X-ray technique for visualization of the bolus flow through an esophageal simulator

Abstract

In the last years, there has been an interest in development of simulators to reproduce the mechanical properties of the human digestive system. Particularly, there have been some approaches in the development of esophagus simulators. Such simulators intend to replicate the peristaltic wave conditions, but the reported experiments are related to indirect measurements in which the use of a fluid is not reported. In this work, an X-ray technique for visualizing the flow of bolus through an artificial esophageal simulator (AES) is proposed. For that purpose, particles of barium sulfate were thoroughly mixed with baby food, in order to create a suspension used as bolus. Barium sulfate particles used in the present work are insoluble in water with non-regular forms, a size distribution from 20 to 80\xa0nm, and a specific surface area ranging from 10 to 50 m2/g. The advantage of using barium sulfate is its high absorption of X-rays, which allows obtaining a good contrast in radiographies, so that the transport of the bolus along the esophagus simulator can be easily tracked. The results revealed the appearance of secondary flows on the wave sides, which displace as the wave contracts. This was verified with the flow fields, in which it was observed that the bolus flows mainly along the central part of the wave and a small volume tends to retract. This confirms that the flow is extensional as the bolus is stretched and compressed during the peristalsis.