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Jørgen Arendt Jensen - One of the best experts on this subject based on the ideXlab platform.

  • A Vector Flow Imaging Method for Portable Ultrasound Using Synthetic Aperture Sequential Beamforming
    IEEE transactions on ultrasonics ferroelectrics and frequency control, 2017
    Co-Authors: Tommaso Di Ianni, Carlos Armando Villagomez Hoyos, Caroline Ewertsen, Thomas Kim Kjeldsen, Jesper Mosegaard, Michael Bachmann Nielsen, Jørgen Arendt Jensen
    Abstract:

    This paper presents a vector flow imaging method for the integration of quantitative blood flow imaging in Portable Ultrasound systems. The method combines directional transverse oscillation (TO) and synthetic aperture sequential beamforming to yield continuous velocity estimation in the whole imaging region. Six focused emissions are used to create a high-resolution image (HRI), and a dual-stage beamforming approach is used to lower the data throughput between the probe and the processing unit. The transmit/receive focal points are laterally separated to obtain a TO in the HRI that allows for the velocity estimation along the lateral and axial directions using a phase-shift estimator. The performance of the method was investigated with constant flow measurements in a flow rig system using the SARUS scanner and a 4.1-MHz linear array. A sequence was designed with interleaved B-mode and flow emissions to obtain continuous data acquisition. A parametric study was carried out to evaluate the effect of critical parameters. The vessel was placed at depths from 20 to 40 mm, with beam-to-flow angles of 65°, 75°, and 90°. For the lateral velocities at 20 mm, a bias between −5% and −6.2% was obtained, and the standard deviation (SD) was between 6% and 9.6%. The axial bias was lower than 1% with an SD around 2%. The mean estimated angles were 66.70° ± 2.86°, 72.65° ± 2.48°, and 89.13° ± 0.79° for the three cases. A proof-of-concept demonstration of the real-time processing and wireless transmission was tested in a commercial tablet obtaining a frame rate of 27 frames/s and a data rate of 14 MB/s. An in vivo measurement of a common carotid artery of a healthy volunteer was finally performed to show the potential of the method in a realistic setting. The relative SD averaged over a cardiac cycle was 4.33%.

  • Performance evaluation of ASICs for CMUT-based Portable Ultrasound scanners
    2017 IEEE International Ultrasonics Symposium (IUS), 2017
    Co-Authors: Pere Llimos Muntal, Ivan H. H. Jørgensen, Soren Elmin Diederichsen, Jørgen Arendt Jensen, Erik Vilain Thomsen
    Abstract:

    Portable Ultrasound scanners (PUS) have shown to have advantages over stationary scanners such as ease of use, accessibility, transportability and cost. However, PUS are severely restricted on size and power which directly limits the area and power consumption of the electronics. In order to fully utilize the available area and power budget to achieve the best picture quality, application specific integrated circuits (ASICs) are required for the electronics. The ASICs are optimized to drive a specific transducer while minimizing the area and power consumption, which is a key target for PUS. For the purpose of implementing compact probes, CMUTs are used due to their highly compatible integration with ASIC fabrication processes. The goal of this work is to assess the impact of the area and power consumption reduction on the acoustic performance of the scanner. For this purpose, a comparison between a commercial Ultrasound pulser and an ASIC optimized for CMUT-based PUS is presented.

  • Transmitting performance evaluation of ASICs for CMUT-based Portable Ultrasound scanners
    2017 IEEE International Ultrasonics Symposium (IUS), 2017
    Co-Authors: Pere Llimos Muntal, Ivan H. H. Jørgensen, Soren Elmin Diederichsen, Jørgen Arendt Jensen, Erik Vilain Thomsen
    Abstract:

    Portable Ultrasound scanners (PUS) have, in recent years, raised a lot of attention, as they can potentially overcome some of the limitations of static scanners. However, PUS have a lot of design limitations including size and power consumption. These restrictions can compromise the image quality of the scanner. In order to overcome these restrictions, application specific integrated circuits (ASICs) are needed to implement the electronics. In this work, a comparative study of the transmitting performance of a capacitive micromachined ultrasonic transducer (CMUT) driven by a commercial generic Ultrasound transmitter and an ASIC optimized for CMUT-based PUS is presented. A single CMUT element is pulsed with a 1% duty cycle at a frequency of 5MHz. The DC bias voltage is 80V and the pulsing voltage is 20V. The acoustic performance is assessed by comparing the ultrasonic signals measured with a hydrophone both in the time and frequency domains. The difference in normalized signal amplitude evaluated at the center frequency of the CMUT is −1.9dB and the measured bandwidth is equivalent. The ASIC consumes only 1.3% of the total power consumption used by the commercial transmitter.

