Advances in EUS

Abstract

Recent developments in endoscopic ultrasonography (EUS) imaging technology have enhanced its diagnostic ability, particularly in terms of characterizing conventional EUS-detected lesions. The newest EUS modalities are tissue elastography and contrast enhancement, which measure elasticity and vascularity, respectively, and thereby can depict tissue structure in detail. Hard elasticity on EUS elastography and hypo-enhancement on contrast-enhanced EUS are suggestive of ductal carcinomas in the pancreas. These methods are also useful for differentiating malignant from benign lymph nodes, characterizing gallbladder lesions, and estimating the malignant potential of gastrointestinal stromal tumors. Moreover, they complement EUS-guided fine-needle aspiration (EUS-FNA) by correctly diagnosing lesions with EUS-FNA false-negative findings and by identifying the most appropriate target site of EUS-FNA. The EUS can also be used to guide interventions, including drainage and injections. A new application is EUS-guided biliary drainage in obstructive jaundice, which employs several puncture sites and stent deployment methods. This method may be useful when endoscopic retrograde cholangiopancreatography (ERCP) is unsuccessful. Although there is risk of some adverse events, such as bile leakage, the technical and clinical success rates of EUS-guided biliary drainage are satisfactory: both exceed 90%. Another EUS-guided intervention is EUS-guided celiac plexus neurolysis (EUS-CPN), which is an effective and safe treatment for cancer-related pain. Pain relief can be obtained in approximately 80% of patients, whereas severe adverse effects are observed in less than 1%. Two recent technological advancements on EUS-CPN are EUS-guided direct celiac ganglia neurolysis and EUS-guided broad plexus neurolysis (EUS-BPN) over the superior mesenteric artery-both have greater pain-relieving efficacy compared to EUS-CPN.