Endoscopic Ultrasound

Overview

Physicians increasingly use endoscopic ultrasound (EUS) to assess gastrointestinal and lung diseases. EUS can provide detailed, cost-effective, nonsurgical assessment of certain diseases. Because it can be technically demanding and complex, an experienced endoscopist, such as those at Mayo Clinic, should perform EUS. Mayo Clinic has offered endoscopic ultrasounds since 1989. Physicians perform more than 3,000 EUS procedures at Mayo Clinic each year.

EUS involves passing a thin, flexible tube (endoscope) through a patient's mouth or anus. A small ultrasound transducer in the endoscope produces sound waves that create a viewable image of surrounding tissue. Physicians use EUS to examine the lining and walls of the upper and lower gastrointestinal tract and nearby organs such as the pancreas, liver, and gallbladder.

Mayo Clinic physicians use two main types of EUS transducers. One is a radial imaging device that produces a 360-degree, cross-sectional image (also called a "slice"). The other is a curved linear array instrument that uses Doppler and pulse Doppler ultrasound that can guide a fine-needle aspiration (biopsy) of lymph nodes and tumors. Physicians choose the transducer that will produce the image they need to assess a patient's problem.

Another kind of ultrasound allows very high-resolution imaging of the surface of the gastrointestinal tract. Physicians use this kind to help determine the size of small nodules and how deeply the nodules involve the wall of the GI tract.

When combined with fine-needle aspiration, EUS is a minimally invasive, state-of-the-art alternative to exploratory surgery to remove tissue samples from abdominal and other organs. Physicians also use EUS to guide pseudocyst drainage, injections, and painkilling treatments.

Endoscopic ultrasound is used to:

• Stage gastrointestinal and lung cancers, including esophageal, gastric, rectal and pancreatic cancers. EUS can accurately determine how deeply a tumor penetrates the gut wall. Examining the size, shape and ultrasound appearance of adjacent lymph nodes also helps determine whether cancer has spread.
• Detect common bile duct stones. Stones in the bile tubes leading from the gallbladder to the intestine have traditionally been detected by an endoscopic retrograde cholangiogram (ERCP), an invasive test. EUS is less invasive and can detect these stones with equal accuracy.
• Assess masses in the submucosal lining of the gastrointestinal tract.
• Assess enlarged stomach folds that may be involved with cancer deep in the stomach wall and unreachable by surface biopsies.
• Diagnose diseases of the internal organs, such as of the pancreas, such as chronic pancreatitis or cysts of the pancreas.
• Safely and accurately collect fluid samples from the lungs or the abdominal cavity for analysis.

Conditions Diagnosed with Endoscopic Ultrasound

EUS may be used to determine the cause of symptoms such as abdominal pain, to evaluate a growth (tumor), and to diagnose diseases of the digestive tract and lungs. Physicians use EUS to evaluate the following organs and problems:

• Anal sphincter and incontinence
• Barrett's esophagus with high-grade dysplasia
• Neuroendocrine tumors
• Common bile duct stones
• Gastric cancer/MALT lymphoma
• Esophageal cancer
• Lung cancer
• Pancreatic cancer
• Pancreatitis
• Cystic neoplasms of the pancreas
• Rectal cancer
• Rectal fistulas
• Smooth muscle tumors
• Enlarged lymph nodes