Research issue
Despite the substantial impact that MRI has had in medical imaging, the long scan times, difficult geometry of the gut organs, their heterogeneous distension together with motion artifacts had severely limited the use of GI MRI for studying GI function in health and disease. More recently technical advances have overcome many of these problems and functional GI MRI has started to show its potential.
Our main research interests are to develop GI MRI and use it to study non-invasively the physiopathology of the GI tract. We study fluid fluxes and the gastro-colonic response to feeding, develop tests of GI function (such as motility and transit) and assess physical factors in food influencing digestion and satiety. We carry out in-body imaging of foods, define mechanisms and subtypes of functional GI disease and study the mode of action of GI drugs and laxative formulations.
What we are doing about...
1. Measuring colonic transit time
Colonic transit tests are used to manage patients with functional GI disorders. Some tests used expose patients to ionizing radiation which is undesirable, particularly because a large part of the patients are children and young females.
We developed novel MRI transit marker capsules and a simple MRI test to measure colonic transit and we are validating it against a standard X-Ray test. Our new MRI transit method is simple, convenient, does not use ionizing radiation and compares well with the ‘gold standard’.
2. Understanding the effects of fructose and fructans on GI symptoms
Irritable bowel syndrome (IBS) is a chronic gastrointestinal condition that is the cause of many consultations in general practice and referrals to gastroenterology clinics. Many IBS patients feel that diet plays a role in causing their symptoms. Recent studies have shown that a diet high in certain sugars, called Fermentable Oligo-, Di-, Mono-saccharides And Polyols (FODMAPs), can trigger abdominal symptoms in IBS patients.
We are carrying out GI MRI studies in healthy volunteers and patients aimed to improve our understanding of the origin of these symptoms. We ask our subjects to drink a glass of water containing different kinds of FODMAPs or glucose (as control, expected to generate no symptoms). After this we image non-invasively their stomach, small bowel and colon at intervals, assessing the volume of gastric contents, liquid in the small bowel and colonic gas. We then assess how a particular sugar distends the small bowel with water or the colon with gas and how this relates to symptoms like bloating.
Current projects
- We are developing novel whole gut transit MRI diagnostic methods and looking at ways to stratify Irritable Bowel Syndrome patients (MRC grant ‘Characterising IBS subtypes and their response to stress using MRI’)
- We are developing new MRI methods to quantify gastrointestinal fluids and colonic function
- We are investigating the gastrointestinal response to fructose and fructan ‘FODMAPs’
- We are studying the mode of action of common laxative formulations
Outcomes
Our research is published in leading peer-reviewed journals:
See list
- Murray K, Wilkinson-Smith V, Hoad C, Costigan C, Cox E, Lam C, Marciani L, Gowland P, Spiller RC. Differential Effects of FODMAPs (Fermentable Oligo-, Di-, Mono-Saccharides and Polyols) on Small and Large Intestinal Contents in Healthy Subjects Shown by MRI. Am J Gastroenterol. 2014 Jan;109:110-9
- Pritchard SE, Marciani L, Garsed KC, Hoad CL, Thongborisute W, Roberts E, Gowland PA, Spiller RC. Fasting and postprandial volumes of the undisturbed colon: normal values and changes in diarrhea-predominant irritable bowel syndrome measured using serial MRI. Neurogastroenterol Motil. 2014 Jan;26:124-30
- Chaddock G, Lam C, Hoad CL, Costigan C, Cox EF, Placidi E, Thexton I, Wright J, Blackshaw PE, Perkins AC, et al. Novel MRI tests of orocecal transit time and whole gut transit time: studies in normal subjects. Neurogastroenterol Motil. 2014 Feb;26:205-14
- Marciani L, Pritchard SE, Hellier-Woods C, Costigan C, Hoad CL, Gowland PA, Spiller RC. Delayed gastric emptying and reduced postprandial small bowel water content of equicaloric whole meal bread versus rice meals in healthy subjects: novel MRI insights. Eur J Clin Nutr. 2013 Jul;67:754-8
- Marciani L, Hall N, Pritchard SE, Cox EF, Totman JJ, Lad M, Hoad CL, Foster TJ, Gowland PA, Spiller RC. Preventing gastric sieving by blending a solid/water meal enhances satiation in healthy humans. J Nutr. 2012 Jul;142:1253-8
- Placidi E, Marciani L, Hoad CL, Napolitano A, Garsed KC, Pritchard SE, Cox EF, Costigan C, Spiller RC, Gowland PA. The effects of loperamide, or loperamide plus simethicone, on the distribution of gut water as assessed by MRI in a mannitol model of secretory diarrhoea. Aliment Pharmacol Ther. 2012 Jul;36:64-73
- Marciani L, EF Cox, CL Hoad, S Pritchard, JJ Totman, S Foley, A Mistry, S Evans, PA Gowland and RC Spiller. Postprandial changes in small bowel water content in healthy subjects and patients with irritable bowel syndrome. Gastroenterology 2010; 138(2): 469-477
Please see each group members' profiles for more publication details.