Barium
What is this appearance of the oesophagus closely associated with?
Gastro-oesophageal reflux. The patient is extremely likely to have reflux even if it is not seen during the study (Ref. 2).
Spot radiograph from a double contrast oesophagram.
There are numerous 1-2 mm radiolucent folds across the oesophagus. The folds are angled with respect to the center of the oesophagus in a "herringbone" pattern.
The folds occur transiently.