Evaluation of Ultrasound Based Point Shear Wave Elastography for Diagnosis of Inflammatory Pancreatic Diseases

Abstract

Introduction: A variety of imaging techniques exists for the diagnosis of pancreatic disorders. None of the broadly accepted diagnostic methods, uses elasticity as an indicator of tissue damage. A well-known fact is that pathological changes influence tissue stiffness and elasticity. US elastography in its different modalities has been widely used for evaluation and characterization of multiple abdominal structures. Point Shear Wave Elastography (pSWE) particularly has been reported to be highly effective in various clinical diagnostic applications. However, data on the role of pSWE in a deep-seated organ like pancreas is scarce. Objective: To prospectively assess the diagnostic value of abdominal US elastography in the form of point shear wave elastography (pSWE) in characterizing and differentiating between normal pancreatic parenchyma and chronic pancreatitis. To establish a cut off value for the diagnosis of chronic pancreatitis. To investigate the influence of certain independent variables and the severity of pancreatitis on the acquired results. Patients Twenty five patients diagnosed with chronic pancreatitis who visited the Department of Gastroenterology in University Hospital Kaspela, between December 2020 and August 2021, for diagnosis and/or treatment and twenty eight individuals with no evidence of pancreatic disorder, admitted at the hospital during the same period of time, were included in the study. Based on the clinical symptomatic criteria, diagnostic imaging and histological findings, patients were divided into chronic pancreatitis (CP) and healthy pancreatic parenchyma group. Methods: The ultrasound based point Shear Wave Elastography (pSWE) imaging techniques were applied. A total of five measurements was obtained in each segment of the gland. The depth of region of interest (ROI) was also recorded. Design Prospective single-center study. Results: The mean shear wave speed (SWS) values of the entire pancreatic parenchyma were 1.71m/s, 1.15m/s for the chronic pancreatitis and the normal pancreatic parenchyma respectively. With a cut off value of 1.43m/s, sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV) and accuracy (Ac) of 89.7%, 95.2%, 94.59%, 90.91% and 92.59% respectively were calculated for the diagnosis of chronic pancreatitis. Neither the independent variables researched, nor the severity of disease, defined according to the Cambridge score, proved to have statistically significant reflection on the SWS in patients with CP. Conclusion: pSWE established considerably higher SWS in patients with chronic pancreatitis, therefore it may be successfully adopted as a diagnostic modality in patients with chronic inflammatory pancreatic disorders. External factors have minor effect on the results obtained, suggesting that the technique is highly objective. High SWS were obtained both in patients with discrete structural abnormalities (Cambridge 2) and advanced forms of pancreatitis (Cambridge 4), which points that pSWE may be utilized as differential diagnostic method in cases in which other imaging techniques provide equivocal and inconclusive results.