Computer Assisted Auscultation System for Phonoangiography of the Carotid Artery

Sühn, Thomas; Mahmoodian, Naghmeh; Sreenivas, Arathi; Maldonado, Iván; Spiller, Moritz; Boese, Axel; Illanes, Alfredo; Friebe, Michael; Bloxton, Michael

doi:10.1515/cdbme-2019-0044

Cited by 3 publications

(2 citation statements)

References 7 publications

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“…The main components of the acquisition system include the sensing hardware, a desktop application for real-time visualization of the acquired signals, a mechanical case to enclose the hardware, and a reliable skin-transducer interface to acquire high-quality signals. The device used for the audio acquisition was first introduced as an auscultation system for vascular sounds by Sühn et al [ 26 , 27 ]. To summarize, the device consisted of two Knowles digital microphones (Knowles Electronics LLC, SPH0645LM4HB, Itasca, Illinois, USA) assembled on a custom-designed printed circuit board and with a raspberry pi (Raspberry Pi Foundation, Raspberry Pi Zero W, Cambridge, United Kingdom) as a host system.…”

Section: Methodsmentioning

confidence: 99%

Vascular Auscultation of Carotid Artery: Towards Biometric Identification and Verification of Individuals

Salvi¹,

Fuentealba

Henze

et al. 2021

Sensors

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Background: Biometric sensing is a security method for protecting information and property. State-of-the-art biometric traits are behavioral and physiological in nature. However, they are vulnerable to tampering and forgery. Methods: The proposed approach uses blood flow sounds in the carotid artery as a source of biometric information. A handheld sensing device and an associated desktop application were built. Between 80 and 160 carotid recordings of 11 s in length were acquired from seven individuals each. Wavelet-based signal analysis was performed to assess the potential for biometric applications. Results: The acquired signals per individual proved to be consistent within one carotid sound recording and between multiple recordings spaced by several weeks. The averaged continuous wavelet transform spectra for all cardiac cycles of one recording showed specific spectral characteristics in the time-frequency domain, allowing for the discrimination of individuals, which could potentially serve as an individual fingerprint of the carotid sound. This is also supported by the quantitative analysis consisting of a small convolutional neural network, which was able to differentiate between different users with over 95% accuracy. Conclusion: The proposed approach and processing pipeline appeared promising for the discrimination of individuals. The biometrical recognition could clinically be used to obtain and highlight differences from a previously established personalized audio profile and subsequently could provide information on the source of the deviation as well as on its effects on the individual’s health. The limited number of individuals and recordings require a study in a larger population along with an investigation of the long-term spectral stability of carotid sounds to assess its potential as a biometric marker. Nevertheless, the approach opens the perspective for automatic feature extraction and classification.

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Section: Methodsmentioning

confidence: 99%

Vascular Auscultation of Carotid Artery: Towards Biometric Identification and Verification of Individuals

Salvi¹,

Fuentealba

Henze

et al. 2021

Sensors

Self Cite

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“…To determine the appropriate physical parameters (eg, shape, surface area, transmission path, acoustic membrane) of the interface, a preliminary phantom study was conducted for different configurations. 21,22 The comparison of various bell-shaped structures similar to an analog stethoscope and with and without incorporated acoustic membrane resulted in the design shown in Figure 3. The proposed interface consists of two bell-shaped structures of similar dimensions located next to each other.…”

Section: Skin-transducer-interface Designmentioning

confidence: 99%

<p>Auscultation System for Acquisition of Vascular Sounds – Towards Sound-Based Monitoring of the Carotid Artery</p>

Sühn

Spiller

Salvi

et al. 2020

MDER

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Introduction Atherosclerotic diseases of the carotid are a primary cause of cerebrovascular events such as stroke. For the diagnosis and monitoring angiography, ultrasound- or magnetic resonance-based imaging is used which requires costly hardware. In contrast, the auscultation of carotid sounds and screening for bruits – audible patterns related to turbulent blood flow – is a simple examination with comparably little technical demands. It can indicate atherosclerotic diseases and justify further diagnostics but is currently subjective and examiner dependent. Methods We propose an easy-to-use computer-assisted auscultation system for a stable and reproducible acquisition of vascular sounds of the carotid. A dedicated skin-transducer-interface was incorporated into a handheld device. The interface comprises two bell-shaped structures, one with additional acoustic membrane, to ensure defined skin contact and a stable propagation path of the sound. The device is connected wirelessly to a desktop application allowing real-time visualization, assessment of signal quality and input of supplementary information along with storage of recordings in a database. An experimental study with 5 healthy subjects was conducted to evaluate usability and stability of the device. Five recordings per carotid served as data basis for a wavelet-based analysis of the stability of spectral characteristics of the recordings. Results The energy distribution of the wavelet-based stationary spectra proved stable for measurements of a particular carotid with the majority of the energy located between 3 and 40 Hz. Different spectral properties of the carotids of one individual indicate the presence of sound characteristics linked to the particular vessel. User-dependent parameters such as variations of the applied contact pressure appeared to have minor influence on the general stability. Conclusion The system provides a platform for reproducible carotid auscultation and the creation of a database of pathological vascular sounds, which is a prerequisite to investigate sound-based vascular monitoring.

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Computational hemodynamics and hemoacoustic study on carotid bifurcation: Effect of stenosis and branch angle

Morab,

Murallidharan,

Sharma

2024

Physics of Fluids

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Investigation of sound-signal-based noninvasive diagnosis of arterial stenosis is an active area of research. This study focuses on computational investigation of hemodynamic and hemoacoustic parameters within the carotid bifurcation. The objective is to analyze the effect of 40 distinct geometric configurations on indicative sound signals, useful for understanding the feasibility of stethoscope-based diagnosis of stenosis. The study employs an in-house flow-solver based on the semi-implicit pressure-projection method on a curvilinear grid. Physiological condition-based pulsatile flow waveforms and three-element Windkessel model-based pressure are utilized at the inlet and outlets of the bifurcating carotid artery. The research involves assessment of parameters like wall shear stress (WSS) and integrated pressure force rate (IPFR) fast Fourier transform (FFT) spectrum. Geometric configurations are varied based on stenosis level S (0, 45%, 60%, and 70%), bifurcation angle BA (30°, 40°, 50°, and 65°), and length of stenosis L (1, 1.5, and 2). In the investigated geometries, WSS exhibits a distinct behavior, reaching a peak at stenosis and subsequently transitioning to a negative value. Furthermore, IPFR-spectrum analysis reveals distinguishable frequencies for S≥ 40%, hinting at the potential for stethoscope-based diagnosis. A novel correlation between the cutoff frequencies of IPFR FFT-spectrum and arterial geometry is established, which reflect the influence of artery geometry on sound signals. Computational fluid dynamics (CFD)-based flow-visualization approach is proposed to calculate characteristic frequencies, which are close to IPFR spectrum frequencies. Our study contributes to a framework for potential sound-based classification of plaque-induced constrictions.

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Computer Assisted Auscultation System for Phonoangiography of the Carotid Artery

Cited by 3 publications

References 7 publications

Vascular Auscultation of Carotid Artery: Towards Biometric Identification and Verification of Individuals

Vascular Auscultation of Carotid Artery: Towards Biometric Identification and Verification of Individuals

<p>Auscultation System for Acquisition of Vascular Sounds – Towards Sound-Based Monitoring of the Carotid Artery</p>

Computational hemodynamics and hemoacoustic study on carotid bifurcation: Effect of stenosis and branch angle

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