Endoscopic ultrasound (EUS) is a procedure that allows a doctor to obtain images and information about the digestive tract and the surrounding tissue and organs, including the lungs. Ultrasound testing uses sound waves to make a picture of internal organs.

During the procedure, a small ultrasound device is installed on the tip of an endoscope. An endoscope is a small, lighted, flexible tube with a camera attached. By inserting the endoscope and camera into the upper or the lower digestive tract, the doctor is able to obtain high-quality ultrasound images of organs. Because the EUS can get close to the organ(s) being examined, the images obtained with EUS are often more accurate and detailed than images provided by traditional ultrasound which must travel from the outside of the body.