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Li M, Zhu R, Li G, Yin S, Zeng L, Bai Z, Chen J, Jiang B, Li L, Wu Y. Point-of-care testing for cerebral edema types based on symmetric cancellation near-field coupling phase shift and support vector machine. Biomed Eng Online 2023; 22:80. [PMID: 37582824 PMCID: PMC10428563 DOI: 10.1186/s12938-023-01145-4] [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: 11/03/2022] [Accepted: 08/07/2023] [Indexed: 08/17/2023] Open
Abstract
BACKGROUND Cerebral edema is an extremely common secondary disease in post-stroke. Point-of-care testing for cerebral edema types has important clinical significance for the precise management to prevent poor prognosis. Nevertheless, there has not been a fully accepted bedside testing method for that. METHODS A symmetric cancellation near-field coupling phase shift (NFCPS) monitoring system is established based on the symmetry of the left and right hemispheres and the fact that unilateral lesions do not affect healthy hemispheres. For exploring the feasibility of this system to reflect the occurrence and development of cerebral edema, 13 rabbits divided into experimental group (n = 8) and control group (n = 5) were performed 24-h NFCPS continuous monitoring experiments. After time difference offset and feature band averaging processing, the changing trend of NFCPS at the stages dominated by cytotoxic edema (CE) and vasogenic edema (VE), respectively, was analyzed. Furthermore, the features under the different time windows were extracted. Then, a discriminative model of cerebral edema types based on support vector machines (SVM) was established and performance of multiple feature combinations was compared. RESULTS The NFCPS monitoring outcomes of experimental group endured focal ischemia modeling by thrombin injection show a trend of first decreasing and then increasing, reaching the lowest value of - 35.05° at the 6th hour. Those of control group do not display obvious upward or downward trend and only fluctuate around the initial value with an average change of - 0.12°. Furthermore, four features under the 1-h and 2-h time windows were extracted. Based on the discriminative model of cerebral edema types, the classification accuracy of 1-h window is higher than 90% and the specificity is close to 1, which is almost the same as the performance of the 2-h window. CONCLUSION This study proves the feasibility of NFCPS technology combined with SVM to distinguish cerebral edema types in a short time, which is promised to become a new solution for immediate and precise management of dehydration therapy after ischemic stroke.
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Affiliation(s)
- Mingyan Li
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054 China
- College of Artificial Intelligence, Chongqing University of Technology, Chongqing, 401135 China
| | - Rui Zhu
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054 China
| | - Gen Li
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054 China
- Department of Neurosurgery, Southwest Hospital, Army Medical University, Chongqing, 400038 China
| | - Shengtong Yin
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054 China
| | - Lingxi Zeng
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054 China
| | - Zelin Bai
- College of Biomedical Engineering, Army Medical University, Chongqing, 400038 China
| | - Jingbo Chen
- College of Biomedical Engineering, Army Medical University, Chongqing, 400038 China
| | - Bin Jiang
- College of Artificial Intelligence, Chongqing University of Technology, Chongqing, 401135 China
| | - Lihong Li
- College of Artificial Intelligence, Chongqing University of Technology, Chongqing, 401135 China
| | - Yu Wu
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400054 China
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Wang C, Xing D, Zhou S, Fang F, Fu Y, Xu F. Electrical bioimpedance measurement and near-infrared spectroscopy in pediatric postoperative neurocritical care: a prospective observational study. Front Neurol 2023; 14:1190140. [PMID: 37416310 PMCID: PMC10322191 DOI: 10.3389/fneur.2023.1190140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/30/2023] [Indexed: 07/08/2023] Open
Abstract
Background To investigate the clinical significance of the disturbance coefficient (DC) and regional cerebral oxygen saturation (rSO2) as obtained through the use of electrical bioimpedance and near-infrared spectroscopy (NIRS) in pediatric neurocritical care. Participants and methods We enrolled 45 pediatric patients as the injury group and 70 healthy children as the control group. DC was derived from impedance analysis of 0.1 mA-50 kHz current via temporal electrodes. rSO2 was the percentage of oxyhemoglobin measured from reflected NIR light on the forehead. DC and rSO2 were obtained at 6, 12, 24, 48 and 72 h after surgery for the injury group and during the health screening clinic visit for the control group. We compared DC and rSO2 between the groups, their changes over time within the injury group and their correlation with intracranial pressure (ICP), cerebral perfusion pressure (CPP), Glasgow coma scale (GCS) score, Glasgow outcome scale (GOS) score, and their ability to diagnose postoperative cerebral edema and predict poor prognosis. Results DC and rSO2 were significantly lower in the injury group than in the control group. In the injury group, ICP increased over the monitoring period, while DC, CPP and rSO2 decreased. DC was negatively correlated with ICP and positively correlated with GCS score and GOS score. Additionally, lower DC values were observed in patients with signs of cerebral edema, with a DC value of 86.5 or below suggesting the presence of brain edema in patients aged 6-16 years. On the other hand, rSO2 was positively correlated with CPP, GCS score, and GOS score, with a value of 64.4% or below indicating a poor prognosis. Decreased CPP is an independent risk factor for decreased rSO2. Conclusion DC and rSO2 monitoring based on electrical bioimpedance and near-infrared spectroscopy not only reflect the degree of brain edema and oxygenation, but also reflect the severity of the disease and predict the prognosis of the patients. This approach offers a real-time, bedside, and accurate method for assessing brain function and detecting postoperative cerebral edema and poor prognosis.
