Plane-Wave Imaging Improves Single-Track Location Shear Wave Elasticity Imaging

Abstract

Single track location shear wave elasticity imaging (STL-SWEI) is immune to speckle bias, but the quality of the images is depth-dependent. We hypothesize that plane wave imaging can reduce the depth dependency of STL-SWEI. To test this hypothesis, we developed a novel technique known as plane-wave single track location shear wave elasticity imaging (pSTL-SWEI). To evaluate the pSTL-SWEI’s potential, we performed studies on phantoms and excised murine pancreatic tumors. The mean shear wave speeds (SWS) measured with STL-SWEI and pSTL-SWEI were similar. However, the elastographic signal-to-noise ratio (SNRe ) of pSTL-SWEI elastograms was noticeably higher than that produced with STL-SWEI. Specifically, we observed an improvement in SNRe ranging from 39.9%−55.1%, depending on tissue stiffness. The spatial resolution of pSTL-SWEI elastograms was 2.7%−12.1% lower than that produced with STL-SWEI. pSTL-SWEI elastograms displayed higher contrast-to-noise ratio (CNRe ) than those produced with STL-SWEI, especially when imaging was performed with low push pulse intensities and low pulse durations.

Elastography Can Map the Local Inverse Relationship between Shear Modulus and Drug Delivery within the Pancreatic Ductal Adenocarcinoma Microenvironment

“…We used the single-track-location-shear wave elastographic imaging (STL-SWEI) method to visualize the shear modulus distribution of excised tumors, which we recently implemented on a Vantage 64 Ultrasound Scanner (Verasonics Inc.) equipped with an L7-4 (Phillips Healthcare) linear transducer array (32). During STL-SWEI, we used ultrasound beams to both induce and track shear wave propagation in tissues.…”

Distributing Synthetic Focusing Over Multiple Push-Detect Events Enhances Shear Wave Elasticity Imaging Performance

“…Dynamic received beamforming was performed on a uniform grid (grid spacing of 0.5λ). We have demonstrated in a previous study that this grid density produced reliable SWS estimates [20]. Smaller axial sampling intervals will improve the precision of the axial motion, but the lateral grid spacing will impact the estimated motion negligibly because the displacements incurred during SWEI are mainly axial.…”

“…The decoding process is less error-prone for configurations with fewer sub-apertures than arrangements with more sub-apertures. Nevertheless, configurations with more sub-apertures (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32) produce better sonograms (higher sonographic SNR s and better resolution) than arrangements with fewer sub-apertures (4)(5)(6)(7)(8). To minimize the impact of physiological motion on the decoding process for configurations employing more than eight sub-apertures, we divide the set of sub-apertures into groups and encode each group separately.…”

Plantar Soft Tissue Characterization Using Reverberant Shear Wave Elastography: A Proof-of-Concept Study

“…Hence a single measure of SSI was used for the purpose of the study. Finally, the comparison between RSWE (at 500 Hz) and SSI was performed by calculating the elastographic signal-tonoise ratio (SNRe) by dividing the mean by the standard deviation (SD) of each ROI of the SWS map (Ahmed et al 2018;Ahmed and Doyley 2020).…”