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Elfouly T, Alouani A. Harnessing the Heart's Magnetic Field for Advanced Diagnostic Techniques. SENSORS (BASEL, SWITZERLAND) 2024; 24:6017. [PMID: 39338762 PMCID: PMC11435997 DOI: 10.3390/s24186017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2024] [Revised: 09/05/2024] [Accepted: 09/14/2024] [Indexed: 09/30/2024]
Abstract
Heart diseases remain one of the leading causes of morbidity and mortality worldwide, necessitating innovative diagnostic methods for early detection and intervention. An electrocardiogram (ECG) is a well-known technique for the preliminary diagnosis of heart conditions. However, it can not be used for continuous monitoring due to skin irritation. It is well known that every body organ generates a magnetic field, and the heart generates peak amplitudes of about 10 to 100 pT (measured at a distance of about 3 cm above the chest). This poses challenges to capturing such signals. This paper reviews the different techniques used to capture the heart's magnetic signals along with their limitations. In addition, this paper provides a comprehensive review of the different approaches that use the heart-generated magnetic field to diagnose several heart diseases. This research reveals two aspects. First, as a noninvasive tool, the use of the heart's magnetic field signal can lead to more sensitive advanced heart disease diagnosis tools, especially when continuous monitoring is possible and affordable. Second, its current use is limited due to the lack of accurate, affordable, and portable sensing technology.
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Affiliation(s)
- Tarek Elfouly
- Department of Electrical and Computer Engineering, Tennessee Technological University, Cookeville, TN 38505, USA
| | - Ali Alouani
- Department of Electrical and Computer Engineering, Tennessee Technological University, Cookeville, TN 38505, USA
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2
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Turk-Browne NB, Aslin RN. Infant neuroscience: how to measure brain activity in the youngest minds. Trends Neurosci 2024; 47:338-354. [PMID: 38570212 DOI: 10.1016/j.tins.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 01/08/2024] [Accepted: 02/09/2024] [Indexed: 04/05/2024]
Abstract
The functional properties of the infant brain are poorly understood. Recent advances in cognitive neuroscience are opening new avenues for measuring brain activity in human infants. These include novel uses of existing technologies such as electroencephalography (EEG) and magnetoencephalography (MEG), the availability of newer technologies including functional near-infrared spectroscopy (fNIRS) and optically pumped magnetometry (OPM), and innovative applications of functional magnetic resonance imaging (fMRI) in awake infants during cognitive tasks. In this review article we catalog these available non-invasive methods, discuss the challenges and opportunities encountered when applying them to human infants, and highlight the potential they may ultimately hold for advancing our understanding of the youngest minds.
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Affiliation(s)
- Nicholas B Turk-Browne
- Department of Psychology, Yale University, New Haven, CT 06520, USA; Wu Tsai Institute, Yale University, New Haven, CT 06510, USA.
| | - Richard N Aslin
- Department of Psychology, Yale University, New Haven, CT 06520, USA; Child Study Center, Yale School of Medicine, New Haven, CT 06520, USA
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3
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Badier JM, Schwartz D, Bénar CG, Kanzari K, Daligault S, Romain R, Mitryukovskiy S, Fourcault W, Josselin V, Le Prado M, Jung J, Palacios-Laloy A, Romain C, Bartolomei F, Labyt E, Bonini F. Helium Optically Pumped Magnetometers Can Detect Epileptic Abnormalities as Well as SQUIDs as Shown by Intracerebral Recordings. eNeuro 2023; 10:ENEURO.0222-23.2023. [PMID: 37932045 PMCID: PMC10748329 DOI: 10.1523/eneuro.0222-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/22/2023] [Accepted: 09/26/2023] [Indexed: 11/08/2023] Open
Abstract
Magnetoencephalography based on superconducting quantum interference devices (SQUIDs) has been shown to improve the diagnosis and surgical treatment decision for presurgical evaluation of drug-resistant epilepsy. Still, its use remains limited because of several constraints such as cost, fixed helmet size, and the obligation of immobility. A new generation of sensors, optically pumped magnetometers (OPMs), could overcome these limitations. In this study, we validate the ability of helium-based OPM (4He-OPM) sensors to record epileptic brain activity thanks to simultaneous recordings with intracerebral EEG [stereotactic EEG (SEEG)]. We recorded simultaneous SQUIDs-SEEG and 4He-OPM-SEEG signals in one patient during two sessions. We show that epileptic activities on intracerebral EEG can be recorded by OPMs with a better signal-to noise ratio than classical SQUIDs. The OPM sensors open new venues for the widespread application of magnetoencephalography in the management of epilepsy and other neurologic diseases and fundamental neuroscience.
