Malrotation of the bowel: malalignment of the superior mesenteric artery-vein complex shown by CT and MR.

A malposition of the superior mesenteric vein on cross-sectional imaging was seen in four adult patients with malrotation of the bowel and is diagnostic of this entity. This sign should be looked for on CT or magnetic resonance to explain ill defined symptomatology and to define who may be at risk for future complications. We also define a "pseudo-superior mesenteric artery-vein sign" due to mass displacement of the pancreas, which must be distinguished from true malrotation.