Published online Sep 21, 2014. doi: 10.3748/wjg.v20.i35.12551
Revised: April 29, 2014
Accepted: June 12, 2014
Published online: September 21, 2014
AIM: To distinguish between the esophagus and adjacent organs using extraesophageal saline injection (ESI) in a canine model.
METHODS: ESI was performed through the esophagus under the guidance of linear-array endoscopic ultrasonography (EUS). Approximately 15 mL of methylene blue saline (0.5%) was then injected through each of the extraesophageal puncture points using a 22 G needle. Radial EUS examinations were conducted before and after ESI. EUS images of the trachea, tracheal bifurcation, arcus aortae and thoracic aorta were recorded. Vital signs were monitored during the ESI procedure and EUS examination. The dogs were then sacrificed for exploratory thoracotomy.
RESULTS: No obvious fluctuation in vital signs or serious adverse events occurred during the ESI procedure. On EUS imaging, an apparent hypoechoic area outside the esophagus, which separated the esophagus and adjacent organs, was visualized. The adventitious of the esophagus and adjacent organs were easily distinguished. The findings of subsequent exploratory thoracotomy confirmed the EUS findings: obvious accumulation of a blue liquid in the extraesophageal tissues, as well as in the esophageal-thoracic aorta space, esophageal-arcus aortae space and esophageal-tracheal space.
CONCLUSION: The esophagus and adjacent organs were successfully separated by ESI, and extraesophageal saline acted as an effective ultrasonic contrast agent.
Core tip: The esophagus and adjacent organs were distinguished by extraesophageal saline injection (ESI) in dogs to identify better the esophageal adventitia and adjacent organs by endoscopic ultrasonography (EUS). EUS showed that the esophagus and adjacent organs were separated clearly in the extraesophageal liquid dark area. The findings provide an adequate basis for combined ESI and EUS for accurate preoperative identification of Stage T3 and T4 esophageal cancer.