Intraportal endovascular ultrasonography for pancreatic cancer.

Intraportal endovascular ultrasonography (IPEUS) is a new diagnostic procedure for pancreatic cancer. In portal invasion, subtle invasion and compression are difficult to differentiate with conventional imaging techniques such as computed tomography and angiography. IPEUS is performed with an 8-French, 20-MHz intravascular ultrasound catheter. IPEUS provides high-resolution, real-time images perpendicular to the portal vein axis. With IPEUS, the portal vein wall is visualized as an echogenic band. A subtle portal invasion can be detected by observing this portal vein wall. Moreover, the segment II of the extrapancreatic nerve plexus is visualized as an echogenic area around the inferior pancreaticoduodenal artery (IPDA). The extrapancreatic nerve plexus invasion can be diagnosed as low echoic infiltration of the area around the IPDA. In the diagnosis of portal vein and extrapancreatic nerve plexus invasion, IPEUS provides a good diagnostic value and important information for the staging of local extension of the pancreatic cancer.