PROLONGED MONITORING OF THE UPPER GASTROINTESTINAL-TRACT USING ECHO-PLANAR MAGNETIC-RESONANCE-IMAGING

Upper gastrointestinal motility and transit has been studied in five h uman volunteers with the ultra high speed, magnetic resonance imaging (MRI) technique MBEST (Modulus Blipped Echo-planar Single pulse Techni que), a variant of echo planar imaging. Snapshot images requiring a da ta acquisition time of only 64-128 msec allowed visualisation of peris talsis in the antrum and duodenum in real time, without motional image degradation, as would normally be seen using conventional MRI. Gastro duodenal 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 mot ility in both transverse and coronal planes was achieved by respirator y 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 p roduce a 'movie loop', allowed identification of fasting motility patt erns of the gastric antrum and proximal small intestine, with depictio n of the phases of the migrating motor complex. Images of the fed patt erns after the ingestion of a test meal showed good separation of soli d and liquid particulate matter and mixing waves in the gastric body. The potential for quantitative measurements with this new imaging moda lity of the gastrointestinal tract is under development, which will al low us to measure transit and correlate this with motility data.