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Background: Colonic motility in constipation can be assessed non-invasively using MRI., Objective: To compare MRI with high-resolution colonic manometry (HRCM) for predicting treatment response., Design: Part 1: 44 healthy volunteers (HVs), 43 patients with irritable bowel syndrome with constipation (IBS-C) and 37 with functional constipation (FC) completed stool diaries and questionnaires and underwent oral macrogol (500-1000 mL) challenge. Whole gut transit time (WGTT), segmental colonic volumes (CV), MRI-derived Motility Index and chyme movement by 'tagging' were assessed using MRI and time to defecation after macrogol recorded. Left colonic HRCM was recorded before and after a 700 kcal meal. Patients then proceeded to Part 2: a randomised cross-over study of 10-days bisacodyl 10 mg daily versus hyoscine 20 mg three times per day, assessing daily pain and constipation., Results: Part 1: Total CVs median (range) were significantly greater in IBS-C (776 (595-1033)) and FC (802 (633-951)) vs HV (645 (467-780)), p<0.001. Patients also had longer WGTT and delayed evacuation after macrogol. IBS-C patients showed significantly reduced tagging index and less propagated pressure wave (PPW) activity during HRCM versus HV. Compared with FC, IBS-C patients were more anxious and reported more pain. Abnormally large colons predicted significantly delayed evacuation after macrogol challenge (p<0.02), impaired manometric meal response and reduced pain with bisacodyl (p<0.05).Part 2: Bisacodyl compared with hyoscine increased bowel movements but caused more pain in both groups (p<0.03)., Conclusion: An abnormally large colon is an important feature in constipation which predicts impaired manometric response to feeding and treatment responses. HRCM shows that IBS-C patients have reduced PPW activity., Trial Registration Number: The study was preregistered on ClinicalTrials.gov, Reference: NCT03226145., Competing Interests: Competing interests: RCS: Grants/research supports: Sanofi-Aventis Deutschland, Nestle Consultant to Enterobiotix. MC: Consultant: Sanofi, Takeda, Biocodex, Mayoly. SMS: honoraria for teaching for the Laborie Group. SAT: grant support from Takeda. Consultancy fees AstraZeneca, Sanofi-Aventis. Share holder Motilent., (© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY. Published by BMJ Group.)

Background: Magnetic resonance imaging (MRI) of the colonic response to a macrogol challenge drink can be used to assess the mechanisms underlying severe constipation. We measured the intrasubject reproducibility of MRI measures of colonic function to aid their implementation as a possible clinical test. Methods: Healthy participants attended for MRI on two occasions (identical protocols, minimum 1 week apart). They underwent a fasted scan and then consumed the macrogol drink. Subjects were scanned at 60 and 120 minutes, with maximum value reached used for comparison. The colonic volume, water content, mixing of colonic content and the movement of the colon walls were measured. Coefficients of variation and intraclass correlation coefficients (ICC) were calculated. Results: Twelve participants completed the study: nine female, mean age 26 years (SD 5) and body mass index 24.8 kg/m2 (SD 3.2). All measures consistently increased above baseline following provocation with macrogol. The volume, water content and content mixing had good intrasubject reproducibility (ICC volume = 0.84, water content = 0.93, mixing = 0.79, P <.001). With the wall movement, the response to the challenge was generally large, but more variable between visits resulting in a lower ICC overall (ascending colon = 0.65, descending colon = 0.76, P <.001). Conclusions: The colonic response to the macrogol stimulus as assessed by MRI is heterogeneous but large compared to baseline, with moderate to good reproducibility, making the test suitable to study potential pathologies underlying GI disorders such as constipation. More data are needed to better define the normal range for comparison with patient groups who may have both hypo‐ and hypermotile responses. [ABSTRACT FROM AUTHOR]

Summary: Background: Chronic constipation affects approximately 17% of the population worldwide and remains an important unmet need since patients are often dissatisfied with treatment. Kiwifruit may offer an alternative to traditional laxatives and have been shown to increase stool volume, frequency and improve consistency. Aims: Using non‐invasive MRI techniques, we assessed the effect of ingestion of kiwifruit on fluid distribution in the intestines and bowel function. Methods: Two period crossover trial of kiwifruit vs control in healthy adults. Intervention: two kiwifruits twice daily vs isocaloric control (maltodextrin) twice daily, consumed for a total of 3 days. Subjects underwent MRI scanning fasted and at hourly intervals for 7 hours on the third day. Primary outcome: T1 relaxation time of ascending colon (T1AC) using MRI. Secondary outcomes: Small bowel water content (SBWC), colonic volume, gut transit time, T1 of descending colon, stool frequency and form. Results: Fourteen volunteers completed the study. T1AC was higher after kiwifruit ingestion (P = 0.029) during the second half of the day (when meal residue would be expected to reach the AC, AUC T1 T240‐420 minutes; mean (SD) 137 (39) s*minute with kiwifruit versus 108 (40) s*minute with control. SBWC (P < 0.001), colon volumes (P = 0.004), as well as stool frequency (1.46 ± 0.66 with kiwifruit vs 1.14 ± 0.46 stools per day with control; P = 0.034) and stool form score (Bristol Stool Chart score 4.1 (0.9) with kiwifruit versus 3.4 (0.7) with control; P = 0.011) were markedly increased in participants consuming kiwifruit compared to control. Conclusion: Consumption of kiwifruit in healthy volunteers increases water retention in the small bowel and ascending colon and increases total colonic volume. The data may explain the observed increase in stool frequency and looser stool consistencies, suggesting that kiwifruit could be used as a dietary alternative to laxatives in mild constipation. [ABSTRACT FROM AUTHOR]