Single- and Multiple-Track-Location Shear Wave and Acoustic Radiation Force Impulse Imaging: Matched Comparison of Contrast, Contrast-to-Noise Ratio and Resolution

Acoustic radiation force impulse imaging and shear wave elasticity imaging (SWEI) use the dynamic response of tissue to impulsive mechanical stimulus to characterize local elasticity. A variant of conventional, multiple-track-location SWEI, denoted single-track-location SWEI, offers the promise of creating speckle-free shear wave images. This work compares the three imaging modalities using a high push and track beam density combined acquisition sequence to image inclusions of different sizes and contrasts. Single-track-location SWEI is found to have a significantly higher contrast-to-noise ratio than multiple-track-location SWEI, allowing for operation at higher resolution. Acoustic radiation force impulse imaging and single-track-location SWEI perform similarly in the larger inclusions, with single-track-location SWEI providing better visualization of small targets ≤2.5 mm in diameter. The processing of each modality introduces different trade-offs between smoothness and resolution of edges and structures; these are discussed in detail.