Endoscopic Ultrasound
Endoscopic ultrasonography (EUS) allows your doctor to examine your esophageal and stomach linings as well as the walls of your upper and lower gastrointestinal tract. The upper tract consists of the esophagus, stomach and duodenum; the lower tract includes your colon and rectum. EUS is also used to study other organs that are near the gastrointestinal tract, including the lungs, liver, gall bladder and pancreas.

Your doctor can use EUS to diagnose certain conditions that may cause abdominal pain or abnormal weight loss.   EUS is also used to evaluate known abnormalities, including lumps or lesions, which were detected at a prior endoscopy or were seen on x-ray tests, such as a computed tomography (CT) scan.   Your endoscopist will use a thin, flexible tube called an endoscope that has a built-in miniature ultrasound probe. Your doctor will pass the endoscope through your mouth or anus to the area to be examined. Your doctor then will use the ultrasound to use sound waves to create visual images of the digestive tract.

Preparation
For EUS of the upper gastrointestinal tract, you should have nothing to eat or drink, usually for six hours before the examination. Your doctor will tell you when to start this fasting and whether it is advisable to take your regular prescription medications.

For EUS of the rectum or colon, your doctor will instruct you to either consume a colonic cleansing solution or to follow a clear liquid diet combined with laxatives or enemas prior to the examination. The procedure might have to be rescheduled if you don't follow your doctor's instructions carefully.

Procedure
If you received sedatives, you will be monitored in the recovery area until most of the sedative medication's effects have worn off. If you had an upper EUS, your throat might be a little sore. You might feel bloated because of the air and water that were introduced during the examination. You'll be able to eat after you leave the procedure area, unless you're instructed otherwise. Your doctor generally can inform you of the preliminary results of the procedure that day, but the results of some tests, including biopsies, may take several days