  • Vector velocity estimation for Portable Ultrasound using directional transverse oscillation and synthetic aperture sequential beamforming
    2016 IEEE International Ultrasonics Symposium (IUS), 2016
    Co-Authors: Tommaso Di Ianni, Martin Christian Hemmsen, Jørgen Arendt Jensen
    Abstract:

    In this paper, a vector flow imaging method is presented, which combines the directional transverse oscillation approach with synthetic aperture sequential beamforming to achieve an efficient estimation of the velocities. A double-oscillating field is synthesized using two sets of focused emissions separated by a distance in the lateral direction. A low-resolution line (LRL) is created for each emission in the first stage beamformer, and a second beamformer provides the high-resolution data used for the velocity estimation. The method makes it possible to have continuously available data in the whole image. Therefore, high and low velocities can be estimated with a high frame rate and a low standard deviation. The first stage is a fixed-focus beamformer that can be integrated in the transducer handle, enabling the wireless transmission of the LRLs. The approach does not require any angle compensation or prior knowledge on the beam-to-flow angle. The feasibility of the method is demonstrated through simulations and flow rig measurements of a parabolic flow in a vessel at 90-degree beam-to-flow angle. The mean bias obtained from 50 independent measurements is equal to −0.67% for the lateral profile and −0.43% for the axial profile. The relative standard deviation is 3.19% and 0.47% for the lateral and axial profiles. It is, therefore, demonstrated that vector velocity estimation can be efficiently integrated in a Portable Ultrasound scanner with state-of-the-art performance.

Fauzia Nausheen - One of the best experts on this subject based on the ideXlab platform.

  • Perception of students and faculty of integrated learning of basic sciences and clinical skills with the use of wireless Portable Ultrasound scanners
    Ultrasound in Medicine & Biology, 2019
    Co-Authors: Fauzia Nausheen
    Abstract:

    Introduction At California university of science and medicine, school of medicine, we implemented a system-based curriculum that was driven by weekly clinical presentations and clinical cases. Because of the increasing role of Ultrasound in clinical evaluation of patients, all courses were developed for hands-on Ultrasound experience along with clinical presentations and case of the week to promote integrated learning of basic sciences with clinical skills. The objective of this study was to evaluate the students and faculty perception of teaching and learning of integrated basic sciences and clinical skills with the use of wireless Portable Ultrasound scanners on simulated patients. Methods In each Ultrasound session, each team of 5 students had 2 wireless Portable Ultrasound scanners to perform Ultrasound on simulated patients. All Ultrasound sessions were supervised by the experienced faculty. Ultrasound sessions had learning outcomes that included: 1) Identification of structures and confirmation by instructors: 2) Integration of anatomical structure with functions: 3) Justification of appearance based on ultrasonographic principals. After each session students completed a survey about their confidence level in identifying structures. Results Around 60 year 1, MD students participated in four Ultrasound sessions in “Sustenance of the Body and Depurative functions of the body” (i.e., Gastrointestinal and Renal system) courses with Portable wireless Ultrasound scanners on simulated patients. The main learning outcomes were; to locate liver, kidneys, Morison's pouch, gall bladder, spleen, pancreas, aorta and IVC, Doppler scan and the FAST exam. The preliminary data showed that there was 90% consistency between the students and faculty perception in identifying the major abdominal organs and blood vessels. According to faculty perception, 60% students were able to identify liver without faculty help and only 40% students could identify spleen on their own. 100% students needed faculty help to locate gall bladder and pancreas. With faculty guidance 30% students were able to locate major branches of aorta, portal vein and bile duct. 40% could locate only two branches of aorta. 30% of students could not locate any branches of aorta. After these sessions, students formed an Ultrasound Interest Group that planned regular sessions of advanced level Ultrasound with Portable wireless scanners. Conclusion Frequent Ultrasound practice sessions with accessibility of wireless Portable Ultrasound scanners improved the integrated learning of basic sciences and clinical skills bridging with the clinical practice. It also improved the confidence level of students to perform independently in different competencies.

