Echo-planar imaging relaxometry to measure the viscosity of a model meal

A method for measuring noninvasively the viscosity of a polysaccharide model meal using the known relationship between relaxation times and polysaccharide concentration in solutionin vitrois presented. The aim is to develop a method for monitoring digesta viscosityin vivo,using EPI to capture the motion of the gastrointestinal lumen. The transverse relaxation rateT−12of locust bean gum solutions was calibrated against the zero-shear viscosity at 37°C. Differences in viscosity were distinguished significantly usingT−12measurements.T−12and viscosity were insensitive to exposure to gastric juice and changes in pH, and the model meal was well received by volunteers and provided good contrastin vivoin EPI images. Therefore it would be possible to use this method to monitor the changes in meal viscosity within the gastric lumenin vivo.