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Affiliation(s)
- Jean-Michel Badier
- Institut de Neurosciences des Systèmes, Institut National de la Santé et de la Recherche Médicale, Aix Marseille Université, Marseille 13005, France
| | - Denis Schwartz
- MEG Departement, CERMEP-Imagerie du Vivant, Lyon 69003, France
| | - Christian-George Bénar
- Institut de Neurosciences des Systèmes, Institut National de la Santé et de la Recherche Médicale, Aix Marseille Université, Marseille 13005, France
| | - Khoubeib Kanzari
- Institut de Neurosciences des Systèmes, Institut National de la Santé et de la Recherche Médicale, Aix Marseille Université, Marseille 13005, France
| | | | - Rudy Romain
- CEA-LETI, MINATEC, Université Grenoble Alpes, Grenoble 38054, France
- MAG4Health, Grenoble 38000, France
| | - Sergey Mitryukovskiy
- CEA-LETI, MINATEC, Université Grenoble Alpes, Grenoble 38054, France
- MAG4Health, Grenoble 38000, France
| | - William Fourcault
- CEA-LETI, MINATEC, Université Grenoble Alpes, Grenoble 38054, France
| | - Vincent Josselin
- CEA-LETI, MINATEC, Université Grenoble Alpes, Grenoble 38054, France
| | - Matthieu Le Prado
- CEA-LETI, MINATEC, Université Grenoble Alpes, Grenoble 38054, France
- MAG4Health, Grenoble 38000, France
| | - Julien Jung
- Centre de Recherche en Neurosciences de Lyon, Unité Mixte de Recherche S1028, Centre National de la Recherche Scientifique, Hospices Civils de Lyon, Institut National de la Santé et de la Recherche Médicale, Université Lyon 1, Lyon 69002, France
| | - Augustin Palacios-Laloy
- CEA-LETI, MINATEC, Université Grenoble Alpes, Grenoble 38054, France
- MAG4Health, Grenoble 38000, France
| | - Carron Romain
- Institut de Neurosciences des Systèmes, Institut National de la Santé et de la Recherche Médicale, Aix Marseille Université, Marseille 13005, France
- Department of Functional and Stereotactic Neurosurgery, Hôpital de la Timone, Assistance Publique-Hôpitaux de Marseille, Marseille 3005, France
| | - Fabrice Bartolomei
- Institut de Neurosciences des Systèmes, Institut National de la Santé et de la Recherche Médicale, Aix Marseille Université, Marseille 13005, France
- Department of Epileptology and Cerebral Rythmology, Hôpital de la Timone, Assistance Publique-Hôpitaux de Marseille, Marseille 3005, France
| | - Etienne Labyt
- CEA-LETI, MINATEC, Université Grenoble Alpes, Grenoble 38054, France
- MAG4Health, Grenoble 38000, France
| | - Francesca Bonini
- Institut de Neurosciences des Systèmes, Institut National de la Santé et de la Recherche Médicale, Aix Marseille Université, Marseille 13005, France
- MEG Departement, CERMEP-Imagerie du Vivant, Lyon 69003, France
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4
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Mason K, Aristovich K, Holder D. Non-invasive imaging of neural activity with magnetic detection electrical impedance tomography (MDEIT): a modelling study. Physiol Meas 2023; 44:114003. [PMID: 37832564 DOI: 10.1088/1361-6579/ad0358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 10/13/2023] [Indexed: 10/15/2023]
Abstract
Objectives.(1) Develop a computational pipeline for three-dimensional fast neural magnetic detection electrical impedance tomography (MDEIT), (2) determine whether constant current or constant voltage is preferable for MDEIT, (3) perform reconstructions of simulated neural activity in a human head model with realistic noise and compare MDEIT to EIT and (4) perform a two-dimensional study in a saline tank for MDEIT with optically pumped magnetometers (OPMs) and compare reconstruction algorithms.Approach.Forward modelling and image reconstruction were performed with a realistic model of a human head in three dimensions and at three noise levels for four