A multimodal evaluation of boiling histotripsy lesion properties in ex vivo bovine liver

• Published in: The Journal of the Acoustical Society of America 2016-10, Vol.140 (4), p.3082-3082
• Main Authors: Wang, Yak-Nam, Khokhlova, Tanya D., Maxwell, Adam D., Kreider, Wayne, Partanen, Ari, Farr, Navid, Schade, George R., Chernikov, Valeriy P., Buravkov, Sergey V., Bailey, Michael R., Khokhlova, Vera A.
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4969601

New types of high intensity focused ultrasound (HIFU) therapy aiming at mechanical homogenization of tissue has shown great promise, namely, cavitation-cloud histotripsy and boiling histotripsy (BH). BH uses millisecond-long bursts of HIFU waves containing shocks to repeatedly induce boiling at the focus; the interaction of incident HIFU waves with vapor bubbles homogenizes tissue. In this study, degassed ex vivo bovine liver samples were sonicated using a 256-element 1.2 MHz array of a clinical MR-HIFU system. The BH lesions were produced using 10-ms long pulses with 80 MPa shocks in situ and pulse repetition frequencies (PRFs) of 1-10 Hz to cover a range of effects from pure mechanical homogenization to thermal ablation. Individual lesions were generated for the multimodal analysis of the lesion including ultrastructure (electron microscopy), molecular (biochemistry), and microstructure (histological) methods. The extent of homogenization and thermal denaturation was evaluated for each lesion. The results of this work showed that the degree of mechanical tissue disruption and the amount of heat generated in large BH lesions can be tailored to result in a range of desired tissue effects dependent on the target clinical application. [Work supported by NIH EB007643, RFBR 16-02-00653, K01 EB015745, and NSBRI through NASA NCC 9-58.]