Sophie Quattrocchi - One of the best experts on this subject based on the ideXlab platform.

  • Silent vs Vocalized Articulation for a Portable Ultrasound-Based Silent Speech Interface
    2010
    Co-Authors: Victoria-m. Florescu, Lise Crevier-buchman, Bruce Denby, Thomas Hueber, Antonia Colazo-simon, Claire Pillot-loiseau, Pierre Roussel, Cédric Gendrot, Sophie Quattrocchi
    Abstract:

    Silent Speech Interfaces have been proposed for communication in silent conditions or as a new means of restoring the voice of persons who have undergone a laryngectomy. To operate such a device, the user must articulate silently. Isolated word recognition tests performed with fixed and Portable Ultrasound based silent speech interface equipment show that systems trained on vocalized speech exhibit reduced performance when tested on silent articulation, but that training with silently articulated speech allows to recover much of this loss.

  • INTERSPEECH - Silent vs Vocalized Articulation for a Portable Ultrasound-Based Silent Speech Interface
    2010
    Co-Authors: Victoria-m. Florescu, Lise Crevier-buchman, Bruce Denby, Thomas Hueber, Antonia Colazo-simon, Claire Pillot-loiseau, Pierre Roussel, Cédric Gendrot, Sophie Quattrocchi
    Abstract:

    Silent Speech Interfaces have been proposed for communication in silent conditions or as a new means of restoring the voice of persons who have undergone a laryngectomy. To operate such a device, the user must articulate silently. Isolated word recognition tests performed with fixed and Portable Ultrasound based silent speech interface equipment show that systems trained on vocalized speech exhibit reduced performance when tested on silent articulation, but that training with silently articulated speech allows to recover much of this loss.

Ivan H. H. Jørgensen - One of the best experts on this subject based on the ideXlab platform.

  • high voltage integrated linear regulator with current sinking capabilities for Portable Ultrasound scanners
    International Symposium on System-on-Chip, 2017
    Co-Authors: Guifre Vendrell Pausas, Pere Llimos Muntal, Ivan H. H. Jørgensen
    Abstract:

    This paper presents a high-voltage integrated regulator capable of sinking current for driving pulse-triggered level shifters in drivers for Ultrasound applications. The regulator utilizes a new topology with a feedback loop and a current sinking circuit to satisfy the requirements of the Portable Ultrasound scanner: a great driving strength in the scanner's transducer and a low undershoot voltage in the output node. The design regulates an output voltage of 45 V from an input voltage of 50 V, and it can sink currents up to 100 mA using no external components with only 340 mV of undershoot voltage. The proposed design has been implemented in high-voltage 0.18 μm process whithin an area of 0.11 mm2 and it is suitable for system-on-chip integration due to its low component count and the fully integrated design.

  • A continuous-time delta-sigma ADC for Portable Ultrasound scanners
    Analog Integrated Circuits and Signal Processing, 2017
    Co-Authors: Pere Llimós Muntal, Ivan H. H. Jørgensen, Erik Bruun
    Abstract:

    A fully differential fourth-order 1-bit continuous-time delta-sigma ADC designed in a 65 nm process for Portable Ultrasound scanners is presented in this paper. The circuit design, implementation and measurements on the fabricated die are shown. The loop filter consists of RC-integrators, programmable capacitor arrays, resistors and voltage feedback DACs. The quantizer contains a pulse generator, a high-speed clocked comparator and a pull-down clocked latch to ensure constant delay in the feedback loop. Using this implementation, a small and low-power solution required for Portable Ultrasound scanner applications is achieved. The converter has a supply voltage of 1.2 V, a bandwidth of 10 MHz and an oversampling ratio of 16 leading to an operating frequency of 320 MHz. The design occupies a die area of $$0.0175\hbox { mm}^2$$ 0.0175 mm 2 . Simulations with extracted parasitics show a SNR of 45.2 dB and a current consumption of $$489 \,\upmu \hbox {A}$$ 489 μ A . However, by adding a model of the measurement setup used, the performance degrades to 42.1 dB. The measured SNR and current consumption are 41.6 dB and $$495\,\upmu \hbox {A}$$ 495 μ A , which closely fit with the expected simulations. Several dies have been measured, and an estimation of the die spread distribution is given.

