Stimulation of colonic motility by oral PEG electrolyte bowel preparation assessed by MRI: comparison of split vs single dose

Abstract

BackgroundMost methods of assessing colonic motility are poorly acceptable to patients. Magnetic resonance imaging (MRI) can monitor gastrointestinal motility and fluid distributions. We predicted that a dose of oral polyethylene glycol (PEG) and electrolyte solution would increase ileo-colonic inflow and stimulate colonic motility. We aimed to investigate the colonic response to distension by oral PEG electrolyte in healthy volunteers (HVs) and to evaluate the effect of single 2 L vs split (2 × 1 L) dosing.MethodsTwelve HVs received a split dose (1 L the evening before and 1 L on the study day) and another 12 HVs a single dose (2 L on the main study day) of PEG electrolyte. They underwent MRI scans, completed symptom questionnaires, and provided stool samples. Outcomes included small bowel water content, ascending colon motility index, and regional colonic volumes.Key ResultsSmall bowel water content increased fourfold from baseline after ingesting both split (p = 0.0010) and single dose (p = 0.0005). The total colonic volume increase from baseline was smaller for the split dose at 35 ± 8% than for the single dose at 102 ± 27%, p = 0.0332. The ascending colon motility index after treatment was twofold higher for the single dose group (p = 0.0103).Conclusions & InferencesIngestion of 1 and 2 L PEG electrolyte solution caused a rapid increase in the small bowel and colonic volumes and a robust rise in colonic motility. The increase in both volumes and motility was dose dependent. Such a challenge, being well-tolerated, could be a useful way of assessing colonic motility in future studies.

A novel semi-automatic segmentation method for volumetric assessment of the colon based on magnetic resonance imaging

“…However, these studies do not report on the volume of the colon. More recent studies comparable to our study use manual segmentation to obtain regional colonic volumes from MRI [9,11,12,30]. These studies found colonic volumes within the range of our results and a wide variation in colon morphology between subjects.…”

“…Quantitative segmental colonic volumetric assessment using MRI has been used to study normal values and changes in irritable bowel syndrome [9], postprandial colonic volumes [10], investigate the effect of oral polyethylene glycol electrolyte on the colon [12], and the effect of stress on colonic volumes [30]. The present method could furthermore find its application in drug studies to assess the drug effect on regional colonic volumes and fecal distribution as MRI already has been used to assess the effect of corticotrophinreleasing hormone on regional colonic volumes [30].…”

“…This enables assessment of the large intestine, which may lead to new insights into gut physiology and add diagnostic value in patients with gastrointestinal disorders such as constipation and irritable bowel syndrome [9][10][11][12]. However, manual segmentation must be performed in order to obtain colonic volumes.…”

Irritable bowel syndrome

“…Antispasmodics are a good example of such drugs that have fallen out of favour because we cannot reliably identify those with excessive motor activity who might be expected to respond. Future novel non-invasive motility assessments, such as MRI 231 , capsule endoscopy 232 and the pressure-sensitive, temperature-sensitive and pH-sensitive SmartPill (Given Imaging Ltd, Yoqneam, Israel) 233 (which can measure intestinal contractions), hold the possibility of identifying such patients in the future.…”

MRI analysis of fecal volume and dryness: Validation study using an experimental oxycodone‐induced constipation model

“…MRI has proved useful in measuring several parameters of GI function, where some promising methods are not far from translation into the clinic . MRI assessments of colonic motility has been investigated in the ascending colon after bowel preparation . Additionally, chyme heterogeneity in the ascending colon has been assessed with subjective observer scores, and more objectively with imaging‐based feature analysis .…”