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Badhwar S, Marais L, Khettab H, Poli F, Li Y, Segers P, Aasmul S, de Melis M, Baets R, Greenwald S, Bruno RM, Boutouyrie P. Clinical Validation of Carotid-Femoral Pulse Wave Velocity Measurement Using a Multi-Beam Laser Vibrometer: The CARDIS Study. Hypertension 2024; 81:1986-1995. [PMID: 38934112 PMCID: PMC11319084 DOI: 10.1161/hypertensionaha.124.22729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 06/04/2024] [Indexed: 06/28/2024]
Abstract
BACKGROUND Carotid-femoral pulse wave velocity (cfPWV) is the gold standard for noninvasive arterial stiffness assessment, an independent predictor of cardiovascular disease, and a potential parameter to guide therapy. However, cfPWV is not routinely measured in clinical practice due to the unavailability of a low-cost, operator-friendly, and independent device. The current study validated a novel laser Doppler vibrometry (LDV)-based measurement of cfPWV against the reference technique. METHODS In 100 (50 men) hypertensive patients, cfPWV was measured using applanation tonometry (Sphygmocor) and the novel LDV device. This device has 2 handpieces with 6 laser beams each that simultaneously measure vibrations from the skin surface at carotid and femoral sites. Pulse wave velocity is calculated using ECG for the identification of cardiac cycles. An ECG-independent method was also devised. Cardiovascular risk score was calculated for patients between 40 and 75 years old using the WHO risk scoring chart. RESULTS LDV-based cfPWV correlated significantly with tonometry (r=0.86, P<0.0001 ECG-dependent [cfPWVLDV_ECG] and r=0.80, P<0.001 ECG-independent [cfPWVLDV_w/oECG] methods). Bland-Altman analysis showed nonsignificant bias (0.65 m/s) and acceptable SD (1.27 m/s) between methods. Intraobserver coefficient of variance for LDV was 4.7% (95% CI, 3.0%-5.5%), and interobserver coefficient of variance was 5.87%. CfPWV correlated significantly with CVD risk (r=0.64, P<0.001; r=0.41, P=0.003; and r=0.37, P=0.006 for tonometry, LDV-with, and LDV-without ECG, respectively). CONCLUSIONS The study demonstrates clinical validity of the LDV device. The LDV provides a simple, noninvasive, operator-independent method to measure cfPWV for assessing arterial stiffness, comparable to the standard existing techniques. REGISTRATION URL: https://clinicaltrials.gov/study/NCT03446430; Unique identifier: NCT03446430.
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Affiliation(s)
- Smriti Badhwar
- Paris Cardiovascular Research Center (PARCC) Institut National de la Santé Et de la Researche Médicale (INSERM), Paris, France (S.B., L.M., F.P., R.M.B., P.B.)
| | - Louise Marais
- Paris Cardiovascular Research Center (PARCC) Institut National de la Santé Et de la Researche Médicale (INSERM), Paris, France (S.B., L.M., F.P., R.M.B., P.B.)
| | - Hakim Khettab
- Hôpital européen Georges-Pompidou (HEGP), Assistance publique-Hôpitaux de Paris (APHP), Paris, France (H.K., R.M.B, P.B.)
| | - Federica Poli
- Paris Cardiovascular Research Center (PARCC) Institut National de la Santé Et de la Researche Médicale (INSERM), Paris, France (S.B., L.M., F.P., R.M.B., P.B.)
| | - Yanlu Li
- Photonics Research Group, Ghent University-imec, Belgium (Y.L., R.B.)
- Center for Nano- and Biophotonics, Ghent University, Belgium (Y.L., R.B.)
| | | | - Soren Aasmul
- Medtronic Bakken Research Center, Maastricht, The Netherlands (S.A., M.d.M.)
| | - Mirko de Melis
- Medtronic Bakken Research Center, Maastricht, The Netherlands (S.A., M.d.M.)
| | - Roel Baets
- Photonics Research Group, Ghent University-imec, Belgium (Y.L., R.B.)
- Center for Nano- and Biophotonics, Ghent University, Belgium (Y.L., R.B.)
| | - Steve Greenwald
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, United Kingdom (S.G.)
| | - Rosa Maria Bruno
- Paris Cardiovascular Research Center (PARCC) Institut National de la Santé Et de la Researche Médicale (INSERM), Paris, France (S.B., L.M., F.P., R.M.B., P.B.)
