New MRI technique is breakthrough tool for diagnosing IBS
14 January 2014
Scientists at The University of Nottingham have conducted three
studies examining the effectiveness of using MRI to study Irritable
Bowel Syndrome (IBS) and have also developed a novel way of
investigating the illness.
The research could have major implications in how IBS is both
diagnosed and treated in the future.
The three papers examine the effectiveness of studying the
colon with MRI, which has a number of unique advantages. Normally
X-rays are used to view the colon, which has limitations due to the
risks associated with radiation. By using MRI as an alternative, the
researchers have been able to image the bowel continuously with no
risk to the patient, enabling them to learn more about the inner
workings of the gut.
The research has been led by academics at The University of
Nottingham’s Digestive Diseases Centre (NDDC) and scientists from
the Sir Peter Mansfield Magnetic Resonance Centre at the University.
The work is funded by the Medical Research Council, the Wellcome
Trust, the National Institute for Health Research, the Biotechnology
and Biological Science Research Council, as well as industry.
In the first study ‘Fasting and post-prandial volumes of the
undisturbed colon’ published online in “Neurogastroenterology and
Motility” scientists were able to image the colon and divide it in
to three functional regions — the ascending colon, which is a
storage and fermentation area, where unabsorbed residue is broken
down by bacteria; the transverse colon, which is a storage area for
the residue remaining after bacterial processing, and the descending
colon which is a propulsive organ which pushes waste down and out of
With MRI, scientists can also measure the volumes of these
regions, which they have never been able to do before.
Professor Robin Spiller is Lead Director of Nottingham Digestive
Diseases Biomedical Research Unit which supported this work. The
NDDBRU is funded by a five year grant from the NIHR.
Professor Spiller said: “We studied people with accelerated
transit and to our surprise, we found that the colon size was rather
similar to those with normal transit — suggesting people regulate
their bowel habit to keep the colonic size constant. We also know
that when you eat a meal the ascending colon expands as the meal is
pushed down into it to make space in the small bowel for the new
“We found that this increase was smaller in IBS patients than in
healthy volunteers, suggesting that the IBS patient’s ascending
colon can’t relax enough. With MRI we can actually measure this
change in a way that we’ve never been able to do before. This will
have other benefits in the future, for instance we will be able to
measure the effect of some drugs on the bowel.”
In the second paper — ‘Novel MRI tests of orocaecal transit time
and whole gut transit time: studies in normal subjects’ published
online in “Neurogastroenterology and Motility”, scientists used MRI
to measure the actual time it takes for contents to transit the
bowel, using specially designed MRI visible markers which subjects
ingest. Scientists can then image the bowel 24 hours later to see
how far they have moved. Previously, motility had to be measured
using x-rays which has seriously limited the situations when the
measurement could be made.
“The use of x-rays in this type of procedure is undesirable for
children or young women of child rearing age — which is unfortunate
as both of these groups can suffer with bowel function that may need
investigating. So developing this alternative method of examination
has particular appeal, particularly in children — who tend to suffer
with a wide range of bowel problems,” says Professor Spiller.
“Previously, clinicians have had to rely on what the children and
their parents say about their illness, which isn’t a reliable guide
to work out what is going on in the bowel. Having an objective
technique, such as our new MRI technique, to be able to assess
whether someone has normal or delayed transit in their bowel, will
be very useful in the management of IBS and also potentially in its
In the third study: Differential effects of FODMAPS on small and
large intestinal contents in healthy subjects shown by MRI,
published online in American Journal of Gastroenterology,
researchers used the colonic imaging technique again, but this time,
to improve their understanding of the causes of IBS.
By looking at fructose, a sugar commonly found in fruit, and
fructans, which are polymers of fructose, researchers were able see
what effects these had on the gut of healthy volunteers.
“We already know that fructose is difficult to absorb, but the
novelty with this new method, is that we are now able to image the
end effect of this mal-absorption which is the distension of the
small intestine and colon. We are currently repeating these studies
in patients with IBS to see whether their symptoms correlate with
the distension of the colon.”
Fructans and fructose are part of a group of chemicals called
FODMAPs — which are Fermentable Oligo, Di, Mono Saccharides and
Polyhydric alcohols, whose characteristics are that they are
relatively hard to absorb, but they are fermentable, so when they go
in to the colon they are exposed to the bacteria and produce gas.
Professor Spiller continues: “It’s been found that diets that
restrict the intake of these things improve symptoms and our MRI
studies show us scientifically why that improvement might occur. We
were able to show that while fructose alone was poorly absorbed and
distended the small bowel, when it was combined with glucose the
poor absorption was prevented. We also found that fructans have
little effect in the small bowel but a large effect on the colon. In
future, will be able to use our MRI techniques to test specific
foods to understand how they will affect IBS.
“By defining the link between the chemistry of food to its impact
on the bowel our technique will enable us to answer specific
questions — e.g — when an apple ripens and the sugar content rises —
does the adverse effect reduce? This might explain why green apples
can cause stomach ache while ripe ones do not. The fructose in the
green apple is malabsorbed but as it ripens the glucose content
rises improves fructose absorption, improving the rate of
1. Pritchard SE, et al. Fasting and postprandial volumes of the
undisturbed colon: normal values and changes in diarrheapredominant
irritable bowel syndrome measured using serial MRI.
Neurogastroenterol Motil (2014) 26, 124–130 doi: 10.1111/nmo.12243
2. Chaddock G, et al. Novel MRI tests of orocecal transit time
and whole gut transit time: studies in normal subjects.
Neurogastroenterol Motil (2013) doi: 10.1111/nmo.12249