CT enterography (CTE) is an examination using neutral oral contrast agents (<20–30 HU) as well as intravenous contrast, with multidetector CT (MDCT) in the evaluation of small-bowel diseases, primarily Crohn’s disease and obscure gastrointestinal bleeding . Currently, this examination is also used worldwide for evaluating acute and chronic mesenteric ischemia (in acute cases, oral contrast media administration may not be necessary), detecting small-bowel neoplasms (often in the setting of obscure gastrointestinal bleeding), and evaluating celiac disease, as well as in the in non traumatic patients who have acute abdominal pain . In most active large centres caring for Crohn’s patients, CT and now MR enterography (MRE) – see the ACR–SAR–SPR Practice Parameter for the Performance of Magnetic Resonance (MR) Enterography – has become the standard of care and has supplanted traditional barium based fluoroscopic techniques (small-bowel series and enteroclysis)
In 2015,a Practice Parameter was developed collaboratively by the American College of Radiology (ACR) and the Society of Abdominal Radiology (SAR) . It spells out the indications and contraindications for the use of modality.
INDICATIONS AND CONTRAINDICATIONS: Clinical indications and contraindications for CT enterography include, but are not limited to, the following:
1. Known Crohn’s disease not in the peri-operative period
2. Suspected Crohn’s disease or other causes of small-bowel inflammation
3. Obscure gastrointestinal bleeding (must use multiphase technique) (best after a negative upper and lower endoscopy)
4. Suspected small-bowel disease (e.g., celiac disease)
5. Chronic diarrhea and/or abdominal pain
6. Suspected chronic mesenteric ischemia
Contraindications (most are relative) Where Other Examinations May be More Efficacious
1. Patients with a known, severe iodinated contrast media allergy who are able to undergo a contrast enhanced MRE
2. Patients with chronic kidney disease, in whom iodinated contrast material or oral fluid volume is considered harmful.
3. Patients who have had multiple CT examinations in their lifetime and in whom the examination is not considered urgent or emergent (consider MRE, especially in younger patients with Crohn’s disease)
4. Patients in the postoperative period (within 2–3 weeks) in whom an abscess or anastomotic leak is considered more likely; This will require the use of a positive oral contrast agent, generally iodinated contrast, either orally or rectally if there is an anastomosis, rather than CTE.
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