Abdominal computed tomography of intensive care unit patients

mm) imaging is performed through the regions of highest clinical concern.The bowel should be uniformly opacified and maximally distended with oral contrast or air to accurately assess mural thickness and to avoid misinterpreting unopacified bowel loops as abscesses, masses, or lymphadenopa-thyY At the University of Pennsylvania Medical Center, this is accomplished by steadily administering approximately 900 to 1,000 mL of a 2% to 3% water-soluble iodinated solution (Gastrograffin, diatrizoate meglumine; Squibb, Princeton, NJ) to all ICU patients over a 45-minute period immediately before the CT examination.In patients who are not alert, the oral contrast should be carefully administered via indwelling nasogastric, gastrostomy, or jejunostomy tubes to reduce the risk of aspiration.Nasogastric tubes should be withdrawn into the distal esophagus before scan initiation to reduce streak artifacts through the upper abdomen.Intravenous contrast administration is an additional vital component of the examination because abnormalities in organ enhancement add important clues to the detection and characterization of intraabdominal diseases.For routine survey examinations, we use a uniphasic intravenous contrast injection of 150 mL of Conray 60% (Ma!linckrodt Medical Inc, St. Louis, MO) delivered via a power injector at a rate of 2 mL/s.Nonionic contrast is used in severely debilitated patients, patients with a history of moderate to severe contrast reaction (eg, laryngospasm or facial edema, cardiac arrythmias, bronchospasrn/wheezing, chest tightness or shortness of breath, or pulmonary edema), patients with significant cardiac disease, patients with a history of asthma, and in patients with a history of significant allergy to other medications or shellfish.Helical CT scanning is initiated approximately 80 seconds after the initiation of the contrast bolus using 7-ram collimation and a pitch of 1.2:1.Our "abdominal" CT examinations are routinely performed from the level of the hemidiaphragms to the pubic symphysis. SMALL BOWEL OBSTRUCTION VERSUS ILEUSPatients in the ICU frequently develop small bowel dilatation owing to a variety of causes, 128