- Hôpital européen Georges-Pompidou (HEGP), Assistance publique-Hôpitaux de Paris (APHP), Paris, France (H.K., R.M.B, P.B.)
- Université Paris Cité, Faculté de Médecine, France (R.M.B, P.B.)
| | - Pierre Boutouyrie
- Paris Cardiovascular Research Center (PARCC) Institut National de la Santé Et de la Researche Médicale (INSERM), Paris, France (S.B., L.M., F.P., R.M.B., P.B.)
- Hôpital européen Georges-Pompidou (HEGP), Assistance publique-Hôpitaux de Paris (APHP), Paris, France (H.K., R.M.B, P.B.)
- Université Paris Cité, Faculté de Médecine, France (R.M.B, P.B.)
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Beeckman S, Li Y, Aasmul S, Baets R, Boutouyrie P, Segers P, Madhu N. Enhancing Multichannel Laser-Doppler Vibrometry Signals with Application to (Carotid-Femoral) Pulse Transit Time Estimation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-7. [PMID: 38083013 DOI: 10.1109/embc40787.2023.10340553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Pulse-wave velocity (PWV) can be used to quantify arterial stiffness, allowing for a diagnosis of this condition. Multi-beam laser-doppler vibrometry offers a cheap, non-invasive and user-friendly alternative to measuring PWV, and its feasibility has been previously demonstrated in the H2020 project CARDIS. The two handpieces of the prototype CARDIS device measure skin displacement above main arteries at two different sites, yielding an estimate of the pulse-transit time (PTT) and, consequently, PWV. The presence of multiple beams (channels) on each handpiece can be used to enhance the underlying signal, improving the quality of the signal for PTT estimation and further analysis. We propose two methods for multi-channel LDV data processing: beamforming and beamforming-driven ICA. Beamforming is done by an SNR-weighted linear combination of the time-aligned channels, where the SNR is blindly estimated from the signal statistics. ICA uses the beamformer to resolve its inherent permutation and scale ambiguities. Both methods yield a single enhanced signal at each handpiece, where spurious peaks in the individual channels as well as stochastic noise are well suppressed in the output. Using the enhanced signals yields individual PTT estimates with a low spread compared to the baseline approach. While the enhancement is introduced in the context of PTT estimation, the approaches can be used to enhance signals in other biomedical applications of multi-channel LDV as well.
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Que S, Verkruijsse W, van Gastel M, Stuijk S. Contactless Heartbeat Measurement Using Speckle Vibrometry. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:4604-4610. [PMID: 36086409 DOI: 10.1109/embc48229.2022.9871712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Monitoring of heart rate in patients in the general ward is necessary to assess the clinical situation of the patient. Currently, this is done via spot-checks on pulse rate manually or on heart rate using Electrocardiogram (ECG) by nurses. More frequent measurements would allow early detection of adverse cardiac events. In this work, we investigate a contactless measurement setup combined with a signal processing pipeline, which is based on speckle vibrometry (SV), to perform contactless heart rate monitoring of human subjects in a supine position, mimicking a resting scenario in the general ward. Our results demonstrate the feasibility of extracting heart rate with SV through varying textile thicknesses (i.e., 8 mm, 32 mm and 64 mm), with an error smaller than 3 beats per minute on average compared to the ground-truth heart rate derived from ECG.
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Galli A, Montree RJH, Que S, Peri E, Vullings R. An Overview of the Sensors for Heart Rate Monitoring Used in Extramural Applications. SENSORS (BASEL, SWITZERLAND) 2022; 22:4035. [PMID: 35684656 PMCID: PMC9185322 DOI: 10.3390/s22114035] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 06/02/2023]
Abstract
This work presents an overview of the main strategies that have been proposed for non-invasive monitoring of heart rate (HR) in extramural and home settings. We discuss three categories of sensing according to what physiological effect is used to measure the pulsatile activity of the heart, and we focus on an illustrative sensing modality for each of them. Therefore, electrocardiography, photoplethysmography, and mechanocardiography are presented as illustrative modalities to sense electrical activity, mechanical activity, and the peripheral effect of heart activity. In this paper, we describe the physical principles underlying the three categories and the characteristics of the different types of sensors that belong to each class, and we touch upon the most used software strategies that are currently adopted to effectively and reliably extract HR. In addition, we investigate the strengths and weaknesses of each category linked to the different applications in order to provide the reader with guidelines for selecting the most suitable solution according to the requirements and constraints of the application.
