CT enteroclysis (protocol)

Computed tomographic (CT) enteroclysis refers to a hybrid technique that combines the methods of fluoroscopic intubation-infusion small-bowel bowel examinations with that of abdominal CT ¹.

Indications

CT enteroclysis is complementary to capsule endoscopy in the elective investigation of small-bowel disease, with a specific role in the investigation of Crohn disease, small-bowel obstruction ^{1, 3}, and unexplained gastrointestinal bleeding.

CT enteroclysis is thought to beconsidered significantly superior to conventional enteroclysis in depicting Crohn's disease-associated intra- and extra-mural abnormalities².

Technique

CT enteroclysis utilises mainly two types of contrast :

• neutral contrast media^{1, 5}
  • these have attenuation attenuation similar to that of water e, e.g. water, methyl cellulose
  • intravenous contrast is used with neutral agents
  • these agents allow better assessment of mucosal enhancement, mural thickness as well as mesenteric vasculature
  • better used in unexplained subacute gastrointestinal bleeding due to vascular malformation and assessment of inflammatory activity and complications of small bowel Crohn’s disease
• ​positive enteral contrast material^{1, 5}
  • ​e.g. (4 to 15% water-soluble (sodium diatrizoate) solution or a dilute dilute (1%) barium solution)
  • no intravenous contrast is used with these agents
  • mainly used to detect lower grades of small bowel obstruction and internal fistula

Procedure

The technique of CT enteroclysis can be summarised and simplified as follows ^1,5,8:

1. Bowel preparation: low-residue diet, ample amount of fluids, laxative on the day prior to the examination, and nil by mouth on the day of the examination.
2. Conscious sedation (optional, according to patient's preference)
3. Introduction of the 12 to 14-F enteroclysis tube (under fluoroscopy or through duodenoscope). The tube tip is usually placed distal to the ligament of Treitz .
4. Contrast is administered either on the fluoroscopy table or after transferring the the patient to the CT unit for commencement of the CT scan (usually 1.5-2L of oral contrast).
5. In the CT unit, the position of the enteroclysis tube is checked in the topogram.
6. In case negative oral contrast willis to be be used, intravenous contrast injection will be given (approximately 100-150ml).
7. After completing the scan, the tube is withdrawn gradually to the stomach and any extra contrast volume is suctioned.

See also

• enteroclysis
• CT enterography
• MR enterography
• MR enteroclysis