Can we ablate liver lesions close to large portal and hepatic veins with MR-guided HIFU? An experimental study in a porcine model
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Invasive treatment of tumors adjacent to large hepatic vessels is a continuous clinical challenge. The primary aim of this study was to examine the feasibility of ablating liver tissue adjacent to large hepatic and portal veins with magnetic resonance imaging–guided high-intensity focused ultrasound (MRgHIFU). The secondary aim was to compare sonication data for ablations performed adjacent to hepatic veins (HV) versus portal veins (PV).
Materials and methods
MRgHIFU ablations were performed in six male land swine under general anesthesia. Ablation cells of either 4 or 8 mm diameter were planned in clusters (two/animal) adjacent either to HV (n = 6) or to PV (n = 6), with diameter ≥ 5 mm. Ablations were made using 200 W and 1.2 MHz. Post-procedure evaluation was made on contrast-enhanced MRI (T1w CE-MRI), histopathology, and ablation data from the HIFU system.
A total of 153 ablations in 81 cells and 12 clusters were performed. There were visible lesions with non-perfused volumes in all animals on T1w CE-MRI images. Histopathology showed hemorrhage and necrosis in all 12 clusters, with a median shortest distance to vessel wall of 0.4 mm (range 0–2.7 mm). Edema and endothelial swelling were observed without vessel wall rupture. In 8-mm ablations (n = 125), heat sink was detected more often for HV (43%) than for PV (19%; p = 0.04).
Ablations yielding coagulative necrosis of liver tissue can be performed adjacent to large hepatic vessels while keeping the vessel walls intact. This indicates that perivascular tumor ablation in the liver is feasible using MRgHIFU.
• High-intensity focused ultrasound ablation is a non-invasive treatment modality that can be used for treatment of liver tumors.
• This study shows that ablations of liver tissue can be performed adjacent to large hepatic vessels in an experimental setting.
• Liver tumors close to large vessels can potentially be treated using this modality.
KeywordsHigh-intensity focused ultrasound ablation Interventional magnetic resonance imaging Liver Portal veins Hepatic veins
Dynamic scan time
Fast field echo
Gradient echo sequence with echo-planar readout
High-intensity focused ultrasound
Magnetic resonance imaging–guided high-intensity focused ultrasound
Proton frequency shift
Turbo field echo
Ultrasound-guided high-intensity focused ultrasound
This study has received funding by The Norwegian Cancer Society (Kreftforeningen).
Compliance with ethical standards
The scientific guarantor of this publication is Per Kristian Hol Prof. M.D., The Intervention Center, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo.
Conflict of interest
The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.
Statistics and biometry
Manuela Zucknick, Oslo Centre for Biostatistics and Epidemiology, Faculty of Medicine, Oslo University, kindly provided statistical advice for this manuscript.
Approval from the Institutional Animal Care Committee was obtained.
- 25.Zhao LY, Liu S, Chen ZG, Zou JZ, Wu F (2016) Cavitation enhances coagulated size during pulsed high-intensity focussed ultrasound ablation in an isolated liver perfusion system. Int J Hyperthermia. https://doi.org/10.1080/02656736.2016.1255918:1-11