perturbations representing neural activity. Images were compared using the error in the position and size of the reconstructed perturbations. Two-dimensional MDEIT was performed in a saline tank with a resistive perturbation and one OPM. Six reconstruction algorithms were compared using the error in the position and size of the reconstructed perturbations.Main results.A computational pipeline was developed in COMSOL Multiphysics, reducing the Jacobian calculation time from months to days. MDEIT reconstructed images with a lower reconstruction error than EIT with a mean difference of 7.0%, 5.5% and 11% for three noise cases representing current noise, reduced current source noise and reduced current source and magnetometer noise. A rank analysis concluded that the MDEIT Jacobian was less rank-deficient than the EIT Jacobian. Reconstructions of a phantom in a saline tank had a best reconstruction error of 13%, achieved using 0th-order Tikhonov regularisation with simulated noise-based correction.Significance.This study demonstrated that three-dimensional MDEIT for neural imaging is feasible and that MDEIT reconstructed superior images to EIT, which can be explained by the lesser rank deficiency of the MDEIT Jacobian. Reconstructions of a perturbation in a saline tank demonstrated a proof of principle for two-dimensional MDEIT with OPMs and identified the best reconstruction algorithm.
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Affiliation(s)
- Kai Mason
- Dept. of Medical Physics and Biomedical Engineering, University College London, Gower St, London, United Kingdom
| | - Kirill Aristovich
- Dept. of Medical Physics and Biomedical Engineering, University College London, Gower St, London, United Kingdom
| | - David Holder
- Dept. of Medical Physics and Biomedical Engineering, University College London, Gower St, London, United Kingdom
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Iivanainen J, Carter TR, Trumbo MCS, McKay J, Taulu S, Wang J, Stephen JM, Schwindt PDD, Borna A. Single-trial classification of evoked responses to auditory tones using OPM- and SQUID-MEG. J Neural Eng 2023; 20:056032. [PMID: 37748476 DOI: 10.1088/1741-2552/acfcd9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 09/25/2023] [Indexed: 09/27/2023]
Abstract
Objective.Optically pumped magnetometers (OPMs) are emerging as a near-room-temperature alternative to superconducting quantum interference devices (SQUIDs) for magnetoencephalography (MEG). In contrast to SQUIDs, OPMs can be placed in a close proximity to subject's scalp potentially increasing the signal-to-noise ratio and spatial resolution of MEG. However, experimental demonstrations of these suggested benefits are still scarce. Here, to compare a 24-channel OPM-MEG system to a commercial whole-head SQUID system in a data-driven way, we quantified their performance in classifying single-trial evoked responses.Approach.We measured evoked responses to three auditory tones in six participants using both OPM- and SQUID-MEG systems. We performed pairwise temporal classification of the single-trial responses with linear discriminant analysis as well as multiclass classification with both EEGNet convolutional neural network and xDAWN decoding.Main results.OPMs provided higher classification accuracies than SQUIDs having a similar coverage of the left hemisphere of the participant. However, the SQUID sensors covering the whole helmet had classification scores larger than those of OPMs for two of the tone pairs, demonstrating the benefits of a whole-head measurement.Significance.The results demonstrate that the current OPM-MEG system provides high-quality data about the brain with room for improvement for high bandwidth non-invasive brain-computer interfacing.
