Endoscopic Ultrasound


What is endoscopic ultrasound (EUS)?

Endoscopic ultrasound (EUS) is a procedure to examine the inside of your digestive tract. A gastroenterologist (a doctor who specializes in the digestive system) performs an EUS.

An EUS test combines:

  • Endoscope, a long, thin, flexible tube with a camera and light on the end.
  • Ultrasound, a probe on the end of the endoscope that sends out sound waves to produce images of your organs, tissues and blood vessels.

Who needs an endoscopic ultrasound (EUS) procedure?

Healthcare providers use EUS to evaluate or diagnose:

What are the types of EUS tests?

An upper endoscopy procedure is an EUS procedure that examines the upper part of the digestive tract, including:

  • Lining of the esophagus, stomach and small intestine.
  • Lymph nodes, blood vessels, cysts and tumors.
  • Nearby organs, such as the pancreas, gallbladder and bile ducts.

A lower EUS procedure examines the lower part of your digestive tract. This includes:

  • Anal sphincter (muscles surrounding the anus).
  • Blood vessels, lymph nodes, cysts and tumors.
  • Lining of the large intestine (rectum and colon).

What other procedures take place during an EUS test?

Your healthcare provider may perform endoscopic ultrasound-guided fine-needle aspiration. In this procedure, your provider uses EUS to guide a needle biopsy to remove a small sample of tissue or fluid. The sample goes to a lab where a lab specialist (pathologist) examines it for signs of disease, such as abnormal or cancerous cells.

Test Details

What happens before an endoscopic ultrasound (EUS) procedure?

Your healthcare provider will tell you what you should and shouldn’t do before an EUS test. In general, you may need to:

  • Adjust the dosage of your medications such as blood thinners or insulin as recommended by your provider.
  • Not eat or drink for a set period of time before the test.
  • Use a prescription bowel prep to clean out your bowels (for a lower EUS only).
  • Hold off “blood-thinning” medications such as Coumadin® or Plavix®.

What happens during an upper endoscopic ultrasound?

An upper EUS test is an outpatient procedure. You’ll go home the same day. Because you receive a sedative (anesthesia), someone needs to drive you home and stay with you for the remainder of the day. An upper EUS procedure takes about 60 minutes.

During an upper EUS test, you lie on your left side. A healthcare provider:

  1. Gives you an IV sedative to help you relax.
  2. Sprays your throat with a numbing medicine.
  3. Places a plastic mouthguard in your mouth. The mouthguard protects your teeth and prevents you from biting down on the endoscope.
  4. Inserts the ultrasound endoscope through your mouth, esophagus and stomach until it reaches the duodenum (top part of the small intestine). You shouldn’t feel any pain. You will be able to breathe as usual.
  5. Looks at ultrasound images on a monitor to examine your upper digestive tract, nearby organs, cysts or tumors.
  6. If needed, uses the ultrasound images to thread a thin needle through the endoscope to take a sample of tissue or fluid.
  7. Gently removes the endoscope and stops anesthesia. You slowly wake up in a recovery room.

What happens during a lower endoscopic ultrasound?

Like an upper EUS test, a lower EUS test is an outpatient procedure. You can go home the same day. Someone should drive you home and stay with you throughout the day.

The procedure takes less than 60 minutes. Fine needle aspirations (needle biopsies) rarely take place during lower EUS procedures.

During a lower EUS test, you lie on your left side. A healthcare provider:

  1. Gives you an IV sedative to help you relax.
  2. Inserts the ultrasound endoscope through your anus and rectum into your large intestine (colon). You shouldn’t feel any pain or discomfort and will be able to breathe as usual.
  3. Looks at ultrasound images on a monitor to examine your lower digestive tract, including nearby organs, cysts or tumors.
  4. Removes the endoscope gently and stops anesthesia, so you slowly wake up.

What happens after an EUS procedure?

The sedative should wear off within 30 minutes to an hour. You may have:

  • Gas, bloating or cramping after a lower EUS.
  • Sore throat after an upper EUS.

These symptoms should go away within 24 hours after the test. You should take it easy for the rest of the day. You can resume work or other activities the next day.

What are the potential risks or complications of an EUS procedure?

An EUS test is a relatively safe procedure. Potential complications include:

  • Allergic reaction to anesthesia.
  • Damage to the digestive tract or bleeding.
  • Lung aspiration (fluid from your mouth or stomach enters the lungs after an upper EUS).
  • Pancreatitis (after an upper EUS and needle biopsy).
  • Tear (perforation) in the intestinal wall.

Results and Follow-Up

When will I know the results of an EUS test?

Your healthcare provider will review EUS test findings with you. It may take a few weeks to get biopsy results back from the lab.

When to call the doctor

When should I call the doctor?

You should call your healthcare provider if you experience:

A note from Cleveland Clinic

An endoscopic ultrasound (EUS) procedure is a safe, effective way for healthcare providers to examine the inside of the digestive tract. It is a minimally invasive outpatient procedure. Providers use EUS tests to diagnose the cause of digestive problems, cancers and cancer spread. You may also have a needle biopsy during an EUS procedure (EUS-guided fine needle aspiration) to examine fluid or tissue for abnormal cells.

Last reviewed by a Cleveland Clinic medical professional on 04/28/2022.


  • American Society for Gastrointestinal Endoscopy. Understanding EUS (Endoscopic Ultrasonography). (https://www.asge.org/home/for-patients/patient-information/understanding-eus) Accessed 4/28/2022.
  • National Cancer Institute. Endoscopic Ultrasound-Guided Fine Needle Aspiration. (https://www.cancer.gov/publications/dictionaries/cancer-terms/def/endoscopic-ultrasound-guided-fine-needle-aspiration) Accessed 4/28/2022.
  • Pancreatic Cancer Action Network. Endoscopic Ultrasound (EUS). (https://www.pancan.org/facing-pancreatic-cancer/diagnosis/endoscopic-ultrasound-eus/) Accessed 4/28/2022.
  • The National Pancreas Foundation. Pancreas Endoscopic Ultrasound (EUS). (https://pancreasfoundation.org/endoscopic-ultrasound-eus/) Accessed 4/28/2022.

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