Endoscopic ultrasound (EUS) is a procedure that uses a specialized device that incorporates an ultrasound probe onto a standard endoscope. This technology allows for not only imaging inside of the lumen of the gastrointestinal (GI) tract similar to a standard endoscope but also allows for the assessment of the wall of the GI tract and surrounding structures via the ultrasound transducer.
In the esophagus, EUS is used in a variety of ways. For cancers, it can be used to stage tumors and determine if they break through the wall of the esophagus, invade surrounding structures, have spread to regional length nodes or metastasized to distant sites such as the liver. It can also be used to assess lumps and bumps in the esophagus to determine if they are due to a growth within the wall of the esophagus or are due to extrinisic compression from a structure in the chest. EUS can also be used to biopsy lesions in the wall of the GI tract or in the chest or abdomen. These biopsies from fine needle aspiration (FNA) or fine needle biopsy (FNB) needles can obtain cells or even core tissue that can confirm if cancer cells have spread to sites adjacent to the GI tract. EUS can also aid in inserting radiopaque markers into the edges of a tumor which can aid in localizing the mass to provide highly selective focal delivery of radiation therapy. Finally, this technique can be used to assess smaller lesions on the surface of the wall of the esophagus in order to determine if they may be able to be removed endoscopically without the need for surgery.
The procedure is typically performed in an outpatient setting and the experience for the patient is similar to a standard upper endoscopy.