# Shear Wave Elastography Implementation on a Portable Research Ultrasound System: Initial Results
## 5 Conclusions  
We presented a complete SWE implementation using a low-cost, portable and fully configurable 256 TX/64 RX research system. To prepare the system for exploring various SWE techniques, its transmit section performance was enhanced by introducing a new dedicated transmit extension module. In the experimental part of the study, three different push beam generation methods (FCUSE, SSI and FCUSE-SSI) were evaluated and compared in both homogeneous and heterogeneous experiments on an industry-standard elastography Q/A phantom. The achieved results for the elasticity estimations were comparable to those presented in the literature. A fair comparison of the push energy in these methods showed that the techniques were complimentary and that each had its own unique advantages and disadvantages. The developed system and processing algorithm were validated experimentally, thus proving the suitability of the proposed solution for research purposes. To our knowledge, this is the first compact and portable solution that implements the SWE technique and thus, could pave the way for new point-of-care scanners that are equipped with elasticity imaging. Conceptualization, D.C. and M.L. ; methodology, D.C.; software, D.C.; validation, D.C. and M.L. ; formal analysis, D.C.; investigation, D.C.; resources, M.L. ; data curation, D.C.; writing--original draft preparation, D.C.; writing--review and editing, M.L. and D.C.; visualization, D.C.; supervision, M.L. ; project administration, M.L. ; funding acquisition, M.L. All authors have read and agreed to the published version of the manuscript. One of the authors ([PERSON]) is the participant of a program by the Polish Ministry of Science and Higher Education entitled \"Doktorat wdrozeniowy\" (Industrial Doctoral Program). Some parts of this study were financed from the funds received under this program. Not applicable. The authors would like to thank [PERSON] for his assistance with the software development and [PERSON] and [PERSON] for their help with the hardware development that was used in this study. Both authors are active employees of us4 us Ltd., which is a manufacturer of the research platform that was used in this study. The following abbreviations are used in this manuscript: \begin{tabular}{l l} ADC & Analog to digital converter \\ ARF & Acoustic radiation force \\ CPWI & Compounded plane wave imaging \\ DOF & Depth of field \\ \end{tabular} \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter** & **FCUSE** & **SSI** & **FCUSE-SSI** \\ \hline \hline \multicolumn{4}{c}{Inclusion Diameter = 16.7 mm} \\ \hline Inclusion SWS (m/s) & 4.48 \(\pm\) 0.30 & 4.42 \(\pm\) 0.42 & 4.39 \(\pm\) 0.41 \\ Inclusion bias (\%) & \(-\)7.9 & \(-\)9.0 & \(-\)9.6 \\ Inclusion SNR (dB) & 23.45 & 19.53 & 20.65 \\ Background SWS (m/s) & 2.71 \(\pm\) 0.24 & 2.62 \(\pm\) 0.19 & 2.76 \(\pm\) 0.18 \\ Background bias (\%) & +14.9 & +11.2 & +16.8 \\ Background SNR (dB) & 21.23 & 22.87 & 23.57 \\ CNR (dB) & 13.3 & 11.07 & 11.27 \\ \hline \multicolumn{4}{c}{Inclusion Diameter = 10.4 mm} \\ \hline Inclusion SWS (m/s) & 3.91 \(\pm\) 0.30 & 4.02 \(\pm\) 0.25 & 4.00 \(\pm\) 0.31 \\ Inclusion bias (\%) & \(-\)19.6 & \(-\)17.3 & \(-\)17.8 \\ Inclusion SNR (dB) & 22.30 & 24.02 & 22.32 \\ Background SWS (m/s) & 2.6 \(\pm\) 0.19 & 2.55 \(\pm\) 0.14 & 2.70 \(\pm\) 0.19 \\ Background bias (\%) & +10.2 & +7.9 & +14.5 \\ Background SNR (dB) & 22.51 & 25.26 & 22.99 \\ CNR (dB) & 11.28 & 14.15 & 11.09 \\ \hline \multicolumn{4}{c}{Inclusion Diameter = 6.5 mm} \\ \hline Inclusion SWS (m/s) & 3.41 \(\pm\) 0.25 & 3.38 \(\pm\) 0.31 & 3.51 \(\pm\) 0.43 \\ Inclusion bias (\%) & \(-\)29.8 & \(-\)30.4 & \(-\)27.7 \\ Inclusion SNR (dB) & 22.30 & 20.90 & 18.27 \\ Background SWS (m/s) & 2.60 \(\pm\) 0.19 & 2.53 \(\pm\) 0.13 & 2.68 \(\pm\) 0.18 \\ Background bias (\%) & +10.2 & +7.3 & +13.4 \\ Background SNR (dB) & 22.51 & 25.95 & 23.50 \\ CNR (dB) & 11.28 & 8.21 & 5.13 \\ \hline \end{tabular}
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