CT enterography (protocol)

Last revised by Dr Daniel J Bell on 08 Sep 2022

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

Indications for CT enterography include 4,8:

  • useful in the assessment of the solid organs and provides a global overview of the abdomen 1

NB: 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 preferences, institutional protocols, and patient factors (e.g. allergy and fluid intake restrictions). 

  1. abstain from all food and drink 4-6 hours before the exam
  2. 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 1-3
      • 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 2.​

  • CT scanning is ideally performed on a multidetector 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

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Cases and figures

  • Case 1: normal CT enterography arterial phase
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  • Case 1: portal venous phase
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  • Case 2: Crohn disease
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  • Case 3: Crohn disease
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  • Case 4: Crohn disease with small bowel obstruction
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