The Experts below are selected from a list of 29190 Experts worldwide ranked by ideXlab platform

G R Lockwood - One of the best experts on this subject based on the ideXlab platform.

  • real time volume imaging using a crossed Electrode Array
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2009
    Co-Authors: Christine E M Demore, Andrew W Joyce, Kieran Wall, G R Lockwood
    Abstract:

    This paper describes a unique crossed Electrode Array for real-time volume ultrasound imaging. By placing orthogonal linear Array Electrode patterns on the opposite sides of a hemispherically shaped composite transducer substrate, a 2D Array can be fabricated using a small fraction of the elements required for a traditional 2D Array. The performance of the Array is investigated using a computer simulation of the radiation pattern. We show that by using a 288-element crossed Electrode pattern it is possible to collect large field of view volume images (60deg times 60degsector) at real-time frame rates (>20 volume images/s), with image contrast and resolution comparable to what can be obtained using a conventional 128-element linear phased Array.

  • real time volume imaging using a crossed Electrode Array
    IEEE Transactions on Biomedical Engineering, 2009
    Co-Authors: Christine E M Demore, Andrew W Joyce, Kieran Wall, G R Lockwood
    Abstract:

    This paper describes a unique crossed Electrode Array for real-time volume ultrasound imaging. By placing orthogonal linear Array Electrode patterns on the opposite sides of a hemispherically shaped composite transducer substrate, a 2-D Array can be fabricated using a small fraction of the elements required for a traditional 2-D Array. The performance of the Array is investigated using a computer simulation of the radiation pattern. We show that by using a 288-element crossed Electrode pattern it is possible to collect large field of view volume images (60° x 60° sector) at real-time frame rates (>20 volume images/s), with image contrast and resolution comparable to what can be obtained using a conventional 128-element linear phased Array.

Christine E M Demore - One of the best experts on this subject based on the ideXlab platform.

  • real time volume imaging using a crossed Electrode Array
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2009
    Co-Authors: Christine E M Demore, Andrew W Joyce, Kieran Wall, G R Lockwood
    Abstract:

    This paper describes a unique crossed Electrode Array for real-time volume ultrasound imaging. By placing orthogonal linear Array Electrode patterns on the opposite sides of a hemispherically shaped composite transducer substrate, a 2D Array can be fabricated using a small fraction of the elements required for a traditional 2D Array. The performance of the Array is investigated using a computer simulation of the radiation pattern. We show that by using a 288-element crossed Electrode pattern it is possible to collect large field of view volume images (60deg times 60degsector) at real-time frame rates (>20 volume images/s), with image contrast and resolution comparable to what can be obtained using a conventional 128-element linear phased Array.

  • real time volume imaging using a crossed Electrode Array
    IEEE Transactions on Biomedical Engineering, 2009
    Co-Authors: Christine E M Demore, Andrew W Joyce, Kieran Wall, G R Lockwood
    Abstract:

    This paper describes a unique crossed Electrode Array for real-time volume ultrasound imaging. By placing orthogonal linear Array Electrode patterns on the opposite sides of a hemispherically shaped composite transducer substrate, a 2-D Array can be fabricated using a small fraction of the elements required for a traditional 2-D Array. The performance of the Array is investigated using a computer simulation of the radiation pattern. We show that by using a 288-element crossed Electrode pattern it is possible to collect large field of view volume images (60° x 60° sector) at real-time frame rates (>20 volume images/s), with image contrast and resolution comparable to what can be obtained using a conventional 128-element linear phased Array.

Kieran Wall - One of the best experts on this subject based on the ideXlab platform.

  • real time volume imaging using a crossed Electrode Array
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2009
    Co-Authors: Christine E M Demore, Andrew W Joyce, Kieran Wall, G R Lockwood
    Abstract:

    This paper describes a unique crossed Electrode Array for real-time volume ultrasound imaging. By placing orthogonal linear Array Electrode patterns on the opposite sides of a hemispherically shaped composite transducer substrate, a 2D Array can be fabricated using a small fraction of the elements required for a traditional 2D Array. The performance of the Array is investigated using a computer simulation of the radiation pattern. We show that by using a 288-element crossed Electrode pattern it is possible to collect large field of view volume images (60deg times 60degsector) at real-time frame rates (>20 volume images/s), with image contrast and resolution comparable to what can be obtained using a conventional 128-element linear phased Array.