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Affiliation(s)
- Alessandra Galli
- Department of Information Engineering, University of Padova, I-35131 Padova, Italy;
| | - Roel J. H. Montree
- Department of Electrical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; (R.J.H.M.); (S.Q.); (E.P.)
| | - Shuhao Que
- Department of Electrical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; (R.J.H.M.); (S.Q.); (E.P.)
| | - Elisabetta Peri
- Department of Electrical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; (R.J.H.M.); (S.Q.); (E.P.)
| | - Rik Vullings
- Department of Electrical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands; (R.J.H.M.); (S.Q.); (E.P.)
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Seoni S, Beeckman S, Li Y, Aasmul S, Morbiducci U, Baets R, Boutouyrie P, Molinari F, Madhu N, Segers P. Template Matching and Matrix Profile for Signal Quality Assessment of Carotid and Femoral Laser Doppler Vibrometer Signals. Front Physiol 2022; 12:775052. [PMID: 35087417 PMCID: PMC8787261 DOI: 10.3389/fphys.2021.775052] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/06/2021] [Indexed: 01/21/2023] Open
Abstract
Background: Laser-Doppler Vibrometry (LDV) is a laser-based technique that allows measuring the motion of moving targets with high spatial and temporal resolution. To demonstrate its use for the measurement of carotid-femoral pulse wave velocity, a prototype system was employed in a clinical feasibility study. Data were acquired for analysis without prior quality control. Real-time application, however, will require a real-time assessment of signal quality. In this study, we (1) use template matching and matrix profile for assessing the quality of these previously acquired signals; (2) analyze the nature and achievable quality of acquired signals at the carotid and femoral measuring site; (3) explore models for automated classification of signal quality. Methods: Laser-Doppler Vibrometry data were acquired in 100 subjects (50M/50F) and consisted of 4-5 sequences of 20-s recordings of skin displacement, differentiated two times to yield acceleration. Each recording consisted of data from 12 laser beams, yielding 410 carotid-femoral and 407 carotid-carotid recordings. Data quality was visually assessed on a 1-5 scale, and a subset of best quality data was used to construct an acceleration template for both measuring sites. The time-varying cross-correlation of the acceleration signals with the template was computed. A quality metric constructed on several features of this template matching was derived. Next, the matrix-profile technique was applied to identify recurring features in the measured time series and derived a similar quality metric. The statistical distribution of the metrics, and their correlates with basic clinical data were assessed. Finally, logistic-regression-based classifiers were developed and their ability to automatically classify LDV-signal quality was assessed. Results: Automated quality metrics correlated well with visual scores. Signal quality was negatively correlated with BMI for femoral recordings but not for carotid recordings. Logistic regression models based on both methods yielded an accuracy of minimally 80% for our carotid and femoral recording data, reaching 87% for the femoral data. Conclusion: Both template matching and matrix profile were found suitable methods for automated grading of LDV signal quality and were able to generate a quality metric that was on par with the signal quality assessment of the expert. The classifiers, developed with both quality metrics, showed their potential for future real-time implementation.
