Optimizing harmonic shear wave elastography over three distinct frequency regimes

Objective.To investigate how excitation frequency and source configuration influence shear wave propagation in bounded soft tissues, and to establish practical guidelines for optimizing shear wave elastography across different operating regimes.Approach.We analyze shear wave propagation using theoretical modeling, numerical simulations, and experimental observations across a wide range of frequencies and source configurations. The study identifies distinct propagation regimes based on the relationship between wavelength, attenuation, and geometry, and evaluates their impact on shear wave behavior.Main results. We demonstrate that shear wave fields exhibit three distinct regimes-quasistatic, modal, and free-space-each associated with different propagation characteristics and limitations for inverse reconstruction. We further show that optimized source configurations can significantly enhance shear wave dominance while minimizing compressional components, leading to order-of-magnitude improvements in signal-to-noise ratio and spatial resolution at higher frequencies.Significance. These findings provide a unified framework for understanding frequency-dependent wave behavior in elastography and highlight that frequency selection is a critical determinant of both wave physics and reconstruction validity. The proposed guidelines offer practical insight for translating experimental optimization strategies into clinically relevant settings.