Endoscopic Ultrasound (EUS) combines endoscopy and ultrasound in order 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. By inserting the endoscope into the upper or the lower digestive tract, one can obtain high quality ultrasound images of the organs inside the body.
Due to the proximity of the EUS transducer to the organ(s) of interest, the images obtained are frequently more accurate and more detailed than the ones obtained by traditional ultrasound. EUS is performed to evaluate abdominal pain, pancreatic masses/cysts, chronic pancreatitis, bile duct abnormalities, submucosal lesions, & staging of cancers of the digestive tract. EUS also can obtain information about the layers of the intestinal wall as well as adjacent areas such as lymph nodes and the blood vessels.
Other uses of EUS include studying the flow of blood inside blood vessels using Doppler ultrasound, and to obtain tissue samples by passing a special needle, under ultrasound guidance, into enlarged lymph nodes or suspicious tumors. The tissue or cells obtained by the needle can be examined by a pathologist under a microscope. The process of obtaining tissue with a thin needle is called fine needle aspiration (FNA).