Tissue harmonic versus contrast‐enhanced harmonic endoscopic ultrasonography for the diagnosis of pancreatic tumors: Prospective multicenter study

Objectives This prospective multicenter study aimed to assess and compare the accuracy of tissue harmonic endoscopic ultrasonography (TH‐EUS) and contrast‐enhanced harmonic endoscopic ultrasonography (CH‐EUS) for differentiating pancreatic carcinoma from other pancreatic tumors. Methods Consecutive patients with solid pancreatic tumors were prospectively enrolled between August 2013 and December 2014. To assess the accuracy of TH‐EUS and CH‐EUS, we compared four parameters of TH‐EUS (fuzzy edge, irregular periphery, hypoechogenicity, and heterogeneous internal echogenicity) and four parameters of CH‐EUS (hypoenhancement and heterogeneous enhancement in the early and late phases, respectively) to investigate which parameter of each method was most suitable to diagnose pancreatic carcinomas. Interobserver agreement and the diagnostic ability of pancreatic carcinoma using TH‐EUS and CH‐EUS were assessed and compared. Results A total of 204 patients were enrolled. For the diagnosis of pancreatic carcinoma, interobserver agreement by experts and nonexperts was 0.33–0.50 and 0.35–0.50 for TH‐EUS, respectively, and 0.72–0.74 and 0.20–0.54 for CH‐EUS, respectively. Irregular periphery was the most accurate diagnostic parameter among TH‐EUS findings for differentiating pancreatic carcinomas, with sensitivity, specificity, and accuracy of 95.0%, 42.9%, and 78.9%, respectively. Late phase hypoenhancement was the most accurate diagnostic parameter among CH‐EUS findings for differentiating pancreatic carcinomas, with sensitivity, specificity, and accuracy of 90.8%, 74.6%, and 85.8%, respectively. The accuracy of CH‐EUS (late phase hypoenhancement) for diagnosis of pancreatic carcinoma was significantly higher than that of TH‐EUS (irregular periphery) (p