Endoscopic ultrasonography

Over the last 15 years, the role of endoscopic ultrasonography (EUS) has progressed from a diagnostic to a therapeutic modality. This chapter outlines the principles of EUS, provides a brief overview of the equipment, and details the indications for EUS in commonly encountered clinical scenarios. Echoendoscopes can be broadly classified into two types, radial and linear. A variety of EUS catheter probes are available for imaging of small submucosal lesions and from within the biliary and pancreatic ducts. Along with the echoendoscope, the standard equipment includes an EUS processor, balloons, and needles for tissue sampling if fine needle aspiration is planned. The chapter also describes different applications of interventional EUS, including EUS-guided biliary drainage, EUS-guided transluminal stenting, EUS-guided pancreatic duct interventions, EUS-guided drainage of peripancreatic fluid collections, EUS-guided celiac plexus neurolysis, EUS-guided fiducial placement, and EUS-guided angiotherapy.