Non-invasive quantification of small bowel water content by MRI: a validation study

Abstract

Substantial water fluxes across the small intestine occur during digestion of food, but so far measuring these has required invasive intubation techniques. This paper describes a non-invasive magnetic resonance imaging (MRI) technique for measuring small bowel water content which has been validated using naso-duodenal infusion. Eighteen healthy volunteers were intubated, with the tube position being verified by MRI. After a baseline MRI scan, each volunteer had eight 40 ml boluses of a non-absorbable mannitol and saline solution infused into their proximal small bowel with an MRI scan being acquired after each bolus. The MRI sequence used was an adapted magnetic resonance cholangiopancreatography sequence. The image data were thresholded to allow for intra- and inter-subject signal variations. The MRI measured volumes were then compared to the known infused volumes. This MRI technique gave excellent images of the small bowel, which closely resemble those obtained using conventional radiology with barium contrast. The mean difference between the measured MRI volumes and infused volumes was 2% with a standard deviation of 10%. The maximum 95% limits of agreement between observers were -15% to +17% while measurements by the same operator on separate occasions differed by only 4%. This new technique can now be applied to study alterations in small bowel fluid absorption and secretion due to gastrointestinal disease or drug intervention.

Effects of a 5‐HT3 antagonist, ondansetron, on fasting and postprandial small bowel water content assessed by magnetic resonance imaging

“…We have recently validated a novel non-invasive magnetic resonance imaging (MRI) technique for assessing small bowel water content (SBWC) 12,13 which is highly acceptable to patients. Postprandially, the SBWC depends on the balance between delivery of fluid via gastric emptying and the removal of fluid by either propulsion into the colon or absorption.…”

Colon Hypersensitivity to Distension, Rather Than Excessive Gas Production, Produces Carbohydrate-Related Symptoms in Individuals With Irritable Bowel Syndrome

“…The methods for measurement of SBWC and colonic volume have been described in detail previously 17,20 . The sigmoid colon, is normally collapsed and not included in the measurement of the descending colon, however in this study it was noted to often be markedly distended and so was measured by our usual technique, as has recently been shown to be feasible by other groups 32 .…”

Role of Physiological Intestinal Water in Oral Absorption

“…Methods for measuring intestinal water volume have evolved from postmortem work (3) to the use of isotopes (4) to the present rather sophisticated magnetic resonance imaging (MRI) (5). Using the magnetic resonance cholangiopancreatography technique, Marciani and coworkers measured the small intestine water volume (SIWV) in one group of 26 control subjects as 90 ml (range 10-250 ml) (6) and in a different group of 16 normals as 165 ml (range 25-350 ml) (7).…”

“…The small intestine contained a total water volume of 105 ml (range 45-319 ml), distributed among four pockets (range [2][3][4][5][6][7][8]. The large intestine water volume (LIWV) was 13 ml (range 1-44 ml) distributed among four pockets (range [1][2][3][4][5][6].…”