EUS-Guided Shear-Wave-Based Elastography: Current Evidence and the Emerging Role of Two-Dimensional Shear-Wave...

Elastography is an ultrasound-based technique that enables the non-invasive assessment of tissue stiffness. In endoscopic ultrasound (EUS), elastography was initially introduced as a strain-based method, providing qualitative or semi-quantitative information on tissue deformation. More recent technological developments have enabled the integration of shear-wave-based elastography into EUS platforms, including shear-wave measurement (SWM), point shear-wave elastography (pSWE), and two-dimensional shear-wave elastography (2D-SWE). Unlike strain elastography, shear-wave techniques provide quantitative estimates of tissue stiffness by measuring shear-wave velocity or a derived elastic modulus. This invited narrative review summarizes the technical principles, terminology, quality-control requirements, and current clinical evidence for EUS-guided shear-wave-based elastography in pancreatic and hepatobiliary diseases. Because much of the available EUS literature derives from EUS-SWM or point SWE rather than true 2D-SWE, acquisition mode is a central determinant when interpreting clinical evidence and clinical readiness. Current data suggest that EUS-guided shear-wave-based elastography is technically feasible and biologically plausible, but its clinical maturity remains indication-specific. Evidence is most encouraging in chronic pancreatitis, early chronic pancreatitis, autoimmune pancreatitis activity monitoring, and selected endo-hepatology settings, particularly liver fibrosis assessment in patients in whom transabdominal techniques may be suboptimal. In contrast, available evidence does not support EUS-guided shear-wave-based elastography as a standalone diagnostic test for differentiating solid pancreatic lesions, including pancreatic ductal adenocarcinoma, because absolute stiffness values often overlap among malignant lesions, inflammatory masses, and background parenchyma. Before routine clinical implementation, standardized acquisition protocols, disease-specific cut-offs, multicenter reproducibility data, and evidence of incremental clinical value beyond established diagnostic pathways are required.