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[IEEE 2018 9th International Conference on Information Technology in Medicine and Education (ITME) - Hangzhou, China (2018.10.19-2018.10.21)] 2018 9th International Conference on Information Technology in Medicine and Education (ITME) - Extracting Photoplethysmographic Waveform from Bulbar Conjunctiva Video
摘要： Recently the conjunctival vascularity measurement based on image analysis has shown great potential in physiological monitoring and biometrics. However, the motion artifacts in the conjunctiva videos cause both large displacement and distinct illumination variety. In this paper, a novel approach is proposed to extract photoplethysmographic waveform from conjunctiva video. Which consists of video stabilization and dual-channel extraction to eliminate the two facets of the motion artifacts respectively. The heart rate measuring results have shown a good agreement between our method and the fingertip oximeter.
关键词： conjunctiva vessel,pulse wave,video stabilization,illumination compensation
更新于2025-09-23 15:23:52
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A novel parameter derived from photoplethysmographic pulse wave to distinguish preeclampsia from non-preeclampsia
摘要： Objective: To describe the comparative hierarchical area ratio (CHAR), a novel parameter derived from the photoplethysmographic (PPG) pulse wave and differences in CHAR values in parturients with and without preeclampsia (PE). Methods: A total of 59 parturients (37 without and 22 with PE) was conducted at the Women’s Hospital of Zhejiang University in Hangzhou, China. We calculated the CHAR values derived from the PPG pulse wave and compared them in parturients with and without PE. Result: The values of CHAR derived from the parturients with PE were lower compared to those without PE (p<0.01). The ROC analysis indicated that the best threshold for the mean value of CHAR was 7.92 to predict PE with a sensitivity of 86.4% and a specificity of 87.1%, while the threshold for the standard deviation of CHAR was 0.76 with a sensitivity of 77.3% and a specificity of 77.4%. The area under the curve (AUC) was 0.91 for mean value of CHAR while 0.78 for standard deviation of CHAR. Meanwhile, a contrast of AUC between CHAR and the former parameter we proposed showed CHAR had better performance in distinguishing PE (0.908 over 0.615, p<0.01). Conclusion: The novel parameter, CHAR, derived from PPG pulse wave differs in parturients with and without PE with high sensitivity and specificity, suggesting that the CHAR might be an effective tool in differentiating the presence of PE.
关键词： Morphology,Characteristics Extraction,Comparative Hierarchical Area Ratio (CHAR),Photoplethysmographic pulse wave,Preeclampsia
更新于2025-09-23 15:23:52
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Arterial Stiffness Assessment by Shear Wave Elastography and Ultrafast Pulse Wave Imaging: Comparison with Reference Techniques in Normotensives and Hypertensives
摘要： Shear wave elastography and ultrafast imaging of the carotid artery pulse wave were performed in 27 normotensive participants and 29 age- and sex-matched patients with essential hypertension, and compared with reference techniques: carotid–femoral pulse wave velocity (cfPWV) determined via arterial tonometry and carotid stiffness (carPWV) determined via echotracking. Shear wave speed in the carotid anterior (a-SWS) and posterior (p-SWS) walls were assessed throughout the cardiac cycle. Ultrafast PWV was measured in early systole (ufPWV-FW) and in end-systole (dicrotic notch, ufPWV-DN). Shear wave speed in the carotid anterior appeared to be the best candidate to evaluate arterial stiffness from ultrafast imaging. In univariate analysis, a-SWS was associated with carPWV (r = 0.56, p = 0.003) and carotid-to-femoral PWV (r = 0.66, p < 0.001). In multivariate analysis, a-SWS was independently associated with age (R2 = 0.14, p = 0.02) and blood pressure (R2 = 0.21, p = 0.004). Moreover, a-SWS increased with blood pressure throughout the cardiac cycle and did not differ between normotensive participants and patients with essential hypertension when compared at similar blood pressures.