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Affiliation(s)
- Chenhao Wang
- Department of Critical Care Medicine, Children’s Hospital of Chongqing Medical University, Chongqing, China
- National Clinical Research Center for Child Health and Disorders, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China
- Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Dianwei Xing
- Department of Critical Care Medicine, Children’s Hospital of Chongqing Medical University, Chongqing, China
- National Clinical Research Center for Child Health and Disorders, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China
- Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Shuoyan Zhou
- Department of Critical Care Medicine, Children’s Hospital of Chongqing Medical University, Chongqing, China
- National Clinical Research Center for Child Health and Disorders, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China
- Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Fang Fang
- Department of Critical Care Medicine, Children’s Hospital of Chongqing Medical University, Chongqing, China
- National Clinical Research Center for Child Health and Disorders, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China
- Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Yueqiang Fu
- Department of Critical Care Medicine, Children’s Hospital of Chongqing Medical University, Chongqing, China
- National Clinical Research Center for Child Health and Disorders, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China
- Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Feng Xu
- Department of Critical Care Medicine, Children’s Hospital of Chongqing Medical University, Chongqing, China
- National Clinical Research Center for Child Health and Disorders, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China
- Chongqing Key Laboratory of Pediatrics, Chongqing, China
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Mirhoseini M, Rezanejad Gatabi Z, Das S, Joveini S, Rezanezhad Gatabi I. Applications of Electrical Impedance Tomography in Neurology. Basic Clin Neurosci 2022; 13:595-608. [PMID: 37313030 PMCID: PMC10258591 DOI: 10.32598/bcn.2021.3087.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/24/2021] [Accepted: 05/14/2021] [Indexed: 11/02/2023] Open
Abstract
Introduction Electrical impedance tomography (EIT) is a non-invasive technique utilized in various medical applications, including brain imaging and other neurological diseases. Recognizing the physiological and anatomical characteristics of organs based on their electrical properties is one of the main applications of EIT, as each variety of tissue structure has its own electrical characteristics. The high potential of brain EIT is established in real-time supervision and early recognition of cerebral brain infarction, hemorrhage, and other diseases. In this paper, we review the studies on the neurological applications of EIT. Methods EIT calculates the internal electrical conductivity distribution of an organ by measuring its surface impedance. A series of electrodes are placed on the surface of the target tissue, and small alternating currents are injected. The related voltages are then observed and analyzed. The electrical permittivity and conductivity distributions inside the tissue are reconstructed by measuring the electrode voltages. Results The electrical characteristic of biological tissues is remarkably dependent on their structures. Some tissues are better electrical conductors than the others since they have more ions that can carry the electrical charges. This difference is attributed to changes in cellular water content, membrane properties, and destruction of tight junctions within cell membranes. Conclusion EIT is an extremely practical device for brain imaging, capturing fast electrical activities in the brain, imaging epileptic seizures, detecting intracranial bleeding, detecting cerebral edema, and diagnosing stroke.
