Intraoperative diagnosis of pancreatic cancer extension using IVUS

Pancreatic cancer easily invades retroperitoneal tissue, especially the portal vein and extrapancreatic nerve plexus. We evaluated the diagnostic accuracy of intraportal endovascular ultrasonography in portal vein and extrapancreatic nerve plexus invasion.

Intraportal endovascular ultrasonography was performed in 78 cases of pancreatic cancer (head 67, body 8, total 3). Intraportal endovascular ultrasonography was performed intraoperatively from the superior mesenteric vein with an 8-French, 20-MHz intravascular ultrasound catheter. Three-dimensional intraportal endovascular ultrasonography was constructed by volume rendering.

Intraportal endovascular ultrasonography visualized the portal vein as an echogenic band with a thickness of 0.5 mm to 1.0 mm. The diagnostic criterion of portal vein invasion was obliteration of this echogenic band. Intraportal endovascular ultrasonography visualized segment II of the extrapancreatic nerve plexus as the high-echoic area around the inferior pancreaticoduodenal artery. The diagnostic criterion of extrapancreatic nerve plexus invasion was low-echoic infiltration around the inferior pancreaticoduodenal artery. The sensitivity, specificity, and overall accuracy of intraportal endovascular ultrasonography for diagnosis of portal vein invasion was, respectively, 97.4%, 92.5%, and 94.9%. The values for diagnosis of extrapancreatic nerve plexus invasion, respectively, were 94.4%, 97.1%, and 96.2%. Three-dimensional intraportal endovascular ultrasonography depicted the invasion area as a defect of the portal vein wall.

Intraportal endovascular ultrasonography detected subtle portal invasion and provided accurate portal invasion area which was useful for portal vein an reconstruction. Intraportal endovascular ultrasonography could also diagnose the extrapancreatic nerve plexus invasion of segment II.