MEMoRIAL-M1.9 | Current visualisation during radiofrequency ablation (RFA) with MR coils

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 was supposed to investigate whether it was 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 required. 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 a MR environment. Here, the heat-based experiments were accompanied by acquisistions of temperature 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 als show a correlation with respect to the simulated MR signal distribution.

Conclusions
Using the concept of an MRI hybrid ablation system it is possible to perfom 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. To date, no comparable, commercially available clinical RFA system exists that allows to monitor RFA with MR thermometry.

Keywords
MRI, radiofrequency ablation (RFA), thermometry, monitoring, hybrid system