scholarly journals Identification of Brain Damage after Seizures Using an MR-Based Electrical Conductivity Imaging Method

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 569
Author(s):  
Sanga Kim ◽  
Bup Kyung Choi ◽  
Ji Ae Park ◽  
Hyung Joong Kim ◽  
Tong In Oh ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Resonance ◽  
Electrical Properties ◽  
Brain Damage ◽  
High Frequency ◽  
Neuronal Cell ◽  
Imaging Method ◽  
Nissl Staining ◽  
Functional Changes ◽  
Conductivity Imaging

Previous imaging studies have shown the morphological malformation and the alterations of ionic mobility, water contents, electrical properties, or metabolites in seizure brains. Magnetic resonance electrical properties tomography (MREPT) is a recently developed technique for the measurement of electrical tissue properties with a high frequency that provides cellular information regardless of the cell membrane. In this study, we examined the possibility of MREPT as an applicable technique to detect seizure-induced functional changes in the brain of rats. Ultra-high field (9.4 T) magnetic resonance imaging (MRI) was performed, 2 h, 2 days, and 1 week after the injection of N-methyl-D-aspartate (NMDA; 75 mg/kg). The conductivity images were reconstructed from B1 phase images using a magnetic resonance conductivity imaging (MRCI) toolbox. The high-frequency conductivity was significantly decreased in the hippocampus among various brain regions of NMDA-treated rats. Nissl staining showed shrunken cell bodies and condensed cytoplasm potently at 2 h after NMDA treatment, and neuronal cell loss at all time points in the hippocampus. These results suggest that the reduced electrical conductivity may be associated with seizure-induced neuronal loss in the hippocampus. Magnetic resonance (MR)-based electrical conductivity imaging may be an applicable technique to non-invasively identify brain damage after a seizure.

Inclusion Compounds of Tetracyano Complexes and Their Electrical Properties

1994 ◽  
Vol 59 (11) ◽  
pp. 2436-2446 ◽  
Author(s):  
Mária Reháková ◽  
Anna Sopková ◽  
Vladimír Šály
Keyword(s):  
Electrical Conductivity ◽  
Chemical Composition ◽  
Electrical Properties ◽  
General Formula ◽  
Inclusion Compounds ◽  
High Frequency ◽  
Iodide Ions ◽  
Structure And Morphology ◽  
Composition Structure ◽  
Tetracyano Complexes

The presence of iodine and iodide ions in tetracyanonickelates inclusion compounds with the general formula Ni(B)mNi(CN)4 . n H2O (B = NH3 or ethylenediamine) changes the properties of these compounds. High frequency conductance measurements in the range of 10 - 105 Hz show that the products with ethylenediamine ligands have a higher electrical conductivity than those with NH3 ligands. The differences in the electrical properties between the compounds studied are mainly caused by chemical composition, structure and morphology.

A robust electrical conductivity imaging method with total variation and wavelet regularization

2020 ◽  
Vol 69 ◽  
pp. 28-39
Author(s):  
Xiangdong Sun ◽  
Lijun Lu ◽  
Li Qi ◽  
Yingjie Mei ◽  
Xiaoyun Liu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Total Variation ◽  
Imaging Method ◽  
Wavelet Regularization ◽  
Conductivity Imaging

scholarly journals Decomposition of High-Frequency Electrical Conductivity into Extracellular and Intracellular Compartments based on Two-Compartment Model using Low-to-High Multi-b Diffusion MRI

2020 ◽  
Author(s):  
Mun Bae Lee ◽  
Hyung Joong Kim ◽  
Oh-In Kwon
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
High Frequency ◽  
Compartment Model ◽  
Biological Tissues ◽  
Extracellular Medium ◽  
Two Compartment Model ◽  
Random Decision Forests ◽  
Human Experiments ◽  
Micro Structures

Abstract Background: As an object's electrical passive property, the electrical conductivity is proportional to the mobility and concentration of charged carriers that reflect the brain micro-structures. The measured Mb-DWI data by controlling the degree of applied diffusion weights can quantify the apparent mobility of water molecules within biological tissues. Without any external electrical stimulation, magnetic resonance electrical properties tomography (MREPT) techniques have successfully recovered the conductivity distribution at a Larmor-frequency. Methods: This work provides a non-invasive method to decompose the high-frequency conductivity into the extracellular medium conductivity based on a two-compartment model using multi-b diffusion-weighted imaging (Mb-DWI). To separate the intra- and extracellular micro-structures from the recovered high-frequency conductivity, we include higher b-values DWI and apply the random decision forests to stably determine the micro-structural diffusion parameters. Results: To demonstrate the proposed method, we conducted human experiments by comparing the results of reconstructed conductivity of extracellular medium and the conductivity in the intra-neurite and intra-cell body. Human experiments verify that the proposed method can recover the extracellular electrical properties from the high-frequency conductivity using a routine protocol sequence of MRI scan. Conclusion: We have proposed a method to decompose the electrical properties in the extracellular, intra-neurite, and soma compartments from the high-frequency conductivity map, reconstructed by solving the electro-magnetic equation with measured B1 phase signals.

scholarly journals Evaluation of Hepatoprotective Effect of Curcumin on Liver Cirrhosis Using a Combination of Biochemical Analysis and Magnetic Resonance-Based Electrical Conductivity Imaging

