Medically reviewed on June 20, 2018
Endoscopic ultrasound (EUS) is a minimally invasive procedure to assess digestive (gastrointestinal) and lung diseases. A special endoscope uses high-frequency sound waves to produce detailed images of the lining and walls of your digestive tract and chest, nearby organs such as the pancreas and liver, and lymph nodes.
When combined with a procedure called fine-needle aspiration, EUS allows your doctor to sample (biopsy) fluid and tissue from your abdomen or chest for analysis. EUS with fine-needle aspiration can be a minimally invasive alternative to exploratory surgery.
EUS techniques are also used in certain treatments, such as draining pseudocysts.
During an endoscopic ultrasound of the pancreas, your doctor inserts a thin, flexible tube (endoscope) down your throat and into your abdomen. An ultrasound device at the end of the tube emits sound waves that generate images of your pancreas and nearby tissues.
EUS is generally safe when performed at a center with an experienced and expert health care team. Your doctor will discuss with you the risk of complications from EUS. These risks are most commonly associated with fine-needle aspiration.
Risks may include:
- Tearing (perforation) of the intestinal wall or throat
- Pancreatitis, if fine-needle aspiration of the pancreas is done
You can reduce your risk of complications by carefully following your doctor's instructions for preparing for EUS.
Call your doctor immediately or go to an emergency room if you experience any of the following signs or symptoms:
- Chest pain
- Shortness of breath
- Black or very dark-colored stool
- Severe or persistent abdominal pain
How you prepare
Your doctor will give you specific instructions to prepare for your EUS. You may be asked to:
- Fast before EUS, to make sure your stomach is empty. Generally, you'll be asked to fast for at least 6 hours before the test.
- Prepare your rectum, if EUS is being done in the rectal area. You may be asked to take a laxative or have an enema and to follow a liquid diet before the procedure.
- Stop taking certain medications, such as blood thinners. Blood thinners may increase your risk of bleeding if fine-needle aspiration is performed during EUS. If you have chronic conditions, such as diabetes or high blood pressure, your doctor will give you specific instructions regarding your medications.
- Plan ahead for your recovery, if you will be sedated before EUS. Most people who have EUS are given medication to relax them. Arrange for someone to drive you home after the procedure.
What you can expect
You likely will be given medicine to help you relax.
During EUS your doctor passes a thin, flexible tube (endoscope) through your mouth and through your digestive tract. A small ultrasound device (transducer) in the tube produces sound waves that create a precise image of surrounding tissue, including lymph nodes in the chest. The endoscope is then gradually withdrawn.
If you have fine-needle aspiration with EUS, your doctor may need to pass a second, curved device through a channel in the endoscope into your digestive tract. That device can guide a very slender needle to your lymph nodes and tumors or other abnormalities. The needle extracts fluid and tissue for analysis.
EUS with fine-needle aspiration generally lasts less than an hour.
A specialist in digestive diseases (gastroenterologist) or lung disease (pulmonologist) with special training in EUS will interpret the EUS images. A doctor trained in analyzing biopsies (pathologist) will report the test results if you have fine-needle aspiration. Your doctor will discuss any important findings and next steps with you.