EUS allows your doctor to examine your stomach lining as well as the walls of your upper and lower gastrointestinal tract. The upper tract is the esophagus, stomach and duodenum; the lower tract includes your colon and rectum. EUS is also used to study internal organs that lie next to the gastrointestinal tract, such as the gallbladder and pancreas.
Your endoscopist will use a thin, flexible tube called an endoscope. Your doctor will pass the endoscope through your mouth or anus to the area to be examined. Your doctor then will turn on the ultrasound attachment to produce sound waves that create visual images of the digestive tract.
EUS provides your doctor with more information than other imaging tests by providing more detailed pictures of your digestive tract.
EUS is also used to evaluate an abnormality, such as a lump, that was detected at a prior endoscopy. EUS provides a picture of the lump, which can help your doctor determine its nature and help him decide the best treatment.
In addition, EUS can be used to diagnose disease of the pancreas, bile duct and gallbladder when other tests are inconclusive.
EUS helps your doctor determine the extent of certain cancers of the digestive and respiratory systems. EUS allows your doctor to accurately assess the cancer's depth and whether it has spread to adjacent lymph nodes. In some patients, EUS can be used to obtain biopsies to help your doctor determine the proper treatment.
Sometimes, a biopsy (tiny bit of tissue) may be done using a thin needle through the endoscope. This is usually done when there is a mass or enlarged lymph node. When there is a fluid filled cyst, it may be drained or fluid is aspirated for analysis.