  • real time volume imaging using a crossed Electrode Array
    IEEE Transactions on Biomedical Engineering, 2009
    Co-Authors: Christine E M Demore, Andrew W Joyce, Kieran Wall, G R Lockwood
    Abstract:

    This paper describes a unique crossed Electrode Array for real-time volume ultrasound imaging. By placing orthogonal linear Array Electrode patterns on the opposite sides of a hemispherically shaped composite transducer substrate, a 2-D Array can be fabricated using a small fraction of the elements required for a traditional 2-D Array. The performance of the Array is investigated using a computer simulation of the radiation pattern. We show that by using a 288-element crossed Electrode pattern it is possible to collect large field of view volume images (60° x 60° sector) at real-time frame rates (>20 volume images/s), with image contrast and resolution comparable to what can be obtained using a conventional 128-element linear phased Array.

Andrew W Joyce - One of the best experts on this subject based on the ideXlab platform.

  • real time volume imaging using a crossed Electrode Array
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2009
    Co-Authors: Christine E M Demore, Andrew W Joyce, Kieran Wall, G R Lockwood
    Abstract:

    This paper describes a unique crossed Electrode Array for real-time volume ultrasound imaging. By placing orthogonal linear Array Electrode patterns on the opposite sides of a hemispherically shaped composite transducer substrate, a 2D Array can be fabricated using a small fraction of the elements required for a traditional 2D Array. The performance of the Array is investigated using a computer simulation of the radiation pattern. We show that by using a 288-element crossed Electrode pattern it is possible to collect large field of view volume images (60deg times 60degsector) at real-time frame rates (>20 volume images/s), with image contrast and resolution comparable to what can be obtained using a conventional 128-element linear phased Array.

  • real time volume imaging using a crossed Electrode Array
    IEEE Transactions on Biomedical Engineering, 2009
    Co-Authors: Christine E M Demore, Andrew W Joyce, Kieran Wall, G R Lockwood
    Abstract:

    This paper describes a unique crossed Electrode Array for real-time volume ultrasound imaging. By placing orthogonal linear Array Electrode patterns on the opposite sides of a hemispherically shaped composite transducer substrate, a 2-D Array can be fabricated using a small fraction of the elements required for a traditional 2-D Array. The performance of the Array is investigated using a computer simulation of the radiation pattern. We show that by using a 288-element crossed Electrode pattern it is possible to collect large field of view volume images (60° x 60° sector) at real-time frame rates (>20 volume images/s), with image contrast and resolution comparable to what can be obtained using a conventional 128-element linear phased Array.

Sung June Kim - One of the best experts on this subject based on the ideXlab platform.

  • CNT bundle-based thin intracochlear Electrode Array
    Biomedical Microdevices, 2019
    Co-Authors: Gwang Jin Choi, Tae Mok Gwon, Seung Ha Oh, Doo Hee Kim, Junbeom Park, Seung Min Kim, Yoonseob Lim, Sang Beom Jun, Sung June Kim
    Abstract:

    Objective: It is known that the insertion of the intracochlear Electrode is critical procedure because the damage around cochlear structures can deteriorate hearing restoration. To reduce the trauma during the Electrode insertion surgery, we developed a thin and flexible intracochlear Electrode Array constructed with carbon nanotube (CNT) bundles. Methods: Each CNT bundle was used for an individual Electrode channel after coated with parylene C for insulation. By encapsulating eight CNT bundles with silicone elastomer, an 8-channel intracochlear Electrode Array was fabricated. The mechanical and electrochemical characteristics were assessed to evaluate the flexibility and feasibility of the Electrode as a stimulation Electrode. The functionality of the Electrode was confirmed by electrically evoked auditory brainstem responses (eABR) recorded from a rat. Results: The proposed Electrode has a thickness of 135 μm at the apex and 395 μm at the base. It was demonstrated that the CNT bundle-based Electrodes require 6-fold the lower insertion force than metal wire-based Electrodes. The Electrode impedance and the cathodic charge storage capacitance (CSCc) were 2.70 kΩ ∠-20.4° at 1 kHz and − 708 mC/cm^2, respectively. The eABR waves III and V were observed when stimulation current is greater than 50 μA. Conclusion: A thin and flexible CNT bundle-based intracochlear Electrode Array was successfully developed. The feasibility of the proposed Electrode was shown in terms of mechanical and electrochemical characteristics. A proposed CNT bundle-based intracochlear Electrode may reduce the risk of trauma during Electrode insertion surgery.