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Affiliation(s)
- Mehri Mirhoseini
- Amol Faculty of Paramedical Sciences, Mazandaran University of Medical Sciences, Sari, Iran
| | - Zahra Rezanejad Gatabi
- Department of Pharmaceutics, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Sayantan Das
- Faculty/College of Science and Mathematics, Texas A&M University, San Antonio, United States
| | - Sepideh Joveini
- Department of Pharmaceutics, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Iman Rezanezhad Gatabi
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, United States
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Wang H, Dai J, Wang C, Gao Z, Liu Y, Dai M, Zhao Z, Yang L, Tan G. Assessment of Low Back Pain in Helicopter Pilots Using Electrical Bio-Impedance Technique: A Feasibility Study. Front Neurosci 2022; 16:883348. [PMID: 35911977 PMCID: PMC9330605 DOI: 10.3389/fnins.2022.883348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 06/07/2022] [Indexed: 11/16/2022] Open
Abstract
Low back pain (LBP) is known to pose a serious threat to helicopter pilots. This study aimed to explore the potential of electrical bio-impedance (EBI) technique with the advantages of no radiation, non-invasiveness and low cost, which is intended to be used as a daily detection tool to assess LBP in primary aviation medical units. The LBP scales (severity) in 72 helicopter pilots were assessed using a pain questionnaire, while the bilateral impedance measurements of the lumbar muscle were carried out with a high precision EBI measurement system. Results showed that the modulus of lumbar muscle impedance increased with LBP scale whereas the phase angle decreased. For different LBP scales, significant differences were found in the modulus of lumbar muscle impedance sum on both sides (Zsum), as well as in the modulus and phase angle of lumbar muscle impedance difference between both sides (Zdiff and ϕdiff), respectively (P < 0.05). Moreover, Spearman’s correlation analysis manifested a strong correlation between Zsum and LBP scale (R = 0.692, P < 0.01), an excellent correlation between Zdiff and LBP scale (R = 0.86, P < 0.01), and a desirable correlation between ϕdiff and LBP scale (R = −0.858, P < 0.01). In addition, receiver operator characteristic analysis showed that for LBP prediction, the area under receiver operator characteristic curve of Zsum, Zdiff, and ϕdiff were 0.931, 0.992, and 0.965, respectively. These findings demonstrated that EBI could sensitively and accurately detect the state of lumbar muscle associated with LBP, which might be the potential tool for daily detection of LBP in primary aviation medical units.
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Affiliation(s)
- Hang Wang
- Department of Aerospace Medicine, Fourth Military Medical University, Xi’an, China
| | - Jing Dai
- Department of Aerospace Medicine, Fourth Military Medical University, Xi’an, China
| | - Chunchen Wang
- Department of Aerospace Medicine, Fourth Military Medical University, Xi’an, China
| | - Zhijun Gao
- Department of Aerospace Medicine, Fourth Military Medical University, Xi’an, China
| | - Yang Liu
- Department of Aerospace Medicine, Fourth Military Medical University, Xi’an, China
| | - Meng Dai
- Department of Biomedical Engineering, Fourth Military Medical University, Xi’an, China
| | - Zhanqi Zhao
- Department of Biomedical Engineering, Fourth Military Medical University, Xi’an, China
- Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Lin Yang
- Department of Aerospace Medicine, Fourth Military Medical University, Xi’an, China
- *Correspondence: Lin Yang,
| | - Guodong Tan
- Air Force Medical Center, Fourth Military Medical University, Beijing, China
- Guodong Tan,
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Arjun BS, Sitaramgupta VSNV, Aswin S, Rao S, Pandya HJ. A System-based Approach for the Evaluation of Electromechanical Properties of Brain Tumors. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:2585-2591. [PMID: 36086534 DOI: 10.1109/embc48229.2022.9871879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We have developed a semi-automated system integrated with MEMS-based electromechanical sensors to characterize human brain tumors. The electrical impedance and elastic moduli of three types of brain tumors and six normal brain regions were evaluated using the system. The impedance and elastic modulus of glioma was found to be significantly lower than the normal region. It was also observed that the white matter tissues had higher impedance and elastic moduli compared with the grey matter of the same neuroanatomic location. There were observable differences in the electromechanical behavior of gliomas, which originate from glial cells to that of schwannoma and meningioma of different cellular origins. Clinical Relevance- The observations suggest that simultaneous electromechanical characterization of brain tumors can serve as an effective tool for tumor delineation. The developed tool can be used alongside gold standard histopathological analysis to better understand human brain tumors.
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Ke XY, Hou W, Huang Q, Hou X, Bao XY, Kong WX, Li CX, Qiu YQ, Hu SY, Dong LH. Advances in electrical impedance tomography-based brain imaging. Mil Med Res 2022; 9:10. [PMID: 35227324 PMCID: PMC8883715 DOI: 10.1186/s40779-022-00370-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 02/08/2022] [Indexed: 11/10/2022] Open
Abstract
Novel advances in the field of brain imaging have enabled the unprecedented clinical application of various imaging modalities to facilitate disease diagnosis and treatment. Electrical impedance tomography (EIT) is a functional imaging technique that measures the transfer impedances between electrodes on the body surface to estimate the spatial distribution of electrical properties of tissues. EIT offers many advantages over other neuroimaging technologies, which has led to its potential clinical use. This qualitative review provides an overview of the basic principles, algorithms, and system composition of EIT. Recent advances in the field of EIT are discussed in the context of epilepsy, stroke, brain injuries and edema, and other brain diseases. Further, we summarize factors limiting the development of brain EIT and highlight prospects for the field. In epilepsy imaging, there have been advances in EIT imaging depth, from cortical to subcortical regions. In stroke research, a bedside EIT stroke monitoring system has been developed for clinical practice, and data support the role of EIT in multi-modal imaging for diagnosing stroke. Additionally, EIT has been applied to monitor the changes in brain water content associated with cerebral edema, enabling the early identification of brain edema and the evaluation of mannitol dehydration. However, anatomically realistic geometry, inhomogeneity, cranium completeness, anisotropy and skull type, etc., must be considered to improve the accuracy of EIT modeling. Thus, the further establishment of EIT as a mature and routine diagnostic technique will necessitate the accumulation of more supporting evidence.
