It’s estimated that hundreds of thousands of endoscopic ultrasound, or EUS, procedures are performed annually in the United States. Significant advances in EUS technology over the last decade and its many benefits in clinical practices have contributed to this growing number.

Gastroenterologist Ishfaq Bhat, MD, is one of two Nebraska Medicine doctors who perform EUS. EUS is a complicated procedure that only a specialized endoscopist should perform. Dr. Bhat explains what an EUS is and how it works.

What is an endoscopic ultrasound?

Endoscopic ultrasound is a procedure that combines flexible endoscopy and high-frequency ultrasound and examines the gastrointestinal tract and surrounding organs. An upper endoscopic ultrasound diagnoses diseases and disorders in the upper gastrointestinal tract, while a lower endoscopic ultrasound examines the lowermost digestive tract and surrounding internal organs. 

An EUS may be required if a doctor sees any abnormalities and needs to look closer at the gastrointestinal tract and nearby organs. This can include the:

• Liver
• Pancreas
• Gallbladder
• Esophagus
• Stomach
• Duodenum
• Bile ducts

“EUS is very valuable for detecting small lesions and evaluating deeper layers of the GI tract,” says Dr. Bhat. “EUS is commonly used for diagnosing and staging various gastrointestinal conditions such as chronic pancreatitis, disorders of the gastrointestinal lumen and pancreatic cancer.”

How does an endoscopic ultrasound work?

A flexible tube with a camera and a mini ultrasound probe at the end is inserted into the mouth and passed into the GI tract to take high-resolution images of the digestive tract and nearby organs. It’s guided slowly into the stomach or rectum, depending on the area of interest, while the patient is under IV sedation.

“The ultrasound probe sends high-frequency sound waves that create detailed high-resolution images that are examined in real-time,” says Dr. Bhat. “This is mostly an outpatient procedure, and patients experience no or minimal discomfort. Because of the anesthesia, patients can return to normal activities the next day.”

How does EUS differ from other imaging methods?

EUS allows for real-time, noninvasive imaging and provides more details and high-resolution images than a CT or MRI, which uses radiation or magnetic fields. Unlike traditional endoscopic procedures, it visualizes not only the gastrointestinal tract's lumen, or cavity, but all surrounding tissue, organs and nearby lymph nodes.

While other imaging techniques can identify masses, EUS allows for direct tissue sampling. EUS has biopsy capabilities, including guiding fine-needle aspiration biopsy of lesions or lymph nodes.

When would a patient need an EUS?

A patient might need an EUS if CT or MRI scans haven’t given clear answers or if they have a family or medical history of certain cancers or diseases. Some reasons include:

• Chronic abdominal pain evaluation.
• Screening and surveillance for high-risk cancers. (e.g. pancreas)
• Establishing a diagnosis of cancers. (e.g. pancreas)
• Staging of cancers. (e.g. esophageal, gastric, rectal)
• Detection of cysts and lesions. (e.g. pancreatic and GI tract)
• Evaluation of biliary obstruction. (e.g. stones and cancers)

“EUS is a generally safe procedure and carries a minimal risk,” says Dr. Bhat. “Once we have the necessary information, whether it’s staging or a diagnosis scenario, we can coordinate with other teams and create a treatment plan for patients in a multidisciplinary fashion.”

This is a standard approach for a majority of patients with bowel or pancreatic cancers.

How is EUS used in cancer care?

EUS is important for evaluating different types of cancers, including:

• Pancreatic
• Esophageal
• Gastric
• Bile duct
• Colorectal

“EUS is critically important for establishing a diagnosis and accurate staging of certain cancers,” says Dr. Bhat. “It assesses the depth of the cancer and also evaluates any surrounding lymph nodes. In some cases, we can find lesions that suggest advanced disease.”

Tissue samples or biopsies can be taken to confirm diagnoses. EUS can differentiate between benign and malignant lesions or tumors based on appearance, which aids in the diagnosis. It can monitor tumor size over time and evaluate how a patient responds to chemotherapy or radiation. EUS has a role in palliation of pain and bowel obstruction in terminally ill patients.

What advances are being made in EUS?

“EUS has evolved significantly over the last 10 to 15 years,” says Dr. Bhat. “Imaging has become more sophisticated; designs of the endoscopes have changed and more devices and accessories are available. EUS, as a minimally interventional procedure, is now considered standard for a variety of conditions for which surgeries were routinely done 15 or 20 years ago.”

Additionally, emerging AI technologies are being integrated into EUS to assist with detailed image analysis and a faster, more accurate diagnosis.

More therapeutic interventions are possible today. In the past, EUS was only available at larger regional hospitals and major academic medical centers, but today, patients can be treated in more accessible settings.

“At Nebraska Medicine, we have the technology, space, support and expertise,” says Dr. Bhat. “We’re able to take care of our patients, and we’re very proud of that.”