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Affiliation(s)
- Joonas Iivanainen
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - Tony R Carter
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - Michael C S Trumbo
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - Jim McKay
- Candoo Systems Inc, Port Coquitlam, BC, Canada
| | - Samu Taulu
- University of Washington, Seattle, WA, United States of America
| | - Jun Wang
- Department of Speech, Language, and Hearing Sciences, The University of Texas at Austin, Austin, TX, United States of America
- Department of Neurology, The University of Texas at Austin, Austin, TX, United States of America
| | - Julia M Stephen
- The Mind Research Network a Division of Lovelace Biomedical Research Institute, Albuquerque, NM 87106, United States of America
| | - Peter D D Schwindt
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - Amir Borna
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
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Cao F, An N, Xu W, Wang W, Li W, Wang C, Xiang M, Gao Y, Ning X. Optical Co-Registration Method of Triaxial OPM-MEG and MRI. IEEE TRANSACTIONS ON MEDICAL IMAGING 2023; 42:2706-2713. [PMID: 37015113 DOI: 10.1109/tmi.2023.3263167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The advent of optically pumped magnetometers (OPMs) facilitates the development of on-scalp magnetoencephalography (MEG). In particular, the triaxial OPM emerged recently, making simultaneous measurements of all three orthogonal components of vector fields possible. The detection of triaxial magnetic fields improves the interference suppression capability and achieves higher source localization accuracy using fewer sensors. The source localization accuracy of MEG is based on the accurate co-registration of MEG and MRI. In this study, we proposed a triaxial co-registration method according to combined principal component analysis and iterative closest point algorithms for use of a flexible cap. A reference phantom with known sensor positions and orientations was designed and constructed to evaluate the accuracy of the proposed method. Experiments showed that the average co-registered position errors of all sensors were approximately 1 mm and average orientation errors were less than 2.5° in the X -and Y orientations and less than 1.6° in the Z orientation. Furthermore, we assessed the influence of co-registration errors on the source localization using simulations. The average source localization error of approximately 1 mm reflects the effectiveness of the co-registration method. The proposed co-registration method facilitates future applications of triaxial sensors on flexible caps.
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Skidchenko E, Butorina A, Ostras M, Vetoshko P, Kuzmichev A, Yavich N, Malovichko M, Koshev N. Yttrium-Iron Garnet Magnetometer in MEG: Advance towards Multi-Channel Arrays. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23094256. [PMID: 37177460 PMCID: PMC10181089 DOI: 10.3390/s23094256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/17/2023] [Accepted: 04/23/2023] [Indexed: 05/15/2023]
Abstract
Recently, a new kind of sensor applicable in magnetoencephalography (MEG) has been presented: a solid-state yttrium-iron garnet magnetometer (YIGM). The feasibility of yttrium-iron garnet magnetometers (YIGMs) was demonstrated in an alpha-rhythm registration experiment. In this paper, we propose the analysis of lead-field matrices for different possible multi-channel on-scalp sensor layouts using YIGMs with respect to information theory. Real noise levels of the new sensor were used to compute signal-to-noise ratio (SNR) and total information capacity (TiC), and compared with corresponding metrics that can be obtained with well-established MEG systems based on superconducting quantum interference devices (SQUIDs) and optically pumped magnetometers (OPMs). The results showed that due to YIGMs' proximity to the subject's scalp, they outperform SQUIDs and OPMs at their respective noise levels in terms of SNR and TiC. However, the current noise levels of YIGM sensors are unfortunately insufficient for constructing a multichannel YIG-MEG system. This simulation study provides insight into the direction for further development of YIGM sensors to create a multi-channel MEG system, namely, by decreasing the noise levels of sensors.
