Endoscopic Ultrasound (EUS)

Endoscopy refers to the procedure of inserting a long flexible tube via the mouth or the rectum into the digestive tract. Ultrasound uses high-frequency sound waves to produce images of the organs and structures inside the body. Endoscopic Ultrasound (EUS) combines endoscopy and ultrasound in order to obtain images and information about the digestive tract and the surrounding tissue and organs.

Using EUS, your doctor can obtain high quality images of organs inside the body as well as detailed information about the layers of the intestinal wall and adjacent areas such as lymph nodes and blood vessels.

EUS can also be used to study the flow of blood inside blood vessels, and to obtain tissue samples by passing a special needle, under ultrasound guidance, into enlarged lymph nodes or suspicious tumors (fine needle aspiration or FNA). The tissue or cells obtained by the needle can be examined by a pathologist under a microscope.

A relatively new diagnostic tool, EUS is presently being used to:

• Determine the severity of cancers of the esophagus, stomach, pancreas, rectum, and lungs
• Evaluate chronic pancreatitis and other masses or cysts of the pancreas
• Study bile duct abnormalities including stones in the bile duct or gallbladder, or bile duct, gallbladder, or liver tumors
• Study the muscles of the lower rectum and anal canal in evaluating reasons for fecal incontinence
• Study nodules or bumps that may be hiding in the intestinal wall covered by normal-appearing lining of the intestinal tract

How do I prepare?

You will need to have an empty stomach for the procedure. That means no eating or drinking for 6 or more hours prior to the procedure. In case of a rectal EUS you will probably need to have an enema or take laxatives. In either case your doctor will provide you with complete instructions.

What happens during and after the procedure?

During the procedure, your physician will observe the inside of your intestinal tract on a TV monitor and the ultrasound image on another monitor. The entire procedure generally takes 30 to 90 minutes depending on the complexity and whether fine needle aspiration (FNA) is performed.
EUS is performed with sedation so you will not be able to return to work or to drive for 24 hours. It also means that you will need to bring a responsible adult with you to take you home after the procedure. The sedation given during the procedure causes drowsiness and dizziness, and impairs your judgment, making it unsafe for you to drive or operate machinery.