Hydro-MRI for the visualization of gastric wall motility using RARE magnetic resonance imaging sequences

Background: Although different imaging techniques such as conventional X-ra y, ultrasonography, and hydro-computed tomography are available for the ima ging of the stomach, none can depict this organ in full size without radiat ion. Therefore, the study of the entire gastric wall motility of the stomac h is difficult and in principle only performable with rapid magnetic resona nce imaging (MRI) techniques. T1-weighted imaging sequences have been used for the dynamic study of gastric wall motility. This technique was combined with the oral intake of para- or superparamagnetic contrast agents to achi eve sufficient intraluminal contrast. The technique described in the presen t study is based on a different contrast mechanism. Methods: The stomach was filled with 500 mL of 10% of aqueous dextrose solu tion, and a strongly T2-weighted fast rapid acquisition with relaxation enh ancement (RARE) type imaging sequence was used for data acquisition. No oth er contrast agents were applied. An ultrafast RARE imaging sequence with an asymmetric phase-encoding scheme was developed to achieve a high temporal and spatial resolution. The scanning time per image was approximately 1 s. Results: The stomach was imaged in full size. The concentric constrictor ri ngs moved from the proximal part of the body toward the antrum. The mean du ration for one contraction cycle was approximately 17.9 +/- 2.5 s, the mean contractile frequency was 3.4 +/- 0.5 s, and the mean spreading velocity w as 65.5 +/- 3.6 cm/min. Conclusions: The purpose of this study was to demonstrate a new technical a pproach for a noninvasive dynamic study of gastric motor function with hydr o-MRI. This robust method may have clinical application, e.g., in the diagn osis of gastroparesis, and may be extended to the rest of the gastrointesti nal tract.