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Ken-ichi Yamakoshi - One of the best experts on this subject based on the ideXlab platform.

  • Experimental and Numerical Study on Optimal Spot-electrodes Arrays in Transthoracic Electrical Impedance Cardiography
    2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2007
    Co-Authors: Akira Ikarashi, Masamichi Nogawa, Shinobu Tanaka, Ken-ichi Yamakoshi
    Abstract:

    Transthoracic electrical impedance (or admittance) cardiography is a simple technique for the non-invasive and continuous monitoring of stroke volume or cardiac output by detecting the electrical impedance of a thorax which is roughly assumed to be a two-compartment coaxial cylindrical model composed of the aorta and its surrounding thoracic tissues. A tetra-polar band-electrodes method by Kubicek et al. has been widely used for the detection of the electrical impedance. However, this band-electrodes attachment makes a subject troublesome. Replacement of the band- to a spot-electrodes array is therefore highly required for practical use. In our previous reports, we have confirmed that a thorax is nearly assumed as an electrical cylinder model when a pair of current injection spot-electrodes are placed far from the thorax like a placement of the forehead - left Medial knee or the mastoid process - lower right abdomen, and that the changes in current distributions associated with cardiac blood ejection are roughly homogeneous around the Medial Line of the thorax. The present study concerns with determination of an optimal spot-electrodes array for voltage pick-up through the detailed measurements of pulsatile components of the thoracic impedance along the Medial Line of the thorax using an 11times2 channels impedance mapping system. Additionally, we have investigated the influence of blood volume change in the heart itself by a finite element method. From these experimental and numerical investigations, it was suggested that the impedance change due to the blood volume change in the aorta without that in the heart can mainly be detected between the level of the clavicle and that of the xiphisternum. Consequently, an optimal electrodes-location for voltage pick-up was to be determined as the Medial portion at the level of the clavicle and the portion above the xiphisternum.

  • An Optimal Spot-electrodes Array for Electrical Impedance Cardiography Through Determination of Impedance Mapping of a Regional Area along the Medial Line on the Thorax
    2006 International Conference of the IEEE Engineering in Medicine and Biology Society, 2006
    Co-Authors: Akira Ikarashi, Masamichi Nogawa, Takehiro Yamakoshi, Shinobu Tanaka, Ken-ichi Yamakoshi
    Abstract:

    Electrical impedance or admittance cardiography is a simple method for non-invasive, continuous measurement the stroke volume and cardiac output. For the electrical impedance cardiography, the band-electrodes array proposed by Kubicek et al has been widely used, and various spot-electrodes array have been experimented in search of a less uncomfortable and equally reliable electrodes array that is easier to attach. From the uniformity of current distribution on the thorax, we have reinvestigated focusing on the measurement of contour maps of static and pulsatile components of a regional area along the Medial Line on the frontal part of the thorax. Consequently, the appropriate electrodes locations for current injection were determined as the back of an ear and on the lower abdomen, while those for voltage pick-up was on the Medial portion at the level of clavicle and on the portion above the xiphisternum. Preliminary comparison experiments between the cardiac output values obtained by the electrical impedance cardiography and by a pulse dye-densitometry showed a fairy good agreement

Akira Ikarashi - One of the best experts on this subject based on the ideXlab platform.

  • Experimental and Numerical Study on Optimal Spot-electrodes Arrays in Transthoracic Electrical Impedance Cardiography
    2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2007
    Co-Authors: Akira Ikarashi, Masamichi Nogawa, Shinobu Tanaka, Ken-ichi Yamakoshi
    Abstract:

    Transthoracic electrical impedance (or admittance) cardiography is a simple technique for the non-invasive and continuous monitoring of stroke volume or cardiac output by detecting the electrical impedance of a thorax which is roughly assumed to be a two-compartment coaxial cylindrical model composed of the aorta and its surrounding thoracic tissues. A tetra-polar band-electrodes method by Kubicek et al. has been widely used for the detection of the electrical impedance. However, this band-electrodes attachment makes a subject troublesome. Replacement of the band- to a spot-electrodes array is therefore highly required for practical use. In our previous reports, we have confirmed that a thorax is nearly assumed as an electrical cylinder model when a pair of current injection spot-electrodes are placed far from the thorax like a placement of the forehead - left Medial knee or the mastoid process - lower right abdomen, and that the changes in current distributions associated with cardiac blood ejection are roughly homogeneous around the Medial Line of the thorax. The present study concerns with determination of an optimal spot-electrodes array for voltage pick-up through the detailed measurements of pulsatile components of the thoracic impedance along the Medial Line of the thorax using an 11times2 channels impedance mapping system. Additionally, we have investigated the influence of blood volume change in the heart itself by a finite element method. From these experimental and numerical investigations, it was suggested that the impedance change due to the blood volume change in the aorta without that in the heart can mainly be detected between the level of the clavicle and that of the xiphisternum. Consequently, an optimal electrodes-location for voltage pick-up was to be determined as the Medial portion at the level of the clavicle and the portion above the xiphisternum.

