Midgut volvulus in infants presents with bilious vomiting, abdominal distention, and pain. Which imaging test confirms the diagnosis?

• A. Abdominal X-ray
• B. Ultrasound
• C. Upper GI series
• D. CT scan

Answer: (C)

The key concept is that confirming malrotation with midgut volvulus relies on directly visualizing the abnormal intestinal rotation and the position of the duodenojejunal junction. An upper GI series does exactly that: it follows the flow of contrast through the stomach into the duodenum and small bowel, revealing where the duodenojejunal junction lies and whether the duodenum takes an abnormal, twisted course. In malrotation with volvulus you may see a corkscrew configuration of the twisted bowel or a displaced DJ junction, which are diagnostic and require urgent surgical intervention.

Other imaging methods can raise suspicion but are less definitive or practical in infants. A plain abdominal X-ray often shows non-specific gas patterns. Ultrasound can hint at malrotation by assessing the relationship of the SMA and SMV or showing a whirlpool sign, but it’s operator-dependent and not as consistently diagnostic. CT provides detailed anatomy but involves radiation and is not the first-line test in this age group.