Endoscopic Ultrasound (EUS)

What is EUS?

Endoscopic ultrasound (EUS) is an advanced imaging method that brings together the features of endoscopy and ultrasound in one instrument.

The procedure uses a special endoscope with an ultrasound probe at its tip. This is passed through the mouth into the oesophagus, the stomach and the duodenum, so that the wall of the digestive tract and the structures immediately around these organs can be examined from very close by.

While standard endoscopy shows mainly the inner surface of the oesophagus, the stomach and the duodenum, EUS can also assess the layers of the wall of the digestive tract and the organs outside the wall.

EUS is an important method particularly for the detailed examination of the pancreas and the bile ducts.

Why is EUS done?

EUS is not an investigation that has to be done routinely in every patient. It is generally used where a finding on ultrasound, computed tomography (CT), magnetic resonance (MR/MRCP) or standard endoscopy needs more detailed assessment.

Its chief uses are:

• Investigating a mass or a suspicious lesion in the pancreas,
• Assessing pancreatic cysts,
• Investigating chronic pancreatitis and certain diseases of the pancreas,
• Assessing certain attacks of acute pancreatitis of unexplained cause,
• Examining the bile ducts and the main bile duct,
• Looking for small stones or sludge in the bile duct,
• Assessing strictures in the bile ducts,
• Examining masses arising from the wall of the stomach, the oesophagus or the duodenum,
• Assessing enlarged lymph nodes around the digestive system,
• Assessing the depth of spread of certain tumours of the oesophagus, stomach, pancreas and other parts of the digestive system, and their relationship to the surrounding tissues,
• Taking a tissue sample from a suspicious area where needed.

Whether EUS is needed is decided according to the patient’s complaints, the results of other investigations and the condition being investigated.

How does EUS differ from other imaging methods?

In an abdominal ultrasound, the ultrasound waves are sent from outside the body. In EUS, the ultrasound probe is much closer to the organ being examined.

The pancreas, for instance, is an organ lying behind the stomach, deep within the abdomen. During EUS the ultrasound probe can be brought into a position very close to the pancreas, from the stomach or the duodenum.

Thanks to this closeness, EUS can be very useful in assessing the pancreas, the bile ducts and certain small or detailed structures in the wall of the digestive tract.

Even so, EUS is not a method that takes the place of CT or MR. These investigations mostly complement one another, and which is needed is decided according to the patient’s situation.

Can a biopsy be taken with EUS?

Yes.

One of the important features of EUS is that a tissue or cell sample can be taken, where needed, from an area seen to be suspicious during the imaging.

This is done as EUS-guided fine needle aspiration (EUS-FNA) or fine needle biopsy (EUS-FNB).

Thanks to the ultrasound image from the endoscope, the doctor sees in real time the area the needle is passing through. A targeted sample can therefore be taken from a mass in the pancreas, from a lymph node, or from certain lesions that are hard to reach.

The material obtained is examined in the pathology laboratory.

A biopsy does not have to be taken from every lesion seen during EUS. The decision to biopsy is made according to the characteristics of the mass, where it lies, the results of other imaging, and whether the result obtained would change the patient’s treatment.

Does being sent for EUS mean pancreatic cancer?

No.

That a patient has been sent for EUS does not mean they have pancreatic cancer.

EUS can also be used:

• In pancreatic cysts,
• In chronic pancreatitis,
• In diseases of the bile ducts,
• Where a stone in the bile duct is suspected,
• In pancreatitis of unexplained cause,
• In lesions in the wall of the stomach or bowel that may well be benign.

The aim of EUS is mostly to understand better what a finding seen on imaging actually is.

Consent form

The clinic’s consent form will be signed.

How is the procedure carried out?

In an EUS examination of the upper digestive system, the instrument is generally passed through the mouth.

The endoscope is passed from the oesophagus into the stomach and, where needed, into the duodenum. Alongside the endoscopic image, the doctor assesses the ultrasound images too.

