An irregular Z-line in an esophageal ultrasound indicates an incorrect joining with the gastroesophageal junction at the base of the esophagus. Irregular Z-lines often lead to a diagnosis of Barrett's esophagus, according to a study published by the National Institutes of Health.
The Z-line is the transition point between the esophageal squamous epithelium and the gastric mucinous columnar epithelium in the tube that connects the throat to the stomach, according to Nature. In healthy individuals, the Z-line coincides with the gastroesophageal junction. In Barrett’s esophagus, the Z-line is displaced proximally relative to the gastroesophageal junction.
Barrett's esophagus is a serious complication of gastroesophageal reflux disease, or GERD, notes WebMD. In Barrett's esophagus, tissue that lines the esophagus is changed to tissue that resembles the lining of the stomach. Symptoms of Barrett's esophagus are similar to those of GERD and include heartburn, chronic cough, laryngitis and nausea. Barrett's esophagus increases the risk of developing esophageal adenocarcinoma, which is a potentially fatal cancer of the esophagus. Both an ultrasound and a biopsy of tissue are required for a diagnosis of Barrett's esophagus. Because of the increased risk of cancer, the tissue sample is also examined for signs of precancerous or cancerous cells. If Barrett's esophagus is diagnosed but there are no signs of cancer cells, periodic, repeated endoscopy is suggested.