Funding period: Nov 2017 to Oct 2021

Researcher: Thomas Gerlach

Wrap-up

Keywords: MRI, Radiofrequency Ablation, Thermometry, Monitoring, Hybrid System

Background:
Real-time monitoring for radiofrequency ablation (RFA) is required to obtain information about the complete destruction of cancerous tissue. However, no RFA system exists that allows real-time MR monitoring. The MRI Hybrid Ablation system is an innovative system, where the MR scanner itself is used as a power source for RFA.

Objective:
It shall be investigated whether it is possible to monitor a RFA procedure using the concept of an MRI hybrid ablation system.

Methods:
By connecting an electrode to the coil port of the MR device, access to the RF infrastructure of the MRI can be acquired. Hereby, the electrode will be used for thermal destruction of tissue, as well as for MR imaging. Electromagnetic and thermal field simulations were performed to numerically evaluate these possibilities. The simulations were validated while performing ablation experiments with protein phantoms and ex-vivo tissue in an MR environment. Here, the heat-based experiments were accompanied by acquisitions of temperature maps and flip angle maps.

Results:
The thermally destroyed tissue correlates with the predictions from MR thermometry, as well as the numerically calculated heat depositions. The flip angle maps also shows a correlation with respect to the simulated MR signal distribution.

Conclusions:
Using the concept of an MRI hybrid ablation system, it is possible to perform a thermal procedure and to monitor the RFA with MR thermometry. The approach of monitoring the ablation process by flip angle mapping is strongly compromised by long measurement times.

Originality:
An approach has been developed to use the MR scanner as an "MR-compatible" therapeutic device. No commercially available clinical RFA system exists that allows to monitor RFA with MR thermometry.