Electrical Properties Tomography (EPT) is a new method to map the dielectric properties (electrical conductivity and permittivity) of tissue at MRI frequencies (64-300MHz). At MRI frequencies, variations in the intra- and extracellular ionic concentration are the major source of conductivity variations. The EPT theory and MR methodology was partly developed at the UMC Utrecht. The reconstruction is based on mapping of the radiofrequency (RF) magnetic field amplitude and phase.
PRS Stijnman, S Mandija, PS Fuchs, CAT van den Berg , RF Remis. Transceive phase corrected 2D contrast source inversion-electrical properties tomography. Magn Reson Med. 2021;85(5):2856-2868.
S Gavazzi, Y Shcherbakova, LW Bartels, LJA Stalpers, JJW Lagendijk, H Crezee, CAT van den Berg, ALHMW van Lier. Transceive phase mapping using the PLANET method and its application for conductivity mapping in the brain. Magn Reson Med. 2020;83(2):590-607.
S Mandija, A Sbrizzi, U Katscher, PR Luijten, CAT Berg. Error analysis of helmholtz-based MR-electrical properties tomography. Magn Reson Med. 2018; 80(1):90-100.
ALHMW van Lier, DO Brunner, KP Pruessmann, DWJ Klomp, PR Luijten, JJW Lagendijk, CAT van den Berg. B1(+) phase mapping at 7 T and its application for in vivo electrical conductivity mapping. Magn Reson Med. 2012 Feb;67(2):552-61.
Deep Learning for EPT
Recently, we have shown that the exploitation of deep-learning methods for EPT and their integration with physics-based reconstructions lead to great improvements in the quality of EPT reconstructions, opening a new horizon for this technique.
S Mandija, EF Meliadò, NRF Huttinga, PR Luijten, CAT van den Berg. Opening a new window on MR-based Electrical Properties Tomography with deep learning. Nature Scientific Reports 2019;9(1):8895.
R Leijsen, CAT van den Berg, AG Webb, RF Remis, S Mandija. Combining deep learning and 3D contrast source inversion in MR-based electrical properties tomography. NMR Biomed 2019;16:4211.
N Hampe, U Katscher, CAT van den Berg, KK Tha, S Mandija. Investigating the challenges and generalizability of deep learning brain conductivity mapping. Physics in Medicine and Biology 2020;65(13):13501.
S Gavazzi , CAT van den Berg, MHF Savenije, HP Kok, P de Boer, LJA Stalpers, JJW Lagendijk, H Crezee, ALHMW van Lier. Deep learning-based reconstruction of in vivo pelvis conductivity with a 3D patch-based convolutional neural network trained on simulated MR data. Magn Reson Med. 2020;84(5):2772-2787.
Clinical applications of EPT
Pathologies with altered ionic homeostasis are of interest to investigate with EPT since changes in the electrical conductivity of tissues reflect changes in tissue viability. Current research aims at using EPT as a biomarker for tumour characterization and radiotherapy treatment monitoring at early-stages of treatment (NWO-Veni grant).
S Mandija, PI Petrov, JJT Vink, SFW Neggers, CAT Berg. Brain Tissue Conductivity Measurements with MR-Electrical Properties Tomography: An In Vivo Study. Brain Topography, 2020;34(1):56-63.
S Gavazzi, ALHMW van Lier, C Zachiu, E Jansen, JJW Lagendijk, LJA Stalpers, H Crezee , HP Kok. Advanced patient-specific hyperthermia treatment planning. Int J Hyperthermia 2020;37(1):992-1007.
ALHMW van Lier, JM. Hoogduin, DL Polders, VO Boer, J Hendrikse, PA Robe,PA Woerdeman, JJW Lagendijk, PR Luijten, CAT van den Berg. Electrical conductivity imaging of brain tumours. ISMRM 2011:127
NWO-VENI 2021-2024 (PI: Stefano Mandija)
qMRI Workshop, Lucca 2022, co-organizers: 1st Joint Workshop on MR phase, magnetic susceptibility and electrical properties mapping.
IMEP Workshop, Utrecht 2019, organizers: 2nd international workshop on MR-based Electrical Properties mapping.