Prolonged monitoring of the upper gastrointestinal tract using echo planar magnetic resonance imaging.

Upper gastrointestinal motility and transit has been studied in five human volunteers with the ultra high speed, magnetic resonance imaging (MRI) technique MBEST (Modulus Blipped Echo-planar Single pulse Technique), a variant of echo planar imaging. Snapshot images requiring a data acquisition time of only 64-128 msec allowed visualisation of peristalsis in the antrum and duodenum in real time, without motional image degradation, as would normally be seen using conventional MRI. Gastroduodenal flow of the luminal contents was visualised using water as a contrast medium, with appropriate adjustment of the time constant (T2) weighting of the system. Rapid (0.3 Hz) imaging of gastroduodenal motility in both transverse and coronal planes was achieved by respiratory gating to the imaging frequency, allowing repetition rates of up to 20 frames per minute for 2-3 hours. Fast replay of stored images, to produce a 'movie loop', allowed identification of fasting motility patterns of the gastric antrum and proximal small intestine, with depiction of the phases of the migrating motor complex. Images of the fed patterns after the ingestion of a test meal showed good separation of solid and liquid particulate matter and mixing waves in the gastric body. The potential for quantitative measurements with this new imaging modality of the gastrointestinal tract is under development, which will allow us to measure transit and correlate this with motility data.