Esophageal Bolus Transit Imaged by Ultrafast Computerized Tomography

Background & Aims: Conventional transit imaging techniques detect only the solid or liquid component of a swallowed bolus within the esophagus. This study aimed to dynamically image the composition, distribution, and propulsion of esophageal contents during swallowing.

Methods: Multiple adjacent cross-sectional images of the esophagus were obtained in 7 subjects using ultrafast computerized tomography. Images from two 10-mL swallows were synchronized and analyzed for bolus distribution and propulsion, cross-sectional area, intraluminal volume, and intraluminal content.

Results: Both liquid and air were swallowed, with the relative distribution varying among levels. Within the ampulla, air occupied 71% of the luminal cross-sectional area. Air was propelled ahead of the liquid bolus at 17 cm/s compared with 7 cm/s for fluid (P < 0.01) and accumulation within the ampulla. Mean bolus velocity was slower through the ampulla. A variable (8-32 mL) volume of air was ingested during swallowing.

Conclusions: Ultrafast computerized tomography studies during transit of a swallowed bolus through the esophagus showed substantial aerophagia and partial bolus separation with air preceding fluid. The ampulla exhibited greater distention that the tubular esophagus because the bolus accumulated at this level before transfer across the hiatus.