What is endoscopic ultrasound (EUS)?
Endoscopic ultrasound is an endoscopic examination that uses high-frequency sound waves (ultrasound) to provide detailed imaging of the inner lining and walls of the upper and lower parts of the digestive tract and nearby organs such as the pancreas, liver, and gallbladder.
Your doctor will use a thin, flexible tube called an endoscope that has a tiny ultrasound sensor built into it. The doctor will insert the endoscope through your mouth or rectum into the area that needs to be examined. They will then use the ultrasound to create visual images of the digestive system.
Endoscopic ultrasound provides more information than other imaging tests, giving detailed images of your digestive system.
Your doctor may recommend an endoscopic ultrasound for various reasons:
To diagnose certain conditions that may cause unexplained abdominal pain or pathological weight loss.
To evaluate known pathological conditions, including tumors or lesions detected during a previous endoscopy or observed in imaging tests such as a CT scan.
Endoscopic ultrasound provides a more detailed image, which can help your doctor determine the cause and contribute to treatment decisions.
To diagnose conditions of the pancreas, bile duct, and gallbladder when other tests are unclear or yield conflicting results.
To determine the extent of certain cancers of the digestive and respiratory systems. Endoscopic ultrasound allows your doctor to accurately assess the extent of cancer and whether it has spread to nearby lymph nodes or adjacent vital structures, such as major blood vessels.
To obtain a needle biopsy of a tumor or lesion in the gastrointestinal tract to help your doctor determine the appropriate treatment.
How is an EUS performed?
For the examination of the upper gastrointestinal tract, you will lie on your left side in the endoscopy room. Before the procedure, you will receive an intravenous dose of sedative medication to help you relax and sleep comfortably during the examination. While the patient is sedated, the anesthesiologist and medical staff will monitor vital signs. Based on your medical conditions, the anesthesiologist may insert a breathing tube into your trachea and connect you to a breathing machine. Once you are sedated, the doctor will insert the ultrasound endoscope through your mouth, into the esophagus, stomach, and duodenum. The instrument does not interfere with your ability to breathe.
The examination of the lower gastrointestinal tract can often be performed safely and comfortably without medication, but you will receive a sedative if the examination needs to be prolonged or if the doctor needs to examine a significant depth in the colon. You will start the examination on your left side with your back toward the doctor.
After the procedure
Recovery
The examination of the upper gastrointestinal tract usually takes less than 60 minutes. Most rectal examinations generally last less than 45 minutes. You should be aware that obtaining a needle biopsy of a lesion or performing a fine-needle aspiration of a cyst during the examination may extend the procedure and can take up to 2 hours. You may experience some discomfort and a feeling of bloating due to the air and water that were introduced during the examination.
You will be able to eat after leaving the examination area unless otherwise instructed. After the procedure, you should remain in the hospital for 1-2 hours until the sedative wears off. The doctor will ensure that you have no signs of complications before you leave. The doctor can generally inform you of the preliminary results of the procedure that day, but results from some tests, including biopsies, may take several days. Discharge instructions should be read carefully and followed.
Patients who develop any of these rare side effects should contact their doctor immediately:
- Severe abdominal pain
- Fever
- Bleeding
- Persistent abdominal pain and distention (perforation).