Figure 1. Supine radiograph: complete small bowel obstruction. Supine radiograph from a patient with complete small bowel obstruction shows distended small bowel loops in the central abdomen with prominent valvulae conniventes (small white arrow). Bowel wall between the loops is thickened and edematous (large white arrow). No air is seen in the colon or the rectum. Note the presence of an isolated small bowel loop in the right lower quadrant (black arrow), which is seen fixed in the same location on upright films, as shown in Figure 4.
Figure 2. Radiograph: acute colonic pseudo-obstruction. Radiograph from a patient with acute colonic pseudo-obstruction shows a dilated colon with haustral markings (white arrow) and edematous small bowel loops (black arrow). Air extends down to the distal sigmoid. This picture is also consistent with rectal obstruction, which could have been excluded by rigid sigmoidoscopy.
Figure 3. Radiograph: postoperative ileus. Radiograph from a patient with postoperative ileus shows massive gastric distention (A), distended small bowel loops (B), air throughout the colon, mild dilatation of the sigmoid colon (C) with air mixed with stool, and a haustral fold in the apex of the sigmoid colon (D).
Figure 4. Upright radiograph: complete small bowel obstruction. Upright radiograph from the same patient as the supine radiograph in Figure 1 shows multiple air-fluid levels of varying size arranged in inverted Us. In the right lower pelvis, a loop of small bowel is seen in exactly the same location as on the supine abdominal film (black arrow), a finding suggestive of adhesive obstruction.
Figure 5. (A), X-ray: massive sigmoid volvulus. Radiograph from a patient with massive sigmoid volvulus shows a distended ahaustral sigmoid loop (white arrow), inferior convergence of the walls of the sigmoid loop to the left of the midline, and approximation of the medial walls of the sigmoid loop as a summation line (black arrow). (B), Barium enema: massive sigmoid volvulus. Barium enema of the colon shows a tapered obstruction at the rectosigmoid junction with a typical bird's-beak deformity (black arrow).
Figure 6. (A), Radiograph: cecal volvulus. Radiograph from a patient with cecal volvulus shows a dilated cecum with no air distally in the colorectum. Convergence of the medial walls of the loop (black arrow) points to the right, a typical finding in cecal volvulus. (B), Barium enema: cecal volvulus. Barium examination demonstrates a bird's-beak deformity tapering at the point of volvulus (large white arrow). Note walls of dilated cecum (small white arrows).
Figure 7. Radiograph: complete colonic obstruction. Shown is a radiograph from a patient with complete colonic obstruction from an obstructing carcinoma in the descending left colon with proximal air-fluid levels. The absence of air distally in the rectum or the sigmoid is suggestive of complete obstruction. The ileocecal valve is competent, and thus, there is no small bowel air.
Figure 8. CT Scan: partial small bowel obstruction. CT scan from a patient with partial small bowel obstruction shows distended, fluid-filled loops of small bowel with air-fluid levels, hyperemia, and bowel wall thickening (large white arrow). Note the discrepancy in caliber between dilated small bowel and decompressed small bowel (dashed white arrow) and the stranding (small black arrow) in the small bowel mesentery. Air in a decompressed descending colon (large black arrow) is indicative of partial obstruction.
Figure 9. CT scan: adhesive partial small bowel obstruction. CT scan from a patient with adhesive partial small bowel obstruction shows massively dilated small intestine (black arrow) proximal to a thick adhesive band (large white arrow) and decompressed small bowel distal to the adhesion (dashed white arrow). The patient was operated on because of the low probability that this obstruction would resolve with conservative management.
Figure 10. CT scan: partial small bowel obstruction. CT scan from a patient with partial small bowel obstruction from cancer shows distended small bowel (dashed white arrows) proximal to a mass (small white arrow). There is air in the cecum (black arrow), the transverse colon, and the descending colon (large white arrow). The small bowel is maximally dilated, with hyperemic, edematous bowel wall (B) just proximal to an obstructing recurrent colon carcinoma. Even though plain radiographs showed partial small bowel obstruction, this CT scan led to early operation because continued nonoperative management would not resolve the problem.
Figure 11. CT scan: early closed-loop small bowel obstruction. Early closed-loop small bowel obstruction CT scan from a patient with early closed-loop obstruction of the small intestine shows markedly edematous, hyperemic small bowel, a finding indicative of early strangulation (white arrow). The patient had minimal symptoms, and there was air in the transverse colon and the descending colon (a finding indicative of partial small bowel obstruction); however, the finding of gangrenous, nonperforated small bowel on this CT scan led to early operation.
Figure 12. Approach to management of ileus. Shown is an algorithm outlining an approach to management of ileus.
Figure 13. Approach to management of pseudo-obstruction. Shown is an algorithm out-lining an approach to management of pseudo-obstruction.