  • An Optimal Spot-electrodes Array for Electrical Impedance Cardiography Through Determination of Impedance Mapping of a Regional Area along the Medial Line on the Thorax
    2006 International Conference of the IEEE Engineering in Medicine and Biology Society, 2006
    Co-Authors: Akira Ikarashi, Masamichi Nogawa, Takehiro Yamakoshi, Shinobu Tanaka, Ken-ichi Yamakoshi
    Abstract:

    Electrical impedance or admittance cardiography is a simple method for non-invasive, continuous measurement the stroke volume and cardiac output. For the electrical impedance cardiography, the band-electrodes array proposed by Kubicek et al has been widely used, and various spot-electrodes array have been experimented in search of a less uncomfortable and equally reliable electrodes array that is easier to attach. From the uniformity of current distribution on the thorax, we have reinvestigated focusing on the measurement of contour maps of static and pulsatile components of a regional area along the Medial Line on the frontal part of the thorax. Consequently, the appropriate electrodes locations for current injection were determined as the back of an ear and on the lower abdomen, while those for voltage pick-up was on the Medial portion at the level of clavicle and on the portion above the xiphisternum. Preliminary comparison experiments between the cardiac output values obtained by the electrical impedance cardiography and by a pulse dye-densitometry showed a fairy good agreement

Masamichi Nogawa - One of the best experts on this subject based on the ideXlab platform.

  • Experimental and Numerical Study on Optimal Spot-electrodes Arrays in Transthoracic Electrical Impedance Cardiography
    2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2007
    Co-Authors: Akira Ikarashi, Masamichi Nogawa, Shinobu Tanaka, Ken-ichi Yamakoshi
    Abstract:

    Transthoracic electrical impedance (or admittance) cardiography is a simple technique for the non-invasive and continuous monitoring of stroke volume or cardiac output by detecting the electrical impedance of a thorax which is roughly assumed to be a two-compartment coaxial cylindrical model composed of the aorta and its surrounding thoracic tissues. A tetra-polar band-electrodes method by Kubicek et al. has been widely used for the detection of the electrical impedance. However, this band-electrodes attachment makes a subject troublesome. Replacement of the band- to a spot-electrodes array is therefore highly required for practical use. In our previous reports, we have confirmed that a thorax is nearly assumed as an electrical cylinder model when a pair of current injection spot-electrodes are placed far from the thorax like a placement of the forehead - left Medial knee or the mastoid process - lower right abdomen, and that the changes in current distributions associated with cardiac blood ejection are roughly homogeneous around the Medial Line of the thorax. The present study concerns with determination of an optimal spot-electrodes array for voltage pick-up through the detailed measurements of pulsatile components of the thoracic impedance along the Medial Line of the thorax using an 11times2 channels impedance mapping system. Additionally, we have investigated the influence of blood volume change in the heart itself by a finite element method. From these experimental and numerical investigations, it was suggested that the impedance change due to the blood volume change in the aorta without that in the heart can mainly be detected between the level of the clavicle and that of the xiphisternum. Consequently, an optimal electrodes-location for voltage pick-up was to be determined as the Medial portion at the level of the clavicle and the portion above the xiphisternum.

  • An Optimal Spot-electrodes Array for Electrical Impedance Cardiography Through Determination of Impedance Mapping of a Regional Area along the Medial Line on the Thorax
    2006 International Conference of the IEEE Engineering in Medicine and Biology Society, 2006
    Co-Authors: Akira Ikarashi, Masamichi Nogawa, Takehiro Yamakoshi, Shinobu Tanaka, Ken-ichi Yamakoshi
    Abstract:

    Electrical impedance or admittance cardiography is a simple method for non-invasive, continuous measurement the stroke volume and cardiac output. For the electrical impedance cardiography, the band-electrodes array proposed by Kubicek et al has been widely used, and various spot-electrodes array have been experimented in search of a less uncomfortable and equally reliable electrodes array that is easier to attach. From the uniformity of current distribution on the thorax, we have reinvestigated focusing on the measurement of contour maps of static and pulsatile components of a regional area along the Medial Line on the frontal part of the thorax. Consequently, the appropriate electrodes locations for current injection were determined as the back of an ear and on the lower abdomen, while those for voltage pick-up was on the Medial portion at the level of clavicle and on the portion above the xiphisternum. Preliminary comparison experiments between the cardiac output values obtained by the electrical impedance cardiography and by a pulse dye-densitometry showed a fairy good agreement

Shinobu Tanaka - One of the best experts on this subject based on the ideXlab platform.