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Affiliation(s)
- Xi-Yang Ke
- Department of Radiation Oncology and Therapy, The First Hospital of Jilin University, 130021, Changchun, China.,Jilin Provincial Key Laboratory of Radiation Oncology and Therapy, The First Hospital of Jilin University, Changchun, 130021, China.,NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun, 130021, China
| | - Wei Hou
- Department of Radiation Oncology and Therapy, The First Hospital of Jilin University, 130021, Changchun, China.,Jilin Provincial Key Laboratory of Radiation Oncology and Therapy, The First Hospital of Jilin University, Changchun, 130021, China.,NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun, 130021, China
| | - Qi Huang
- CAS Key Laboratory of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, Jiangsu, China
| | - Xue Hou
- Department of Radiation Oncology and Therapy, The First Hospital of Jilin University, 130021, Changchun, China.,Jilin Provincial Key Laboratory of Radiation Oncology and Therapy, The First Hospital of Jilin University, Changchun, 130021, China.,NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun, 130021, China
| | - Xue-Ying Bao
- Department of Radiation Oncology and Therapy, The First Hospital of Jilin University, 130021, Changchun, China.,Jilin Provincial Key Laboratory of Radiation Oncology and Therapy, The First Hospital of Jilin University, Changchun, 130021, China.,NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun, 130021, China
| | - Wei-Xuan Kong
- Department of Radiation Oncology and Therapy, The First Hospital of Jilin University, 130021, Changchun, China.,Jilin Provincial Key Laboratory of Radiation Oncology and Therapy, The First Hospital of Jilin University, Changchun, 130021, China
| | - Cheng-Xiang Li
- Department of Radiation Oncology and Therapy, The First Hospital of Jilin University, 130021, Changchun, China.,Jilin Provincial Key Laboratory of Radiation Oncology and Therapy, The First Hospital of Jilin University, Changchun, 130021, China.,NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun, 130021, China
| | - Yu-Qi Qiu
- Department of Radiation Oncology and Therapy, The First Hospital of Jilin University, 130021, Changchun, China.,Jilin Provincial Key Laboratory of Radiation Oncology and Therapy, The First Hospital of Jilin University, Changchun, 130021, China.,NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun, 130021, China
| | - Si-Yi Hu
- CAS Key Laboratory of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, Jiangsu, China.
| | - Li-Hua Dong
- Department of Radiation Oncology and Therapy, The First Hospital of Jilin University, 130021, Changchun, China. .,Jilin Provincial Key Laboratory of Radiation Oncology and Therapy, The First Hospital of Jilin University, Changchun, 130021, China. .,NHC Key Laboratory of Radiobiology, School of Public Health, Jilin University, Changchun, 130021, China.
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Moura FS, Beraldo RG, Ferreira LA, Siltanen S. Anatomical atlas of the upper part of the human head for electroencephalography and bioimpedance applications. Physiol Meas 2021; 42. [PMID: 34673557 DOI: 10.1088/1361-6579/ac3218] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 10/21/2021] [Indexed: 11/11/2022]
Abstract
Objective.The objective of this work is to develop a 4D (3D+T) statistical anatomical atlas of the electrical properties of the upper part of the human head for cerebral electrophysiology and bioimpedance applications.Approach.The atlas was constructed based on 3D magnetic resonance images (MRI) of 107 human individuals and comprises the electrical properties of the main internal structures and can be adjusted for specific electrical frequencies. T1w+T2w MRI images were used to segment the main structures of the head while angiography MRI was used to segment the main arteries. The proposed atlas also comprises a time-varying model of arterial brain circulation, based on the solution of the Navier-Stokes equation in the main arteries and their vascular territories.Main results.High-resolution, multi-frequency and time-varying anatomical atlases of resistivity, conductivity and relative permittivity were created and evaluated using a forward problem solver for EIT. The atlas was successfully used to simulate electrical impedance tomography measurements indicating the necessity of signal-to-noise between 100 and 125 dB to identify vascular changes due to the cardiac cycle, corroborating previous studies. The source code of the atlas and solver are freely available to download.Significance.Volume conductor problems in cerebral electrophysiology and bioimpedance do not have analytical solutions for nontrivial geometries and require a 3D model of the head and its electrical properties for solving the associated PDEs numerically. Ideally, the model should be made with patient-specific information. In clinical practice, this is not always the case and an average head model is often used. Also, the electrical properties of the tissues might not be completely known due to natural variability. Anatomical atlases are important tools forin silicostudies on cerebral circulation and electrophysiology that require statistically consistent data, e.g. machine learning, sensitivity analyses, and as a benchmark to test inverse problem solvers.
