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In this paper, we propose a new method for classifying patients with pulmonary emphysema and healthy subjects using lung sounds. Using conventional classification methods, every boundary between inspiratory and expiratory phases in successive respiratory sounds are detected manually prior to automatic classification. However, manual segmentation must be performed accurately and has therefore created...
Quantitatively assessing the tissue stiffness with acoustic radiation force impulse (ARFI) method has proved its worth in clinical trials. Much attention has been focused on the research of the displacement estimation algorithm in ARFI. However, the subsequent shear wave speed estimation part can also affect the accuracy and reliability of the results. In this study, several algorithms for shear wave...
One to five transvaginal ultrasound scans were taken of 63 women to estimate the microstructural changes in cervix using ultrasonic attenuation. Spectral log difference algorithm showed a clear decrease in attenuation as the time to delivery comes closer. The decrease in attenuation occurs earlier in preterm birth compared to full term birth which can be used as a predictor for preterm birth. Attenuation...
Ultrasound contrast agents are gas filled microbubbles which produced enhanced echoes in ultrasound imaging thus allowing the acquisition of detailed information on the path of blood. It is theoretically known that the size of a vessel affects the behavior of a microbubble, which could potentially be used to discriminate different sized vessels. This information would be useful in the monitoring of...
A ventricular assist device (VAD) is a device with mechanical pumps implanted adjacent to the patient's native heart to support the blood flow. Mechanical circulatory support using VADs has been an essential therapeutic tool for patients with severe heart failure waiting for a heart transplant in clinical site. Adaptive control of VADs that automatically adjust the pump output with changes in a patient...
Transcranial high-intensity focused ultrasound has recently been used to noninvasively treat several types of brain disorders. However, due to the large differences in acoustic properties of skulls and the surrounding soft tissue, it can be a challenge to adequately focus an ultrasonic beam through the skull. We present a novel, fast, full-wave method of correcting the aberrations caused by the skull...
Micro-electrocorticography (μECoG) displays advantages over traditional invasive methods. The μECoG electrode can record neural activity with high spatial-temporal resolution and it can reduce implantation side effects (e.g. vascular and local-neuronal damage, tissue encapsulation, infection). In this study, we propose a printable transparent μECoG electrode for optogenetic applications by using ultrasonic...
In order to design a 50MHz intravascular ultrasound (IVUS) transducer with good pulse-echo responses, in this paper, a finite element model (FEM) was built to simulate the transducer acoustic performances with different layer thicknesses. According to comparisons of the acoustic fields and the admittance curves, the optimum thickness parameters are gained. And then, an IVUS PZT transducer with controlled...
This paper models and experimentally measures the acoustic interference from two low intensity 3MHz continuous ultrasound transducers of the sam® wearable ultrasound device. Resulting data show that placement configuration, which dictates interference depth, and frequency phase variation are the main factors to acoustic pressure distribution. Mathematical analysis reveals that the acoustic pressure...
We present a mixed-signal architecture for implementation of independent component analysis designed for the task of blind source separation of acoustic sources interfacing miniature microphone array. The matrix-vector multiplication is implemented through integration of switched current sources controlled by the pulse-width modulated signals. The proposed architecture implementing 3×3 static ICA...
In the process of fracture healing, several phases of recovery are observed as the mechanical stability, continuity and normal load carrying capacity are gradually restored. The ultrasonic monitoring and discrimination of different healing stages is a complex process due to the significant microstructure and porous nature of osseous and callus tissues. In this study, we investigate the influence of...
Tracheal activity recognition can play an important role in continuous health monitoring for wearable systems and facilitate the advancement of personalized healthcare. Neck-worn systems provide access to a unique set of health-related data that other wearable devices simply cannot obtain. Activities including breathing, chewing, clearing the throat, coughing, swallowing, speech and even heartbeat...
This paper presents a method to automatically estimate lung tidal volumes from the acoustic signals generated in the respiratory track. The signal is measured with an acoustic based sensor placed in the suprasternal notch. The method does not require any previous knowledge or modelling of the individual respiratory track, and relies on just one calibration parameter. The proposed algorithm is tested...
In this paper, control of a thin catheter bending by using acoustic radiation force was carried out to develop precise and noninvasive surgery in small blood vessel. First, it was elucidated that the acting force to a thin catheter made from perfluoroalkoxy (PFA) copolymer could be obtained from the cantilever equation in the effective range, where the displacement of the catheter divided by the cube...
In this paper, we examine the use of beamforming techniques to interrogate a multitude of neural implants in a distributed, ultrasound-based intra-cortical recording platform known as Neural Dust [1]. We propose a general framework to analyze system design tradeoffs in the ultrasonic beamformer that extracts neural signals from modulated ultrasound waves that are backscattered by free-floating neural...
This paper presents the development of a single platform that records auditory evoked potential synchronized to specific acoustic stimuli of the gap prepulse inhibition method for objective tinnitus diagnosis research. The developed system enables to program various parameters of the generated acoustic stimuli. Moreover, only by simple filter modification, the developed system provides high flexibility...
Novel diagnostic method named “sonocytometry”, in which streaming blood cell is diagnosed by the reflection of high frequency ultrasound from the cell, is proposed. In the present study, the differentiation of the particle size is performed as a basic study on sonocytometry. Ultrasonic backscatter signal from either 80 or 100 цm diameter polystyrene particles was measured by an ultrasonic transducer...
Snoring is one of the representative phenomena of the sleep disorder and detection of snoring is quite important for improving quality of daily human life. The purpose of this research is to define the noises of the ordinary sleep situation and to find its characteristics as a preliminary research of snoring detection. Differently from previous snoring researches, we use a built-in sound recording...
Obstructive sleep apnea (OSA) is a common sleep disorder. OSA is associated with several anatomical and functional abnormalities of the upper airway. It was shown that these abnormalities in the upper airway are also likely to be the reason for increased rate of apneic events in the supine position. Functional and structural changes in the vocal tract can affect the acoustic properties of speech....
Recently, it has been demonstrated that through the use of contrast agents and multi-frequency transducer technology, high resolution and high signal to noise ultrasound images can be obtained which illustrate microvascular structure in unprecedented detail for an ultrasound modality. The enabling technology is ultrasound transducers which are fabricated with elements which can excite microbubble...
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