Recent advances in endoscopic ultrasonography.

Endoscopic ultrasonography is recognized as an important tool in the diagnosis and staging of esophageal, gastric, colorectal, pancreatic, and biliary tumors. It also is a reliable method for the evaluation of submucosal tumors of the gastrointestinal tract, the differentiation between benign and malignant giant gastric folds, the evaluation of gastric ulcer healing, and the detection of common bile duct stones. The recent introduction of endoscopic ultrasonographic fine-needle aspiration provides for the cytologic and histologic diagnosis of gastrointestinal submucosal and extraluminal tumors and regional lymph nodes. This new technique may also be used for the intrasphincteric injection of botulinum toxin in the treatment of achalasia, for the steroid injection treatment of refractory esophageal strictures, for celiac nerve block, for pseudocyst drainage, and for drug delivery into pancreatic tumors. High-frequency thin ultrasonic probes can be used to make a more accurate diagnosis of superficial carcinomas of the gastrointestinal tract and for intraductal ultrasonography of the extrahepatic bile duct and pancreatic duct. In the future, three-dimensional imaging of gastrointestinal tumors will provide more accurate information regarding cancer extent. Endoscopic ultrasonography is a powerful tool which can be used in the diagnosis and treatment of a variety of gastrointestinal diseases.