Adequate bowel preparation is required for magnetic resonance enterography (MRE) which can be achieved by two methods including administering contrast solution after mid-gut tubing and taking contrast solution orally. We present the design of randomized controlled trial to compare the efficacy and compliance of bowel preparation through mid-gut tubing with taking contrast orally for MRE in patients with Crohn's disease (CD).

This is a open label, multicenter, randomized controlled trial. 96 patients are planed to be 1:1 randomized into one of two groups: (1) Tube group, mid-gut tubing prior to the MRE examination, administer contrast solution through the mid-gut tube; (2) Oral group, administer contrast solution orally, mid-gut tubing after the MRE examination. The primary outcome measures are: (1) grade of bowel distention evaluated by a 5-grade scale (1 = 0-20% segmental distention, 2 = 20-40% distention, 3 = 40-60% distention, 4 = 60-80% distention, 5 = 80-100% distention); (2) degree of discomfort before/during/after bowel preparation for MRE using a visual 5-grade to describe the severity of nervousness, nausea, vomiting, bloating, abdominal pain, and diarrhea (1 = few, 5 = very severe). The secondary outcome measure is the accuracy of lesion detection through MRE confirmed by endoscopy (within 1 month before MRE and during this hospitalization) will be evaluated by a 5-point scale (lesions locating at the terminal ileum, ileocecal junction, hepatic flexure of colon, splenic flexure of colon, and rectosigmoid colon, consistency of lesion detection from each bowel segment scoring 1 point, otherwise not scoring).

Inclusion Criteria:

• Patients with CD need MRE examination and mid-gut tubing (prepared for fecal microbiota transplantation and/or enteral nutrition);
• Age ≥ 14 years old.

Exclusion Criteria:

• Unable to understand or provide informed consent;
• Had difficulty in swallowing, or dysphagia;
• Allergic to laxative and/or contrast;
• Claustrophobia or implanted metal objects or cardiac pacemaker precluding performance of MRI;
• Known or suspected intestinal obstruction or severe stricture.