A normal sonogram does not exclude malrotation

Abstract

We present case reports of three recent patients to reinforce the argument that upper gastrointestinal series is the method of choice with which to document malrotation. It has been 9 years since there was a major discussion of this subject in the literature. Ultrasonography cannot confidently exclude malrotation. Radiographic study with contrast continues to be the best diagnostic tool.

Is ultrasonography a good screening test for intestinal malrotation?

“…This group of 9 children represented 30% of the children with malrotation in whom the mesenteric vessels were visualized. Ashley et al [6] reported 1 case with similar findings, and Zerin and DiPietro [8] noted that 3 (33%) of 9 children with malrotation had a normal orientation of the mesenteric vessels. It is unclear why these reports differ from our results.…”

“…In those cases where the SMV lies anterior to the SMA the incidence of malrotation decreases to 25% to 28% [2,3]. However, it has been shown by other authors that inversion of the SMV/SMA relationship can also be seen in patients with normal midgut rotation [5,6] and in patients with abdominal masses and distal ileocolic intussusception [5,7]. Furthermore, not all cases of malrotation have abnormal SMV/SMA orientation on US [2,6,8].…”

“…However, it has been shown by other authors that inversion of the SMV/SMA relationship can also be seen in patients with normal midgut rotation [5,6] and in patients with abdominal masses and distal ileocolic intussusception [5,7]. Furthermore, not all cases of malrotation have abnormal SMV/SMA orientation on US [2,6,8]. Because of the lower sensitivity and specificity of US compared with UGI, and because of the fact that US cannot estimate the length of the mesenteric base (which determines the risk of midgut volvulus) [2,9,10], UGI has remained the gold standard diagnostic modality.…”

“…This suggests that a normal US definitively rules out the danger of midgut volvulus and precludes the need for further investigation. However, a few studies have shown that cases of malrotation in the presence of normal relationship of the mesenteric vessels do occur [2,6,8]. Dufour et al [2] found that 9 (2.76%) of 326 children with recurrent abdominal pain and/or vomiting who had a normal SMV/SMA orientation on US did have malrotation on UGI.…”

Diagnostic Accuracy of Ultrasound in Determining the Cause of Bilious Vomiting in Neonates

“…However, this inversion is neither specific nor sensitive enough. A normal sonogram does not exclude malrotation (10). There are also other data which show that sonography is a good screening tool that effectively rules out malrotation at risk for volvulus (7).…”