EUS elastography of the pancreas:: feasibility and pattern description of the normal pancreas, chronic pancreatitis, and focal pancreatic lesions

Background: Initial clinical applications have shown that US elastography might be able to distinguish tissues because of their specific consistency. Objective: (1) To investigate the feasibility of EUS elastography of the pancreas and (2) to describe elastographic patterns of the normal pancreas and the pancreas affected by inflammatory or focal disease. Design: Prospective single-center study. Setting: Academic center of the University of Witten/Herdecke. Patients: Twenty patients with normal pancreas, 20 patients with chronic pancreatitis, and 33 patients with focal pancreatic lesion, histologically later proven in 32 of these 33 cases. Interventions: Commercially available US equipment was used. The elasticity of tissue was reconstructed in real time within a sample area and was translated into a color scale imaging relative tissue elasticity within this area. Representative loops of at least 20 seconds were recorded regarding each region of interest. Results: Adequate elastographic recordings could be obtained in all 73 patients. Patients with hypoechoic and intermediately echogenic normal pancreas revealed a relatively homogeneous elastographic pattern. Thirty-one focal lesions, including 30 neoplasms and most of the chronically inflamed pancreata had a honeycomb pattern dominated by hard strands. This pattern showed analogies to the histologic structure of 10 resected tumors. Other patients with chronic pancreatitis and those with hyperechoic healthy pancreas had miscellaneous elastographic appearances. Conclusions: EUS elastography of the pancreas is feasible and produces plausible results. The examination of homogeneous tissue is impaired by the relative scale used. Chronic pancreatitis and hard tumors cannot be distinguished by elastography, probably because of their similar fibrous structure.