Are laxatives required prior to a Computed Tomography (CT) Enterography procedure?

CT Enterography Preparation: Laxatives Not Required

Laxatives are not required for routine CT enterography; patients only need to fast from solids for 4-6 hours and ingest oral contrast agents (typically 900-1,500 mL of hyperosmolar solution) 45 minutes before the examination. 1, 2

Standard Preparation Protocol

Fasting Requirements

• Patients must fast from solids for 4-6 hours prior to CT enterography 1, 2
• Liquids should be restricted during this period, though water remains permissible 1, 2

Oral Contrast Administration

• Administer 900-1,500 mL of oral contrast over 45-60 minutes before scanning, with specific volume based on patient weight 2
• Volumes exceeding 1,000 mL provide superior bowel distension, though diagnostically acceptable images can be obtained with as little as 450 mL 1, 2
• Suitable hyperosmolar agents include mannitol, polyethylene glycol (PEG), sorbitol, or combinations thereof 1
• No current evidence favors one oral contrast preparation over another 1

Key Distinction from CT Colonography

This is a critical pitfall to avoid: CT enterography differs fundamentally from CT colonography in preparation requirements. 1

• CT colonography requires cathartic bowel cleansing with agents like polyethylene glycol or sodium phosphate 1
• CT enterography explicitly does not require additional colonic preparation or laxatives for routine examination 1

When Colonic Evaluation Is Needed

If colonic assessment is required during CT enterography, diagnostic accuracy for colonic inflammation improves with colonic filling achieved through either:

• Prolonged oral contrast administration 1
• Rectal liquid enema 1

However, additional colonic preparation remains unnecessary for routine MR enterography or CT enterography focused on small bowel evaluation 1

Important Caveats

Inadequate Preparation Consequences

• Studies performed without oral contrast preparation demonstrate inferior diagnostic accuracy due to insufficient bowel distension 1
• This represents the most common technical failure in CT enterography 1

Patient Warnings

• Patients should be counseled that they may experience cramping and diarrhea after ingesting hyperosmolar oral contrast agents 1
• These side effects are expected and do not indicate preparation failure 1

Spasmolytic Agents

• Administration of spasmolytic agents (hyoscine butylbromide or glucagon) improves bowel distension and is currently recommended, though diagnostically acceptable images can be acquired without them 1