Ultrasound scanning uses sound waves to produce pictures of internal organs (see also Ultrasonography Ultrasonography Ultrasonography uses high-frequency sound (ultrasound) waves to produce images of internal organs and other tissues. A device called a transducer converts electrical current into sound waves... read more 
).
An ultrasound scan can show the size and shape of many organs, such as the liver and pancreas, and can also show abnormalities within them, such as cysts and some tumors. It can also show fluid in the abdominal cavity (ascites Ascites Ascites is the accumulation of protein-containing (ascitic) fluid within the abdomen. Many disorders can cause ascites, but the most common is high blood pressure in the veins that bring blood... read more ). Ultrasound scanning with a probe placed on the outside of the abdomen 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 a similar risk of complications as endoscopy Complications Endoscopy is an examination of internal structures using a flexible viewing tube (endoscope). In addition to examinations, doctors can use endoscopy to do biopsies and give treatment. Endoscopes... read more .
