Radiofrequency ablation (RFA) is emerging as an effective image-guided minimally invasive therapeutic alternative to surgical treatment of cancer tumors. RFA appears well suited to nonresectable tumors in liver. The ablation process is highly dependent on the electrical conductivity of these tissues yet there is no easy way to predict the current pathways or how focused the current will be on the tumor. For example, bone and fatty pockets can shield tumor from ablation currents. Consequently, repeatable ablation volumes are difficult to produce. Our goal is to enhance the planning, control and efficacy of tumor ablation by using an MRI system that can map RF ablation currents local to the electrodes during ablation and map thermal changes. RF current maps will show where power is being deposited, and MR thermometry will show where heat flowed during the ablation. Our approach exploits a new MRI technique that estimates RF current density in tissue. The ablation electrode can be injected with RF currents at the resonant frequency of the MRI scanner, and can also act as an MRI receiver. The MRI scanner can directly image the intense magnetic fields associated with the ablation current, and then derive the local electrode current flow to tissue. In our preliminary work, we have already visualized the current flow in an MR compatible ablation electrode. These tests demonstrated that fatty tissue effectively insulates and blocks the ablation current. Moreover, the current pathway itself lights up high conductivity tissue and creates a medically significant contrast. To fully exploit this capability, we will merge RF current mapping with MR thermometry and ablation devices to form a comprehensive interventional MRI system for RF ablation. Enhanced RF hardware, pulse sequences and reconstructions will be developed. Upon completion, we will perform ex-vivo tissue sample and in-vivo animal studies to demonstrate the clinical potential of this system.

Public Health Relevance

MR guided RF ablation imaging and thermal monitoring should enable better treatment planning, and better control of RF ablation, thus improving time and spatial monitoring as tumor ablation progresses. MR guided RF ablation gives the patient an effective option for a minimally invasive treatment of cancer tumors and a more controllable therapy.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Program Projects (P01)
Project #
Application #
Study Section
Special Emphasis Panel (ZCA1-GRB-P (M1))
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Stanford University
United States
Zip Code
Weber, Hans; Hargreaves, Brian A; Daniel, Bruce L (2018) Artifact-reduced imaging of biopsy needles with 2D multispectral imaging. Magn Reson Med 80:655-661
Webb, Taylor D; Leung, Steven A; Rosenberg, Jarrett et al. (2018) Measurements of the Relationship Between CT Hounsfield Units and Acoustic Velocity and How It Changes With Photon Energy and Reconstruction Method. IEEE Trans Ultrason Ferroelectr Freq Control 65:1111-1124
Weber, Hans; Ghanouni, Pejman; Pascal-Tenorio, Aurea et al. (2018) MRI monitoring of focused ultrasound sonications near metallic hardware. Magn Reson Med 80:259-271
Zheng, Yuan; Marx, Michael; Miller, G Wilson et al. (2018) High sensitivity MR acoustic radiation force imaging using transition band balanced steady-state free precession. Magn Reson Med 79:1532-1537
Han, Amy Kyungwon; Bae, Jung Hwa; Gregoriou, Katerina C et al. (2018) MR-Compatible Haptic Display of Membrane Puncture in Robot-Assisted Needle Procedures. IEEE Trans Haptics :
Gibbons, Eric K; Le Roux, Patrick; Pauly, John M et al. (2018) Slice profile effects on nCPMG SS-FSE. Magn Reson Med 79:430-438
Dixit, Neerav; Stang, Pascal P; Pauly, John M et al. (2018) Thermo-Acoustic Ultrasound for Detection of RF-Induced Device Lead Heating in MRI. IEEE Trans Med Imaging 37:536-546
Gibbons, Eric K; Le Roux, Patrick; Vasanawala, Shreyas S et al. (2018) Robust Self-Calibrating nCPMG Acquisition: Application to Body Diffusion-Weighted Imaging. IEEE Trans Med Imaging 37:200-209
Marx, Michael; Ghanouni, Pejman; Butts Pauly, Kim (2017) Specialized volumetric thermometry for improved guidance of MRgFUS in brain. Magn Reson Med 78:508-517
Dababou, Susan; Marrocchio, Cristina; Rosenberg, Jarrett et al. (2017) A meta-analysis of palliative treatment of pancreatic cancer with high intensity focused ultrasound. J Ther Ultrasound 5:9

Showing the most recent 10 out of 64 publications