Effect of Aging and Diffuse Chronic Pancreatitis on Pancreas Elasticity Evaluated using Semiquantitative EUS Elastography

Abstract

Endosonographic elastography has been introduced as a method of estimating the stiffness of pancreatic tumors. This prospective single-center study was conducted to evaluate changes in the stiffness of the pancreas related to age and diffuse chronic pancreatitis. 46 individuals each up to age 60 (group 1) and over age 60 (group 2) with healthy pancreata and 26 patients with diffuse chronic pancreatitis (group 3) were included. Three elastograms were obtained in each case by endosonography in a defined section through the pancreatic body. Elastograms were further evaluated by histogram analysis. Mean strain values, based on a range from 0 (hardest) to 255 (softest), and their standard deviation were calculated from the histogram. The three groups were compared statistically with regard to pancreatic stiffness. A cut-off level for the diagnosis of chronic pancreatitis was defined by testing receiver operating characteristics curves. The strain values (mean, SD) measured in the pancreatic body in groups 1 - 3 were 110.2 (23.9), 80.0 (16.4), and 32.4 (11.9), respectively. Pairwise comparison of the groups revealed highly significant differences (p < 0.001). At a cut-off value of 50, the area under the curve was 0.993 for distinguishing between chronic pancreatitis and healthy pancreata in people aged over 60. Semiquantitative elastography shows that pancreata become significantly harder during aging, but remain softer than in chronic pancreatitis. A cut-off value of 50 is suggested as a possible diagnostic criterion for diffuse chronic pancreatitis.