FUNDAMENTAL AND CLINICAL STUDIES OF ULTRASONIC MICROPROBE IN BILIARY TRACT

Abstract

An intra-corporal scanning ultrasonic micro-probe used through a forceps channel of conventional endoscope was applied for evaluation of biliary diseases. This newly developed radial scanning ultrasonic micro-probe is 2.4 mm in diameter and equipped with 15MHz transducer. As a fundamental study, the gastric wall of mouse was scanned at the intra-stomach using the ultrasonic micro-probe. As the result, the gastric wall, approximately 0.5 mm thick, visualized into 3 to 5 layers. On the clinical study, the ultrasonic micro probe was inserted into biliary tract under surgical operation for 5 patients with diseases of biliary tract (1 cholecystolithiasis, 2 choledocholithiasis, 1 choledochal cancer, 1 choledochal obstruction due to invasion by colon cancer). By scanning intra-biliary tract using the ultrasonic micro-probe, the sphincter of Oddi was clearly demonstrated as a hypoechoic layer at the papilla of Vater and the wall of bile duct was imaged as three layered structure. Simultaneously, the surrounding organs such as portal vein, hepatic artery and pancreatic duct were also clearly demonstrated. In patient with chronic cholangitis accompanied by choledocholithiasis, the wall of bile duct was visualized as a regular thick wall, and separated into multiple layers. In the meantime choledochal cancer was demonstrated as an irregular and low echoic thick wall. The ultrasonic micro-probe was superior to conventional ultrasonic endoscopes in evaluating diseases of biliary tract, particularly in determining the extent of the tumorous lesions and differentiating between chronic cholangitis and bile duct cancer.