Pseudo-obstruction Assessment With MRI

Inclusion Criteria: * Ability to give informed consent * Sufficient level of English language to understand study information and respond to symptom questionnaires * CASES: a clinical diagnosis of primary or secondary Chronic Intestinal Pseudo-Obstruction, excluding adhesional obstruction. PICs will be asked to send clinical documentation that the diagnosis has been confirmed on crosssectional imaging. * CONTROLS: a Chronic constipation disorder diagnosed according to Rome IV criteria for functional constipation, constipation-predominant irritable bowel syndrome or opioid-induced constipation (diagnostic criteria as listed in Lacy et al 2016) Exclusion Criteria: * Inability to tolerate 400 ml liquid challenge meal (oral or through established gastrostomy; 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, such as antiemetics, fast release opioids, laxatives, and anti-diarrhoeals, on the day before the study (24h before baseline scan; i.e. a total of circa 30h) as well as antibiotics for three days before the study. This only applies to long-term antibiotics commonly given for dysbiosis (small intestinal bacterial overgrowth). A short course of antibiotics given for acute infections will not be interrupted but the study day will be delayed until the course is finished. Patches, long act…