Department of Radiology, University of Wiscosin-Madison, E3/311 CSC, 600 Highland Ave, Madison, WI, 53792, USA.
Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, 325 Stanger St, Blacksburg, VA, USA.
Cardiovasc Intervent Radiol. 2021 Oct;44(10):1643-1650. doi: 10.1007/s00270-021-02914-1. Epub 2021 Jul 9.
To determine whether histotripsy can create human-scale transcostal ablations in porcine liver without causing severe thermal wall injuries along the beam path.
Histotripsy was applied to the liver using a preclinical prototype robotic system through a transcostal window in six female swine. A 3.0 cm spherical ablation zone was prescribed. Duration of treatment (75 min) was longer than a prior subcostal treatment study (24 min, 15 s) to minimize beam path heating. Animals then underwent contrast-enhanced MRI, necropsy, and histopathology. Images and tissue were analyzed for ablation zone size, shape, completeness of necrosis, and off-target effects.
Ablation zones demonstrated complete necrosis with no viable tissue remaining in 6/6 animals by histopathology. Ablation zone volume was close to prescribed (13.8 ± 1.8 cm vs. prescribed 14.1 cm). Edema was noted in the body wall overlying the ablation on T2 MRI in 5/5 (one animal did not receive MRI), though there was no gross or histologic evidence of injury to the chest wall at necropsy. At gross inspection, lung discoloration in the right lower lobe was present in 5/6 animals (mean size: 1 × 2 × 4 cm) with alveolar hemorrhage, preservation of blood vessels and bronchioles, and minor injuries to pneumocytes noted at histology.
Transcostal hepatic histotripsy ablation appears feasible, effective, and no severe injuries were identified in an acute porcine model when prolonged cooling time is added to minimize body wall heating.
确定在不沿光束路径造成严重热壁损伤的情况下，组织爆破是否可以在猪的肝脏中创建人类规模的经胸廓消融。
使用临床前机器人系统通过六头母猪的经胸廓窗将组织爆破应用于肝脏。规定了 3.0cm 的球形消融区。治疗持续时间（75 分钟）长于先前的肋下治疗研究（24 分钟，15 秒），以最大程度地减少光束路径加热。然后，动物接受了对比增强 MRI、尸检和组织病理学检查。对图像和组织进行了分析，以评估消融区的大小、形状、坏死的完整性和非靶标效应。
在 6/6 动物的组织病理学检查中，消融区表现出完全坏死，没有存活的组织。消融区体积接近规定值（13.8±1.8cm 与规定值 14.1cm 相比）。在 T2 MRI 上，5/5（一只动物未接受 MRI）动物的消融区上方的体壁中观察到水肿，但在尸检中没有发现胸壁的大体或组织学损伤。大体检查时，5/6 动物的右下肺叶出现肺变色（平均大小：1×2×4cm），伴有肺泡出血、血管和细支气管保留，以及肺细胞的轻微损伤。
在延长冷却时间以最大程度减少体壁加热的急性猪模型中，经胸廓肝组织爆破消融似乎是可行的、有效的，并且未发现严重损伤。
