Diagnosis and staging of chronic pancreatitis-Diagnostic accuracy and agreement between endoscopic ultrasound and transabdominal ultrasound shear wave elastography

Background: Diagnosis of chronic pancreatitis (CP) is invasive and depending on endoscopic ultrasound (EUS) evaluation using Rosemont Criteria (RC). Non invasive ultrasound (US) based tests are necessary to detect CP. Aim: We compared transabdominal 2D Shear Wave Elastography (SWE) of the pancreas and the Gemelli Ultrasound Chronic Pancreatitis Score to EUS/RC for the diagnosis of chronic pancreatitis. Methods: We conducted a single center prospective case-control study. EUS with RC defined cohorts with (n = 51) and without CP (n = 51). Patients underwent US evaluation of the pancreas using 2D SWE and USCP. Results: Median SWE values were different between groups (no CP 1.45m/s; IQR 1.34–1.60 and with CP 1.72m/s; IQR 1.63–1.96; p < 0.0001) and different between RC subgroups (RC indeterminate for CP 1.67m/s, IQR 1.52–1.72 vs. RC suggestive 1.72m/s, IQR 1.62–1.97 vs. RC consistent with CP 1.90 m/s, IQR 1.72–2.12 m/s; p < 0.0001). Median USCP was different between groups. 2D SWE correlated with USCP (p < 0.0001) and RC (p < 0.0001). We defined a cut off SWE value of <1.42m/s to rule out CP (Sensitivity 96 %; NPV 92 %) and a SWE cut off >1.87m/s to diagnose CP (Specifity 96 %;PPV 90 %). Conclusion: Pancreatic US evaluation with 2D SWE is a widely applicable and unexpensive tool for the diagnosis of CP. Larger studies are needed to confirm these results.