CT enterography: review of technique and practical tips

Abstract

CT enterography is a new non-invasive imaging technique that offers superior small bowel visualisation compared with standard abdomino-pelvic CT, and provides complementary diagnostic information to capsule endoscopy and MRI enterography. CT enterography is well tolerated by patients and enables accurate, efficient assessment of pathology arising from the small bowel wall or surrounding organs. This article reviews the clinical role of CT enterography, and offers practical tips for optimising technique and accurate interpretation.

Figure 1

Normal CT enterography. Coronal CT enterography image showing normal jejunal (short arrows) and ileal (long arrrows) loops. Note the prominent mucosal pattern in the proximal jejunal loops.

Figure 2

Collapsed small bowel. Axial CT enterography image showing a collapsed small bowel mimicking pathology (long arrow) compared with a normal fluid-filled loop (short arrow). Note the absence of any associated changes.

Figure 3

Small bowel spasm. Axial CT enterography image showing two areas of focal small bowel spasm mimicking pathology (arrows). Note the absence of any associated changes.

Figure 4

Spectrum of findings in active Crohn's disease. (a) Active distal ileal Crohn's disease in a 36-year-old male. Coronal CT enterography image showing mural thickening and mucosal hyperenhancement (long arrows). Compare the normal enhancement of the unaffected small bowel (short arrow). (b) Enlarged vasa recta involving the actively inflamed neoterminal ileum producing a comb sign (arrows). Note the presence of enlarged mesenteric lymph nodes. (c) Axial CT enterography image in a 40-year-old female with a 7-year history of Crohn's disease showing perienteric fibro-fatty proliferation resulting in loop separation (arrows).

Figure 5

Different types of mural stratification. (a) Soft tissue density mural thickening of the terminal ileum representing inflammatory infiltrate in a 34-year-old male with newly diagnosed active Crohn's disease. (b) Fluid density mural thickening of the distal ileum representing submucosal oedema in a 62-year-old female with recurrent Crohn's disease. (c) Fat density mural thickening of the terminal ileum in a 62-year-old female, representing chronic active inflammation.

Figure 6

Complications of Crohn's disease: complex ileo-colonic Crohn's disease in a 62-year-old female. Axial CT enterographic image demonstrating the presence of a retroperitoneal abscess (long arrow) and a sinus tract (short arrow) connecting the abscess and the inflamed distal ileum.

Figure 7

Small bowel tumour: jejunal gastrointestinal stromal tumours in a 77-year-old male with gastrointestinal bleeding (multiple endoscopies including capsule endoscopy examinations were negative). Coronal CT enterography image demonstrates an exoenteric gastrointestinal stromal tumour of the jejunum (arrow).

Figure 8

Meckel's diverticulum with ectopic gastric mucosa in a 31-year-old male with gastrointestinal bleeding. Coronal CT enterography image showing a blind-ending gas-filled tubular structure with thickened, hyperenhancing mucosa in the left lateral margin (arrows, with nodule identified by shorter arrow).