关键词： Hypertension,Vascular ultrasound,Arterial stiffness,Pulse wave velocity,Shear wave elastography,Ultrafast imaging,Echotracking
更新于2025-09-23 15:22:29
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Method of Photoplethysmography Diagnostics of Domesticated Animals Cardiovascular Diseases
摘要： At present time the standard procedure to diagnose cardiovascular diseases (CVD) of domesticated animals (dogs) is electrocardiography (ECG) monitoring at animal clinic. Sadly, results, obtained that way, are often mistaken because of stressful state of the animal, caused by medical manipulations [1]. The usage of photoplethysmography (PPG) method can become a good substitute for CVD monitoring. Main advantages of PPG, in compare with ECG, are single probe placement (on the ear or tailset), no need of gel electrodes and capability of measuring actual CVS parameters without need of special medical training or laboratory conditions. It is one of non-invasive methods for measuring the amount of the blood volume changes inside the blood vessels, applicable for cardio activity estimation by calculating heart rate variability. In most cases, PPG monitoring devises are small, easy to place and can monitor different physiological parameters of the animal, such as heart rate, pulse wave characteristics, blood oxygen saturation, etc.
关键词： Photoplethysmography,Health monitoring systems,Cardiovascular diseases,Pulse wave,Remote diagnostics
更新于2025-09-23 15:21:21
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Pulse Wave Imaging in Carotid Artery Stenosis Human Patients in Vivo
摘要： Carotid stenosis involves narrowing of the lumen in the carotid artery potentially leading to a stroke, which is the third leading cause of death in the United States. Several recent investigations have found that plaque structure and composition may represent a more direct biomarker of plaque rupture risk compared with the degree of stenosis. In this study, pulse wave imaging was applied in 111 (n = 11, N = 13 plaques) patients diagnosed with moderate (>50%) to severe (>80%) carotid artery stenosis to investigate the feasibility of characterizing plaque properties based on the pulse wave-induced arterial wall dynamics captured by pulse wave imaging. Five (n = 5 patients, N = 20 measurements) healthy volunteers were also imaged as a control group. Both conventional and high-frame-rate plane wave radiofrequency imaging sequences were used to generate piecewise maps of the pulse wave velocity (PWV) at a single depth along stenotic carotid segments, as well as intra-plaque PWV mapping at multiple depths. Intra-plaque cumulative displacement and strain maps were also calculated for each plaque region. The Bramwell(cid:3)Hill equation was used to estimate the compliance of the plaque regions based on the PWV and diameter. Qualitatively, wave convergence, elevated PWV and decreased cumulative displacement around and/or within regions of atherosclerotic plaque were observed and may serve as biomarkers for plaque characterization. Intra-plaque mapping revealed the potential to capture wave re?ections between calci?ed inclusions and differentiate stable (i.e., calci?ed) from vulnerable (i.e., lipid) plaque components based on the intra-plaque PWV and cumulative strain. Quantitatively, one-way analysis of variance indicated that the pulse wave-induced cumulative strain was signi?cantly lower (p < 0.01) in the moderately and severely calci?ed plaques compared with the normal controls. As expected, compliance was also signi?cantly lower in the severely calci?ed plaques regions compared with the normal controls (p < 0.01). The results from this pilot study indicated the potential of pulse wave imaging coupled with strain imaging to differentiate plaques of varying stiffness, location and composition. Such ?ndings may serve as valuable information to compensate for the limitations of currently used methods for the assessment of stroke risk. (E-mail: ek2191@columbia.edu) ? 2018 World Federation for Ultrasound in Medicine & Biology. All rights reserved.
关键词： Arterial wall elasticity maps,Arterial wall motion,Atherosclerosis,Pulse wave velocity,Pulse wave imaging,High-frame-rate ultrasound,Calci?ed plaque,Arterial compliance
更新于2025-09-23 15:21:01
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Noncontact measurement of heart rate using facial video illuminated under natural light and signal weighted analysis
摘要： Non-contact and remote measurements of vital physical signals are important for reliable and comfortable physiological self-assessment. We presented a novel optical imaging-based method to measure the vital physical signals. Using a digital camera and ambient light, the cardiovascular pulse waves were extracted better from human color facial videos correctly. And the vital physiological parameters like heart rate were measured using a proposed signal-weighted analysis method. The measured HRs consistent with those measured simultaneously with reference technologies (r=0.94, p<0.001 for HR). The results show that the imaging–based method is suitable for measuring the physiological parameters, and provide a reliable and comfortable measurement mode. The study lays a physical foundation for measuring multi-physiological parameters of human noninvasively.
