Endoscopic Ultrasound (EUS)

EUS, otherwise known as endoscopic ultrasound is a specialist investigation that combines the use of an endoscope with an ultrasound device on the end of the endoscope. Images, not only of the lumen and the lining of the bowel, but also of the underlying tissues, captured by the ultrasound probe can be transmitted from the tip of the endoscope to a screen which is visible to the endoscopist. Such images can then be used to define the underlying structures or to guide biopsies. Bipsies can then be undertaken through the endoscope using a steerable fine needle as illustrated below.

 

Examples where this technique may be used include where biopsies are required of undelying structures, such as tumours or lymph nodes Oesophageal or pancreatic cancer) or where a there is a question of whether small stones are present within the bile duct (choledocholithiasis). The endoscopic ultrasound gives finer resolution of the structures near the tip of the endoscope than many other imaging modalities.