Feline Oesophagus

These transient lines (they disappear with a subsequent swallow)represent contraction of the muscularis mucosa. It is most commonly seen in patients with gastroesophageal reflux. This patient has a large hiatus hernia and reflux on subsequent imaging.
Reference: Gohel VK, Edell SL, Laufer I, Rhodes WH. Transverse folds in the human esophagus. Radiology 1978;128:303-308
Credit: Dr Evan Stein
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