  • Experimental and Numerical Study on Optimal Spot-electrodes Arrays in Transthoracic Electrical Impedance Cardiography
    2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2007
    Co-Authors: Akira Ikarashi, Masamichi Nogawa, Shinobu Tanaka, Ken-ichi Yamakoshi
    Abstract:

    Transthoracic electrical impedance (or admittance) cardiography is a simple technique for the non-invasive and continuous monitoring of stroke volume or cardiac output by detecting the electrical impedance of a thorax which is roughly assumed to be a two-compartment coaxial cylindrical model composed of the aorta and its surrounding thoracic tissues. A tetra-polar band-electrodes method by Kubicek et al. has been widely used for the detection of the electrical impedance. However, this band-electrodes attachment makes a subject troublesome. Replacement of the band- to a spot-electrodes array is therefore highly required for practical use. In our previous reports, we have confirmed that a thorax is nearly assumed as an electrical cylinder model when a pair of current injection spot-electrodes are placed far from the thorax like a placement of the forehead - left Medial knee or the mastoid process - lower right abdomen, and that the changes in current distributions associated with cardiac blood ejection are roughly homogeneous around the Medial Line of the thorax. The present study concerns with determination of an optimal spot-electrodes array for voltage pick-up through the detailed measurements of pulsatile components of the thoracic impedance along the Medial Line of the thorax using an 11times2 channels impedance mapping system. Additionally, we have investigated the influence of blood volume change in the heart itself by a finite element method. From these experimental and numerical investigations, it was suggested that the impedance change due to the blood volume change in the aorta without that in the heart can mainly be detected between the level of the clavicle and that of the xiphisternum. Consequently, an optimal electrodes-location for voltage pick-up was to be determined as the Medial portion at the level of the clavicle and the portion above the xiphisternum.

  • An Optimal Spot-electrodes Array for Electrical Impedance Cardiography Through Determination of Impedance Mapping of a Regional Area along the Medial Line on the Thorax
    2006 International Conference of the IEEE Engineering in Medicine and Biology Society, 2006
    Co-Authors: Akira Ikarashi, Masamichi Nogawa, Takehiro Yamakoshi, Shinobu Tanaka, Ken-ichi Yamakoshi
    Abstract:

    Electrical impedance or admittance cardiography is a simple method for non-invasive, continuous measurement the stroke volume and cardiac output. For the electrical impedance cardiography, the band-electrodes array proposed by Kubicek et al has been widely used, and various spot-electrodes array have been experimented in search of a less uncomfortable and equally reliable electrodes array that is easier to attach. From the uniformity of current distribution on the thorax, we have reinvestigated focusing on the measurement of contour maps of static and pulsatile components of a regional area along the Medial Line on the frontal part of the thorax. Consequently, the appropriate electrodes locations for current injection were determined as the back of an ear and on the lower abdomen, while those for voltage pick-up was on the Medial portion at the level of clavicle and on the portion above the xiphisternum. Preliminary comparison experiments between the cardiac output values obtained by the electrical impedance cardiography and by a pulse dye-densitometry showed a fairy good agreement

Balázs Benyó - One of the best experts on this subject based on the ideXlab platform.

  • Identification of dental root canals and their Medial Line from micro-CT and cone-beam CT records
    BioMedical Engineering OnLine, 2012
    Co-Authors: Balázs Benyó
    Abstract:

    Background Shape of the dental root canal is highly patient specific. Automated identification methods of the Medial Line of dental root canals and the reproduction of their 3D shape can be beneficial for planning endodontic interventions as severely curved root canals or multi-rooted teeth may pose treatment challenges. Accurate shape information of the root canals may also be used by manufacturers of endodontic instruments in order to make more efficient clinical tools.

  • CIARP - Identification of the root canal from dental Micro-CT records
    Progress in Pattern Recognition Image Analysis Computer Vision and Applications, 2011
    Co-Authors: László Szilágyi, Csaba Dobó-nagy, Balázs Benyó
    Abstract:

    This paper presents a novel semi-automated image processing procedure dedicated to the identification and characterization of the dental root canal, based on high-resolution micro-CT records. After the necessary image enhancement, parallel slices are individually segmented via histogram based quick fuzzy c-means clustering. The 3D model of root canal is built up from the segmented cross sections using the reconstruction of the inner surface, and the Medial Line is extracted by a 3D curve skeletonization algorithm. The central Line of the root canal can finally be approximated as a 3D spLine curve. The proposed procedure may support the planning of several kinds of endodontic interventions.