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

Area of Science:

• Gastroenterology
• Medical Imaging
• Physiology

Background:

• Significant water movement occurs in the small intestine during digestion.
• Current methods for measuring small bowel water content are invasive, requiring intubation.
• There is a need for non-invasive techniques to assess small bowel fluid dynamics.

Purpose of the Study:

• To develop and validate a non-invasive magnetic resonance imaging (MRI) technique for quantifying small bowel water content.
• To compare MRI-derived water volumes with known infused volumes in healthy volunteers.

Main Methods:

• Utilized an adapted magnetic resonance cholangiopancreatography (MRCP) sequence for MRI acquisition.
• Verified naso-duodenal tube placement via MRI.
• Infused non-absorbable mannitol and saline solution in 40 ml boluses into the proximal small bowel.
• Applied image thresholding to account for signal variations and compared measured MRI volumes to infused volumes.

Main Results:

• The MRI technique produced high-quality images of the small bowel, comparable to conventional radiology.
• The mean difference between measured and infused volumes was 2% (SD 10%).
• Observer agreement was high, with inter-observer limits of agreement of -15% to +17% and intra-observer variability of 4%.

Conclusions:

• The developed non-invasive MRI technique accurately measures small bowel water content.
• This method offers a reliable alternative to invasive intubation for assessing fluid dynamics.
• The technique has potential applications in studying gastrointestinal diseases and the effects of drug interventions on small bowel function.