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, high quality ultrasound images of the organs inside the body can be obtained. Because of 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. The EUS also can obtain information about the layers of the intestinal wall as well as adjacent areas such as lymph nodes and blood vessels. Other uses of EUS include studying the flow of blood inside blood vessels and obtaining tissue samples from enlarged lymph nodes or suspicious tumors.