Correlation Between Brain Tissue Damage and Inertial Cavitation Dose Quantified Using Passive Cavitation Imaging

Overview	This paper demonstrates that brain inertial cavitation dose quantified based on passive cavitation imaging had a linear correlation with the scale of histologic-level tissue damage. The authors used an animal model (mice) sonicated by focused ultrasound with different peak negative pressures in the presence of systemically injected microbubbles. Findings from this study suggested that passive cavitation imaging can be used to predict histologic-level tissue damage associated with the focused ultrasound-induced cavitation.
Authors	Shanshan Xu, Dezhuang Ye, Leighton Wan, Yujia Shentu, Yimei Yue, Mingxi Wan, Hong Chen
Journal	Ultrasound in Medicine and Biology, October 2019, Volume 45, Issue 10, Pages 2758-2766
Recommendation/Comment	Relevant for neurosonography.
Clinical implication	Passive cavitation imaging might be useful to monitor the safety of focused ultrasound-induced cavitation-mediated brain therapies, which are emerging as therapeutic modalities for neurologic diseases.
Link (DOI)	https://doi.org/10.1016/j.ultrasmedbio.2019.07.004
Ultrasound speciality	physics and US equipment; therapeutic ultrasound

Original abstract:

Shanshan Xu, Dezhuang Ye, Leighton Wan, Yujia Shentu, Yimei Yue, Mingxi Wan, Hong Chen

Ultrasound in Medicine and Biology, October 2019, Volume 45, Issue 10, Pages 2758-2766

DOI: https://doi.org/10.1016/j.ultrasmedbio.2019.07.004

Abstract

Focused ultrasound (FUS)-induced cavitation-mediated brain therapies have become emerging therapeutic modalities for neurologic diseases. Cavitation monitoring is essential to ensure the safety of all cavitation-mediated therapeutic techniques as inertial cavitation can be associated with tissue damage. The objective of this study was to reveal the correlation between the inertial cavitation dose, quantified by passive cavitation imaging (PCI), and brain tissue histologic-level damage induced by FUS in combination with microbubbles. An ultrasound image-guided FUS system consisting of a single-element FUS transducer (1.5 MHz) and a co-axially aligned 128-element linear ultrasound imaging array was used to perform FUS treatment of mice. Mice were sonicated by FUS with different peak negative pressures (0.5 MPa, 1.1 MPa, 4.0 MPa and 6.5 MPa) in the presence of systemically injected microbubbles. The acoustic emissions from the FUS-activated microbubbles were passively detected by the imaging array. The pre-beamformed channel data were acquired and processed offline using the frequency-domain delay, sum and integration algorithm to generate inertial cavitation maps. All the mice were sacrificed after the FUS treatment, and their brains were harvested and processed for hematoxylin and eosin staining. The obtained inertial cavitation maps revealed the dynamic changes of microbubble behaviors during FUS treatment at different pressure levels. It was found that the inertial cavitation dose quantified based on PCI had a linear correlation with the scale of histologic-level tissue damage. Findings from this study suggested that PCI can be used to predict histologic-level tissue damage associated with the FUS-induced cavitation.

Keywords:

Brain therapies; Cavitation; Focused ultrasound; Passive cavitation imaging; Tissue damage