Fig. 9

Schematic illustration of (a) strain USE and (b) SWE for a hard (red) and soft (green) nodule. In strain USE, tissues are deformed mechanically by the operator via motion of the transducer or by an external source. Relative displacement (strain) is greater in soft compared to stiff tissues. In SWE, focused acoustic impulses from the transducer induce laterally propagating shear waves, whose velocities are higher in stiffer tissues. Tissue displacements in both techniques are tracked by ultrasound detection impulses (not shown)