Demonstration of differences in colonic volumes, transit, chyme consistency, and response to psyllium between healthy and constipated subjects using magnetic resonance imaging

Abstract

MRI measurements can objectively demonstrate the mode of action of therapy targeting intestinal fluid content in constipation.

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

“…Hence, the results from the porridge model is strongly limited. A more optimal validation method would include MRI scans immediately before defecation and then collect the stool and measure the water by freeze-drying the stool, as performed by Major et al 38 In conclusion, the MRI analysis methods were reliable with low week-to-week variation in colonic fecal volume and T 2 -weighted signal intensity (as a proxy of colonic stool dryness) for most colonic segments. The analysis showed differences in colonic fecal volume and signal intensity after treatment with oxycodone.…”

“…However, if any foods or especially liquids were ingested before scans against instructions, it would be expected to be shown in the proximal colon reflecting water content of ileal effluent, which could explain some of the high variation in the ascending colon. Major et al recently introduced another approach to measure colonic contents using MRI . They used T 1 /T 2 ‐relaxometry and fitted signal intensity data to a model of signal evolution of the tissue in drawn regions inside the ascending and descending colon.…”

“…Hence, the results from the porridge model is strongly limited. A more optimal validation method would include MRI scans immediately before defecation and then collect the stool and measure the water by freeze‐drying the stool, as performed by Major et al…”

“…Major et al recently introduced another approach to measure colonic contents using MRI. 38 They used T 1 /T 2 -relaxometry and fitted signal intensity data to a model of signal evolution of the tissue in drawn regions inside the ascending and descending colon. The results correlated well with fecal water content measured after defecation from healthy controls.…”

Randomised clinical trial: faecal microbiota transplantation versus autologous placebo administered via colonoscopy in irritable bowel syndrome

“…The water content of the stool also decreased in the placebo group although this change did not reach statistical significance. The stool water content correlates with both gut microbiota 40 and bowel transit time 33 . Thus, in our study, FMT resulted in a long‐term alteration of the gut microbiota which seems to have contributed to the reduction in the amount of faecal water.…”