Helical CT in the Diagnosis of Small Bowel Obstruction

Abstract

With recent technologic developments, the role of computed tomography (CT) in the diagnosis of bowel obstruction has expanded. CT is recommended when clinical and initial radiographic findings remain indeterminate or strangulation is suspected. This modality clearly demonstrates pathologic processes involving the bowel wall as well as the mesentery, mesenteric vessels, and peritoneal cavity. CT should be performed with intravenous injection of contrast material, and use of thin sections is recommended to evaluate a particular region of interest. CT is reported to have a sensitivity of 78%-100% for the detection of complete or high-grade small bowel obstruction but may not allow accurate diagnosis in cases involving incomplete obstruction. In such cases, the use of adjunct enteroclysis is indicated. Furthermore, multiplanar reformatted imaging may help identify the site, level, and cause of obstruction when axial CT findings are indeterminate. CT can also demonstrate findings that indicate the presence of closed-loop obstruction or strangulation, both of which necessitate emergency exploratory laparotomy. Unfortunately, these pathologic conditions may be missed, and patients with suspected severe obstruction or bowel ischemia in whom CT and clinical findings are widely disparate must also undergo laparotomy. In general, however, CT allows appropriate and timely management of these emergency cases.

Concomitant obturator hernia and midgut volvulus in an elderly woman

“…The bowel loop is twisted around an underlying point of fixation, causing closedloop obstruction at two fixed points due to acquired or congenital lesions [10]. The most frequently encountered cause is postoperative adhesions.…”

“…Characteristics CT findings in closedloop obstruction include a Cshaped, Ushaped, or 'coffee bean' appearance of the bowel loop, mesenteric vessels converging towards the point of obstruction, fluidfilled bowel loop, a triangular loop, the beak sign and whirl sign at the site of obstruction [10]. Whirl sign represents twisting of the bowel loop with the superior mesenteric artery at the center of the whirl and is a CT sign of midgut volvulus.…”

“…A volvulus represents the most common cause of strangulation with associated bowel ischemia. Midgut volvulus may be primary without an associated underlying cause, or secondary to a congenital or acquired condition [7][8][9][10]. We present a case of concomitant obturator hernia and midgut volvulus in a 94yearold woman with a series of imaging studies.…”

Congenital Internal Hernia a Rare Cause of Acute Intestinal Obstruction

“…At present CT has a high diagnostic accuracy not only in detecting SBO but also in defining its severity and aetiology. The later is determined by meticulous analysis of the tranisition zone between dilated and collapsed loops allowing for the correct diagnosis of the cause in 73-95 % [6,7]. The other aetiologies in the differential diagnosis of CIH include Crohn's disease, incarcerated femoral or obturator hernia, an obstructing phytobezoar, gall stone ileus and obstructing neoplasms [8].…”

Computed Tomography Findings of Small Bowel Obstruction due to Bezoar Impaction: A Case Series

“…Identifying the cause of obstruction is important for early management. The multiplanar reformatted imaging feature of CT may help accurately characterize the presence, site, degree, cause, and associated complications of obstruction [2]. SBO is diagnosed when abdominal CT scans show distended small bowel loops with air-fluid levels proximal to collapsed loops.…”