Smartphone-Based Point-of-Care System Using Continuous-Wave Portable Doppler

Jana, Biswabandhu; Biswas, Rakesh; Nath, Pallab Kumar; Saha, Goutam; Banerjee, Swapna

doi:10.1109/tim.2020.2987654

Cited by 14 publications

(10 citation statements)

References 25 publications

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“…The automatic range-gatepositioning scheme, along with the hysteresis slicing function, has been implemented in the FPGA. Most of other single-element-based pulsed-wave Doppler devices adopt a manual adjustment of the range gate [13][14][15]. In addition, a recent work which includes a vesselwall-detection algorithm presents an automatic tracking of the vessel wall [16].…”

Section: Discussionmentioning

confidence: 99%

“…There are several approaches to implementing an ultrasound blood-flow monitor by using a single transducer [13][14][15][16]. A single-transducer-based ultrasound blood-flow monitor basically needs only single-channel interface circuitry and a digital signal processor with fewer computation requirements.…”

Section: Introductionmentioning

confidence: 99%

“…One of primary issues of single-transducer-based ultrasound blood-flow monitoring is positioning of a range gate on a scanline to acquire sample volumes from the vessel region without an ultrasound image. The work of [13] developed a continuous-wave Doppler scheme. This means the echo signal does not include depth information.…”

Section: Introductionmentioning

confidence: 99%

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Image-Free Ultrasound Blood-Flow Monitoring Circuit System with Automatic Range-Gate Positioning Scheme: A Pilot Study

Park¹,

2021

Applied Sciences

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This work proposes a proof-of-concept ultrasound blood-flow-monitoring circuit system using a single-element transducer. The circuit system consists of a single-element ultrasonic transducer, an analog interface circuit, and a field-programmable gate array (FPGA). Since the system uses a single-element transducer, an ultrasound image cannot be reconstructed unless scanning with mechanical movement is used. An ultrasound blood-flow monitor basically needs to acquire a Doppler sample volume by positioning a range gate at a vessel region on a scanline. Most recent single-transducer-based ultrasound pulsed-wave Doppler devices rely on a manual adjustment of the range gate to acquire Doppler sample volumes. However, the manual adjustment of the range gate depends on the user’s experience, and it can be time consuming if a transducer is not properly positioned. Thus, automatic range-gate-positioning is more desirable for image-free pulsed-wave Doppler devices. This work proposes a circuit system which includes a new automatic range-gate-positioning scheme. It blindly tracks the position of a blood vessel on a scanline by using the accumulation of Doppler amplitude deviations and a hysteresis slicing function. The proposed range-gate-positioning scheme has been implemented in an FPGA for real-time operation and is based on addition-only computations, except for filter parts to reduce the complexity of computation in the hardware. The proposed blood-flow-monitoring circuit system has been implemented with discrete commercial chips for proof-of-concept purposes. It uses a center frequency of 2 MHz and a system-clock frequency of 20 MHz. The FPGA only utilizes 5.6% of slice look-up-tables (LUTs) for implementation of the range-gate-positioning scheme. For measurements, the circuit system was utilized to interrogate a customized flow phantom model, which included two vessel-mimicking channels. The circuit system successfully acquired Doppler sample volumes by positioning a range gate on a fluid channel. In addition, the estimated Doppler shift frequency shows a good agreement with the theoretical value.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Image-Free Ultrasound Blood-Flow Monitoring Circuit System with Automatic Range-Gate Positioning Scheme: A Pilot Study

Park¹,

2021

Applied Sciences

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“…Ultrasound technique is a significant development in the field of traditional diagnostic medicine and has a wide range of clinical applications ( Kranjec et al, 2014 ; Jana et al, 2020 ). In recent years, transcranial focused ultrasound (tFUS) has gained wide attention in the fields of neuromodulation ( Tufail et al, 2010 ; Deffieux et al, 2013 ; Mueller et al, 2014 ; Lee et al, 2016 ; Legon et al, 2018 ) and neuroimaging ( Song et al, 2021 ; Zhou et al, 2021 ).…”

