Contrast-enhanced endoscopic ultrasonography in the diagnosis of pancreato-biliary diseases

In diagnostic imaging, techniques represented by computed tomography (CT) and magnetic resonance imaging (MRI), diagnosis by evaluation of plain images in combination with contrast-enhanced images is considered important. Recently, the ultrasound contrast media that can be administered from peripheral veins have been developed, and their utility is reported not only for the circulatory organ area but also the digestive organ area, mainly for liver diseases. As for the pancreato-biliary diseases, there often are the cases that visualization of the diseases itself is not easy by transabdominal ultrasonography, so, the evaluation of contrast-enhanced ultrasonography remains difficult. In contrast, endoscopic ultrasonography (EUS) is thought to be one of the most valuable modality for those diseases. The mainstream of an operation method of EUS was mechanical radial type, but in late years, endoscopic ultrasonography of an electronic linear method and an electronic radial method have been developed. Because an electronic scan method was adopted, we get possible to apply technology of color Doppler flow imaging and power Doppler flow imaging and harmonic imaging methods to EUS. We would like to outline the usefulness of contrast-enhanced color/power Doppler EUS and contrast-enhanced harmonic EUS, moreover, tissue harmonic imaging and three dimensional imaging, on the basis of our experiences.