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Norbert Weiler - One of the best experts on this subject based on the ideXlab platform.

  • Regional Lung Perfusion Analysis in Experimental ARDS by Electrical Impedance and Computed Tomography
    IEEE transactions on medical imaging, 2020
    Co-Authors: Michael Kircher, Gunnar Elke, Birgit Stender, Maria Hernandez Mesa, Felix Schuderer, Olaf Dössel, Matthew K. Fuld, Ahmed F. Halaweish, Eric A. Hoffman, Norbert Weiler
    Abstract:

    Electrical Impedance tomography is clinically used to trace ventilation related changes in Electrical conductivity of lung tissue. Estimating regional pulmonary perfusion using Electrical Impedance tomography is still a matter of research. To support clinical decision making, reliable bedside information of pulmonary perfusion is needed. We introduce a method to robustly detect pulmonary perfusion based on indicator-enhanced Electrical Impedance tomography and validate it by dynamic multidetector computed tomography in two experimental models of acute respiratory distress syndrome. The acute injury was induced in a sublobar segment of the right lung by saline lavage or endotoxin instillation in eight anesthetized mechanically ventilated pigs. For Electrical Impedance tomography measurements, a conductive bolus (10% saline solution) was injected into the right ventricle during breath hold. Electrical Impedance tomography perfusion images were reconstructed by linear and normalized Gauss-Newton reconstruction on a finite element mesh with subsequent element-wise signal and feature analysis. An iodinated contrast agent was used to compute pulmonary blood flow via dynamic multidetector computed tomography. Spatial perfusion was estimated based on first-pass indicator dilution for both Electrical Impedance and multidetector computed tomography and compared by Pearson correlation and Bland-Altman analysis. Strong correlation was found in dorsoventral (r = 0.92) and in right-to-left directions (r = 0.85) with good limits of agreement of 8.74% in eight lung segments. With a robust Electrical Impedance tomography perfusion estimation method, we found strong agreement between multidetector computed and Electrical Impedance tomography perfusion in healthy and regionally injured lungs and demonstrated feasibility of Electrical Impedance tomography perfusion imaging.

  • assessment of changes in distribution of lung perfusion by Electrical Impedance tomography
    Respiration, 2009
    Co-Authors: Inez Frerichs, Gunnar Elke, Sven Pulletz, Florian Reifferscheid, Dirk Schadler, Jens Scholz, Norbert Weiler
    Abstract:

    Background: Electrical Impedance tomography (EIT) is able to detect variations in regional lung Electrical Impedance associated with changes in both air and blood content and potent

Gunnar Elke - One of the best experts on this subject based on the ideXlab platform.

  • Regional Lung Perfusion Analysis in Experimental ARDS by Electrical Impedance and Computed Tomography
    IEEE transactions on medical imaging, 2020
    Co-Authors: Michael Kircher, Gunnar Elke, Birgit Stender, Maria Hernandez Mesa, Felix Schuderer, Olaf Dössel, Matthew K. Fuld, Ahmed F. Halaweish, Eric A. Hoffman, Norbert Weiler
    Abstract:

    Electrical Impedance tomography is clinically used to trace ventilation related changes in Electrical conductivity of lung tissue. Estimating regional pulmonary perfusion using Electrical Impedance tomography is still a matter of research. To support clinical decision making, reliable bedside information of pulmonary perfusion is needed. We introduce a method to robustly detect pulmonary perfusion based on indicator-enhanced Electrical Impedance tomography and validate it by dynamic multidetector computed tomography in two experimental models of acute respiratory distress syndrome. The acute injury was induced in a sublobar segment of the right lung by saline lavage or endotoxin instillation in eight anesthetized mechanically ventilated pigs. For Electrical Impedance tomography measurements, a conductive bolus (10% saline solution) was injected into the right ventricle during breath hold. Electrical Impedance tomography perfusion images were reconstructed by linear and normalized Gauss-Newton reconstruction on a finite element mesh with subsequent element-wise signal and feature analysis. An iodinated contrast agent was used to compute pulmonary blood flow via dynamic multidetector computed tomography. Spatial perfusion was estimated based on first-pass indicator dilution for both Electrical Impedance and multidetector computed tomography and compared by Pearson correlation and Bland-Altman analysis. Strong correlation was found in dorsoventral (r = 0.92) and in right-to-left directions (r = 0.85) with good limits of agreement of 8.74% in eight lung segments. With a robust Electrical Impedance tomography perfusion estimation method, we found strong agreement between multidetector computed and Electrical Impedance tomography perfusion in healthy and regionally injured lungs and demonstrated feasibility of Electrical Impedance tomography perfusion imaging.

  • assessment of changes in distribution of lung perfusion by Electrical Impedance tomography
    Respiration, 2009
    Co-Authors: Inez Frerichs, Gunnar Elke, Sven Pulletz, Florian Reifferscheid, Dirk Schadler, Jens Scholz, Norbert Weiler
    Abstract:

    Background: Electrical Impedance tomography (EIT) is able to detect variations in regional lung Electrical Impedance associated with changes in both air and blood content and potent

S. I. Shchukin - One of the best experts on this subject based on the ideXlab platform.

  • Peripheral vein detection using Electrical Impedance method
    Journal of Electrical Bioimpedance, 2019
    Co-Authors: Mugeb Baggash Al-harosh, S. I. Shchukin
    Abstract:

    The Electrical Impedance method of peripheral vein detection is a novel approach, which offers the advantages of not being expensive and the capability of minimizing and reducing the difficulty of achieving intravenous access in many patients, especially pediatric and obese patients. The Electrical Impedance method of peripheral vein detection is based on the measurement of Electrical Impedance using the 4-electrode technique by applying a known alternating current of frequency 100 kHz and constant amplitude to a set of current electrodes and measuring the resulting surface potential at two separate electrodes. This paper presents the results of investigations to estimate the efficiency of this method.

