Extrapancreatic nerve plexus invasion by carcinoma of the head of the pancreas

Abstract

The intraportal endovascular ultrasonography (IPEUS) could diagnose the second portion of the extrapancreatic nerve plexus invasion and provide precise information in operative strategy. But, the first portion was not visualized clearly owing to poor tissue penetration of the ultrasound beam, which may have reduced diagnostic accuracy. Improvement of the scanning area is expected to make intraportal endovascular US even more useful. Pancreatic cancer easily invades the retroperitoneal tissue, especially the extrapancreatic nerve plexus. We evaluated the extrapancreatic nerve plexus invasion of the pancreatic cancer with IPEUS. IPEUS was performed intraoperatively in 20 consecutive resected cases with carcinoma of the head of the pancreas. IPEUS was performed with an 8-French, 20 MHz intravascular ultrasound catheter. IPEUS visualized the inferior pancreaticoduodenal artery (IPDA) in the extrapancreatic nerve plexus. The high-echoic area around the IPDA corresponds to the second portion of the extrapancreatic nerve plexus. The sonographic criterion for detection of the extrapancreatic nerve plexus invasion is low-echoic infiltration around the IPDA. Extrapancreatic nerve plexus invasion was confirmed with resected specimens in 10 patients. The IPDA could not be visualized in two patients. In 18 patients, the diagnostic accuracy of invasion was evaluated. For diagnosis of extrapancreatic nerve plexus invasion with intraportal endovascular US, the sensitivity, specificity, and overall accuracy were 87.5, 90, and 88.7%, respectively.