Ultrasound Elastography in Diffuse and Focal Parotid Gland Lesions

In Europe, ultrasound (US) is the diagnostic gold standard for the visualisation of parotid gland disorders. While high-resolution B-mode US reliably visualises focal lesions, its diagnostic capacity to distinguish tumour entities or to characterise diffuse lesions remains poor. Strain elastography (SE) and shear wave elastography (SWE) are novel imaging techniques that provide additional information about tissue elasticity. SE analyses the strain or displacement in response to force or compression and, therefore, shows the relative tissue elasticity within a selected region of interest (ROI). Recent studies suggest that SE might be able to predict parotid gland malignancy. In SWE, push pulses generate localised displacements within an ROI that describes mechanical tissue properties expressed in absolute values. Recent studies indicate that SWE can predict tissue fibrosis in different organs. This review article highlights the current role of SE and SWE modalities in diffuse and focal changes of the parotid gland.