EUS

Patient Guide to Endoscopic Ultrasound

General Overview

Endoscopic ultrasound is state of the art technology that allows for detailed pictures of the esophagus, stomach, rectum and organs adjacent to the intestinal tract (lung, bile duct and pancreas). The test involves passing a thin, flexible tube called an endoscope into the mouth or anus. The endoscope contains a transducer that produces sound waves that create a detailed image of the surrounding tissues.

These high-resolution images allow for differentiation of the layers of the intestinal tract as well as detection of small lymph nodes. These features are sometimes not appreciated by other imaging modalities such as CT, MRI and PET scans. EUS technology also allows for sampling of growths and lymph nodes, which plays an important role in the staging of various gastrointestinal as well as lung neoplasms.

Frequently Asked Questions

What can I expect during EUS?

EUS is an outpatient procedure that is performed at the St Jo's Hospital Endoscopy Unit on the fourth floor. EUS examination of the upper gastrointestinal tract is performed with intravenous sedation while the patient is positioned on their left side. The exam usually takes 30 minutes to an hour to perform.

EUS examination of the lower gastrointestinal tract can be performed comfortably without sedation but the decision to use sedation is at the discretion of the physician performing the exam. EUS of the lower GI tract usually takes 15 to 30 minutes.

What is cancer staging and what role does EUS play in staging cancers?

Cancer staging defines the extent of a patient's cancer using the TNM classification system (T = tumor size N = lymph node involvement M = tumor spread to distant sites or metastasis) EUS is a non-invasive and accurate way to determine the T and N staging of most gastrointestinal tumors. A CT scan is often used in combination with EUS to determine whether there is evidence of metastatic disease. Accurate staging is crucial in determining what type of therapy is appropriate. Early stage tumors can often be treated with endoscopic therapy or surgery. Advanced stage tumors usually require chemotherapy and radiation followed by surgery. On occasions, detecting advanced disease with EUS may prevent unhelpful and invasive therapy.

What are the possible complications with EUS?

Complications during EUS are a rare occurrence when performed by an experienced physician. Complications are similar those reported with standard endoscopy of the upper gastrointestinal tract, which include sore throat, bleeding, perforation, backwash of stomach contents into the lung, or an unstable heart or lung condition. There is a small risk of infection when a fine needle biopsy is performed on a cystic growth. Antibiotics may be administered before and after the procedure to reduce the risk of infection.