If your doctor has recommended an Endoscopic Ultrasound (EUS), you may be wondering why you need another test.
Perhaps you have already had an ultrasound, CT scan, MRI or endoscopy. So why would your doctor recommend EUS?
The answer is that EUS provides a different kind of information.
Endoscopic Ultrasound combines endoscopy with ultrasound imaging, allowing doctors to examine the digestive tract and structures located close to it in considerable detail.
It is an advanced diagnostic procedure used in a wide range of gastrointestinal and pancreatic conditions.
And importantly, being advised to undergo an EUS does not automatically mean that your doctor thinks you have cancer.
What Is EUS?
An Endoscopic Ultrasound uses a specially designed flexible endoscope with a small ultrasound probe attached near its tip.
During an upper EUS, the endoscope is gently passed through the mouth into the esophagus, stomach and first part of the small intestine.
The ultrasound probe then produces detailed images of the digestive tract and nearby structures.
Because the ultrasound probe is located inside the body and close to the area being examined, it can provide information that may not be possible to obtain from an ultrasound performed through the skin.
How Is EUS Different From a Normal Endoscopy?
A traditional upper gastrointestinal endoscopy primarily allows the doctor to look at the inner surface of the esophagus, stomach and duodenum.
It is excellent for identifying abnormalities on the lining, such as ulcers, inflammation, bleeding or certain growths.
EUS goes one step further.
It allows the doctor to examine the layers of the digestive tract wall and structures outside the digestive tract.
A simple way to remember the difference is:
Endoscopy looks at the surface. EUS can look beyond the surface.
Why Might Your Doctor Recommend EUS?
There are several reasons.
Evaluating the Pancreas
EUS is particularly useful for examining the pancreas.
If another scan has identified a pancreatic cyst, mass or unexplained abnormality, EUS can provide a closer look.
It can help the doctor understand the size, appearance and location of an abnormality and its relationship with nearby structures.
Examining a Cyst
Pancreatic cysts are increasingly discovered because modern imaging is used more frequently.
Many pancreatic cysts are benign or low-risk, but some require monitoring or further assessment.
EUS can help doctors characterize certain cysts more accurately and, when appropriate, obtain fluid or tissue for further analysis.
Investigating a Mass
Sometimes a CT scan or MRI detects a mass but cannot provide enough information to determine exactly what it is.
EUS may allow a more detailed examination.
In selected cases, a needle can also be passed through the endoscope to collect a sample.
Looking at the Bile Ducts
EUS can also help doctors examine the bile ducts and surrounding structures.
Depending on the clinical situation, it may be used when investigating certain causes of jaundice, suspected bile duct stones or unexplained abnormalities.
Evaluating the Digestive Tract Wall
EUS can show the different layers of the gastrointestinal tract.
This makes it useful when evaluating certain subepithelial lesions or abnormalities that appear to be beneath the surface lining.
Can EUS Detect Cancer?
EUS can be an important part of the evaluation of certain cancers, including cancers involving the esophagus, stomach, pancreas and nearby structures.
It can help doctors assess the depth of a tumor and examine nearby lymph nodes.
In selected cases, EUS can also guide tissue sampling.
However, an EUS recommendation does not mean that cancer has been diagnosed.
There are many non-cancerous reasons for performing EUS.
Sometimes the purpose is simply to clarify an abnormal finding from another scan.
What Is EUS-Guided Biopsy?
One of the major advantages of EUS is that imaging and tissue sampling can sometimes be performed during the same procedure.
If the doctor identifies an area that needs further evaluation, a very small needle can be guided through the endoscope toward the lesion.
The needle may obtain cells or a small tissue sample.
This procedure is often called EUS-guided fine-needle aspiration or fine-needle biopsy.
The sample can then be examined by a pathologist.
This can be particularly useful when doctors need to distinguish between different types of masses or determine the nature of an abnormality.
Is EUS Painful?
EUS is generally performed with sedation or anesthesia, so most patients are comfortable during the procedure.
Afterward, some patients may experience a mild sore throat, bloating or temporary discomfort.
If a biopsy or another intervention is performed, the recovery experience may be slightly different.
Your doctor will explain what to expect based on the specific procedure planned.
How Should You Prepare for EUS?
Preparation depends on the type of EUS and whether any additional procedure will be performed.
For an upper EUS, you will generally be asked to avoid eating and drinking for a specific period before the procedure.
It is important to tell your doctor about:
- All medicines you are taking
- Blood-thinning medicines
- Drug allergies
- Previous reactions to anesthesia
- Significant medical conditions
- Any other relevant health concerns
Do not stop prescription medicines on your own. Your medical team will tell you if any medication needs to be adjusted.
Is EUS Safe?
EUS is generally considered a safe procedure when performed by a trained and experienced team.
However, no invasive procedure is completely without risk.
Potential complications may include bleeding, infection, perforation or complications related to sedation.
If tissue sampling or another intervention is performed, there may be additional risks depending on the location and type of procedure.
Your doctor should discuss the potential benefits and risks before you give consent.
What Happens After the Procedure?
You will usually spend some time in a recovery area while the effects of sedation wear off.
Because sedation can temporarily affect your alertness and coordination, you may need someone to accompany you home depending on the sedation used and your hospital’s instructions.
Your doctor will tell you when you can resume food and regular activities.
If a biopsy was performed, the final report may take additional time because the tissue needs to be examined in the laboratory.
Why Can’t My Doctor Just Rely on a CT or MRI?
CT and MRI are extremely valuable imaging tests.
However, each imaging method has its own strengths.
EUS provides a close-up ultrasound view from inside the digestive tract and can also allow tissue sampling when appropriate.
Therefore, EUS is not necessarily a replacement for CT or MRI.
In many cases, doctors use these tests together to build a more complete picture.
Does EUS Mean Something Serious Was Found?
Not necessarily.
A doctor may recommend EUS because an imaging scan showed something that needs clarification.
For example, a cyst may need characterization, a pancreatic abnormality may need closer examination, or a lesion may need to be evaluated more precisely.
The purpose of the test is often to answer an important question before deciding on the next step.
Questions You Can Ask Your Doctor
If you are nervous about undergoing EUS, consider asking:
“What are you looking for with this test?”
“Do I need a biopsy?”
“What did my previous scan show?”
“Will I be sedated?”
“When can I return to normal activities?”
“When will I receive the results?”
Understanding the purpose of the test can make the experience much less stressful.
The Bottom Line
Endoscopic Ultrasound is a powerful diagnostic tool that combines the advantages of endoscopy and ultrasound.
It can provide detailed information about the digestive tract, pancreas, bile ducts and surrounding tissues. In selected patients, it can also allow doctors to obtain a tissue or fluid sample without the need for a separate procedure.
If your doctor has recommended EUS, remember that the recommendation itself does not mean that you have cancer.
It means your doctor wants better information to make the most appropriate decision about your care.