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Eun Jung Kyung ◽  
Hyun Bum Kim ◽  
Eun Sang Hwang ◽  
Seok Lee ◽  
Bup Kyung Choi ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Liver Cirrhosis ◽  
Magnetic Resonance ◽  
Biochemical Analysis ◽  
Normal Liver ◽  
Hepatoprotective Effect ◽  
Curcumin Treatment ◽  
Conductivity Imaging ◽  
Inflammatory Effect ◽  
Liver Tissues

In oriental medicine, curcumin is used to treat inflammatory diseases, and its anti-inflammatory effect has been reported in recent research. In this feasibility study, the hepatoprotective effect of curcumin was investigated using a rat liver cirrhosis model, which was induced with dimethylnitrosamine (DMN). Together with biochemical analysis, we used a magnetic resonance-based electrical conductivity imaging method to evaluate tissue conditions associated with a protective effect. The effects of curcumin treatment and lactulose treatment on liver cirrhosis were compared. Electrical conductivity images indicated that liver tissues damaged by DMN showed decreased conductivity compared with normal liver tissues. In contrast, cirrhotic liver tissues treated with curcumin or lactulose showed increased conductivity than tissues in the DMN-only group. Specifically, conductivity of cirrhotic liver after curcumin treatment was similar to that of normal liver tissues. Histological staining and immunohistochemical examination showed significant levels of attenuated fibrosis and decreased inflammatory response after both curcumin and lactulose treatments compared with damaged liver tissues by DMN. The conductivity imaging and biochemical examination results indicate that curcumin’s anti-inflammatory effect can prevent the progression of irreversible liver dysfunction.

scholarly journals MR-Based Electrical Conductivity Imaging Using Second-Order Total Generalized Variation Regularization

2020 ◽  
Vol 10 (21) ◽  
pp. 7910
Author(s):  
Xiangdong Sun ◽  
Lijun Lu ◽  
Li Qi ◽  
Yingjie Mei ◽  
Xiaoyun Liu ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Electrical Properties ◽  
Second Order ◽  
Noise Robustness ◽  
Laplacian Operator ◽  
Head Model ◽  
Essential Information ◽  
Total Generalized Variation ◽  
Conductivity Imaging ◽  
Generalized Variation

Electrical properties provide essential information for cancer detection and specific absorption rate (SAR) estimation. Magnetic resonance electrical properties tomography (MREPT) is an approach to retrieve the distribution of electrical properties. The conventional method suffers from the locally homogeneous assumption and amplification of noise. In this study, a novel approach was introduced to improve the accuracy and the noise robustness of conductivity imaging. The proposed approach reformulated the central equation of the gradient-based method to avoid the calculation of the Laplacian operator. The equation was regularized using the second-order total generalized variation, which formulates an objective function. The optimization problem was solved by the alternating direction method of multipliers (ADMM) method. The proposed method was validated by the simulation data of the cylindrical phantom and Ella head model, and the performance was compared with existing methods. The results demonstrated that the proposed method reconstructed an accurate conductivity image and alleviated the noise effects. Furthermore, phantom and healthy volunteer experiments were implemented at a 3 Tesla (T) magnetic resonance imaging (MRI) scanner. The results suggested that the developed method can provide solutions for improved conductivity reconstruction and show potential for clinical application.

Electrical conductivity imaging by magnetic resonance electrical impedance tomography (MREIT)

2003 ◽  
Vol 50 (4) ◽  
pp. 875-878 ◽  
Author(s):  
Suk H. Oh ◽  
Jae Y. Han ◽  
Soo Y. Lee ◽  
Min H. Cho ◽  
Byung I. Lee ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Resonance ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Impedance Tomography ◽  
Conductivity Imaging

scholarly journals Decomposition of high-frequency electrical conductivity into extracellular and intracellular compartments based on two-compartment model using low-to-high multi-b diffusion MRI

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Mun Bae Lee ◽  
Hyung Joong Kim ◽  
Oh In Kwon
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
High Frequency ◽  
Compartment Model ◽  
Biological Tissues ◽  
Extracellular Medium ◽  
Two Compartment Model ◽  
Random Decision Forests ◽  
Human Experiments ◽  
Micro Structures

Abstract Background As an object’s electrical passive property, the electrical conductivity is proportional to the mobility and concentration of charged carriers that reflect the brain micro-structures. The measured multi-b diffusion-weighted imaging (Mb-DWI) data by controlling the degree of applied diffusion weights can quantify the apparent mobility of water molecules within biological tissues. Without any external electrical stimulation, magnetic resonance electrical properties tomography (MREPT) techniques have successfully recovered the conductivity distribution at a Larmor-frequency. Methods This work provides a non-invasive method to decompose the high-frequency conductivity into the extracellular medium conductivity based on a two-compartment model using Mb-DWI. To separate the intra- and extracellular micro-structures from the recovered high-frequency conductivity, we include higher b-values DWI and apply the random decision forests to stably determine the micro-structural diffusion parameters. Results To demonstrate the proposed method, we conducted phantom and human experiments by comparing the results of reconstructed conductivity of extracellular medium and the conductivity in the intra-neurite and intra-cell body. The phantom and human experiments verify that the proposed method can recover the extracellular electrical properties from the high-frequency conductivity using a routine protocol sequence of MRI scan. Conclusion We have proposed a method to decompose the electrical properties in the extracellular, intra-neurite, and soma compartments from the high-frequency conductivity map, reconstructed by solving the electro-magnetic equation with measured B1 phase signals.

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