MRI Coregistered Rodent Histotripsy Array for Orthotopic Liver Models.

Area of Science:

• Medical physics
• Oncology
• Biomedical engineering

Background:

• Histotripsy is an emerging non-invasive therapy for liver tumors, recently gaining FDA approval.
• Current preclinical models do not fully replicate the liver tumor microenvironment (TME).
• Orthotopic models are needed to accurately study histotripsy in the liver TME.

Purpose of the Study:

• To design and develop a miniature, MRI-guided histotripsy array for orthotopic murine liver tumor models.
• To validate the system's targeting accuracy and in vivo efficacy.
• To address limitations in preclinical histotripsy research.

Main Methods:

• Integration of an 89-element phased array with a 7.0-T small animal MRI scanner.
• Validation of targeting precision using red blood cell (RBC) phantoms ($0.24~\pm ~0.1$ mm).
• In vivo demonstration of liver ablation in naïve mice.

Main Results:

• The system achieved precise targeting in phantoms.
• Successful liver ablations were confirmed histologically in vivo.
• Undesired collateral damage (lung hemorrhages) due to grating lobes was observed.

Conclusions:

• The developed MRI-guided histotripsy system is a foundational step towards orthotopic liver tumor modeling.
• Further design adjustments are needed to mitigate collateral damage.
• This work facilitates more accurate preclinical evaluation of histotripsy for liver cancer.