the axial and longitudinal planes, D3 was seen between the SMA and the aorta in all 33 infants, including some with abundant bowel gas. The mean length of time to acquire diagnostic images was 34 s. Bedside US successfully illustrated the retromesenteric position of D3 in all 33 infants. Overlying gas-filled bowel was effectively effaced by graded compression. The short study duration indicates the practicality of the method. Further studies in broader patient populations and in correlation with other imaging and/or surgical findings is required to validate our technique.