According to the region being examined, the pancreas, the bile ducts, the gallbladder, the surrounding blood vessels, the lymph nodes and the wall of the digestive tract can all be imaged in detail.

If it is thought necessary, a tissue sample can be taken with a needle during the same procedure.

The length of the procedure can vary with the examination being carried out and with whether a biopsy is needed.

Does the patient feel pain during EUS?

EUS is mostly carried out under sedation or anaesthesia.

For this reason most patients feel no marked discomfort during the procedure, or do not remember it.

The method of sedation or anaesthesia used is decided according to the patient’s age, their other illnesses, the characteristics of the procedure to be carried out and the practice of the centre.

How should I prepare for EUS?

The stomach must be empty before EUS.

Be sure to follow the rules on fasting and taking fluids that you have been given. In patients who are to have anaesthesia or deep sedation in particular, these rules matter for reducing the risk of aspiration — the passing of stomach contents into the airways.

Tell your doctor the medicines you take regularly before the procedure.

You should ask your doctor’s advice before the procedure in particular if you take:

• Aspirin,
• Clopidogrel,
• Warfarin,
• Apixaban,
• Blood-thinning medicines such as rivaroxaban or dabigatran,
• Diabetes medicines and insulin.

Do not stop blood-thinning medicines on your own decision.

If you have previously had a serious allergic reaction to a medicine or to anaesthesia, be sure to say so before the procedure.

What happens after the procedure?

Once the procedure is finished the patient is observed until the effects of the sedation or anaesthesia have passed.

After the procedure there may temporarily be:

• Mild burning or pain in the throat,
• Wind in the abdomen,
• Bloating,
• Mild nausea.

If a biopsy has been taken, the pathological examination has to be completed for a definite result.

Patients who have had sedation or anaesthesia should not drive that day, work with machinery requiring attention, or make important decisions. It is best for someone to accompany the patient.

Are there risks with EUS?

EUS is generally a safe procedure. But, as with all medical interventions, it is not entirely without risk.

In diagnostic EUS done for imaging alone, serious complications are uncommon.

Where a needle biopsy or another intervention is carried out in particular, there may uncommonly be:

• Bleeding,
• Infection,
• Pancreatitis,
• Injury or perforation of the wall of the digestive tract,
• Breathing and circulatory problems related to sedation or anaesthesia.

The risk varies with the kind of procedure to be carried out and with the patient’s general state of health. Your doctor will discuss the risks specific to the planned intervention with you before the procedure.

When should I contact a healthcare provider after the procedure?

It is best to contact the centre that carried out the procedure, or your doctor, if any of the following develops after EUS:

• Severe or increasing abdominal pain,
• Continuing vomiting,
• Fever or shivering,
• Shortness of breath,
• Vomiting blood,
• Black, tarry stools,
• Fainting or marked weakness.

These symptoms do not necessarily mean a serious complication, but they do need to be assessed.

What can be learnt from EUS?

At the end of EUS your doctor assesses the appearance of the organs examined.

If no biopsy has been taken, the EUS findings can mostly be explained after the procedure.

If a tissue sample has been taken, then although the EUS image gives important information, the pathology result may need to be awaited for a definite assessment.

Assessing the EUS result together with CT, MR/MRCP, blood tests and any previous endoscopy results gives the most accurate approach.

EUS in brief

Endoscopic ultrasound (EUS) is an advanced investigation that brings endoscopy and ultrasound together.

It allows detailed assessment particularly of the pancreas, the bile ducts, the wall of the digestive tract and the structures neighbouring these regions. Where needed, a tissue sample can be taken from a suspicious area during the same procedure.

Being sent for EUS does not on its own mean that a serious or malignant disease is present. The aim of the procedure is to help build an accurate diagnosis and treatment plan by assessing the existing findings in more detail.

This information has been prepared for general patient information. Every patient’s state of health, and the purpose of the EUS to be carried out, may differ. Your doctor’s own advice to you should be followed before the procedure.