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Affiliation(s)
- Silvia Seoni
- PoliToBIOMed Lab, Biolab, Politecnico di Torino, Turin, Italy
| | - Simeon Beeckman
- IBiTech-bioMMeda, Ghent University, Ghent, Belgium
- IDLab-imec, Ghent University, Ghent, Belgium
| | - Yanlu Li
- Photonics Research Group, Center for Nano- and Biophotonics, Tech Lane Ghent Science Park/Campus A, Ghent University-imec, Ghent, Belgium
| | - Soren Aasmul
- Medtronic Bakken Research Center, Maastricht, Netherlands
| | - Umberto Morbiducci
- Department of Mechanical and Aerospace Engineering, Polytechnic University of Turin, Turin, Italy
| | - Roel Baets
- Photonics Research Group, Center for Nano- and Biophotonics, Tech Lane Ghent Science Park/Campus A, Ghent University-imec, Ghent, Belgium
| | - Pierre Boutouyrie
- INSERM U970, Université de Paris, Assistance Publique Hôpitaux de Paris, Paris, France
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Ultra-broadband local active noise control with remote acoustic sensing. Sci Rep 2020; 10:20784. [PMID: 33247208 PMCID: PMC7695846 DOI: 10.1038/s41598-020-77614-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 11/12/2020] [Indexed: 11/30/2022] Open
Abstract
One enduring challenge for controlling high frequency sound in local active noise control (ANC) systems is to obtain the acoustic signal at the specific location to be controlled. In some applications such as in ANC headrest systems, it is not practical to install error microphones in a person’s ears to provide the user a quiet or optimally acoustically controlled environment. Many virtual error sensing approaches have been proposed to estimate the acoustic signal remotely with the current state-of-the-art method using an array of four microphones and a head tracking system to yield sound reduction up to 1 kHz for a single sound source. In the work reported in this paper, a novel approach of incorporating remote acoustic sensing using a laser Doppler vibrometer into an ANC headrest system is investigated. In this “virtual ANC headphone” system, a lightweight retro-reflective membrane pick-up is mounted in each synthetic ear of a head and torso simulator to determine the sound in the ear in real-time with minimal invasiveness. The membrane design and the effects of its location on the system performance are explored, the noise spectra in the ears without and with ANC for a variety of relevant primary sound fields are reported, and the performance of the system during head movements is demonstrated. The test results show that at least 10 dB sound attenuation can be realised in the ears over an extended frequency range (from 500 Hz to 6 kHz) under a complex sound field and for several common types of synthesised environmental noise, even in the presence of head motion.
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Gong P, Heiss C, Sampson DM, Wang Q, Yuan Z, Sampson DD. Detection of localized pulsatile motion in cutaneous microcirculation by speckle decorrelation optical coherence tomography angiography. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200112R. [PMID: 32935499 PMCID: PMC7490763 DOI: 10.1117/1.jbo.25.9.095004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 08/18/2020] [Indexed: 05/21/2023]
Abstract
SIGNIFICANCE Pulsatility is a vital characteristic of the cardiovascular system. Characterization of the pulsatility pattern locally in the peripheral microvasculature is currently not readily available and would provide an additional source of information, which may prove important in understanding the pathophysiology of arterial stiffening, vascular ageing, and their linkage with cardiovascular disease development. AIM We aim to confirm the suitability of speckle decorrelation optical coherence tomography angiography (OCTA) under various noncontact/contact scanning protocols for the visualization of pulsatility patterns in vessel-free tissue and in the microvasculature of peripheral human skin. RESULTS Results from five healthy subjects show distinct pulsatile patterns both in vessel-free tissue with either noncontact or contact imaging and in individual microvessels with contact imaging. Respectively, these patterns are likely caused by the pulsatile pressure and pulsatile blood flow. The pulse rates show good agreement with those from pulse oximetry, confirming that the pulsatile signatures reflect pulsatile hemodynamics. CONCLUSIONS This study demonstrates the potential of speckle decorrelation OCTA for measuring localized peripheral cutaneous pulsatility and defines scanning protocols necessary to undertake such measurements. Noncontact imaging should be used for the study of pulsatility in vessel-free tissue and contact imaging with strong mechanical coupling in individual microvessels. Further studies of microcirculation based upon this method and protocols are warranted.
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Affiliation(s)
- Peijun Gong
- The University of Western Australia, Optical+Biomedical Engineering Laboratory, Department of Electrical, Electronic, and Computer Engineering, Perth, Western Australia, Australia
- Address all correspondence to Peijun Gong, E-mail:
| | - Christian Heiss
- The University of Surrey, Department of Clinical and Experimental Medicine, Faculty of Health and Medical Sciences, Guildford, Surrey, United Kingdom
- Surrey and Sussex Healthcare NHS Trust, Redhill, United Kingdom
| | - Danuta M. Sampson
- The University of Surrey, Centre for Vision, Speech, and Signal Processing, Surrey Biophotonics, Guildford, Surrey, United Kingdom
- The University of Surrey, School of Biosciences and Medicine, Surrey Biophotonics, Guildford, Surrey, United Kingdom
| | - Qiang Wang
- The University of Western Australia, Optical+Biomedical Engineering Laboratory, Department of Electrical, Electronic, and Computer Engineering, Perth, Western Australia, Australia
| | - Zhihong Yuan
- The University of Western Australia, Optical+Biomedical Engineering Laboratory, Department of Electrical, Electronic, and Computer Engineering, Perth, Western Australia, Australia
| | - David D. Sampson
- The University of Surrey, School of Biosciences and Medicine, Surrey Biophotonics, Guildford, Surrey, United Kingdom
- The University of Surrey, Advanced Technology Institute, School of Physics, Surrey Biophotonics, Guildford, Surrey, United Kingdom
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Tunable Optical Delay Line Based on a Racetrack Resonator with Tunable Coupling and Stable Wavelength. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9245483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
For optical sensing or biomedical sensing where the light source usually has a stable and narrow linewidth, the design rule of the tunable optical delay line (ODL) can be different from the ODLs for optical communications and buffering. We present here a novel way to tune a racetrack resonator-based ODL by push–pull operation to stabilize the resonant wavelength. Full device simulation that accounts for the thermal tuning effect and the photonic characteristics of the whole integrated device is conducted to verify the characteristics of the tunable ODLs. With the simple racetrack resonator, the group delay can simply be tuned by changing the coupling coefficient of the resonator while the wavelength is stabilized by tuning the racetrack loop. A tuning of hundreds of picoseconds is achievable with a very compact device and small power consumption.