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Affiliation(s)
| | - Anna Butorina
- CNBR, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia
| | - Maxim Ostras
- M-Granat, Russian Quantum Center, 121205 Moscow, Russia
| | - Petr Vetoshko
- M-Granat, Russian Quantum Center, 121205 Moscow, Russia
- Laboratory of Magnetic Phenomena in Microelectronics, Kotelnikov Institute of Radioengineering and Electronics of RAS, 125009 Moscow, Russia
| | | | - Nikolay Yavich
- CNBR, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia
- Computational Geophysics Lab, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | - Mikhail Malovichko
- Computational Geophysics Lab, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | - Nikolay Koshev
- CNBR, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia
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Gutteling TP, Bonnefond M, Clausner T, Daligault S, Romain R, Mitryukovskiy S, Fourcault W, Josselin V, Le Prado M, Palacios-Laloy A, Labyt E, Jung J, Schwartz D. A New Generation of OPM for High Dynamic and Large Bandwidth MEG: The 4He OPMs-First Applications in Healthy Volunteers. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23052801. [PMID: 36905007 PMCID: PMC10006929 DOI: 10.3390/s23052801] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/16/2023] [Accepted: 02/24/2023] [Indexed: 06/06/2023]
Abstract
MagnetoEncephaloGraphy (MEG) provides a measure of electrical activity in the brain at a millisecond time scale. From these signals, one can non-invasively derive the dynamics of brain activity. Conventional MEG systems (SQUID-MEG) use very low temperatures to achieve the necessary sensitivity. This leads to severe experimental and economical limitations. A new generation of MEG sensors is emerging: the optically pumped magnetometers (OPM). In OPM, an atomic gas enclosed in a glass cell is traversed by a laser beam whose modulation depends on the local magnetic field. MAG4Health is developing OPMs using Helium gas (4He-OPM). They operate at room temperature with a large dynamic range and a large frequency bandwidth and output natively a 3D vectorial measure of the magnetic field. In this study, five 4He-OPMs were compared to a classical SQUID-MEG system in a group of 18 volunteers to evaluate their experimental performances. Considering that the 4He-OPMs operate at real room temperature and can be placed directly on the head, our assumption was that 4He-OPMs would provide a reliable recording of physiological magnetic brain activity. Indeed, the results showed that the 4He-OPMs showed very similar results to the classical SQUID-MEG system by taking advantage of a shorter distance to the brain, despite having a lower sensitivity.
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Affiliation(s)
- Tjerk P. Gutteling
- CERMEP-Imagerie du Vivant, MEG Departement, 69000 Lyon, France
- CRNL, UMR_S 1028, HCL, Université Lyon 1, 69000 Lyon, France
| | | | - Tommy Clausner
- CRNL, UMR_S 1028, HCL, Université Lyon 1, 69000 Lyon, France
| | | | | | | | - William Fourcault
- CEA LETI, Minatec Campus, Université Grenoble Alpes, 38000 Grenoble, France
| | - Vincent Josselin
- CEA LETI, Minatec Campus, Université Grenoble Alpes, 38000 Grenoble, France
| | | | | | | | - Julien Jung
- CRNL, UMR_S 1028, HCL, Université Lyon 1, 69000 Lyon, France
| | - Denis Schwartz
- CERMEP-Imagerie du Vivant, MEG Departement, 69000 Lyon, France
- CRNL, UMR_S 1028, HCL, Université Lyon 1, 69000 Lyon, France
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Liu Y, Peng X, Wang H, Wang B, Yi K, Sheng D, Guo H. Femtotesla 4He magnetometer with a multipass cell. OPTICS LETTERS 2022; 47:5252-5255. [PMID: 36240335 DOI: 10.1364/ol.471557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 09/17/2022] [Indexed: 06/16/2023]
Abstract
In this Letter, we propose a single-beam nonlinear magneto-optical rotation (NMOR) magnetometer with a multipass 4He gas-discharged cell. In contrast to the single-pass cell, the multipass cell allowed laser beams to pass through the metastable-state atomic ensemble 22 times, which directly increases the optical path length and significantly enhances magneto-optical rotation in the 4He gas sample. Based on nonlinear Faraday rotation, the 4He magnetometer with the multipass cell demonstrates a noise floor of 9 fT/Hz1/2, which approaches the photon-shot noise floor limit of 6.4 fT/Hz1/2. In addition, the wider linewidth in metastable-state atoms realizes an NMOR 4He magnetometer with a 3 dB bandwidth of 4.3 kHz, in contrast to the ultranarrow linewidth in the antirelaxation-coated cells or spin-exchange relaxation-free regime alkali-metal cells with buffer gas. Since the 4He cell functions without heating or cryogenic cooling, the femtotesla sensitivity and kilohertz-bandwidth 4He magnetometer exhibits potential in biomagnetic applications such as magnetocardiography and magnetoencephalography.
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