Gastric Emptying Validation Pilot Study (MRI Val)

The primary aim of this study is to assess (in healthy volunteers) the rate at which a glucose drink leaves the stomach by sequential magnetic resonance imaging (MRI) of the stomach contents using a 0.5 tesla upright MRI scanner, and comparing with the rate derived from a standard method which uses a stable isotope tracer and breath testing. The main question it aims to answer are: * Do MRI derived images of stomach contents at low magnetic field (0.5 Tesla) have sufficient resolution to provide a reproducible assessment of gastric emptying * What is the agreement and relationship between the rate of gastric emptying determined from the 2 methods Participants will be asked to attend the imaging centre on one occasion in the morning after fasting from midnight and to sit within an upright MRI scanner for a period of approximately 140 minutes. Images of their stomach will be taken before and for 2 hours after consuming a drink containing glucose and a small amount of sodium acetate which contains a heavier form of carbon. Before each image is taken, participants will be asked to exhale into a 500ml bag to collect a breath sample.