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Nabeel PM, Kiran VR, Joseph J, Abhidev VV, Sivaprakasam M. Local Pulse Wave Velocity: Theory, Methods, Advancements, and Clinical Applications. IEEE Rev Biomed Eng 2019; 13:74-112. [PMID: 31369386 DOI: 10.1109/rbme.2019.2931587] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Local pulse wave velocity (PWV) is evolving as one of the important determinants of arterial hemodynamics, localized vessel stiffening associated with several pathologies, and a host of other cardiovascular events. Although PWV was introduced over a century ago, only in recent decades, due to various technological advancements, has emphasis been directed toward its measurement from a single arterial section or from piecewise segments of a target arterial section. This emerging worldwide trend in the exploration of instrumental solutions for local PWV measurement has produced several invasive and noninvasive methods. As of yet, however, a univocal opinion on the ideal measurement method has not emerged. Neither have there been extensive comparative studies on the accuracy of the available methods. Recognizing this reality, makes apparent the need to establish guideline-recommended standards for the measurement methods and reference values, without which clinical application cannot be pursued. This paper enumerates all major local PWV measurement methods while pinpointing their salient methodological considerations and emphasizing the necessity of global standardization. Further, a summary of the advancements in measuring modalities and clinical applications is provided. Additionally, a detailed discussion on the minimally explored concept of incremental local PWV is presented along with suggestions of future research questions.
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Detecting carotid stenosis from skin vibrations using Laser Doppler Vibrometry - An in vitro proof-of-concept. PLoS One 2019; 14:e0218317. [PMID: 31220141 PMCID: PMC6586301 DOI: 10.1371/journal.pone.0218317] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 05/31/2019] [Indexed: 02/02/2023] Open
Abstract
Early detection of asymptomatic carotid stenosis may help identifying individuals at risk of stroke. We explore a new method based on laser Doppler vibrometry (LDV) which could allow the non-contact detection of stenosis from neck skin vibrations due to stenosis-induced flow disturbances. Experimental fluid dynamical tests were performed with water on a severely stenosed patient-specific carotid bifurcation model. Measurements were taken under various physiological flow regimes both in a compliant and stiff-walled version of the model, at 1 to 4 diameters downstream from the stenosis. An inter-arterial pressure catheter was positioned as reference. Increasing flow led to corresponding increase in power spectral density (PSD) of pressure and LDV recordings in the 0-500 Hz range. The stiff model lead to higher PSD. PSD of the LDV signal was less dependent on the downstream measurement location than pressure. The strength of the association between PSD and flow level, model material and measuring location was highest in the 0-50 Hz range, however useful information was found up to 200 Hz. This proof-of-concept suggests that LDV has the potential to detect stenosis-induced disturbed flow. Further computational and clinical validation studies are ongoing to assess the sensitivity and specificity of the technique for clinical screening.
