sigmoid volvulus

CT scans obtained after patient was lying in right (D and F) and left (E and G) lateral decubitus positions confirm shift and clockwise rotation of liver and portal vein (arrowhead, D), left portal vein (black arrow, E), and gallbladder (arrowhead, F and G). Spleen and retroperitoneal structures have not shifted, including azygos vein (white arrow, E).