Extrapancreatic neural plexus invasion by carcinomas of the pancreatic head region: evaluation using thin-section helical CT

Abstract

The aim of this study was to determine the computed tomographic (CT) criteria for diagnosing the second portion of the extrapancreatic neural plexus (PLX-II) invasion by carcinoma of the pancreatic head region on thin-section helical CT. A total of 41 patients with carcinoma of the pancreatic head region (17 in the pancreas, 24 in the lower common bile duct) underwent three-phase helical CT (collimation 5 mm; reconstruction 2.5 mm) before surgery. Two criteria were established for the assessment of the PLX-II running between the superior mesenteric artery (SMA) and the medial margin of the uncinate process: criterion A: assessment of the area around the SMA and inferior pancreaticoduodenal artery; criterion B: assessment of the jejunal trunk. PLX-II invasion was pathologically confirmed in 19 patients with pancreatobiliary carcinoma. For criterion A, all 19 patients with positive PLX-II invasion and 20 of the 22 with negative PLX-II invasion were correctly diagnosed (sensitivity 100%; specificity 91%; accuracy 95%). For criterion B, 3 of the 17 patients with positive PLX-II invasion and all 20 with negative PLX-II invasion were correctly diagnosed (sensitivity 18%; specificity 100%; accuracy 62%). The two false-positive cases using criterion A were correctly diagnosed using criterion B. Thin-section helical CT provides sufficient diagnostic ability regarding PLX-II invasion by carcinoma of the pancreatic head region.