Prostate Shear Wave Elastography: Multiresolution Reconstruction Dependence on Push Beam Spacing
This study demonstrates the implementation of a multiresolution shear wave tracking algorithm that enables elasticity imaging of prostate cancer and zonal anatomy. The combined ARFI/SWEI sequence uses closely-spaced push beams across the lateral field of view, with on-axis and off-axis data simultaneously acquired after each push. The shear wave arrival times were determined with cross-correlation of velocity signals in two dimensions after 3-D directional filtering. To combine data from serially interrogated lateral push locations, arrival times from different pushes were aligned by estimating the propagation time between push locations. Shear wave data acquired in an elasticity lesion phantom and reconstructed using this algorithm demonstrate benefits to target contrast-to-noise ratio with increased push beam density and 3-D directional filtering. In human in vivo data, histologically-confirmed prostate cancer appears stiff in both SWEI and ARFI images, and regions of the prostate, including the peripheral zone, central gland, and urethra, are visualized.
