CT enterography

Computed tomographic (CT) enterography is a non-invasive technique for the diagnosis of small bowel disorders.

Indications

CT enterography, similarly to MRI enterography, is most commonly used to evaluate patients with Crohn disease where it is used for assessment of the primary disease and any complications. Other indications include celiac disease, postoperative adhesions, radiation enteritis, scleroderma, small bowel malignancies, and polyposis syndromes.

Advantages

useful in the assessment of the solid organs and provides a global overview of the abdomen

Disadvantages

exposure to ionizing radiation

Technique

Note: This article is intended to outline some general principles of protocol design. The specifics will vary depending on CT hardware and software, radiologist's and referrer's preference, institutional protocols, and patient factors (e.g. allergy and fluid intake restrictions).

Bowel preparation

abstain from all food and drink 4-6 hours before the exam

patients drink about 1.5 L of oral contrast over 30-60 minute

adequate luminal distension is necessary as collapsed bowel loops may mimic pathology
CT enterography utilizes negative or neutral oral contrast
- attenuation similar to that of water - e.g. water, PEG, mannitol, methylcellulose, locust bean gum, and low-density barium sulphate preparations (Volumen, 0.1% W/V)

Fluid distension of the small bowel allows better assessment of mucosal enhancement, mural thickness as well as mesenteric vasculature, this is important especially in the evaluation of Crohn disease .

Procedure

CT scanning is ideally performed on a multi-detector computed tomography (MDCT) scanner
intravenous contrast
- Crohn disease, celiac disease, postoperative adhesions, radiation enteritis, and scleroderma: a single enteric phase where peak mucosal enhancement is achieved is sufficient - either enteric phase (45-50s) or portal venous phase (60-70s)
- small bowel tumors: an additional arterial phase can be performed, in particular for the assessment of hypervascular lesions (e.g. neuroendocrine tumors)
- in cases of suspected GI bleeding, pre-contrast, arterial, portal venous, and delayed phases should be considered
data interpretation with the use of axial and coronal reformatted images for proper evaluation

Findings

inflammatory bowel disease and its complications e.g. Crohn disease or ulcerative colitis
small bowel tumors, including benign tumors (e.g. hamartomatous or hyperplastic polyps) or malignant tumors (e.g. adenocarcinoma, carcinoid, lymphoma and gastrointestinal stromal tumors)
mesenteric ischemia and gastrointestinal tract bleeding
Celiac disease