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Affiliation(s)
- Fernando S Moura
- Engineering, modelling and Applied Social Sciences Center, Federal University of ABC São Bernardo do Campo, São Paulo, Brazil.,Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland
| | - Roberto G Beraldo
- Engineering, modelling and Applied Social Sciences Center, Federal University of ABC São Bernardo do Campo, São Paulo, Brazil
| | - Leonardo A Ferreira
- Engineering, modelling and Applied Social Sciences Center, Federal University of ABC São Bernardo do Campo, São Paulo, Brazil
| | - Samuli Siltanen
- Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland
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Yang L, Dai M, Cao Q, Ding S, Zhao Z, Cao X, Wen Z, Wang H, Xie M, Fu F. Real-time monitoring hypoxia at high altitudes using electrical bioimpedance technique: an animal experiment. J Appl Physiol (1985) 2021; 130:952-963. [PMID: 33270508 DOI: 10.1152/japplphysiol.00712.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypoxia poses a serious threat to pilots. The aim of this study was to examine the efficacy of electrical bioimpedance (EBI) in detecting the onset of hypoxia in real time in a rabbit hypoxia model. Thirty-two New Zealand rabbits were divided equally into four groups (control group and three hypoxia groups, i.e., mild, moderate, and severe). Hypoxia was induced by simulating various altitudes in the hypobaric oxygen chamber (3,000 m, 5,000 m, and 8,000 m). Both cerebral impedance and blood oxygen (SpO2) were monitored continuously. Results showed that the cerebral impedance increased immediately during the period of increasing altitude and decreased quickly to the initial baseline at the phase of descending altitude. Moreover, the change of cerebral impedance in the mild hypoxia group (3,000 m) was significantly smaller than those in the other two groups (5,000 m and 8,000 m, P < 0.05). The changes in cerebral impedance and SpO2 were significantly correlated based on the total of measurement data (r2 = 0.628, P < 0.001). Furthermore, the agreement analysis performed with Bland-Altman and standardized residual plots exhibited high concordance between cerebral impedance and SpO2. Receiver operator characteristic analysis manifested that the sensitivity, specificity, and area under the curve using cerebral impedance for changes in SpO2 >10% were 0.735, 0.826, and 0.845, respectively. These findings demonstrated that EBI could sensitively and accurately monitor changes of cerebral impedance induced by hypoxia, which might provide a potential tool for the real-time and noninvasive monitoring of hypoxic condition of pilots in flight for early identification of hypoxia.NEW & NOTEWORTHY This study is the first to examine the efficacy of electrical bioimpedance (EBI) in detecting the onset of high-altitude hypoxia in real time. The novelty of this research includes three aspects. First, the cerebral impedance of rabbits increased immediately during the rising of altitude and decreased quickly to the initial baseline at the phase of descending altitude. Second, there was a significant correlation and high concordance between cerebral impedance and SpO2. Third, cerebral impedance could determine the change of SpO2 resulting from hypoxia.
