< i > In vitro < /i > assessment of stiffness-dependent histotripsy bubble cloud activity in gel phantoms and blood clots.

In this study, histotripsy pulses were generated in agarose phantoms of Young's moduli ranging from 12.3 to 142 kPa, and &amp;lt;i&amp;gt;in vitro&amp;lt;/i&amp;gt; clot models with mild and strong platelet-activated retraction. Bubble cloud emissions were tracked with passive cavitation imaging, and the threshold acoustic power associated with phantom liquefaction was extracted with receiver operator characteristic analysis. The power of histotripsy-generated emissions and the degree of liquefaction were tabulated for both clot models. For the agarose phantoms, the acoustic power associated with liquefaction increased with Young's modulus. When grouped based on agarose concentration, only two arms displayed a significant difference in the liquefaction threshold acoustic power (22.1 kPa vs. 142 kPa Young's modulus). The bubble cloud dynamics tracked with passive cavitation imaging indicated no strong changes in the bubble dynamics based on the phantom stiffness. For identical histotripsy exposure, the power of acoustic emissions and degree of clot lysis did not vary based on the clot model. Overall, these results indicate that a fixed threshold acoustic power mapped with passive cavitation imaging can be utilized for predicting histotripsy liquefaction over a wide range of tissue stiffness.
PMID: 31146275 [PubMed - as supplied by publisher]

Source: Physics in Medicine and Biology - May 29, 2019 Category: Physics Authors: Hendley S, Bollen V, Anthony GJ, Paul JD, Bader KB Tags: Phys Med Biol Source Type: research