Contrast-harmonic Endoscopic Ultrasound (CH-EUS) for the Diagnosis of Pancreatic Adenocarcinoma

Ductal adenocarcinoma is the most frequent pancreatic solid lesion and the most common tumor of the pancreas. Given its poor prognosis and the major therapeutic consequences, the discrimination between PA and other pancreatic solid lesions is mandatory. EUS is admitted as the most sensitive imaging procedure for the detection and characterization of pancreatic tumors \[1-3\]. Nevertheless it remains difficult to differentiate, on morphological features, PA from other solid masses. For 15 years, endoscopic ultrasound fine needle aspiration (EUS-FNA) has demonstrated its efficiency for tissue sampling and cyto-histologic diagnosis of PA. However, the negative predictive value (NPV) for the diagnosis of pancreatic adenocarcinoma (PA) remains low (30-70%) in the published prospective series \[4\]. So, in case of negative result, the choice between surgery and follow-up remains difficult. Additional criteria to get the decision are then warranted. The assessment of pancreatic tumor enhancement using ultrasound contrast agents (UCAs) in real time with imaging specific methods seems useful to improve their characterization \[4-8\] either by contrast-enhanced EUS (CE-EUS) or, more recently, by contrast-enhanced harmonic EUS (CH-EUS). The aims of this prospective multicenter study is: 1. to compare the NPV of contrast-enhanced endoscopic ultrasound (CH-EUS) and EUS-FNA for the diagnosis of PA; 2. to assess the intra- and inter-observer concordances of CH-EUS for the diagnosis of PA.