Brain Tissue Conductivity Measurements with MR-Electrical Properties Tomography: An In Vivo Study
Open Access
- 8 December 2020
- journal article
- research article
- Published by Springer Science and Business Media LLC in Brain Topography
- Vol. 34 (1), 56-63
- https://doi.org/10.1007/s10548-020-00813-1
Abstract
First in vivo brain conductivity reconstructions using Helmholtz MR-Electrical Properties Tomography (MR-EPT) have been published. However, a large variation in the reconstructed conductivity values is reported and these values differ from ex vivo conductivity measurements. Given this lack of agreement, we performed an in vivo study on eight healthy subjects to provide reference in vivo brain conductivity values. MR-EPT reconstructions were performed at 3 T for eight healthy subjects. Mean conductivity and standard deviation values in the white matter, gray matter and cerebrospinal fluid (σWM, σGM, and σCSF) were computed for each subject before and after erosion of regions at tissue boundaries, which are affected by typical MR-EPT reconstruction errors. The obtained values were compared to the reported ex vivo literature values. To benchmark the accuracy of in vivo conductivity reconstructions, the same pipeline was applied to simulated data, which allow knowledge of ground truth conductivity. Provided sufficient boundary erosion, the in vivo σWM and σGM values obtained in this study agree for the first time with literature values measured ex vivo. This could not be verified for the CSF due to its limited spatial extension. Conductivity reconstructions from simulated data verified conductivity reconstructions from in vivo data and demonstrated the importance of discarding voxels at tissue boundaries. The presented σWM and σGM values can therefore be used for comparison in future studies employing different MR-EPT techniques.Keywords
Funding Information
- ENIAC Joint Undertaking
This publication has 45 references indexed in Scilit:
- Recent Progress and Future Challenges in MR Electric Properties TomographyComputational and Mathematical Methods in Medicine, 2013
- Analysis of the local worst-case SAR exposure caused by an MRI multi-transmit body coil in anatomical models of the human bodyPhysics in Medicine & Biology, 2011
- Toward individualized SAR models and in vivo validationMagnetic Resonance in Medicine, 2011
- Quantitative conductivity and permittivity imaging of the human brain using electric properties tomographyMagnetic Resonance in Medicine, 2011
- Magnetic resonance electrical impedance tomography (MREIT) for high-resolution conductivity imagingPhysiological Measurement, 2008
- Estimation of electrical conductivity distribution within the human head from magnetic flux density measurementPhysics in Medicine & Biology, 2005
- Magnetic resonance electrical impedance tomography (MREIT): conductivity and current density imagingJournal of Physics: Conference Series, 2005
- The dielectric properties of biological tissues: III. Parametric models for the dielectric spectrum of tissuesPhysics in Medicine & Biology, 1996
- The dielectric properties of biological tissues: II. Measurements in the frequency range 10 Hz to 20 GHzPhysics in Medicine & Biology, 1996
- The dielectric properties of biological tissues: I. Literature surveyPhysics in Medicine & Biology, 1996