Indian Journal of Radiology and Imaging Indian Journal of Radiology and Imaging

ABDOMINAL
Year
: 2006  |  Volume : 16  |  Issue : 1  |  Page : 71--74

"Small bowel feces sign" - a ct sign in small bowel obstruction


J Singh, R Kumar, A Kalyanpur 
 From the Teleradiology solutions, Bangalore - 560066, India

Correspondence Address:
J Singh
Consultant Radiologist, Teleradiology Solutions, Villa 2, Regent Place, Whitefield Main Road, Bangalore -560066
India




How to cite this article:
Singh J, Kumar R, Kalyanpur A. "Small bowel feces sign" - a ct sign in small bowel obstruction.Indian J Radiol Imaging 2006;16:71-74


How to cite this URL:
Singh J, Kumar R, Kalyanpur A. "Small bowel feces sign" - a ct sign in small bowel obstruction. Indian J Radiol Imaging [serial online] 2006 [cited 2019 Nov 22 ];16:71-74
Available from: http://www.ijri.org/text.asp?2006/16/1/71/29053


Full Text

 Introduction



Small bowel obstruction is a common cause of abdominal emergency. Diagnosis helps effective management and prevents complications. CT is an effective tool in evaluation of small bowel obstruction. The small bowel feces sign is a finding observed in small bowel obstruction on Helical CT [6]. It is defined as presence of feces like material in the lumen of dilated loops of small bowel proximal to the site of obstruction. This section will illustrate the small bowel feces sign with examples

 Discussion



Small bowel obstruction is a common cause of acute abdomen. It accounts for approximately 4% of patients presenting with an acute abdomen [1]. Clinical signs and symptoms are not always diagnostic. Identifying the cause of obstruction is important for early management. Many other clinical conditions like adynamic ileus, intraabdominal abscess, and gastroenteritis present with similar clinical presentation.

CT scan of abdomen has shown to be effective in diagnosing small bowel obstruction [2], with high degree of sensitivity. It can provide information about the specific cause and site of obstruction. The role of CT in the diagnosis of small bowel obstruction is to identify small bowel dilation and a transition point. The degree of obstruction can be mild, moderate or high grade depending on caliber difference between the dilated and nondilated segment of bowel. High-grade obstruction is greater than 50% difference in caliber of proximal dilated small bowel and collapsed distal small bowel CT in addition to confirming the diagnosis of obstruction is also useful in determining the degree and cause of obstruction, and also complications that require immediate surgery (e.g. closed loop obstruction or bowel ischemia) [3].

Adhesions are the most common case of small bowel obstruction, accounting for 60-80% of all the cases (ref 4). The other causes include external hernias, inflammatory strictures and tumors. Identifying the transition point (transition point is the zone where the dilated loops abruptly change in caliber to normal/nondilated bowel) helps in evaluating the cause of obstruction and initiating appropriate treatment. Although the identification of transition zone of the obstruction is easy in case of external hernias [Figure 1] or tumors, it is difficult to visualize in cases of adhesions.

On CT, the usual way is to trace the bowel to the point of transition. However is not always easy on the axial images. It requires either scrolling through the images back and forth or requires multiplanar reformats to identify the zone of transition and the underlying cause.

Small bowel feces sign is a useful CT sign that helps identifying the transition zone [Figure 2][Figure 3]. It is defined as presence of feces like material mixed with gas bubbles in the lumen of dilated loops of small bowel proximal to the site of obstruction. This sign tends to be most prominent at the zone of transition from the dilated to the collapsed portion of the small bowel. It is likely caused by stasis within the obstructed loop, allowing more time for fluid absorption from the bowel and accumulation of undigested food particles. This sign is seen in mechanical small bowel obstruction due to adhesions, hernias to tumors, and inflammatory stenosis. Mottled material with air collections within the small bowel may also be seen in other conditions such as infections or metabolic bowel disease, rapid jejunostomy tube feedings or bezoars [5]; however by definition the small bowel feces sign is presence of feculent material with dilation of proximal bowel and signs of obstruction. Sometime feculent material is seen as normal finding in non-dilated distal ileal loops, which usually results from reflux of fecal material from the cecum secondary to an incompetent ileocecal valve [Figure 4].

The feces sign may be seen in a high percentage of patients with small bowel obstruction. In one of the series it was reported in as many as 82% (18/22) of the sample population with mechanical small bowel obstruction [6].

In summary small bowel obstruction is a common clinical problem. Identifying the zone of transition helps in determining the underlying cause and there by guiding appropriate treatment. The identification of the small bowel feces sign on CT is important because this sign is usually seen at the zone of transition, thus facilitating identification of the site and many times leading to the cause of obstruction. The CT appearance and knowledge of this sign is of value and helps the radiologist in the diagnosis of small bowel obstruction.

References

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4Balthazar EJ CT of small bowel obstruction AJR 1994;162:356-375.
5Quiroga S, Alvarez- castells A sebastia C, Pallisa E, Barluenga E. small bowel obstruction secondary to bezoar; CT diagnosis, Abdom imaging 1997;22:315-317.
6Mayo-Smith WW, Wittenberg J, Bennett GL, Gervais DA, Gazelle GS, Mueller PR. The CT small bowel feces signs; description and clinical significance. Clin Radiol 1995; 50:765-767.