Cargando…

Silicon Carbide and MRI: Towards Developing a MRI Safe Neural Interface

An essential method to investigate neuromodulation effects of an invasive neural interface (INI) is magnetic resonance imaging (MRI). Presently, MRI imaging of patients with neural implants is highly restricted in high field MRI (e.g., 3 T and higher) due to patient safety concerns. This results in...

Descripción completa

Detalles Bibliográficos
Autores principales: Beygi, Mohammad, Dominguez-Viqueira, William, Feng, Chenyin, Mumcu, Gokhan, Frewin, Christopher L., La Via, Francesco, Saddow, Stephen E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7911642/
https://www.ncbi.nlm.nih.gov/pubmed/33530350
http://dx.doi.org/10.3390/mi12020126
_version_ 1783656389669814272
author Beygi, Mohammad
Dominguez-Viqueira, William
Feng, Chenyin
Mumcu, Gokhan
Frewin, Christopher L.
La Via, Francesco
Saddow, Stephen E.
author_facet Beygi, Mohammad
Dominguez-Viqueira, William
Feng, Chenyin
Mumcu, Gokhan
Frewin, Christopher L.
La Via, Francesco
Saddow, Stephen E.
author_sort Beygi, Mohammad
collection PubMed
description An essential method to investigate neuromodulation effects of an invasive neural interface (INI) is magnetic resonance imaging (MRI). Presently, MRI imaging of patients with neural implants is highly restricted in high field MRI (e.g., 3 T and higher) due to patient safety concerns. This results in lower resolution MRI images and, consequently, degrades the efficacy of MRI imaging for diagnostic purposes in these patients. Cubic silicon carbide (3C-SiC) is a biocompatible wide-band-gap semiconductor with a high thermal conductivity and magnetic susceptibility compatible with brain tissue. It also has modifiable electrical conductivity through doping level control. These properties can improve the MRI compliance of 3C-SiC INIs, specifically in high field MRI scanning. In this work, the MRI compliance of epitaxial SiC films grown on various Si wafers, used to implement a monolithic neural implant (all-SiC), was studied. Via finite element method (FEM) and Fourier-based simulations, the specific absorption rate (SAR), induced heating, and image artifacts caused by the portion of the implant within a brain tissue phantom located in a 7 T small animal MRI machine were estimated and measured. The specific goal was to compare implant materials; thus, the effect of leads outside the tissue was not considered. The results of the simulations were validated via phantom experiments in the same 7 T MRI system. The simulation and experimental results revealed that free-standing 3C-SiC films had little to no image artifacts compared to silicon and platinum reference materials inside the MRI at 7 T. In addition, FEM simulations predicted an ~30% SAR reduction for 3C-SiC compared to Pt. These initial simulations and experiments indicate an all-SiC INI may effectively reduce MRI induced heating and image artifacts in high field MRI. In order to evaluate the MRI safety of a closed-loop, fully functional all-SiC INI as per ISO/TS 10974:2018 standard, additional research and development is being conducted and will be reported at a later date.
format Online
Article
Text
id pubmed-7911642
institution National Center for Biotechnology Information
language English
publishDate 2021
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-79116422021-02-28 Silicon Carbide and MRI: Towards Developing a MRI Safe Neural Interface Beygi, Mohammad Dominguez-Viqueira, William Feng, Chenyin Mumcu, Gokhan Frewin, Christopher L. La Via, Francesco Saddow, Stephen E. Micromachines (Basel) Article An essential method to investigate neuromodulation effects of an invasive neural interface (INI) is magnetic resonance imaging (MRI). Presently, MRI imaging of patients with neural implants is highly restricted in high field MRI (e.g., 3 T and higher) due to patient safety concerns. This results in lower resolution MRI images and, consequently, degrades the efficacy of MRI imaging for diagnostic purposes in these patients. Cubic silicon carbide (3C-SiC) is a biocompatible wide-band-gap semiconductor with a high thermal conductivity and magnetic susceptibility compatible with brain tissue. It also has modifiable electrical conductivity through doping level control. These properties can improve the MRI compliance of 3C-SiC INIs, specifically in high field MRI scanning. In this work, the MRI compliance of epitaxial SiC films grown on various Si wafers, used to implement a monolithic neural implant (all-SiC), was studied. Via finite element method (FEM) and Fourier-based simulations, the specific absorption rate (SAR), induced heating, and image artifacts caused by the portion of the implant within a brain tissue phantom located in a 7 T small animal MRI machine were estimated and measured. The specific goal was to compare implant materials; thus, the effect of leads outside the tissue was not considered. The results of the simulations were validated via phantom experiments in the same 7 T MRI system. The simulation and experimental results revealed that free-standing 3C-SiC films had little to no image artifacts compared to silicon and platinum reference materials inside the MRI at 7 T. In addition, FEM simulations predicted an ~30% SAR reduction for 3C-SiC compared to Pt. These initial simulations and experiments indicate an all-SiC INI may effectively reduce MRI induced heating and image artifacts in high field MRI. In order to evaluate the MRI safety of a closed-loop, fully functional all-SiC INI as per ISO/TS 10974:2018 standard, additional research and development is being conducted and will be reported at a later date. MDPI 2021-01-26 /pmc/articles/PMC7911642/ /pubmed/33530350 http://dx.doi.org/10.3390/mi12020126 Text en © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Beygi, Mohammad
Dominguez-Viqueira, William
Feng, Chenyin
Mumcu, Gokhan
Frewin, Christopher L.
La Via, Francesco
Saddow, Stephen E.
Silicon Carbide and MRI: Towards Developing a MRI Safe Neural Interface
title Silicon Carbide and MRI: Towards Developing a MRI Safe Neural Interface
title_full Silicon Carbide and MRI: Towards Developing a MRI Safe Neural Interface
title_fullStr Silicon Carbide and MRI: Towards Developing a MRI Safe Neural Interface
title_full_unstemmed Silicon Carbide and MRI: Towards Developing a MRI Safe Neural Interface
title_short Silicon Carbide and MRI: Towards Developing a MRI Safe Neural Interface
title_sort silicon carbide and mri: towards developing a mri safe neural interface
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7911642/
https://www.ncbi.nlm.nih.gov/pubmed/33530350
http://dx.doi.org/10.3390/mi12020126
work_keys_str_mv AT beygimohammad siliconcarbideandmritowardsdevelopingamrisafeneuralinterface
AT dominguezviqueirawilliam siliconcarbideandmritowardsdevelopingamrisafeneuralinterface
AT fengchenyin siliconcarbideandmritowardsdevelopingamrisafeneuralinterface
AT mumcugokhan siliconcarbideandmritowardsdevelopingamrisafeneuralinterface
AT frewinchristopherl siliconcarbideandmritowardsdevelopingamrisafeneuralinterface
AT laviafrancesco siliconcarbideandmritowardsdevelopingamrisafeneuralinterface
AT saddowstephene siliconcarbideandmritowardsdevelopingamrisafeneuralinterface