Gastrointestinal Imaging by Endoscopic Ultrasound

Gastrointestinal Imaging by Endoscopic Ultrasound

What is Endoscopic Ultrasound of the Gastrointestinal System (EUS)?

Endoscopic Ultrasound of the Gastrointestinal System (EUS) is an advanced diagnostic technique that combines the capabilities of endoscopic vision with the precision of ultrasound imaging. The procedure provides detailed images of the gastrointestinal tract and surrounding organs, enabling precise insights for diagnosis and treatment planning.

How does endoscopic gastrointestinal ultrasound work?

• Endoscope: A thin, flexible tube with a small ultrasound probe at the end is inserted into the body through the mouth or anus.
• Ultrasound: The probe emits high-frequency sound waves that penetrate tissues. These waves reflect off internal structures, and the resulting echoes are translated into real-time images that are displayed on a screen.
• Visualisation: EUS provides high-resolution images of the digestive system, including the oesophagus, stomach, small and large intestine. It can also visualise nearby organs such as the pancreas, liver, gallbladder, and lymph nodes.

What are the benefits of endoscopic ultrasound of the gastrointestinal tract?

• Accurate diagnosis: EUS provides better visualisation compared to conventional endoscopy, enabling more accurate diagnosis of various conditions.
• Staging: Helps determine the extent of diseases such as cancer, especially in the pancreas, oesophagus and stomach.
• Guiding procedures: It can guide simple medical procedures such as:
• Fine needle aspiration (FNA): Taking tissue samples for examination.
• Drainage: Removing fluid from cysts or abscesses.
• Stent placement: Opening blocked bile or pancreatic ducts.
• Minimise the risk of complications: EUS provides precise guidance that minimises the risk of invasive surgical procedures.

What conditions can endoscopic ultrasound of the gastrointestinal tract diagnose?

• Diseases of the pancreas: Pancreatic cancer, chronic pancreatitis, and pseudocysts.
• Oesophageal diseases: Oesophageal cancer, Barrett’s oesophagus, and achalasia.
• Stomach diseases: Stomach cancer, ulcers, and lymphoma.
• Diseases of the bile ducts: Gallstones, bile duct stenosis, cholecystitis.
• Evaluation of lymph nodes: Evaluation of the spread of cancer to nearby lymph nodes.

What is the role of endoscopic ultrasound of the gastrointestinal tract in cancer care?

EUS can help diagnose cancers and other disorders within the GI tract and determine the stage of the cancer.

The digestive tract is about 3 millimetres thick and has different layers. Imaging techniques such as CT and MRI can detect distant spread of cancer, but they cannot determine how many layers are affected by localised spread. We can achieve this level of accuracy with EUS.’

EUS can also help doctors determine if the cancer has spread to lymph nodes or other organs.

The endoscope with a small needle can also be used to take tissue samples for biopsy, a procedure called ultrasound-guided fine-needle aspiration.

What are the risks of endoscopic ultrasound of the gastrointestinal tract?

Complications are rare and include:

• Bleeding: Minor bleeding may occur at the puncture site.
• Infection: There is a small risk of infection.
• Pancreatitis: In rare cases, pancreatitis may occur, especially during procedures involving the pancreas.

How do you prepare for an endoscopic ultrasound of the gastrointestinal tract?

• Upper imaging procedure: Usually requires overnight fasting.
• Lower imaging procedure: Requires thorough colon cleansing with a laxative solution.

Your doctor will give you specific instructions about diet, fasting, and medications to take or stop before the procedure.

What can you expect during a gastrointestinal endoscopic ultrasound procedure?

• Preparation: You may be asked to fast for several hours before the procedure.
• Anaesthesia: You will usually receive medications to help you relax during the procedure.
• Procedure: EUS is usually performed by a gastroenterologist at a hospital or outpatient centre.
• Recovery: You will be monitored for a short time after the procedure, and you can usually go home the same day.

What are the new developments in the use of endoscopic ultrasound of the gastrointestinal tract?

Thanks to its accuracy, EUS has become the most accurate method for early detection of pancreatic cancer.

In some cases, doctors use EUS guidance to place small gold seeds in the tumours of patients who will undergo radiotherapy. These seeds help target the tumour with radiation while protecting nearby organs.