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Affiliation(s)
- Lin Yang
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Meng Dai
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Qinglin Cao
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Shuai Ding
- School of Preclinical Medicine, Fourth Military Medical University, Xi'an, China
| | - Zhanqi Zhao
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.,Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Xinsheng Cao
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Zhihong Wen
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Hang Wang
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Manjiang Xie
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Feng Fu
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
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Wang L, Wang H, Xu C, Ji Z, Li J, Dong X, Shi X. Dielectric Properties of Human Active Liver, Kidney and Spleen Compared to Those of Respective Inactive Tissues, Porcine Tissues and the Data Provided by a Database in the Frequency Range of 10 Hz to 100 MHz. IEEE Trans Biomed Eng 2021; 68:3098-3109. [PMID: 33687834 DOI: 10.1109/tbme.2021.3065016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The purpose of this work is to study whether the active state and species of biological tissues can influence changes in their dielectric properties. METHODS In this paper, the dielectric properties of liver, kidney and spleen tissues from human active, human inactive and animal tissues are measured in the frequency range of 10 Hz to 100 MHz. The four- and two-electrode methods are used to measure dielectric properties at different frequencies. Statistical analysis and the pattern recognition method are used to compare the dielectric properties of human active tissues, human inactive tissues, animal tissues and data provided by the IFAC database. RESULTS The results show that the dielectric properties of human active tissues are significantly different from those of human inactive tissues and animal tissues, resulting in a great difference between the dielectric properties provided by the IFAC database and those of human active tissues. The dielectric properties of human active tissues can be identified by the pattern recognition method based on principal component analysis, which further proves that the dielectric properties of human active tissues cannot be replaced. CONCLUSION The dielectric properties of biological tissues are closely related to the activity and species of tissues. The dielectric properties of human active tissues cannot be replaced by those of human cadaver tissues or animal tissues. SIGNIFICANCE The significance of this study is suggesting that the IFAC database should be updated with the dielectric properties of human active tissues to provide accurate data for bioelectromagnetics research.
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Zhao SL, Jin G, Bai ZL, Chen JB, Li MW, Li G, Zhuang W, Liu YN, Qin MX. Twenty-four-hour real-time continuous monitoring of acute focal cerebral ischemia in rabbits based on magnetic inductive phase shift. Biomed Eng Online 2020; 19:83. [PMID: 33176808 PMCID: PMC7659095 DOI: 10.1186/s12938-020-00829-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 11/05/2020] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND As a serious clinical disease, ischemic stroke is usually detected through magnetic resonance imaging and computed tomography. In this study, a noninvasive, non-contact, real-time continuous monitoring system was constructed on the basis of magnetic induction phase shift (MIPS) technology. The "thrombin induction method", which conformed to the clinical pathological development process of ischemic stroke, was used to construct an acute focal cerebral ischemia model of rabbits. In the MIPS measurement, a "symmetric cancellation-type" magnetic induction sensor was used to improve the sensitivity and antijamming capability of phase detection. METHODS A 24-h MIPS monitoring experiment was carried out on 15 rabbits (10 in the experimental group and five in the control group). Brain tissues were taken from seven rabbits for the 2% triphenyl tetrazolium chloride staining and verification of the animal model. RESULTS The nonparametric independent-sample Wilcoxon rank sum test showed significant differences (p < 0.05) between the experimental group and the control group in MIPS. Results showed that the rabbit MIPS presented a declining trend at first and then an increasing trend in the experimental group, which may reflect the pathological development process of cerebral ischemic stroke. Moreover, TTC staining results showed that the focal cerebral infarction area increased with the development of time CONCLUSIONS: Our experimental study indicated that the MIPS technology has a potential ability of differentiating the development process of cytotoxic edema from that of vasogenic edema, both of which are caused by cerebral ischemia.
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Affiliation(s)
- Shuang-Lin Zhao
- College of Biomedical Engineering, Army Medical University, Chongqing, 400038, China
| | - Gui Jin
- College of Biomedical Engineering, Army Medical University, Chongqing, 400038, China
| | - Ze-Lin Bai
- College of Biomedical Engineering, Army Medical University, Chongqing, 400038, China
| | - Jing-Bo Chen
- College of Biomedical Engineering, Army Medical University, Chongqing, 400038, China
| | - Meng-Wei Li
- Department of Medical Engineering, Beidaihe Rehabilitation and Recuperation Center, Hebei, 066100, China
| | - Gen Li
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, 400020, China
| | - Wei Zhuang
- College of Biomedical Engineering, Army Medical University, Chongqing, 400038, China
| | - Yue-Ning Liu
- College of Biomedical Engineering, Army Medical University, Chongqing, 400038, China
| | - Ming-Xin Qin
- College of Biomedical Engineering, Army Medical University, Chongqing, 400038, China.