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High-Frequency Fluctuations in Post-stenotic Patient Specific Carotid Stenosis Fluid Dynamics: A Computational Fluid Dynamics Strategy Study. Cardiovasc Eng Technol 2019; 10:277-298. [PMID: 30937853 PMCID: PMC6527791 DOI: 10.1007/s13239-019-00410-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 03/15/2019] [Indexed: 12/16/2022]
Abstract
Purpose Screening of asymptomatic carotid stenoses is performed by auscultation of the carotid bruit, but the sensitivity is poor. Instead, it has been suggested to detect carotid bruit as neck’s skin vibrations. We here take a first step towards a computational fluid dynamics proof-of-concept study, and investigate the robustness of our numerical approach for capturing high-frequent fluctuations in the post-stenotic flow. The aim was to find an ideal solution strategy from a pragmatic point of view, balancing accuracy with computational cost comparing an under-resolved direct numerical simulation (DNS) approach vs. three common large eddy simulation (LES) models (static/dynamic Smagorinsky and Sigma). Method We found a reference solution by performing a spatial and temporal refinement study of a stenosed carotid bifurcation with constant flow rate. The reference solution \documentclass[12pt]{minimal}
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\begin{document}$$\left( {\Delta x = 1.92 \times 10^{ - 4} \;{\text{m}},\; \Delta t = 5 \times 10^{ - 5} \;{\text{s}}} \right)$$\end{document}Δx=1.92×10-4m,Δt=5×10-5s was compared against LES for both a constant and pulsatile flow. Results Only the Sigma and Dynamic Smagorinsky models were able to replicate the flow field of the reference solution for a pulsatile simulation, however the computational cost of the Sigma model was lower. However, none of the sub-grid scale models were able to replicate the high-frequent flow in the peak-systolic constant flow rate simulations, which had a higher mean Reynolds number. Conclusions The Sigma model was the best combination between accuracy and cost for simulating the pulsatile post-stenotic flow field, whereas for the constant flow rate, the under-resolved DNS approach was better. These results can be used as a reference for future studies investigating high-frequent flow features.
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Agusanto K, Lau GK, Liu T, Zhu C. Effect of oblique retroreflection from a vibrating mirror on laser Doppler shift. APPLIED OPTICS 2019; 58:2277-2283. [PMID: 31044922 DOI: 10.1364/ao.58.002277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 02/16/2019] [Indexed: 06/09/2023]
Abstract
A laser Doppler vibrometer (LDV) fails to measure a large out-of-plane vibration of a rotating mirror when the mirror obliquely reflects the laser beam away, causing a signal loss from being detected. To solve this problem, an external retroreflective tape was used to recover the oblique reflection. However, the reading of LDV obtained from the recovered signal is not right because the retroreflection adds extra Doppler frequency shifts to the oblique reflection. Here, we first derive the relationship of Doppler shift to the oblique angle of retroreflection. For the first time with the help of retroreflection, a standard LDV can measure the largely vibrating mirror as well as a high-speed camera, albeit without the need for heavy computation.
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Li Y, Zhu J, Duperron M, O'Brien P, Schüler R, Aasmul S, de Melis M, Kersemans M, Baets R. Six-beam homodyne laser Doppler vibrometry based on silicon photonics technology. OPTICS EXPRESS 2018; 26:3638-3645. [PMID: 29401891 DOI: 10.1364/oe.26.003638] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/29/2018] [Indexed: 06/07/2023]
Abstract
This paper describes an integrated six-beam homodyne laser Doppler vibrometry (LDV) system based on a silicon-on-insulator (SOI) full platform technology, with on-chip photo-diodes and phase modulators. Electronics and optics are also implemented around the integrated photonic circuit (PIC) to enable a simultaneous six-beam measurement. Measurement of a propagating guided elastic wave in an aluminum plate (speed ≈ 909 m/s @ 61.5 kHz) is demonstrated.
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Wang R, Vasiliev A, Muneeb M, Malik A, Sprengel S, Boehm G, Amann MC, Šimonytė I, Vizbaras A, Vizbaras K, Baets R, Roelkens G. III-V-on-Silicon Photonic Integrated Circuits for Spectroscopic Sensing in the 2-4 μm Wavelength Range. SENSORS 2017; 17:s17081788. [PMID: 28777291 PMCID: PMC5579498 DOI: 10.3390/s17081788] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 07/29/2017] [Accepted: 07/31/2017] [Indexed: 11/16/2022]
Abstract
The availability of silicon photonic integrated circuits (ICs) in the 2-4 μm wavelength range enables miniature optical sensors for trace gas and bio-molecule detection. In this paper, we review our recent work on III-V-on-silicon waveguide circuits for spectroscopic sensing in this wavelength range. We first present results on the heterogeneous integration of 2.3 μm wavelength III-V laser sources and photodetectors on silicon photonic ICs for fully integrated optical sensors. Then a compact 2 μm wavelength widely tunable external cavity laser using a silicon photonic IC for the wavelength selective feedback is shown. High-performance silicon arrayed waveguide grating spectrometers are also presented. Further we show an on-chip photothermal transducer using a suspended silicon-on-insulator microring resonator used for mid-infrared photothermal spectroscopy.