  • Application of Tetrapolar Electrode Systems in Electrical Impedance Measurements
    Biomedical Engineering, 2019
    Co-Authors: A. V. Kobelev, S. I. Shchukin, Steffen Leonhardt
    Abstract:

    The specifics of using tetrapolar electrode systems for a wide class of Electrical Impedance measurements are discussed. The key factors affecting the error in solving the inverse Electrical Impedance problem using a tetrapolar electrode system are determined.

  • Numerical Modeling Of The Electrical Impedance Method Of Peripheral Veins Localization
    IFMBE Proceedings, 2015
    Co-Authors: Mugeb Baggash Al-harosh, S. I. Shchukin
    Abstract:

    Veins in biological tissue produce Electrical Impedance to the alternating current passes through it. BioImpedance method based on measuring this Electrical Impedance value using an array of surface electrodes has the capability of detecting peripheral veins. This paper presents the theoretical and experimental studies, reflecting the possibility of Impedance method of peripheral veins localization. Mathematical model has been proposed to calculate the resistivity anomalies of vein in soft tissues and reflects the Electrical Impedance characteristic, depending on the location of the electrode system and the vein. A system electrode has been designed to be attached to the body in order to measure the Electrical Impedance value. The data obtained will determine the capabilities of the method. Experimental studies confirm the adequacy of the proposed mathematical model.

Guy Cloutier - One of the best experts on this subject based on the ideXlab platform.

  • Acousto-Electrical speckle pattern in Lorentz force Electrical Impedance tomography
    Physics in Medicine and Biology, 2015
    Co-Authors: Pol Grasland-mongrain, José María Navarro Marí, Stefan Catheline, Francois Destrempes, Jean-yves Chapelon, Remi Souchon, Cyril Lafon, Guy Cloutier
    Abstract:

    Ultrasound speckle is a granular texture pattern appearing in ultrasound imaging. It can be used to distinguish tissues and identify pathologies. Lorentz force Electrical Impedance tomography is an ultrasound-based medical imaging technique of the tissue Electrical conductivity. It is based on the application of an ultrasound wave in a medium placed in a magnetic field and on the measurement of the induced electric current due to Lorentz force. Similarly to ultrasound imaging, we hypothesized that a speckle could be observed with Lorentz force Electrical Impedance tomography imaging. In this study, we first assessed the theoretical similarity between the measured signals in Lorentz force Electrical Impedance tomography and in ultrasound imaging modalities. We then compared experimentally the signal measured in both methods using an acoustic and Electrical Impedance interface. Finally, a bovine muscle sample was imaged using the two methods. Similar speckle patterns were observed. This indicates the existence of an " acousto-Electrical speckle " in the Lorentz force Electrical Impedance tomography with spatial characteristics driven by the acoustic parameters but due to Electrical Impedance inhomogeneities instead of acoustic ones as is the case of ultrasound imaging.

  • Acousto-Electrical speckle pattern in Electrical Impedance Tomography
    2014 IEEE International Ultrasonics Symposium, 2014
    Co-Authors: Pol Grasland-mongrain, Jean-martial Mari, Stefan Catheline, Francois Destrempes, Jean-yves Chapelon, Remi Souchon, Cyril Lafon, Guy Cloutier
    Abstract:

    Lorentz Force Electrical Impedance Tomography (LFEIT) is a medical imaging technique of the tissue Electrical Impedance. It is based on the transmission of an ultrasound beam in a medium placed in a magnetic field, which induces an Electrical current due to Lorentz force. The measurement of this current with electrodes allows to produce Electrical Impedance images with a spatial resolution close to ultrasound (US) imaging. The goal of this study is to assess the existence of an “acousto-electric speckle” in the LFEIT technique, by similarity to the US speckle.

Arkadiusz Jawień - One of the best experts on this subject based on the ideXlab platform.

  • In vivo Electrical Impedance measurement in human skin assessment
    Pure and Applied Chemistry, 2019
    Co-Authors: Leszek Kubisz, Dorota Hojan-jezierska, Maria T. Szewczyk, Anna C. Majewska, Weronika Kawałkiewicz, Edward Pankowski, Marta Janus, Justyna Cwajda-białasik, Paulina Mościcka, Arkadiusz Jawień
    Abstract:

    Abstract Structural and chemical alterations in living tissue are reflected in Electrical Impedance changes. However, due to the complexity of skin structure, the relation between Electrical parameters and physiological/pathological conditions is difficult to establish. The Impedance dispersion reflects the clinical status of the examined skin tissue and, therefore, it is frequently used in a non-invasive evaluation of exposing skin to various factors. The method has been used to assess the effect of the fish collagen on the skin of patients suffering from the leg ulcer. Therefore, from a number of different approaches to skin Electrical Impedance dispersion, the one considered to be safe was selected and applied. This paper presents a short review of different technical approaches to in vivo Electrical Impedance measurements, as well as an analysis of the results and the effect of fish collagen locally administered on human skin.