  • Fabrication and evaluation of an improved polymer-based cochlear Electrode Array for atraumatic insertion
    Biomedical Microdevices, 2015
    Co-Authors: Tae Mok Gwon, Kyou Sik Min, Ho Sun Lee, Min-hyun Park, Seung Ha Oh, Jin-ho Kim, Sung June Kim
    Abstract:

    An atraumatic cochlear Electrode Array has become indispensable to high-performance cochlear implants such as electric acoustic stimulation (EAS), wherein the preservation of residual hearing is significant. For an atraumatic implantation, we propose and demonstrate a new improved design of a cochlear Electrode Array based on liquid crystal polymer (LCP), which can be fabricated by precise batch processes and a thermal lamination process, in contrast to conventional wire-based cochlear Electrode Arrays. Using a thin-film process of LCP-film-mounted silicon wafer and thermal press lamination, we devise a multi-layered structure with variable layers of LCP films to achieve a sufficient degree of basal rigidity and a flexible tip. A peripheral blind via and self-aligned silicone elastomer molding process can reduce the width of the Array. Measuring the insertion and extraction forces in a human scala tympani model, we investigate five human temporal bone insertion trials and record electrically evoked auditory brainstem responses (EABR) acutely in a guinea pig model. The diameters of the finalized Electrode Arrays are 0.3 mm (tip) and 0.75 mm (base). The insertion force with a displacement of 8 mm from a round window and the maximum extraction force are 2.4 mN and 34.0 mN, respectively. The Electrode Arrays can be inserted from 360° to 630° without trauma at the basal turn. The EABR data confirm the efficacy of the Array. A new design of LCP-based cochlear Electrode Array for atraumatic implantation is fabricated. Verification indicates that foretells the development of an atraumatic cochlear Electrode Array and clinical implant.

  • A polymer-based multichannel cochlear Electrode Array.
    Otology & neurotology : official publication of the American Otological Society American Neurotology Society [and] European Academy of Otology and Neu, 2014
    Co-Authors: Kyou Sik Min, Min-hyun Park, Joonsoo Jeong, Sung June Kim
    Abstract:

    OBJECTIVE Compared with conventional cochlear Electrode Arrays, which are hand assembled and wire-based, polymer-based implants have several advantages. They are very precise, and their fabrication is inexpensive because of the use of thin-film processes. In the present study, a cochlear Electrode Array based on a high-performance liquid crystal polymer material is devised. Furthermore, the device is encapsulated in silicone elastomer. METHODS The fabrication steps introduced here include thin-film processes with liquid crystal polymer (LCP) films and customized self-aligning molding processes for the Electrode Array. To assess the feasibility of the proposed Electrode Array, the charge storage capacitance and impedance were measured using a potentiostat. Vertical and horizontal deflection forces were measured using a customized fixture and a force sensor. Insertion and extraction forces were also measured using a transparent human cochlear plastic model, and five cases involving human temporal insertion trials were undertaken to assess the level of safety during the insertion process. RESULTS The charge storage capacity and impedance at 1 kHz were 33.26 mC/cm and 1.02 kΩ, respectively. Likewise, the vertical force and horizontal force of the Electrode Array were 3.15 g and 1.07 g. The insertion force into a transparent plastic cochlear model with displacement of 8 mm from a round window was 8.2 mN, and the maximum extraction force was 110.4 mN. Two cases of human temporal bone insertion showed no observable trauma, whereas 3 cases showed a rupture of the basilar membrane. CONCLUSION An LCP-based intracochlear Electrode Array was fabricated, and its electrical and mechanical properties were found to be suitable for clinical use.

  • Modiolus-Hugging Intracochlear Electrode Array with Shape Memory Alloy
    Computational and mathematical methods in medicine, 2013
    Co-Authors: Kyou Sik Min, Yoonseob Lim, Sang Beom Jun, Ik Park, Sung June Kim
    Abstract:

    In the cochlear implant system, the distance between spiral ganglia and the Electrodes within the volume of the scala tympani cavity significantly affects the efficiency of the electrical stimulation in terms of the threshold current level and spatial selectivity. Because the spiral ganglia are situated inside the modiolus, the central axis of the cochlea, it is desirable that the Electrode Array hugs the modiolus to minimize the distance between the Electrodes and the ganglia. In the present study, we propose a shape-memory-alloy-(SMA-) embedded intracochlear Electrode which gives a straight Electrode a curved modiolus-hugging shape using the restoration force of the SMA as triggered by resistive heating after insertion into the cochlea. An eight-channel ball-type Electrode Array is fabricated with an embedded titanium-nickel SMA backbone wire. It is demonstrated that the Electrode Array changes its shape in a transparent plastic human cochlear model. To verify the safe insertion of the Electrode Array into the human cochlea, the contact pressures during insertion at the Electrode tip and the contact pressures over the Electrode length after insertion were calculated using a 3D finite element analysis. The results indicate that the SMA-embedded Electrode is functionally and mechanically feasible for clinical applications.