Contrast enhancement and elastography in endoscopic ultrasound: an update of clinical applications in pancreatic diseases

It is well established that endoscopic ultrasound (EUS) is fundamental in the characterization of many diseases concerning different organs, i.e. pancreaticobiliary diseases, gastrointestinal pathologic conditions, and lymph nodes of unknown origin. It is also well known that many factors can hamper the accuracy of EUS, i.e. biliary stents, chronic pancreatitis, poor operator's expertise. These factors can also lead to suboptimal accuracy when cytological confirmation through EUS-fine needle aspiration (EUS-FNA) is indicated. In recent years, new technological tools have rapidly increased their clinical impact improving the diagnostic power of EUS and EUS-FNA. Among these new tools, the most investigated and useful ones are represented by contrast harmonic-EUS (CH-EUS) and EUS-elastography (EUS-E). The purpose of this paper is to provide, through a review of the literature, an update of the applications of CH-EUS and EUS-E in the routine clinical practice in pancreatic diseases. We discussed the first reports and applications of these techniques in our previous review published in Minerva Medica. The applications of CH-EUS and EUS-E to the study of pancreatic diseases appear feasible and safe. The use of both techniques is very simple and does not require any relevant additional workload for the endoscopic personnel. CH-EUS is now considered an important and accurate tool in the diagnosis of solid pancreatic masses and in the differential diagnosis of pancreatic cystic lesions. CH-EUS targeted FNA is an active field of research. However the available studies show that CH-EUS increases FNA accuracy by a little extent, without statistical significance; moreover, CH-EUS FNA showed a trend toward being more efficient vs. simple EUS FNA (less needle passes and more abundance in cytological material) but this trend did not reach statistical significance. On the other hand, the clinical impact of EUS-E in terms of differential diagnosis of pancreatic masses is still under investigation. Chronic pancreatitis evaluation represents the most recent field of application of EUS-E that shows promising results.