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Affiliation(s)
- Ruijun Wang
- Photonics Research Group, Ghent University-imec, Technologiepark-Zwijnaarde 15, Ghent 9052, Belgium.
- Center for Nano- and Biophotonics (NB-Photonics), Ghent University, Ghent 9000, Belgium.
| | - Anton Vasiliev
- Photonics Research Group, Ghent University-imec, Technologiepark-Zwijnaarde 15, Ghent 9052, Belgium.
- Center for Nano- and Biophotonics (NB-Photonics), Ghent University, Ghent 9000, Belgium.
| | - Muhammad Muneeb
- Photonics Research Group, Ghent University-imec, Technologiepark-Zwijnaarde 15, Ghent 9052, Belgium.
- Center for Nano- and Biophotonics (NB-Photonics), Ghent University, Ghent 9000, Belgium.
| | - Aditya Malik
- Photonics Research Group, Ghent University-imec, Technologiepark-Zwijnaarde 15, Ghent 9052, Belgium.
- Center for Nano- and Biophotonics (NB-Photonics), Ghent University, Ghent 9000, Belgium.
| | - Stephan Sprengel
- Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, Garching 85748, Germany.
| | - Gerhard Boehm
- Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, Garching 85748, Germany.
| | - Markus-Christian Amann
- Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, Garching 85748, Germany.
| | - Ieva Šimonytė
- Brolis Semiconductors UAB, Moletu pl. 73, Vilnius LT-14259, Lithuania.
| | | | | | - Roel Baets
- Photonics Research Group, Ghent University-imec, Technologiepark-Zwijnaarde 15, Ghent 9052, Belgium.
- Center for Nano- and Biophotonics (NB-Photonics), Ghent University, Ghent 9000, Belgium.
| | - Gunther Roelkens
- Photonics Research Group, Ghent University-imec, Technologiepark-Zwijnaarde 15, Ghent 9052, Belgium.
- Center for Nano- and Biophotonics (NB-Photonics), Ghent University, Ghent 9000, Belgium.
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15
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Casacanditella L, Cosoli G, Casaccia S, Tomasini EP, Scalise L. Indirect measurement of the carotid arterial pressure from vibrocardiographic signal: Calibration of the waveform and comparison with photoplethysmographic signal. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2016:3568-3571. [PMID: 28324990 DOI: 10.1109/embc.2016.7591499] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The detection of arterial Blood Pressure waveform provides important information about the subject health status. Laser Doppler Vibrometry (LDV) is a non-contact technique with high sensitivity able to detect mechanical movements of the arterial wall; several previous studies have shown that LDV is able to characterize cardiac activity. Photoplethysmogram (PPG) quantifies the digital volume artery pulse, which has been demonstrated to be closely related to the pressure signal measured by an arterial tonometer. In this paper, an indirect measurement of carotid arterial pressure by means of LDV is presented. Moreover, a comparison between LDV and PPG is conducted in order to estimate the time interval between opening and closing of the aortic valve, that is the Left Ventricular Ejection Time (LVET). Results show an average reduction of around 20% of the systolic pressure derived from LDV signal measured over the carotid artery with respect to the systolic pressure measured at brachial level (i.e. peripheral pressure value). Finally, the comparison between LDV and PPG in the estimation of LVET shows a mean percentage deviation <;10%. So, in conclusion, it can be stated that LDV technique has the potential of providing a displacement waveform that, adequately calibrated, can furnish significant information about pressure waveform.
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16
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Ney M, Safrani A, Abdulhalim I. Three wavelengths parallel phase-shift interferometry for real-time focus tracking and vibration measurement. OPTICS LETTERS 2017; 42:719-722. [PMID: 28198848 DOI: 10.1364/ol.42.000719] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Instantaneous high-resolution, wide-range focus tracking and a vibrometry system based on three-wavelength (3λ) parallel phase-shift polarization interferometry using three detectors per wavelength is presented. The system, implementing 3λ in-parallel three-phase-shift-interferometry channels for the first time, to the best of our knowledge, allows single-shot position tracking of motion profiles with extremely high velocities and vibration rates, long inter-step heights, and sub-nanometer scale accuracy. The system's simple design and algorithm presented here do not rely on active optical components, making its performance limited only by the detectors' bandwidths and allowing the setting up of a very high-performance low-cost vibrometry system.
