Real-time high-resolution MRI for the assessment of gastric motility: Pre- and postpharmacological stimuli

Purpose: To determine the practicality of MRI using a new real-time sequence for the assessment of gastric motion, and quantify the effects of motility-modifying substances. Materials and Methods: Six healthy volunteers ingested 400 mL of a high-calorie liquid nutrient. Two-dimensional real-time TrueFISP sequences were acquired for up to 30 minutes following the ingestion. The acquisition plane was chosen parallel to the axis of the gastric antrum. The examination was performed on three separate days with and without i.v. administration of 10 mg metoclopramide or 20 mg scopolamine. A motility index was calculated for each real-time data set. Results: Delineation of the gastric lumen proved easy and robust. The intravenous application of motility-modifying agents resulted in significant changes in the motility index. The administration of metoclopramide resulted in an average increase of the index by a factor of 1.5, whereas the application of scopolamine led to a decrease of the index by a factor of 3.0. Conclusion: TrueFISP MRI performed well in depicting the gastric lumen and assessing gastric motility. Furthermore, we were able to evaluate and quantify the effect of motility-modifying agents. The noninvasive nature of MRI makes this imaging modality an attractive alternative to conventional invasive diagnostic tools for gastric motility disorders and monitoring of therapy.