Endoscopic Ultrasound (EUS)

Endoscopic ultrasound, commonly referred to as EUS, is an advanced endoscopic procedure that combines high-resolution ultrasound imaging with endoscopy to evaluate structures within and around the gastrointestinal tract.

EUS allows gastroenterologists to obtain detailed images of the digestive tract walls as well as nearby organs, including the pancreas, bile ducts, gallbladder, liver, and lymph nodes. It is one of the most precise tools available for diagnosing and staging a wide range of gastrointestinal conditions.

Why Is Endoscopic Ultrasound Performed?

EUS may be recommended to evaluate or further characterize:

Pancreatic masses or cysts
Submucosal or deep gastrointestinal lesions
Abnormal findings on CT, MRI, or PET scans
Unexplained abdominal pain or weight loss
Suspected gastrointestinal or pancreatic cancer
Enlarged lymph nodes
Bile duct abnormalities

EUS is often used when detailed imaging is needed beyond what standard endoscopy or radiologic studies can provide.

How Is EUS Different from Standard Endoscopy?

Unlike standard endoscopy, which evaluates only the inner lining of the gastrointestinal tract, EUS uses an ultrasound probe located at the tip of the endoscope to visualize deeper layers and surrounding structures.

This allows for:

High-resolution imaging of tissues beneath the GI lining
Precise assessment of lesion depth
Evaluation of nearby organs not directly visible with standard endoscopy

What Happens During an Endoscopic Ultrasound?

EUS is performed while you are comfortably sedated.

During the procedure:

An endoscope with an ultrasound probe is passed through the mouth or rectum, depending on the area being evaluated
Ultrasound images are obtained in real time
If needed, fine-needle aspiration (FNA) or biopsy may be performed to obtain tissue samples

The procedure typically takes 30–60 minutes, depending on the complexity of the evaluation.

What Conditions Can Be Diagnosed or Evaluated with EUS?

Endoscopic ultrasound is commonly used to evaluate:

Pancreatic cancer and cystic lesions
Gastrointestinal cancers and tumor staging
Neuroendocrine tumors
Subepithelial masses
Chronic pancreatitis
Bile duct disorders
Lymph node abnormalities

When combined with tissue sampling, EUS provides highly accurate diagnostic information that helps guide treatment decisions.