Endoscopic ultrasound: Abbreviated EUS. A procedure that combines endoscopy and ultrasound to obtain images and information about the digestive tract and the surrounding tissue and organs. In EUS a small ultrasound transducer is installed on the tip of the endoscope allowing the transducer to get close to the organs inside the body so the resultant ultrasound images are often more accurate and detailed than ones obtained by traditional ultrasound.
EUS is used in many situations, including the following: the staging of cancers of the esophagus, stomach, pancreas, rectum, and lung; evaluating chronic pancreatitis and other masses or cysts of the pancreas; studying bile duct abnormalities including stones in the bile duct or gallbladder, or bile duct, gallbladder, or liver tumors; studying the muscles of the lower rectum and anal canal in evaluating reasons for fecal incontinence; and studying "submucosal lesions" such as nodules or "bumps" that may be hiding in the intestinal wall covered by normal-appearing lining of the intestinal tract.
The complication rate for EUS is about 1 in 2,000. Sometimes there are reactions such as hives, skin rash or nausea to the medications used during EUS. The main serious complication is perforation (making a hole in the intestinal wall) that may require surgical repair. This is quite rare.