Endoscopic ultrasonography (EUS) is used to view the walls of your digestive tract and other nearby organs. An ultrasound uses sound waves to make images of the inside of the body. In an EUS, the ultrasound probe is passed down the throat or up the rectum and into the digestive tract.
Reasons for Test
EUS may be used to:
- Diagnose or find the cause of a pain or abnormality in the digestive tract
- Locate and view tumors or abnormalities in the pancreas, bile ducts, and chest cavity
- Understand the extent of certain cancers and whether they have spread to lymph glands or other vital organs
Take tissue samples to diagnose a condition—biopsy
- Provide needle aspiration to drain a cyst
Complications are rare, but no test is completely free of risk. If you are planning to have EUS, your doctor will review a list of possible complications, which may include:
- Mild sore throat for 1-2 days
- Reaction to sedatives
- Regurgitation of stomach contents into the lungs
- Tissue or organ perforation
Factors that may increase the risk of complications include:
- Increased age
- Having other medical conditions
Be sure to discuss these risks with your doctor before the test.
What to Expect
Prior to Test
Leading up to the test, your doctor may instruct you to:
- Avoid eating or drinking (not even water) for at least 6 hours before the test.
- Take a special cleansing solution, laxative, or enema. This will clean out your intestines. You may also be asked to follow a clear liquid diet.
- Arrange for a ride home after the test if you have to take a sedative.
In most cases, it is okay to take aspirin and other blood-thinning medications before the test. Ask your doctor if you take these medications.
Description of the Test
Your doctor may spray your throat with a local anesthetic. This will numb your throat, so you will not feel discomfort. You may also be given a sedative. This will help you to relax and reduce anxiety.
In most cases, you will lie on your left side. A thin, flexible tube, called an endoscope, will be inserted either through your throat or anus. The endoscope will have an ultrasound probe on the end of it. The ultrasound machine will create images of the digestive tract. When the imaging is done, your doctor will gently pull the endoscope out.
In some cases, the doctor might use the ultrasound to help take a biopsy or drain a cyst. If this happens, the doctor will insert tools through the endoscope to the area.
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After the test, you will go to a recovery room. Your throat may be a little sore. Slight bloating is normal from the air and water that entered the digestive tract.
How Long Will It Take?
Will It Hurt?
EUS is slightly uncomfortable.
Your doctor may talk to you about the results right away. If you had a biopsy, it may take longer to receive results.
Call Your Doctor
It is important to monitor your recovery. Alert your doctor to any problems. If any of the following occur, call your doctor:
- Pain or discomfort that does not go away or worsens
- Vomiting blood, blood in stool, or dark black stool
- New or unexpected symptoms
If you think you have an emergency, call for emergency medical services right away.
American Society for Gastrointestinal Endoscopy
National Institute of Diabetes and Digestive and Kidney Diseases
Canadian Association of Gastroenterology
Canadian Digestive Health Foundation
Jacobson B, Chak A, e Hoffman B, et al. Quality indicators for endoscopic ultrasonography.
American Journal of Gastroenterology. 2006;101(4):898-901.
Understanding EUS (endoscopic ultrasonography). American Society for Gastrointestinal Endoscopy website. Available at:
https://www.asge.org/home/for-patients/patient-information/understanding-eus. Accessed October 3, 2017.
- Reviewer: EBSCO Medical Review Board
Daus Mahnke, MD
- Update Date: