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Development and testing of implanted carbon electrodes for electromagnetic field mapping during neuromodulation
Author(s) -
Ashok Kumar Neeta,
Chauhan Munish,
Kandala Sri Kirthi,
Sohn SungMin,
Sadleir Rosalind J.
Publication year - 2020
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28273
Subject(s) - electrode , materials science , neuromodulation , imaging phantom , biomedical engineering , nuclear magnetic resonance , artifact (error) , deep brain stimulation , chemistry , nuclear medicine , medicine , neuroscience , biochemistry , physics , receptor , disease , pathology , parkinson's disease , biology
Purpose Deep brain stimulation electrodes composed of carbon fibers were tested as a means of administering and imaging magnetic resonance electrical impedance tomography (MREIT) currents. Artifacts and heating properties of custom carbon‐fiber deep brain stimulation (DBS) electrodes were compared with those produced with standard DBS electrodes. Methods Electrodes were constructed from multiple strands of 7‐μm carbon‐fiber stock. The insulated carbon electrodes were matched to DBS electrode diameter and contact areas. Images of DBS and carbon electrodes were collected with and without current flow and were compared in terms of artifact and thermal effects in phantoms or tissue samples in 7T imaging conditions. Effects on magnetic flux density and current density distributions were also assessed. Results Carbon electrodes produced magnitude artifacts with smaller FWHM values compared to the magnitude artifacts around DBS electrodes in spin echo and gradient echo imaging protocols. DBS electrodes appeared 269% larger than actual size in gradient echo images, in sharp contrast to the negligible artifact observed in diameter‐matched carbon electrodes. As expected, larger temperature changes were observed near DBS electrodes during extended RF excitations compared with carbon electrodes in the same phantom. Magnitudes and distribution of magnetic flux density and current density reconstructions were comparable for carbon and DBS electrodes. Conclusion Carbon electrodes may offer a safer, MR‐compatible method for administering neuromodulation currents. Use of carbon‐fiber electrodes should allow imaging of structures close to electrodes, potentially allowing better targeting, electrode position revision, and the facilitation of functional imaging near electrodes during neuromodulation.