Reference-less MR thermometry on pre-clinical thiel human cadaver for liver surgery with MRgFUS

Abstract

Purpose: Reference-less MR thermometry can be a promising technique for temperature mapping during liver treatment with Magnetic Resonance-guided Focused Ultrasound (MRgFUS), as it is more robust to breathing motion than Proton Resonance Frequency MR thermometry. However, there is a lack of a pre-clinical model for repeatable testing of reference-less thermometry. The purpose of this work was to verify the explanted Thiel embalmed human liver and whole Thiel embalmed human cadaver for application of a custom made reference-less thermometry algorithm during MRgFUS sonication.

Material and methods: Phase maps were generated during sonication as an input to the algorithm. A square Region-of-Interest (ROI) was designed around the heated area. The ROI was interpolated using a two-dimensional polynomial to the surrounding phase map to calculate the background phase.

Results: Using the phase information from the images, the temperature rise was measured. Validation of the methodology showed accordance of temperatures with actual temperatures.

Conclusions: The explanted liver and the whole cadaver constitute a promising and feasible model to study reference-less techniques for thermometry during MRgFUS, before clinical trials.

Keywords:

• Focused ultrasound
• liver surgery
• MR-guided
• pre-clinical
• reference-less thermometry

Acknowledgements

The authors are thankful to Dr. Yuval Zur from GE Healtchare (Tirat Carmel, Israel) for support with programming for the reference-less thermometry algorithm. We would also like to thank Dr. Roos Eisma from CAHID (University of Dundee) for providing us with Thiel embalmed human tissue. We also want to thank the European Community’s Seventh Framework Programmes (FP7/2007–2017) and (FP7/2014–2019) under grant agreement numbers 270186 (FUSIMO project) and 611889 (TRANS-FUSIMO project) for the funding and also I.K.Y. (State Scholarships Foundation), as part of this post-doctoral research was accomplished under an I.K.Y. scholarship, which was funded by the Act ‘Support of Post-doctoral Researchers’ from funds of Research Programme ‘Development of Human Resource, Education and Continued Learning’, with priority bases 6,8,9 and co-funded by the European Social Fund (ESF) and the Greek State.

Declaration of interest

The authors report no conflict of interest.