Faculty Collaboration Database

Robotically Assisted Sonic Therapy (RAST) for Noninvasive Hepatic Ablation in a Porcine Model: Mitigation of Body Wall Damage with a Modified Pulse Sequence. Cardiovasc Intervent Radiol 2019 Jul;42(7):1016-1023

Date

05/02/2019

Pubmed ID

31041527

Pubmed Central ID

PMC7456499

DOI

10.1007/s00270-019-02215-8

Scopus ID

2-s2.0-85065223231 (requires institutional sign-in at Scopus site)   22 Citations

Abstract

PURPOSE: Robotically assisted sonic therapy (RAST) is a nonthermal, noninvasive ablation method based on histotripsy. Prior animal studies have demonstrated the ability to create hepatic ablation zones at the focal point of an ultrasound therapy transducer; however, these treatments resulted in thermal damage to the body wall within the path of ultrasound energy delivery. The purpose of this study was to evaluate the efficacy and safety of a pulse sequence intended to mitigate prefocal body wall injury.

MATERIALS AND METHODS: Healthy swine (n = 6) underwent hepatic RAST (VortxRx software version 1.0.1.3, HistoSonics, Ann Arbor MI) in the right hepatic lobe. A 3.0 cm spherical ablation zone was prescribed for each. Following treatment, animals underwent MRI which was utilized for ablation zone measurement, evaluation of prefocal injury, and assessment of complications. Each animal was euthanized, underwent necropsy, and the tissue was processed for histopathologic analysis of the ablation zone and any other sites concerning for injury.

RESULTS: No prefocal injury was identified by MRI or necropsy in the body wall or tissues overlying the liver. Ablation zones demonstrated uniform cell destruction, were nearly spherical (sphericity index = 0.988), and corresponded closely to the prescribed size (3.0 × 3.1 × 3.4 cm, p = 0.70, 0.36, and 0.01, respectively). Ablation zones were associated with portal vein (n = 3, one occlusive) and hepatic vein thrombosis (n = 4, one occlusive); however, bile ducts remained patent within ablation zones (n = 2).

CONCLUSIONS: Hepatic RAST performed with a modified ultrasound pulse sequence in a porcine model can mitigate prefocal body wall injuries while maintaining treatment efficacy. Further study of hepatic RAST appears warranted, particularly in tumor models.

Author List

Longo KC, Knott EA, Watson RF, Swietlik JF, Vlaisavljevich E, Smolock AR, Xu Z, Cho CS, Mao L, Lee FT Jr, Ziemlewicz TJ

MESH terms used to index this publication - Major topics in bold

Ablation Techniques
Animals
Female
Liver
Magnetic Resonance Imaging
Models, Animal
Robotic Surgical Procedures
Swine
Treatment Outcome
Ultrasonic Therapy