Section: Introductionmentioning

confidence: 99%

Mathematical Model of Ultrasound Attenuation With Skull Thickness for Transcranial-Focused Ultrasound

et al. 2022

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Transcranial-focused ultrasound (tFUS) has potential for both neuromodulation and neuroimaging. Due to the influence of head tissue, especially the skull, its attenuation is a key issue affecting precise focusing. The objective of the present study was to construct a mathematical model of ultrasound attenuation inclusive of skull thickness. First, combined with real skull phantom experiments and simulation experiments, tFUS attenuation of different head tissues was investigated. Furthermore, based on the system identification method, a mathematical model of ultrasound attenuation was constructed taking skull thickness into account. Finally, the performance of the mathematical model was tested, and its potential applications were investigated. For different head tissues, including scalp, skull, and brain tissue, the skull was found to be the biggest influencing factor for ultrasound attenuation, the attenuation caused by it being 4.70 times and 7.06 times that of attenuation caused by the brain and scalp, respectively. Consistent with the results of both the simulation and phantom experiments, the attenuation of the mathematical model increased as the skull thickness increased. The average error of the mathematical model was 1.87% in the phantom experiment. In addition, the experimental results show that the devised mathematical model is suitable for different initial pressures and different skulls with correlation coefficients higher than 0.99. Both simulation and phantom experiments validated the effectiveness of the proposed mathematical model. It can be concluded from this experiment that the proposed mathematical model can accurately calculate the tFUS attenuation and can significantly contribute to further research and application of tFUS.

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“…They integrate, for example, the receiver front end and the beamformer [ 7 ], the transmitter and the piezoelectric transducers array [ 8 ], and the complete transmission–reception transceiver [ 9 ]. The availability of these devices fosters the development of compact and economical ultrasound systems [ 10 , 11 , 12 , 13 , 14 ], even based on smartphones [ 15 ], and can change the ultrasound paradigm, opening new scenarios for their employment. These apparatuses represent an important contribution, but they alone do not completely solve the problem, since, as noted before, the presence of an expert operator is still required.…”

Section: Introductionmentioning

confidence: 99%

Automatic Measurement of the Carotid Blood Flow for Wearable Sensors: A Pilot Study

Matera

Ricci

2021

Sensors

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The assessment of the velocity of blood flowing in the carotid, in modern clinical practice, represents an important exam performed both in emergency situations and as part of scheduled screenings. It is typically performed by an expert sonographer who operates a complex and costly clinical echograph. Unfortunately, in developing countries, in rural areas, and even in crowded modern cities, the access to this exam can be limited by the lack of suitable personnel and ultrasound equipment. The recent availability of low-cost, handheld devices has contributed to solving part of the problem, but a wide access to the exam is still hampered by the lack of expert sonographers. In this work, an automated procedure is presented with the hope that, in the near future, it can be integrated into a low-cost, handheld instrument that is also suitable for self-measurement, for example, as can be done today with the finger oximeter. The operator should only place the probe on the neck, transversally with respect to the common tract of the carotid. The system, in real-time, automatically locates the vessel lumen, places the sample volume, and performs an angle-corrected velocity measurement of the common carotid artery peak velocity. In this study, the method was implemented for testing on the ULA-OP 256 scanner. Experiments on flow phantoms and volunteers show a performance in sample volume placement similar to that achieved by expert operators, and an accuracy and repeatability of 3.2% and 4.5%, respectively.

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Smartphone-Based Point-of-Care System Using Continuous-Wave Portable Doppler

Cited by 14 publications

References 25 publications

Image-Free Ultrasound Blood-Flow Monitoring Circuit System with Automatic Range-Gate Positioning Scheme: A Pilot Study

Image-Free Ultrasound Blood-Flow Monitoring Circuit System with Automatic Range-Gate Positioning Scheme: A Pilot Study

Mathematical Model of Ultrasound Attenuation With Skull Thickness for Transcranial-Focused Ultrasound

Automatic Measurement of the Carotid Blood Flow for Wearable Sensors: A Pilot Study

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