Magnetic Resonance Mediated Radiofrequency Ablation

Area of Science:

• Medical Imaging
• Interventional Radiology
• Biomedical Engineering

Background:

• Radiofrequency ablation (RFA) is a minimally invasive technique for tumor treatment.
• Magnetic Resonance Imaging (MRI) offers excellent soft-tissue contrast and real-time monitoring capabilities.
• Integrating RFA with MRI could enhance treatment precision and safety.

Purpose of the Study:

• To introduce and evaluate Magnetic Resonance-guided Radiofrequency Ablation (MR-RFA).
• To demonstrate the feasibility of using MRI scanners for both diagnostic and therapeutic roles in RFA.
• To assess the efficacy of MR-RFA in achieving therapeutic temperatures and creating thermal lesions.

Main Methods:

• MR-RFA device utilizing Larmor frequency RF pickup and needle system.
• Simulation of electric and magnetic fields to predict specific absorption rate (SAR).
• Temperature measurements in phantoms and ex vivo liver using proton resonance frequency (PRF) method and fiber-optic thermometry.
• In vivo ablation in porcine livers.

Main Results:

• Simulations predicted a near tenfold increase in SAR at the RFA needle tip.
• MR-RFA achieved temperature increases sufficient for ablation in various configurations.
• Real-time temperature monitoring via PRF method validated with fiber-optic thermometry.
• Successful thermal lesions observed in resected porcine livers.

Conclusions:

• MR-RFA successfully integrates MRI guidance with radiofrequency ablation therapy.
• The technique demonstrates potential for precise tumor ablation with real-time monitoring of temperature, perfusion, and coagulation.
• MR-RFA may enhance MRI's value by incorporating a disposable ablation device for integrated diagnostic and therapeutic procedures.