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17
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Sirevaag EJ, Casaccia S, Richter EA, O'Sullivan JA, Scalise L, Rohrbaugh JW. Cardiorespiratory interactions: Noncontact assessment using laser Doppler vibrometry. Psychophysiology 2016; 53:847-67. [PMID: 26970208 DOI: 10.1111/psyp.12638] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/17/2016] [Indexed: 01/02/2023]
Abstract
The application of a noncontact physiological recording technique, based on the method of laser Doppler vibrometry (LDV), is described. The effectiveness of the LDV method as a physiological recording modality lies in the ability to detect very small movements of the skin, associated with internal mechanophysiological activities. The method is validated for a range of cardiovascular variables, extracted from the contour of the carotid pulse waveform as a function of phase of the respiration cycle. Data were obtained from 32 young healthy participants, while resting and breathing spontaneously. Individual beats were assigned to four segments, corresponding with inspiration and expiration peaks and transitional periods. Measures relating to cardiac and vascular dynamics are shown to agree with the pattern of effects seen in the substantial body of literature based on human and animal experiments, and with selected signals recorded simultaneously with conventional sensors. These effects include changes in heart rate, systolic time intervals, and stroke volume. There was also some evidence for vascular adjustments over the respiration cycle. The effectiveness of custom algorithmic approaches for extracting the key signal features was confirmed. The advantages of the LDV method are discussed in terms of the metrological properties and utility in psychophysiological research. Although used here within a suite of conventional sensors and electrodes, the LDV method can be used on a stand-alone, noncontact basis, with no requirement for skin preparation, and can be used in harsh environments including the MR scanner.
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Affiliation(s)
- Erik J Sirevaag
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sara Casaccia
- Preston M. Green Department of Electrical and Systems Engineering, School of Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Industrial Engineering and Mathematical Science, Università Politecnica delle Marche, Ancona, Italy
| | - Edward A Richter
- Preston M. Green Department of Electrical and Systems Engineering, School of Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Joseph A O'Sullivan
- Preston M. Green Department of Electrical and Systems Engineering, School of Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Lorenzo Scalise
- Department of Industrial Engineering and Mathematical Science, Università Politecnica delle Marche, Ancona, Italy
| | - John W Rohrbaugh
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, USA
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18
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Pereira T, Correia C, Cardoso J. Novel Methods for Pulse Wave Velocity Measurement. J Med Biol Eng 2015; 35:555-565. [PMID: 26500469 PMCID: PMC4609308 DOI: 10.1007/s40846-015-0086-8] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/14/2015] [Indexed: 12/22/2022]
Abstract
The great incidence of cardiovascular (CV) diseases in the world spurs the search for new solutions to enable an early detection of pathological processes and provides more precise diagnosis based in multi-parameters assessment. The pulse wave velocity (PWV) is considered one of the most important clinical parameters for evaluate the CV risk, vascular adaptation, and therapeutic efficacy. Several studies were dedicated to find the relationship between PWV measurement and pathological status in different diseases, and proved the relevance of this parameter. The commercial devices dedicate to PWV estimation make a regional assessment (measured between two vessels), however a local measurement is more precise evaluation of artery condition, taking into account the differences in the structure of arteries. Moreover, the current devices present some limitations due to the contact nature. Emerging trends in CV monitoring are moving away from more invasive technologies to non-invasive and non-contact solutions. The great challenge is to explore the new instrumental solutions that allow the PWV assessment with fewer approximations for an accurately evaluation and relatively inexpensive techniques in order to be used in the clinical routine.
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Affiliation(s)
- Tânia Pereira
- Physics Department, Instrumentation Center, University of Coimbra, Rua Larga, 3004-516 Coimbra, Portugal
| | - Carlos Correia
- Physics Department, Instrumentation Center, University of Coimbra, Rua Larga, 3004-516 Coimbra, Portugal
| | - João Cardoso
- Physics Department, Instrumentation Center, University of Coimbra, Rua Larga, 3004-516 Coimbra, Portugal
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