Transcostal Histotripsy Ablation in an In Vivo Acute Hepatic Porcine Model

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 cmTranscostal 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.