Multi-echo gradient echo pulse sequences

Multi-echo gradient echo pulse sequences: which is best for PRFS MR thermometry guided hyperthermia?

Feddersen, Theresa V. (Erasmus MC)
Poot, Dirk H.J. (Erasmus MC)
Paulides, Margarethus M. (Erasmus MC; Eindhoven University of Technology)
Salim, Ghassan (Erasmus MC)
van Rhoon, G.C. (TU Delft RST/Applied Radiation & Isotopes; Erasmus MC)
Hernandez-Tamames, J.A. (TU Delft ImPhys/Vos group; Erasmus MC)

2023

Purpose: MR thermometry (MRT) enables noninvasive temperature monitoring during hyperthermia treatments. MRT is already clinically applied for hyperthermia treatments in the abdomen and extremities, and devices for the head are under development. In order to optimally exploit MRT in all anatomical regions, the best sequence setup and post-processing must be selected, and the accuracy needs to be demonstrated. Methods: MRT performance of the traditionally used double-echo gradient-echo sequence (DE-GRE, 2 echoes, 2D) was compared to multi-echo sequences: a 2D fast gradient-echo (ME-FGRE, 11 echoes) and a 3D fast gradient-echo sequence (3D-ME-FGRE, 11 echoes). The different methods were assessed on a 1.5 T MR scanner (GE Healthcare) using a phantom cooling down from 59 °C to 34 °C and unheated brains of 10 volunteers. In-plane motion of volunteers was compensated by rigid body image registration. For the ME sequences, the off-resonance frequency was calculated using a multi-peak fitting tool. To correct for B0 drift, the internal body fat was selected automatically using water/fat density maps. Results: The accuracy of the best performing 3D-ME-FGRE sequence was 0.20 °C in phantom (in the clinical temperature range) and 0.75 °C in volunteers, compared to DE-GRE values of 0.37 °C and 1.96 °C, respectively. Conclusion: For hyperthermia applications, where accuracy is more important than resolution or scan-time, the 3D-ME-FGRE sequence is deemed the most promising candidate. Beyond its convincing MRT performance, the ME nature enables automatic selection of internal body fat for B0 drift correction, an important feature for clinical application.

hyperthermia
MRT
proton resonance frequency shift (PRFS)
temperature mapping
thermal therapy
Thermometry

http://resolver.tudelft.nl/uuid:6284b72f-bc73-4db5-9770-520710cdac28

https://doi.org/10.1080/02656736.2023.2184399

0265-6736

International Journal of Hyperthermia, 40 (1)

Institutional Repository

journal article

© 2023 Theresa V. Feddersen, Dirk H.J. Poot, Margarethus M. Paulides, Ghassan Salim, G.C. van Rhoon, J.A. Hernandez-Tamames