Malrotation

Michael P. Federle, MD, FACR

Key Facts

Terminology

Rotational abnormality of the gut due to arrest of gut rotation and fixation during fetal development

Imaging

Many variations and classifications
Complete nonrotation
- Jejunum to right of spine
- Ileum to left of spine or in pelvis
Upper GI series with small bowel follow through
- Normal barium enema does not exclude malrotation nor volvulus
Classic malrotation
- Cecum lies in midline or to left
- Fixed in position by bands from undersurface of liver (Ladd bands)
- Ladd bands cross duodenum and may obstruct it
- Oral contrast medium ends abruptly or in “corkscrew” pattern within duodenum
CT: Superior mesenteric vein (SMV) ventral to or on left of SMA
- Volvulus of midgut indicated by “whirlpool” or “swirl” sign of twisted mesenteric vessels and bowel
- CT shows congenital anomalies and complications

Top Differential Diagnoses

Paraduodenal hernia

Clinical Issues

Up to 40% diagnosed by 1 week of age
- 50% by 1 month
- 75% by 1 year
- 25% after 1 year
Some cases of volvulus or obstruction occur in older children or adults

(Left) 27-year-old man with pain and vomiting. Axial CECT shows all of the small bowel, even the duodenum

, lying to the right of midline. The cecum is midline, and the remaining colon lies to the left of midline. (Right) Upper GI series in the same patient shows partial obstruction at the level of the distal duodenum. The duodenum never crosses the midline but has a peculiar “Z” or “corkscrew” configuration