Use of Shear Wave Elastography to Diagnose Acute Pancreatitis: A Cross-sectional Study

Abstract

Introduction: Acute inflammation process of the pancreas with or without involvement of surrounding tissues and remote organ systems is termed as Acute Pancreatitis (AP). Contrast Enhanced Computed Tomography (CECT) if performed immediately may underestimate the severity. Therefore, ultrasound examination remains the first imaging diagnostic method in suspected cases of AP. The sensitivity of B-mode sonography for the early diagnosis of AP can be increased by the detection of an increase in pancreatic tissue stiffness with Shear Wave Elastography (SWE). Aim: To evaluate the efficacy of SWE in the analysis of AP. Materials and Methods: A cross-sectional study was conducted in Tertiary Care Hospital attached to Mysore Medical College and Research Institute, Mysuru, Karnataka, India, from August 2019 to September 2019. The pancreatic parenchyma of 30 patients with symptoms of AP that included acute onset of severe central epigastric pain, poorly localised tenderness and pain increased by supine positioning radiating to the back. The study also included 40 healthy, asymptomatic volunteer who were examined using B-mode sonography and SWE. Computed Tomography (CT) was performed in all patients with AP with a SEIMENS SOMATOM DEFINITION EDGE 128 slice CT scanner. Elastographic measurements were performed and quantitative SWE values represented in kilopascal (kPa) of the patients and asymptomatic volunteers group were compared. Patients’ amylase and lipase levels were done by biochemical tests. Descriptive and Inferential statistical analysis was carried out in the present study. Student’s t-test (two tailed, independent), Leven’s test for homogeneity of variance and Chi-square test was used to find the significance of study parameters. Results: The mean SWE values for the asymptomatic volunteers with normal pancreatic parenchyma were 9.53±2.62 kPa. The mean SWE values for the pancreatic parenchyma of the patients with AP were 17.23±6.24 kPa. The mean SWE value for the patients with AP was significantly higher than the value for the control group (p<0.001). A SWE cut-off value of 13.5 kPa was associated with 70% sensitivity and 92.5% specificity for diagnosis of AP. Conclusion: For the diagnosis of AP at initial hospital admission, SWE can be used as it is a rapid, radiation-free, and noninvasive tool. It is a useful imaging method with high sensitivity and specificity for the diagnosis of AP.

Keywords

• computed tomography
• pancreas
• sonography