Strain histogram (SH) is a semi-quantitative elastographic method that characterizes tissue stiffness. Developing a pancreatic SH reference range would help detect parenchymal diseases, especially early chronic pancreatitis (CP). This study aimed to determine a pancreatic SH reference range using endoscopic ultrasound (EUS) in patients without evidence of pancreatic disease, comparing it with a sample of CP. 

In this single-center, retrospective osservational study, all patients aged ≥18 years undergoing pancreatic EUS, without pancreatic focal lesions, were consecutively enrolled. The machine-integrated software calculated pancreatic SH in a region of interest (ROI) placed on the parenchyma. Three measurements were taken for each pancreas segment, including the head, body, and tail. The baseline clinical parameters were documented. In the first step were conducted descriptive-inferential analyses of the entire sample and the subgroups (healthy vs CP), then was performed a predictive analysis using univariate and multivariate linear regression in the subgroups of healthy controls to identify the most important predictive features of pancreatic stiffness.

We enrolled 143 patients (54,5% female, mean age 63 years), 95 of whom were healthy and 48 with CP.In inferential analysis it’s possible to notice the difference between SH values of every segment in the subgroups, with greater values for the healthy controls group (116,8 vs 69,1, p<0,01). There is also a difference in prevalence of smoke, with a higher frequency in patients with CP (58,3% vs 23,2%, p<0,01), and of alcol abuse, although the latter was more nuanced and not statistically significant (25% vs 11,6%, p=0,13).In the predictive analysis, the results of the previous inferences were confirmed: smoking and alcohol abuse are strongly predictive of a lower pancreatic stiffness of healthy controls (β = -16 and -21, p<0,01), while female sex is associated with a higher stiffness although not in a statistically significant way (β = 5 and p-value 0,2).

SH enables real-time assessment of pancreatic stiffness and, given our findings, could assist in clinical practice in identifying early parenchymal disease, particularly early CP, due to the notable difference in stiffness values. Furthermore, associating clinical factors with EUS findings may aid the diagnosis of CP, as we have demonstrated with smoking and alcohol abuse. External validation of our SH reference range and more extensive studies are necessary.