Polymer thick film technology for improved simultaneous dEEG/MRI recording: Safety and MRI data quality

Poulsen, Catherine; Wakeman, Daniel G.; Atefi, Seyed Reza; Luu, Phan; Konyn, Amy; Bonmassar, Giorgio

doi:10.1002/mrm.26116

Cited by 17 publications

(21 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, only a minimal quantity of conductive gel should be used, so that it does not induce appreciable image artifacts while still providing acceptable electrode impedance ( Krakow et al, 2000 ). Novel EEG caps have been developed using different technologies in order to minimize the impact of simultaneous EEG-fMRI recordings on subject safety and MR data quality ( Vasios et al, 2006 ), and ultimately to make feasible the recording of high-density EEG data at ultra-high magnetic field strengths ( Poulsen et al, 2017 ).…”

Section: Mr Data Qualitymentioning

confidence: 99%

EEG-Informed fMRI: A Review of Data Analysis Methods

Abreu

Leal

Figueiredo

2018

Front. Hum. Neurosci.

140

126

View full text Add to dashboard Cite

The simultaneous acquisition of electroencephalography (EEG) with functional magnetic resonance imaging (fMRI) is a very promising non-invasive technique for the study of human brain function. Despite continuous improvements, it remains a challenging technique, and a standard methodology for data analysis is yet to be established. Here we review the methodologies that are currently available to address the challenges at each step of the data analysis pipeline. We start by surveying methods for pre-processing both EEG and fMRI data. On the EEG side, we focus on the correction for several MR-induced artifacts, particularly the gradient and pulse artifacts, as well as other sources of EEG artifacts. On the fMRI side, we consider image artifacts induced by the presence of EEG hardware inside the MR scanner, and the contamination of the fMRI signal by physiological noise of non-neuronal origin, including a review of several approaches to model and remove it. We then provide an overview of the approaches specifically employed for the integration of EEG and fMRI when using EEG to predict the blood oxygenation level dependent (BOLD) fMRI signal, the so-called EEG-informed fMRI integration strategy, the most commonly used strategy in EEG-fMRI research. Finally, we systematically review methods used for the extraction of EEG features reflecting neuronal phenomena of interest.

show abstract

Section: Mr Data Qualitymentioning

confidence: 99%

EEG-Informed fMRI: A Review of Data Analysis Methods

Abreu

Leal

Figueiredo

2018

Front. Hum. Neurosci.

140

126

View full text Add to dashboard Cite

show abstract

“…While simulations performed with competing solvers such as the finite differences time domain (FDTD) would require much larger resources, such as CUDA cards with a memory of several terabytes, and computing times an order of magnitude or greater compared to the FEM solution. Preliminary validation of the accuracy of the FEM simulations was performed by comparing them with in vitro temperature measurements in a gel-filled head phantom, which is known as CHEMA, and that was previously used in many other similar MRI/safety studies (Angelone et al, 2006Poulsen et al, 2016;Atefi et al, 2018). Further validations of the numerical simulations, such as the rotating B1 field generated by the head coil and the SAR, are presented in the Supplementary Material.…”

Section: Discussionmentioning

confidence: 99%

MRI-Induced Heating of Coils for Microscopic Magnetic Stimulation at 1.5 Tesla: An Initial Study

Bonmassar

Serano

2020

Front. Hum. Neurosci.

Self Cite

View full text Add to dashboard Cite

Purpose: Deep brain stimulation (DBS) has proved to be effective in the treatment of movement disorders. However, the direct contact between the metal contacts of the DBS electrode and the brain can cause RF heating in magnetic resonance imaging (MRI) scanning, due to an increase of local specific absorption rate (SAR). Recently, micro coils (µMS) have demonstrated excitation of neuronal tissue through the electromagnetic induction both in vitro and in vivo experiments. In contrast to electrical stimulation, in µMS, there is no direct contact between the metal and the biological tissue.Methods: We compared the heating of a µMS coil with a control case of a metal wire. The heating was induced by RF fields in a 1.5 T MRI head birdcage coil (often used for imaging patients with implants) at 64 MHz, and normalized results to 3.2 W/kg whole head average SAR. Results:The µMS coil or wire implants were placed inside an anatomically accurate head saline-gel filled phantom inserted in the RF coil, and we observed approximately 1 • C initial temperature rise at the µMS coil, while the wire exhibited a 10 • C temperature rise in the proximity of the exposed end. The numerical simulations showed a 32-times increase of local SAR induced at the tips of the metal wire compared to the µMS. Conclusion:In this work, we show with measurements and electromagnetic numerical simulations that the RF-induced increase in local SAR and induced heating during MRI scanning can be greatly reduced by using magnetic stimulation with the proposed µMS technology.

show abstract

“…A hole was present at the bottom of the mold to pour the following mix: 5.5-L distilled H 2 O, 550 g of GL Red Algae powder, and 49.5-g NaCl (purity: 98% Catalog No. 31, 016-6 Sigma Aldrich) [8]. This homogeneous GL phantom [8] was used to study temperature changes with the EEG leads and compare to the simulation results.…”

Section: E Experimental B1 Maps and Temperature Measurementsmentioning

confidence: 99%

“…31, 016-6 Sigma Aldrich) [8]. This homogeneous GL phantom [8] was used to study temperature changes with the EEG leads and compare to the simulation results.…”

Section: E Experimental B1 Maps and Temperature Measurementsmentioning

confidence: 99%

Numerical and Experimental Analysis of Radiofrequency-Induced Heating Versus Lead Conductivity During EEG-MRI at 3 T

Atefi

Serano

Poulsen

et al. 2019

IEEE Trans. Electromagn. Compat.

Self Cite

View full text Add to dashboard Cite

This study investigates radiofrequency (RF)-induced heating in a head model with a 256-channel electroencephalogram (EEG) cap during magnetic resonance imaging (MRI). Nine computational models were implemented each with different EEG lead electrical conductivity, ranging from 1 to 5.8 × 10 7 S/m. The peak values of specific absorption rate (SAR) averaged over different volumes were calculated for each lead conductivity. Experimental measurements were also performed at 3-T MRI with a Gracilaria Lichenoides (GL) phantom with and without a low-conductive EEG lead cap ("InkNet"). The simulation results showed that SAR was a nonlinear function of the EEG lead conductivity. The experimental results were in line with the numerical simulations. Specifically, there was a ΔT of 1.7 °C in the GL phantom without leads compared to ΔT of 1.8 °C calculated with the simulations. Additionally, there was a ΔT of 1.5 °C in the GL phantom with the InkNet compared to a ΔT of 1.7 °C in the simulations with a cap of similar conductivity. The results showed that SAR is affected by specific location, number of electrodes, and the volume of tissue considered. As such, SAR averaged over the whole head, or even SAR averaged over volumes of 1

show abstract

Polymer thick film technology for improved simultaneous dEEG/MRI recording: Safety and MRI data quality

Cited by 17 publications

References 49 publications

EEG-Informed fMRI: A Review of Data Analysis Methods

EEG-Informed fMRI: A Review of Data Analysis Methods

MRI-Induced Heating of Coils for Microscopic Magnetic Stimulation at 1.5 Tesla: An Initial Study

Numerical and Experimental Analysis of Radiofrequency-Induced Heating Versus Lead Conductivity During EEG-MRI at 3 T

Contact Info

Product

Resources

About