Pseudo-obstruction Assessment With MRI

Inclusion Criteria:

• Ability to give informed consent
• Sufficient level of English language to understand study information and respond tosymptom questionnaires
• CASES: a clinical diagnosis of primary or secondary Chronic IntestinalPseudo-Obstruction, excluding adhesional obstruction. PICs will be asked to sendclinical documentation that the diagnosis has been confirmed on crosssectionalimaging.
• CONTROLS: a Chronic constipation disorder diagnosed according to Rome IV criteria forfunctional constipation, constipation-predominant irritable bowel syndrome oropioid-induced constipation (diagnostic criteria as listed in Lacy et al 2016)

Exclusion Criteria:

• Inability to tolerate 400 ml liquid challenge meal (oral or through establishedgastrostomy; according to self-assessment)
• Contra-indication to MRI scanning, such as metal implants, pacemaker etc
• Pregnancy declared by candidate (no formal testing)
• Inability to stop short-acting medications likely to alter small bowel motility, suchas antiemetics, fast release opioids, laxatives, and anti-diarrhoeals, on the daybefore the study (24h before baseline scan; i.e. a total of circa 30h) as well asantibiotics for three days before the study. This only applies to long-termantibiotics commonly given for dysbiosis (small intestinal bacterial overgrowth). Ashort course of antibiotics given for acute infections will not be interrupted but thestudy day will be delayed until the course is finished. Patches, long actingformulations such as slow release medication or depot injection medication will beallowed to continue
• Inability to omit parenteral nutrition for 12 hours before the fasting MRI scan (~16htotal)
• Medical comorbidity that means subject will not be able to undergo multiple scans e.g.severe respiratory disorder limiting time lying flat; severe musculoskeletal disorderlimiting mobility
• Previous small bowel resection (excluding ileostomy, insertion of venting tube orpercutaneous endoscopic gastrostomy, appendectomy or cholecystectomy). Patients whohave had a colectomy for their CIPO will be eligible.
• Other gastrointestinal disorder likely to alter small bowel function e.g. uncontrolledcoeliac disease, Crohn's disease. A diagnosis of small intestinal bacterial overgrowthwill not be a reason for exclusion. PICs will be asked to supply information onresections and comorbidities for CIPO participants.