Ileus (intestinal obstruction) ◼ Mechanical intestinal obstruction – Simple obstruction：occlusion/constriction of bowel lumen – Strangulated obstruction：impaired blood supply of obstructed segment ◼ Ileus (adynamic/non-obstructive) – Paralytic & spasm – Derangement impairing proper distal propulsion of intestinal contents Cautions to barium exam due to the possibility of obstruction aggravating