  • Performance evaluation of ASICs for CMUT-based Portable Ultrasound scanners
    2017 IEEE International Ultrasonics Symposium (IUS), 2017
    Co-Authors: Pere Llimos Muntal, Ivan H. H. Jørgensen, Soren Elmin Diederichsen, Jørgen Arendt Jensen, Erik Vilain Thomsen
    Abstract:

    Portable Ultrasound scanners (PUS) have shown to have advantages over stationary scanners such as ease of use, accessibility, transportability and cost. However, PUS are severely restricted on size and power which directly limits the area and power consumption of the electronics. In order to fully utilize the available area and power budget to achieve the best picture quality, application specific integrated circuits (ASICs) are required for the electronics. The ASICs are optimized to drive a specific transducer while minimizing the area and power consumption, which is a key target for PUS. For the purpose of implementing compact probes, CMUTs are used due to their highly compatible integration with ASIC fabrication processes. The goal of this work is to assess the impact of the area and power consumption reduction on the acoustic performance of the scanner. For this purpose, a comparison between a commercial Ultrasound pulser and an ASIC optimized for CMUT-based PUS is presented.

  • Transmitting performance evaluation of ASICs for CMUT-based Portable Ultrasound scanners
    2017 IEEE International Ultrasonics Symposium (IUS), 2017
    Co-Authors: Pere Llimos Muntal, Ivan H. H. Jørgensen, Soren Elmin Diederichsen, Jørgen Arendt Jensen, Erik Vilain Thomsen
    Abstract:

    Portable Ultrasound scanners (PUS) have, in recent years, raised a lot of attention, as they can potentially overcome some of the limitations of static scanners. However, PUS have a lot of design limitations including size and power consumption. These restrictions can compromise the image quality of the scanner. In order to overcome these restrictions, application specific integrated circuits (ASICs) are needed to implement the electronics. In this work, a comparative study of the transmitting performance of a capacitive micromachined ultrasonic transducer (CMUT) driven by a commercial generic Ultrasound transmitter and an ASIC optimized for CMUT-based PUS is presented. A single CMUT element is pulsed with a 1% duty cycle at a frequency of 5MHz. The DC bias voltage is 80V and the pulsing voltage is 20V. The acoustic performance is assessed by comparing the ultrasonic signals measured with a hydrophone both in the time and frequency domains. The difference in normalized signal amplitude evaluated at the center frequency of the CMUT is −1.9dB and the measured bandwidth is equivalent. The ASIC consumes only 1.3% of the total power consumption used by the commercial transmitter.

  • NORCAS - High-voltage integrated linear regulator with current sinking capabilities for Portable Ultrasound scanners
    2017 IEEE Nordic Circuits and Systems Conference (NORCAS): NORCHIP and International Symposium of System-on-Chip (SoC), 2017
    Co-Authors: Guifre Vendrell Pausas, Pere Llimos Muntal, Ivan H. H. Jørgensen
    Abstract:

    This paper presents a high-voltage integrated regulator capable of sinking current for driving pulse-triggered level shifters in drivers for Ultrasound applications. The regulator utilizes a new topology with a feedback loop and a current sinking circuit to satisfy the requirements of the Portable Ultrasound scanner: a great driving strength in the scanner's transducer and a low undershoot voltage in the output node. The design regulates an output voltage of 45 V from an input voltage of 50 V, and it can sink currents up to 100 mA using no external components with only 340 mV of undershoot voltage. The proposed design has been implemented in high-voltage 0.18 μm process whithin an area of 0.11 mm2 and it is suitable for system-on-chip integration due to its low component count and the fully integrated design.

Nafikudin Mahmud - One of the best experts on this subject based on the ideXlab platform.

  • Measurement of thyroid volume in children using a Portable Ultrasound machine: a technical note.
    Asia-Pacific journal of public health, 2001
    Co-Authors: Nafikudin Mahmud
    Abstract:

    The data on thyroid volume measurements that determines prevalence of goitre in children is very important for public health consideration as the presence of goitre in children effectively reflects the status of iodine deficiency disorders (IDD) in the general population. Ultrasound is an excellent modality to evaluate thyroid size. Local experience in using a Portable Ultrasound machine to measure thyroid volume is presented. The thyroid anatomy and techniques of Ultrasound assessment are highlighted. Proper training of public health doctors to perform thyroid gland ultrasonography is crucial to ensure that the thyroid volume data collected would be more accurate and reliable for the planning of health programmes to eliminate IDD in the particular areas. Asia Pac J Publk Health 2001;13(1): 36-39