Ultrasound scanning uses sound waves to produce pictures of internal organs (see also Ultrasonography). An ultrasound scan can show the size and shape of many organs, such as the liver and pancreas, and can also show abnormal areas within them, such as cysts and some tumors. It can also show fluid in the abdominal cavity (ascites). Ultrasound scanning with a probe on the abdominal wall is not a good method for examining the lining or the wall of the digestive tract. Endoscopic ultrasound, however, shows the wall of the digestive tract or some abdominal organs more clearly because the probe is placed on the tip of an endoscope.
An ultrasound scan is painless and poses no risk of complications.
Endoscopic ultrasound poses the same risk of complications as endoscopy.