Imaging Modalities for Evaluation of Intestinal Obstruction

Abstract

It is essential for the colon and rectal surgeon to understand the evaluation and management of patients with both small and large bowel obstructions. Computed tomography is usually the most appropriate and accurate diagnostic imaging modality for most suspected bowel obstructions. Additional commonly used imaging modalities include plain radiographs and contrast imaging/fluoroscopy, while less commonly utilized imaging modalities include ultrasonography and magnetic resonance imaging. Regardless of the imaging modality used, interpretation of imaging should involve a systematic, methodological approach to ensure diagnostic accuracy.

Keywords: abdominal radiography; bowel obstruction; computed tomography; contrast enema; imaging; large bowel obstruction; magnetic resonance imaging; small bowel follow-through; small bowel obstruction; ultrasound.

Fig. 1

Postoperative ileus with distended small bowel with plicae circulares (thin arrow) and large bowel with haustra (large arrowhead).

Fig. 2

Supine abdominal X-ray of small bowel obstruction: dilated small bowel and paucity of colonic gas.

Fig. 3

( A ) Abdominal X-ray of large bowel obstruction (LBO), demonstrating significant proximal colonic fecal load. ( B ) Abdominal X-ray of LBO, demonstrating significant transverse colon redundancy and distention.

Fig. 4

Supine abdominal X-ray: gasless abdomen with relative paucity of gas. The patient had a CT on the same day that demonstrated small bowel obstruction.

Fig. 5

Upright abdominal X-ray of small bowel obstruction: Multiple air–fluid levels, including multiple within the same bowel loop.

Fig. 6

Upright abdominal X-ray of cecal volvulus demonstrating “C” loop with concavity pointing to right lower quadrant.

Fig. 7

CT without IV contrast demonstrating a transition point (arrow) in the midabdomen with a smooth taper due to a postoperative adhesive small bowel obstruction.

Fig. 8

Coronal CT: “small bowel feces sign” (arrow). Although not easily visualized on this image, this is immediately proximal to a Crohn's stricture.

Fig. 9

Coronal CT with “whirl sign” (arrow) in the setting of sigmoid volvulus.

Fig. 10

( A ) Axial CT showing colonic intussusception with “target sign” (arrow). ( B ) Coronal CT showing colonic intussusception with “sausage sign” (arrow).

Fig. 11

( A ) Water-soluble contrast enema in a patient with obstructing sigmoid colon cancer demonstrating an “apple core lesion” (arrow). ( B ) Water-soluble contrast enema showing in-stent stenosis after prior colonoscopic stent placement. ( C ) Supine abdominal radiograph in the same patient status post–repeat colonic stent placement within prior stent.

Fig. 12

( A ) MRE T2 axial HASTE sequence image in a patient with Crohn's ileitis revealing ileal stricture (thin arrow) and upstream small bowel dilation (large arrowhead). ( B ) MRE trace diffusion-weighted sequence image in the same patient revealing high-signal intensity in the ileus (arrow) consistent with active Crohn's disease. ( C ) MRE T1 coronal VIBE Dixon method sequence image post contrast in the same patient with Crohn's ileitis revealing ileal mural hyperenhancement (thick arrow), thickening, and “comb sign” (thin arrow).