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Chen J, Li G, Chen M, Jin G, Zhao S, Bai Z, Yang J, Liang H, Xu J, Sun J, Qin M. A noninvasive flexible conformal sensor for accurate real-time monitoring of local cerebral edema based on electromagnetic induction. PeerJ 2020; 8:e10079. [PMID: 33083136 PMCID: PMC7546241 DOI: 10.7717/peerj.10079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/11/2020] [Indexed: 12/24/2022] Open
Abstract
Cerebral edema (CE) is a non-specific pathological swelling of the brain secondary to any type of neurological injury. The real-time monitoring of focal CE mostly found in early stage is of great significance to reduce mortality and disability. Magnetic Induction Phase Shift (MIPS) is expected to achieve non-invasive continuous monitoring of CE. However, most existing MIPS sensors are made of hard materials which makes it difficult to accurately retrieve CE information. In this article, we designed a conformal two-coil structure and a single-coil structure, and studied their sensitivity map using finite element method (FEM). After that, the conformal MIPS sensor that is preferable for local CE monitoring was fabricated by flexible printed circuit (FPC). Next, physical experiments were conducted to investigate its performance on different levels of simulated CE solution volume, measurement distance, and bending. Subsequently, 14 rabbits were chosen to establish CE model and another three rabbits were selected as controls. The 24-hour MIPS real-time monitoring experiments was carried out to verify that the feasibility. Results showed a gentler attenuation trend of the conformal two-coil structure, compared with the single-coil structure. In addition, the novel flexible conformal MIPS sensor has a characteristic of being robust to bending according to the physical experiments. The results of animal experiments showed that the sensor can be used for CE monitoring. It can be concluded that this flexible conformal MIPS sensor is desirable for local focusing measurement of CE and subsequent multidimensional information extraction for predicting model. Also, it enables a much more comfortable environment for long-time bedside monitoring.
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Affiliation(s)
- Jingbo Chen
- College of Biomedical Engineering, Third Military Medical University (Army Medical University), Chongqing, China
| | - Gen Li
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China
| | - Mingsheng Chen
- College of Biomedical Engineering, Third Military Medical University (Army Medical University), Chongqing, China
| | - Gui Jin
- College of Biomedical Engineering, Third Military Medical University (Army Medical University), Chongqing, China
| | - Shuanglin Zhao
- College of Biomedical Engineering, Third Military Medical University (Army Medical University), Chongqing, China
| | - Zelin Bai
- College of Biomedical Engineering, Third Military Medical University (Army Medical University), Chongqing, China
| | - Jun Yang
- College of Biomedical Engineering, Third Military Medical University (Army Medical University), Chongqing, China
| | - Huayou Liang
- China Aerodynamics Research and Development Center Low Speed Aerodynamic Institute, Mianyang, China
| | - Jia Xu
- College of Biomedical Engineering, Third Military Medical University (Army Medical University), Chongqing, China
| | - Jian Sun
- College of Biomedical Engineering, Third Military Medical University (Army Medical University), Chongqing, China.,Department of Neurosurgery, Southwest Hospital, Chongqing, China
| | - Mingxin Qin
- College of Biomedical Engineering, Third Military Medical University (Army Medical University), Chongqing, China
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Cao L, Li H, Fu D, Liu X, Ma H, Xu C, Dong X, Yang B, Fu F. Real-time imaging of infarction deterioration after ischemic stroke in rats using electrical impedance tomography. Physiol Meas 2020; 41:015004. [PMID: 31918414 DOI: 10.1088/1361-6579/ab69ba] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE This study investigated the feasibility of electrical impedance tomography (EIT) for monitoring the deterioration of ischemic lesion after the onset of stroke. APPROACH Fifteen rats were randomly distributed into two groups: rats operated to establish a right middle cerebral artery occlusion (MCAO) (n = 10), and sham-operated rats (n = 5). Then, the operated rats were kept 2 h under anesthesia for EIT monitoring. Subsequently, descriptive statistical analysis was performed on whole-brain resistivity changes, and repeated-measures analysis of variance (ANOVA) on the average resistivity variation index. Additionally, pathological examinations were performed after 6 h of infarction. MAIN RESULTS The results obtained showed that ischemic damage developed in the right corpus striatum of the rats with MCAO, whereas the brains of the sham group showed no anomalies. The descriptive statistical analysis revealed that the whole-brain resistivity changes after 30, 60, 90, and 120 min of infarction were 0.063 ± 0.038, 0.097 ± 0.046, 0.141 ± 0.062, and 0.204 ± 0.092 for the rats with MCAO and 0.029 ± 0.021, 0.002 ± 0.002, 0.017 ± 0.011, and -0.001 ± 0.011 for the sham-operated rats, respectively. The repeated-measures ANOVA revealed that the right MCAO model resulted in a significant impedance increase in the right hemisphere, which continued to increase over time after infarction. SIGNIFICANCE The overall study results indicate that EIT facilitates monitoring of local impedance variations caused by MCAO and may be a solution for real-time monitoring of intracranial pathological changes in ischemic stroke patients.
