The M ultifaceted R ole o f R adiology in S mall B owel O bstruction

Small bowel obstruction is a common clinical condition, often presenting with signs and symptoms similar to those seen in other acute abdominal disorders. The diagnosis and treatment of this dynamic process continues to evolve. The imaging approach in the work-up of patients with known or suspected small bowel obstruction and the timing of surgical intervention in this disease have undergone considerable changes over the past two decades. This article examines the changes related to the use of imaging technology in the diagnosis and management of patients with small bowel obstruction. The meaning of frequently used but poorly defined terms in describing intestinal obstruction is clarified and illustrated. about 12%-15% of acute abdominal admissions. 1 History and physical findings are often suggestive of the diagnosis, which is straightforward when the classic picture of crampy abdominal pain, bilious vomiting, and abdominal distension is present. Plain abdominal radiographs in this setting often show multiple air fluid levels within dilated loops of small bowel, accompanied by a reduced amount of colonic gas. In many cases of confirmed SBO, however, the clinical picture is frequently vague. Plain radiography is often unhelpful, and the diag- nosis may be in doubt. In these situations a routine abdomino-pelvic computed tomography (CT), flu- oroscopic enteroclysis, or the combined study of CT and enteroclysis (CT enteroclysis) should be considered. Even when the diagnosis of SBO is unequivocal, further imaging may be required to identify the cause, site, and severity of the obstruc- tion, and to determine whether bowel ischemia has developed. Specific radiological findings can often impact directly on the decision of whether a trial of nonoperative therapy can be safely undertaken or whether urgent surgical intervention is required. The radiologist may also aid clinical management by taking responsibility for the insertion of long naso-jejunal tubes to decompress the distended small bowel. In this article, we discuss the various imaging techniques to assess SBO, the features of complicated SBO, diagnostic clues to ascertain the etiology of SBO, and outline the role of the radi- ologist in the investigation and management of SBO. ABDOMINAL RADIOGRAPHY The accuracy of abdominal radiography (AR) in diagnosing SBO is 50%-60%. 2-6 In up to 10% of