Investigations of Anti-Reflux Formulations Containing Alginates Using MRI: A Feasibility Study Using Conventional 3.0T and 0.5T Open Upright Scanning.

Sodium alginates are widely used for their gelling, thickening, and stabilizing properties. Raft-producing formulations have been used widely for many years to treat the symptoms of anti-reflux disease and those suffering occasional symptoms. The aim of this study was to determine the feasibility of characterizing rafts formed from alginate-containing anti-reflux formulations in vivo using either a supine high-field 3T scanner or an upright low-field 0.5T MRI scanner. Six healthy participants (one male, five female, age range 23-50 years) attended three study visits following an overnight fast and were scanned at one field strength (N = 3 at 0.5T, N = 3 at 3T) before and after ingestion of an acidic drink followed by one of three different alginate antireflux formulations. These formulations had identical quantities (by mass) of sodium alginate, calcium carbonate, and sodium bicarbonate. Raft position and volume were measured along with gastric contents and gas using T2-weighted MRI. Additionally, the image textures of the raft and T2 properties were investigated at 3T. In vitro properties (raft strength, mass, and NMR chemical analysis) of the three different formulations were also determined. Alginate rafts were generated in all volunteers for all formulations. Gastric emptying of the acidic drink was consistent across all study days. Raft volumes measured showed some differences between body positions, with upright maintaining a higher volume of raft for longer. In vitro analysis showed significant differences in strength and mass between two of the formulations, which were likely caused by differences in the chemical structure of the alginates used in the formulations. In conclusion, characterization of anti-reflux alginate raft properties can be achieved using both low-field upright and high-field supine MRI. Larger scale studies are needed to determine the differences between formulations in vivo.