关键词： noncontact cardiovascular measurement,heart rate,pulse wave,Biomedical engineering,blood pressure
更新于2025-09-19 17:15:36
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Size-controlled synthesis of gold nanoparticles by ultrafine bubbles and pulsed ultrasound
摘要： Size-controlled gold nanoparticles (AuNPs) were synthesized by ultrasonic irradiation of HAuCl4 aqueous solutions with the aid of ultrafine bubbles (UFBs) in the absence of any capping and reducing agents. Upon addition of air-UFBs, the mean diameter of the spherical AuNPs decreased. This result was attributed to the sonochemical reduction of gold ions in aqueous solution being accelerated by the UFBs. Moreover, the AuNPs were stable in a solution containing UFBs because AuNPs electrostatically adsorbed onto UFBs, whose lifetime in water was very long. Compared with the mean diameter of AuNPs synthesized with argon-, nitrogen- and oxygen-UFBs, that of AuNPs synthesized with air-UFBs was smaller. Pulsed ultrasound delivered with the same time-averaged power as continuous-wave irradiation further decreased the mean diameter of the AuNPs. Size-controlled synthesis of AuNPs without the use of a capping or reducing agent was successful through optimization of the number air-UFBs and the pulsed ultrasound conditions.
关键词： Gold nanoparticles,Size control,Ultrasound,Pulse wave,Ultrafine bubbles,Colloidal stabilization
更新于2025-09-19 17:13:59
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Arterial stiffness in normal pregnancy as assessed by digital pulse wave analysis by photoplethysmography – A longitudinal study
摘要： Introduction: It might in the future be valuable to screen for increased maternal arterial stiffness, i.e. low compliance, since it is associated with development of hypertensive complications in pregnancy. Digital pulse wave analysis (DPA) is an easy and manageable method for arterial stiffness assessment. We aimed to investigate gestational influence on DPA variables longitudinally, and establish gestational age-adjusted reference values in normal pregnancy. Methods: DPA measurements were performed longitudinally up to five times during pregnancy in 139 healthy women. Reference curves for DPA variables aging index (AI), b/a and d/a relative to gestational age were calculated with linear and polynomial mixed-effects models, and the influences of age and parity investigated with analysis of variance and analysis of covariance. A p<0.05 was regarded significant. Results: All DPA variables were significantly associated with GA with best fit for a quadratic model. Arterial compliance peaked in the late second trimester. Age and parity independently influenced DPA variables but did not change the associations with gestational age. Conclusions: DPA reflects longitudinal changes in arterial compliance in normal pregnancy but individual variance of DPA changes were greater than the influence of GA. Normal distributions of AI, b/a and d/a at 14-24 weeks are presented, but it remains to show whether these can be used to detect pathological hemodynamic alterations in pregnancy.
关键词： cardiovascular adaption,photoplethysmography,digital pulse wave analysis,arterial stiffness,pregnancy
更新于2025-09-10 09:29:36
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[IEEE 2018 XIV International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE) - Novosibirsk, Russia (2018.10.2-2018.10.6)] 2018 XIV International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE) - Up-to-Date Thermal Imaging Systems in the Multichannel Automated Measurements
摘要： A highly informative methodology, the essence of which is to obtain the parameters of an object under study by means of the data synchronous acquisition from several measurement channels, predominantly based on different physical principles, infrared thermography (IRT) as a leading research tool included in such a multichannel (multimodal) measuring system is considered in some detail. The IRT-aided multichannel approach is demonstrated with studying the physiological characteristics in humans. The measurement synchronism of different technical means is realized by the computerization and automation of the experiment. The programmable microcontroller ESP32 served as main operating and readout unit. With a time resolution of 100-200 measurements per second, the experimental data were obtained. It made it possible to reveal the human physiological characteristics as follows: the extremities temperature change, pulse waves and their velocity in the radial artery, breathing dynamics, blood pressure evaluated in two different regimes of brachial cuff air filling – inflation and deflation. The brachial cuff inflation also served as external interventional impact on the organism. It is found that, after the brachial artery cross-clamping, the pulse wave velocity in the radial artery is capable of doubling in comparison with that measured before compression. It is shown that the multimodal technology is a promising means in modern experimental science.
关键词： SEIRT,blood pressure measurement,breathing dynamics,experiment automation,multichannel (multimodal) measurements,pulse wave velocity,Infrared thermography,thermal imaging,programmable microcontroller,pulse wave,computer-aided measurements
更新于2025-09-04 15:30:14