Figure 3.

Representative T2-weighted MR images for (a) untreated control, (b) histotripsy-treated tumor showing complete regression, and (c) histotripsy-treated tumor with local tumor progression. (a) Untreated control tumor appeared hyperintense compared to surrounding liver parenchyma at pre-treatment timepoint, developed metastases at week 1 which grew aggressively by week 2. White arrows show the tumor location. (b) Post-ablation, the ablated region appears hyperintense (yellow arrow) compared to untargeted tumor (blue arrow) likely due to edema (image acquired 8 h post-treatment). By week 2, tumor appeared to regress (blue arrow) and was undetectable from week 3 onwards. (c) Post-ablation, the ablated region (yellow arrow) appears hypointense (image acquired within 2 h post-treatment). At week 2, the tumor did not show signs of size regression (blue arrow). Local tumor progression and metastases were observed by week 6 (white arrow).