Gastric outlet obstruction can be the result of events, such as in utero vascular accidents, that occur during the embryologic development of the GI tract. When there is an obstructive lesion, distention of the intestine proximal to the obstruction will be noted on the x-ray. A flat plate film, sometimes referred to as a plain film or KUB (kidney, ureter, and bladder), is most commonly used to identify GI abnormalities. A lateral film, which is helpful in identifying free air or fluid may also be obtained. In addition to the flat plate film, x-ray studies using contrast material are instrumental in identifing the location of many obstructions