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Affiliation(s)
- Lu Cao
- Lu Cao and Haoting Li contributed equally to this work
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Yang J, Zhao H, Li G, Ran Q, Chen J, Bai Z, Jin G, Sun J, Xu J, Qin M, Chen M. An experimental study on the early diagnosis of traumatic brain injury in rabbits based on a noncontact and portable system. PeerJ 2019; 7:e6717. [PMID: 30997290 PMCID: PMC6463870 DOI: 10.7717/peerj.6717] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/05/2019] [Indexed: 12/21/2022] Open
Abstract
Closed cerebral hemorrhage (CCH) is a common symptom in traumatic brain injury (TBI) patients who suffer intracranial hemorrhage with the dura mater remaining intact. The diagnosis of CCH patients prior to hospitalization and in the early stage of the disease can help patients get earlier treatments that improve outcomes. In this study, a noncontact, portable system for early TBI-induced CCH detection was constructed that measures the magnetic induction phase shift (MIPS), which is associated with the mean brain conductivity caused by the ratio between the liquid (blood/CSF and the intracranial tissues) change. To evaluate the performance of this system, a rabbit CCH model with two severity levels was established based on the horizontal biological impactor BIM-II, whose feasibility was verified by computed tomography images of three sections and three serial slices. There were two groups involved in the experiments (group 1 with 10 TBI rabbits were simulated by hammer hit with air pressure of 600 kPa by BIM-II and group 2 with 10 TBI rabbits were simulated with 650 kPa). The MIPS values of the two groups were obtained within 30 min before and after injury. In group 1, the MIPS values showed a constant downward trend with a minimum value of −11.17 ± 2.91° at the 30th min after 600 kPa impact by BIM-II. After the 650 kPa impact, the MIPS values in group 2 showed a constant downward trend until the 25th min, with a minimum value of −16.81 ± 2.10°. Unlike group 1, the MIPS values showed an upward trend after that point. Before the injury, the MIPS values in both group 1 and group 2 did not obviously change within the 30 min measurement. Using a support vector machine at the same time point after injury, the classification accuracy of the two types of severity was shown to be beyond 90%. Combined with CCH pathological mechanisms, this system can not only achieve the detection of early functional changes in CCH but can also distinguish different severities of CCH.
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Affiliation(s)
- Jun Yang
- College of Biomedical Engineering, Army Medical University, Chongqing, China
| | - Hui Zhao
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Third Military Medical University, Chongqing, China
| | - Gen Li
- Department of Biomedical Engineering, Chongqing University of Technology, Chongqing, China
| | - Qisheng Ran
- Department of Radiology, Army Medical Center, Chongqing, China
| | - Jingbo Chen
- College of Biomedical Engineering, Army Medical University, Chongqing, China
| | - Zelin Bai
- College of Biomedical Engineering, Army Medical University, Chongqing, China
| | - Gui Jin
- College of Biomedical Engineering, Army Medical University, Chongqing, China
| | - Jian Sun
- College of Biomedical Engineering, Army Medical University, Chongqing, China
| | - Jia Xu
- College of Biomedical Engineering, Army Medical University, Chongqing, China
| | - Mingxin Qin
- College of Biomedical Engineering, Army Medical University, Chongqing, China
| | - Mingsheng Chen
- College of Biomedical Engineering, Army Medical University, Chongqing, China
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Xu J, Konijnenburg M, Song S, Ha H, van Wegberg R, Mazzillo M, Fallica G, Van Hoof C, De Raedt W, Van Helleputte N. A 665 μW Silicon Photomultiplier-Based NIRS/EEG/EIT Monitoring ASIC for Wearable Functional Brain Imaging. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2018; 12:1267-1277. [PMID: 30489273 DOI: 10.1109/tbcas.2018.2883289] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This paper presents a sub-mW ASIC for multimodal brain monitoring. The ASIC is co-integrated with electrode(s) and optodes (i.e., optical source and detector) as an active sensor to measure electroencephalography (EEG), bio-impedance (BioZ), and near-infrared spectroscopy (NIRS) on scalp. The target is to build a wearable EEG-NIRS headset for low-cost functional brain imaging. The proposed NIRS readout utilizes the near-infrared light to measure the pulse oximetry and blood oxygen saturation (SpO2). While traditional photodiodes are supported, the readout also allows the use of silicon photomultipliers (SiPMs) as optical detectors. The SiPM improves optical sensitivity while significantly reducing the average power of two LEDs to 150 μW. On circuit level, a SAR-based calibration compensates maximum 40 μA current from ambient light, while digital DC-servo loops reduces the baseline static SiPM current up to 400 μA, leading to an overall dynamic range of 87 dB. The EEG readout exhibits 720 MΩ input impedance at 50 Hz. The BioZ readout has 3 mΩ/√(Hz) impedance sensitivity by employing dynamic circuit techniques. When EEG, BioZ, and NIRS are enabled at the same time, one ASIC consumes 665 μW including the power of LEDs.
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