What is an Endoscopic Ultrasound (EUS)?
For many patients who have, or who are suspected of having pancreatic disease or hepatobiliary disease, mediastinal disease their doctor may recommend that they undergo a type of procedure called an endoscopic ultrasound, or more often known as EUS.
An EUS is a type of endoscopic examination. It involves the insertion of a thin tube into the mouth and down into the stomach and the first part of the small intestine. At the tip of the tube is a small ultrasound probe that emits sound waves. These sound waves bounce off of the surrounding structures, such as the stomach, small intestine, pancreas, bile ducts, and liver. These sound waves are then recaptured by the probe and converted into black and white images that are then interpreted by your doctor. Because the pancreas sits next to the stomach and small intestine, EUS allows the physician to get very detailed images of the pancreas. This procedure is typically performed in an outpatient setting, and usually takes between 20 and 45 minutes.
What are the reasons why I need an EUS?
EUS allows for very detailed imaging and analysis of the pancreas and other various parts which are inaccessible to normal endoscope. As such, it is an excellent test for evaluating many different kinds of diseases that can occur in the pancreas. Examples of such pancreatic conditions for which EUS can be extremely useful are:
- Pancreatic masses and tumors
- Pancreatic cysts
- Chronic pancreatitis
- Autoimmune pancreatitis
- Acute pancreatitis
One of the most common reasons that patients are referred for an EUS of the pancreas is to evaluate abnormal findings on a CT (CAT scan), MRI, or ultrasound of the abdomen, or for further investigation of abnormal blood tests such as elevated liver function tests (AST, ALT, bilirubin) or elevated pancreatic enzymes (amylase, lipase). Patients with certain types of abdominal pain may also be referred for an EUS. Examples of reasons for referral for an EUS include:
- Dilated pancreatic duct
- Dilated bile duct
- Swollen/inflamed pancreas
- Suspected stones in the pancreas duct or bile duct
- Suspected blockage of the pancreas or bile duct
- History of recurrent episodes of acute pancreatitis
Can biopsies of the pancreas be taken at the time of my EUS?
One of the advantages of performing an EUS is that pancreatic biopsies can be obtained at the time of the examination. These biopsies, often referred to as FNA, or fine-needle aspiration, can allow for your physician to collect tissue samples which can later be analyzed under a microscope. Special needles, designed to be used with the EUS scope, allow the physician to insert a small needle through the wall of the stomach or intestine directly into the pancreas. Because this is done at the time of the EUS, the physician is able to direct the needle to the exact location of interest all while watching the needle with the EUS.
FNA is most commonly performed to evaluate masses or tumors of the pancreas, in order to determine if cancer is present. Another very common reason for performing an FNA is in the evaluation of pancreatic cysts. In these cases, the needle is used to sample the fluid which is contained in the cyst. This fluid can be sent for biochemical, cytologic, and molecular analysis in order to help characterize the type of pancreatic cyst you have.
In certain circumstances, larger biopsy samples of the pancreas may be required. EUS allows the physician to obtain “core biopsies” of the pancreas in a similar fashion to FNA.
Can biopsies of the pancreas be taken at the time of my EUS?
One of the advantages of performing an EUS is that pancreatic biopsies can be obtained at the time of the examination. These biopsies, often referred to as FNA, or fine-needle aspiration, can allow for your physician to collect tissue samples which can later be analyzed under a microscope. Special needles, designed to be used with the EUS scope, allow the physician to insert a small needle through the wall of the stomach or intestine directly into the pancreas. Because this is done at the time of the EUS, the physician is able to direct the needle to the exact location of interest all while watching the needle with the EUS.
FNA is most commonly performed to evaluate masses or tumors of the pancreas, in order to determine if cancer is present. Another very common reason for performing an FNA is in the evaluation of pancreatic cysts. In these cases, the needle is used to sample the fluid which is contained in the cyst. This fluid can be sent for biochemical, cytologic, and molecular analysis in order to help characterize the type of pancreatic cyst you have.
In certain circumstances, larger biopsy samples of the pancreas may be required. EUS allows the physician to obtain “core biopsies” of the pancreas in a similar fashion to FNA.
EUS can be used to take biopsies from mediastinal lymph nodes or mass. It also help to insert metal stent into biliary system.