Figure 1.

CT scan of the case 1. A: Plain abdominal radiograph showing distention of a short segment of the small bowel (arrow) and a few air-fluid levels (*), suggesting obstruction of the small bowel. The cecum (long dashed arrow) is of normal caliber and shows normal fecal densities. Plain radiograph signs are not specific at this stage, and further evaluation with CT is indicated. B: CT scan showing a narrow transition point forming a "beak sign" (long white arrow). There are the proximal dilated small bowel loop (*) and the normal caliber more distal small bowel (#). There is some stranding in the small bowel mesentery (thin dashed arrow). The cecum (white arrowhead) is normal. C: CT slice just inferior to Figure 1B reveals mural edema (thin arrow) of the small bowel and free peritoneal fluid (thick arrow). There is a significant stranding of the small bowel mesentery (thin dashed arrow).

Figure 2.

CT scan of the case 2. A: Plain abdominal radiograph showed multiple loops of slightly distended small bowel (thin arrow) but no intestinal obstruction and focal narrowing of the small bowel (thick arrow). B: Axial CT scan showing the center of the twist point (*) with a markedly thickened small bowel loop (arrows) leading to it. C: Coronal reformatted CT scan images better demonstrate a closed loop of the small bowel which forms a U-shaped configuration (dashed arrows).There is the tapering or "rat-tailing" (long thin arrow) of the small bowel at the thickened twist point (thick arrow). The more proximal ejunal loops are dilated (#). There is a nasogastric tube in the stomach (*).

Figure 3.

CT scan of the case 3. A: Plain abdominal radiograph showing distended bowel loops with mural thickening (arrow) and a Tenckhoff catheter in-situ; B: The axial CT scan shows a very abnormal segment of the small bowel (long white arrow), which is infarcted. There is no enhancement with contrast and the small bowel walls (multiple thin arrows) are barely perceptible. There is significant free fluid in the peritoneal cavity (*). Compared this to the clearly visible and enhancing bowel wall, more distally (dashed arrow), which is edematous but not infarcted. There may be gas within the bowel wall itself i.e. pneumatosis intestinalis or free gas due to perforation (not shown); C: CT scan demonstrating a "small bowel feces sign" (arrow). This is not actually fecal material, but has an appearance similar to the mixed solid densities and gas lucencies which are normally seen in the large bowel (cecum in Figuer 1B and 1C) but not normally visible in the small bowel. This is due to a stagnation of small bowel motility owing to obstruction; D: CT scan showing an area of mesenteric congestion (long arrow). The small bowel mesentery shows thickened veins (small arrows) and fat stranding, which refers to areas of increased density within the normally black (lucent) fat (*). Again, significant free fluid (#) can be seen.