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

How do you prepare for an endoscopic ultrasound (EUS)?

To prepare for an EUS, you will be asked to follow specific instructions such as:

• Drinking a laxative in order to clear your bowels, if you are undergoing EUS from the rectum.
• Not consuming any food for 6 – 8 hours before the procedure.
• Not consuming any fluid 2 – 3 hours before the procedure.
• Stopping certain blood-thinning medications before the procedure. Your doctor will guide you on this.
• As with all endoscopic procedures carried out under sedation, it is advisable to get someone to drive you home.

Once your procedure is scheduled, your doctor will provide you with more detailed advice.

What can you expect in an endoscopic ultrasound?

An endoscopic ultrasound is performed while you are sedated, so you will be sleepy and relaxed during the procedure. This is a day procedure and you may go home to rest afterwards.

Estimated duration

The procedure takes about 30 – 90 minutes.

During the procedure

During an endoscopic ultrasound:

• An endoscope is inserted either through the mouth or anus, depending on your preliminary diagnosis.
• It is guided through the gastrointestinal tract.
• During the procedure, your doctor will observe the images taken on a screen and ultrasound monitor.
• In fine needle aspiration, a needle is passed through the scope to obtain tissue samples for further examination by the pathologist.

Care and recovery after an endoscopic ultrasound

After the EUS, you will be transferred to a recovery area and monitored for around 1 hour.

The medical team will go over the results of the EUS with you and advise you on when you can resume eating and drinking, and if any medications are required.

You will be allowed to go home once your vital signs are stable. You should arrange for someone to drive you home.

Seek medical attention if you experience any symptoms after EUS, such as:

• Bleeding
• Fever
• Pain
• Vomiting

You may require a follow-up visit to discuss the biopsy results with your doctor.