Diagnosis: Endoscopic Ultrasound (EUS)

What is endoscopic ultrasound?
Endoscopic ultrasound (EUS) is a procedure used to image the digestive tract, including the pancreas.  A thin, flexible, lighted tube with a small ultrasound probe attached to the end (echoendoscope) is passed through the patient’s mouth into the stomach and the top part of the small intestine called the duodenum.  The ultrasound component of the endoscope uses sound waves to create visual images of the pancreas.

Why is EUS used?
The images created from an EUS procedure are detailed ultrasound pictures of the digestive tract.  The doctor can use these pictures to determine the size and location of a tumor in the pancreas and whether the tumor has spread to nearby blood vessels or other structures.  EUS can also allow passage of a needle into a suspected tumor to obtain tissue samples.  This is a type of biopsy called fine-needle aspiration.  Cells obtained from the biopsy can then be analyzed to see if they are cancerous and can help in deciding the best course of treatment.

What happens during an EUS?
During an EUS, the patient lies on his/her side and the doctor passes the endoscope through the mouth, esophagus and stomach and into the duodenum.  The tube will not affect the patient’s ability to breathe normally.  Once in place, the ultrasound probe at the end of the endoscope uses sound waves to create images of the pancreas and surrounding structures.

Usually, the EUS procedure lasts 15 to 45 minutes and is considered by most patients to be mildly uncomfortable.

What should I do to prepare for an EUS?
The healthcare team will give the patient exact instructions before an EUS procedure.  In general, the patient will not be allowed to eat or drink anything six hours before the examination.  Some patients receive antibiotics before the procedure to avoid infection.  The doctor will tell the patient whether to continue taking these or other medications before the EUS procedure.

EUS is performed under heavy conscious sedation so the patient may feel drowsy, but will be awake during the procedure.

Just before the EUS, the patient will receive sedative medication through a vein in the arm and local anesthetic spray to the throat, in order to be comfortable during the procedure.  Since sedative medications are used, the patient should prepare in advance to have someone else drive him/her home after the procedure. 

Image courtesy of Shawn Mallery, MD & Minnesota Pancreas and Liver Center

What can I expect after an EUS?
After the EUS procedure is completed, the patient will remain in the recovery room until the sedative medication has worn off.  The patient should not drive a vehicle after receiving sedative medication.  It is not unusual for the patient to experience a feeling of fullness or the need to pass gas after the procedure.  Also, the patient may have changes in bowel habits, for instance, soft stool, after the procedure.  The healthcare team will provide instructions regarding eating and drinking following an EUS procedure.

What complications can occur with an EUS?
Complications are very rare, but they include infection of a pancreatic cyst, pancreatitis, gastrointestinal bleeding, tearing from the endoscope, reactions to anesthesia medications and sore throat for a day or more.  Overall, EUS is safer than another endoscopic procedure called ERCP.

Where would I go for an EUS procedure?
EUS is usually performed in a hospital endoscopy unit or ambulatory surgery center.  It is an outpatient procedure, so patients do not have to stay overnight in the hospital.

How does EUS compare with other techniques used to image the pancreas?
EUS is one of the most common imaging procedures used to diagnose pancreatic cancer.  It is often the best procedure to obtain samples of a suspected tumor to make a definitive diagnosis of cancer.  EUS may be able to find small pancreatic masses undetected by computed tomography (CT) scans but suspected by the doctor.  Studies show that EUS is equal to or better than CT scans for detection of early pancreatic cancer. 

The patient’s experience during an EUS procedure is similar to that of an endoscopic retrograde cholangiopancreatography (ERCP), but the images produced are different.  EUS is generally a safer test than ERCP.

New studies involving EUS:
Studies using EUS to screen individuals at higher risk for developing pancreatic cancer are underway.  EUS has the ability to detect early abnormal changes in the pancreas in this population.

Other Resources:
American Gastroenterological Association (AGA)
American Society of Gastrointestinal Endoscopy (ASGE)

For more information about jaundice, stents or other the other imaging tests mentioned above, contact a Patient and Liaison Services (PALS) Associate toll free at 877-272-6226 or email pals@pancan.org.  PALS Associates are available M-F 7am-5pm Pacific Time.

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