Although positive oral contrast agents are used for the majority of abdominopelvic CT scans in the United States, the quality of bowel opacification has not been compared between the three major classes of positive oral contrast material (barium sulfate, ionic iodinated contrast material, and non-ionic iodinate contrast material). The investigators will retrospectively identify 250 patients each who received oral barium sulfate, diatrizoate, and iohexol for CT scanning of the abdomen and pelvis (total 750 patients) and assess the quality of bowel lumen opacification by the positive oral contrast agents.~Primary objective:~To show the uniformity of bowel opacification is different between the three main types of CT oral contrast material used in the United States (Barium sulfate, Diatrizoate, and Iohexol).~Secondary objectives:~To show whether or not one of the oral contrast agents provides more uniform opacification than the others in the proximal or distal bowel~To assess the relative opacification of the distal small bowel (ileum) by the three contrast agents.
Although positive oral contrast agents are used for the majority of abdominopelvic CT scans in the United States, the quality of bowel opacification has not been compared between the three major classes of positive oral contrast material (barium sulfate, ionic iodinated contrast material, and non-ionic iodinate contrast material). This is a retrospective single institution study of clinical records to show whether the uniformity of bowel opacification is different between the three main types of positive CT oral contrast material used in the United States (Barium sulfate, Diatrizoate, and Iohexol). The investigators will retrospectively identify 250 patients each who received oral barium sulfate, diatrizoate, and iohexol for CT scanning of the abdomen and pelvis (total 750 patients) and assess the quality of bowel lumen opacification by the positive oral contrast agents.