Endoscopic Ultrasound (EUS)

What is endoscopic ultrasound (EUS)?

An endoscopic ultrasound (EUS) is a safe and minimally invasive diagnostic procedure for viewing the inside of the digestive tract. It uses an endoscope (a thin and flexible tube with a small ultrasound probe attached), which is inserted into the mouth or the anus. Various tools can also be guided through the endoscope as needed.

EUS generates enhanced and detailed images of the digestive tract, and allows examination of the lining and walls of the gastrointestinal tract as well as neighbouring organs, including the pancreas, liver and gall bladder.

Endoscopic ultrasound versus endoscopy

Endoscopic ultrasound and endoscopy are both used to examine the digestive tract.

An endoscopic ultrasound:

  • Uses high-frequency sound waves to generate a detailed virtual image of the GI tract.
  • Is used to evaluate abnormalities which are identified through an endoscopy in the wall of the GI tract.
  • Is also used to analyse and possibly perform biopsies of structures next to the wall of the GI tract, which have been identified on scans such as a computerised tomography (CT) scan or magnetic resonance imaging (MRI).

Meanwhile, endoscopy:

  • Uses a video camera to capture images of the GI tract.
  • Cannot be used to evaluate structures outside the GI tract which are not seen on the scope.

Why do you need an endoscopic ultrasound (EUS)?

An endoscopic ultrasound (EUS) may be recommended to:

  • Diagnose and evaluate lesions which have been found on endoscopy or scans
  • Examine the bile duct for gallstones
  • Examine abnormal growths within the central chest and upper abdomen
  • Assess diseases that affect the pancreas (e.g. chronic pancreatitis and pancreatic cysts)
  • Determine the cause of bowel incontinence (loss of bowel control)

It is also used to study previously diagnosed lumps or lesions. EUS enables your doctor to take a sample of fluid and tissue from your abdomen or chest through a procedure called fine needle aspiration. This procedure is a minimally invasive alternative to an open exploratory surgery.

What are the risks and complications of an endoscopic ultrasound (EUS)?

EUS is a generally safe procedure. It is considered low-risk because it is a minimally invasive procedure.

Note that a procedure with fine needle aspiration has a slightly higher risk than the EUS procedure alone.

The risks are generally small, and they include:

  • Adverse reactions to the sedation administered
  • Bleeding
  • Infection or inflammation around the area of needle puncture
  • Injury to the lining of the digestive tract

In the unlikely event that you experience a fever, chest pain or shortness of breath, you should see a doctor immediately.

You should also see a doctor if you have serious symptoms such as:

  • Severe or persistent pain in your abdomen
  • Having black or dark-coloured stools
This page has been reviewed by our medical content reviewers.

Need help?


For appointment bookings, please Whatsapp
+65 8198 7777

For clinic or corporate matters, please call
+65 6227 7777