Journal articles: 'Power Doppler parameters'

1

Sultan, Yasmin. "The Reproducibility of 3D power Doppler in Intrauterine Growth Restriction." Obstetrics Gynecology and Reproductive Sciences 6, no. 5 (October 26, 2022): 01–07. http://dx.doi.org/10.31579/2578-8965/129.

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Objective: it is to examine the reproducibility of 3D power Doppler in the management of intrauterine growth restriction compared with the conventional 2d Doppler. Patients and Methods: This study was performed between Jan 2021 and Feb 2022 and included 100 pregnant women recruited from outpatient clinic at Elgalaa Teaching Hospital, 3D power Doppler US was done for assessment of IUGR and compare the findings with 2D Doppler. Results: it is found that 3D Power Doppler parameters were significant in prediction of poor neonatal outcome regarding development of respiratory complications, neurological complications and IUFD as complications to IUGR comparing to 2D colour Doppler parameters which were non-significant in these cases. Our results also showed that the only parameter of 2D Colour Doppler that showed significance and positive correlation to birth weight among these cases was Middle Cerebral Artery Pulpability Index. Conclusion: 2D Doppler flow-velocity waveforms are of limited value in the prediction of poor neonatal outcome in IUGR except for MCAPI. 3D power Doppler was superior in the diagnosis and prediction of neonatal outcome.

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Algin, Oktay. "Spectral power doppler ultrasound parameters: Are they really significant?" Laryngoscope 119, no. 7 (May 14, 2009): 1452. http://dx.doi.org/10.1002/lary.20297.

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Dogandzic, A., and B. Zhang. "Estimating Jakes' Doppler power spectrum parameters using the whittle approximation." IEEE Transactions on Signal Processing 53, no. 3 (March 2005): 987–1005. http://dx.doi.org/10.1109/tsp.2004.842197.

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Li, Yanhui, Hua Zhao, Ruochen Huang, Geng Zhang, Hangtian Zhou, Chenglin Han, and Lu Bai. "Laser Backscattering Analytical Model of Doppler Power Spectra about Convex Quadric Bodies of Revolution during Precession." Remote Sensing 16, no. 6 (March 21, 2024): 1104. http://dx.doi.org/10.3390/rs16061104.

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In the realm of ballistic target analysis, micro-motion attributes, such as warhead precession, nutation, and decoy oscillations, play a pivotal role. This paper addresses these critical aspects by introducing an advanced analytical model for assessing the Doppler power spectra of convex quadric revolution bodies during precession. Our model is instrumental in calculating the Doppler shifts pertinent to both precession and swing cones. Additionally, it extends to delineate the Doppler power spectra for configurations involving cones and sphere–cone combinations. A key aspect of our study is the exploration of the effects exerted by geometric parameters and observation angles on the Doppler spectra, offering a comparative perspective of various micro-motion forms. The simulations distinctly demonstrate how different micro-motion patterns of a cone influence the Doppler power spectra and underscore the significance of geometric parameters and observational angles in shaping these spectra. This research not only contributes to enhancing LIDAR target identification methodologies but also lays a groundwork for future explorations into complex micro-motions like nutation.

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O’Connor, Ewan J., Robin J. Hogan, and Anthony J. Illingworth. "Retrieving Stratocumulus Drizzle Parameters Using Doppler Radar and Lidar." Journal of Applied Meteorology 44, no. 1 (January 1, 2005): 14–27. http://dx.doi.org/10.1175/jam-2181.1.

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Abstract Stratocumulus is one of the most common cloud types globally, with a profound effect on the earth’s radiation budget, and the drizzle process is fundamental in understanding the evolution of these boundary layer clouds. In this paper a combination of 94-GHz Doppler radar and backscatter lidar is used to investigate the microphysical properties of drizzle falling below the base of stratocumulus clouds. The ratio of the radar to lidar backscatter power is proportional to the fourth power of mean size, and so potentially it can provide an accurate size estimate. Information about the shape of the drop size distribution is then inferred from the Doppler spectral width. The algorithm estimates vertical profiles of drizzle parameters such as liquid water content, liquid water flux, and vertical air velocity, assuming that the drizzle size spectrum may be represented by a gamma distribution. The depletion time scale of cloud liquid water through the drizzle process can be estimated when the liquid water path of the cloud is available from microwave radiometers, and observations suggest that this time scale varies from a few days in light drizzle to a few hours in strong drizzle events. Radar and lidar observations from Chilbolton (in southern England) and aircraft size spectra taken during the Atlantic Stratocumulus Transition Experiment have both been used to derive the following power-law relationship between liquid water flux (LWF) (g m−2 s−1) and radar reflectivity (Z) (mm6 m−3): LWF = 0.0093Z0.69. This relation is valid for frequencies up to 94 GHz and therefore would allow a forthcoming spaceborne radar to measure liquid water flux around the globe to within a factor of 2 for values of Z above −20 dBZ.

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Kim, Yeong M., and Song B. Park. "Modeling of Doppler Signal considering Sample Volume and Field Distribution." Ultrasonic Imaging 11, no. 3 (July 1989): 175–96. http://dx.doi.org/10.1177/016173468901100302.

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The ultrasound Doppler amplitude spectrum for a single scatterer and the power spectrum for multiple scatterers were calculated in terms of the echo signal from scatterers crossing the sample volume, defined by the transmitted pulse and the diffracted field distribution for cw. The observation time for the Doppler signal is also considered. Statistical parameters such as mean and variance of the Doppler power spectrum are studied as continuous functions of the intersection angle between the beam axis and the flow direction, the pulse length and the viewing position. The derived equations are valid whether the transit time is governed by the pulse length, or beam geometry, or both. It is shown that the Doppler power spectra calculated by the proposed model and by the Doppler signal obtained from field theory are in good agreement. It is also shown that, when the Doppler signal broadening due to the transmitted pulse and beam geometry is constant without regard to the intersection angle, the degree of spread of the velocity distribution can be estimated from the variance of the Doppler power spectrum measured by the Doppler system once the intersection angle is known.

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Tamsel, S., G. Demirpolat, M. Erdogan, D. Nart, M. Karadeniz, H. Uluer, and A. G. Ozgen. "Power Doppler US patterns of vascularity and spectral Doppler US parameters in predicting malignancy in thyroid nodules." Clinical Radiology 62, no. 3 (March 2007): 245–51. http://dx.doi.org/10.1016/j.crad.2006.10.003.

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Babb, David M., Johannes Verlinde, and Bruce A. Albrecht. "Retrieval of Cloud Microphysical Parameters from 94-GHz Radar Doppler Power Spectra." Journal of Atmospheric and Oceanic Technology 16, no. 5 (May 1999): 489–503. http://dx.doi.org/10.1175/1520-0426(1999)016<0489:rocmpf>2.0.co;2.

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Bisi, Melissa Cláudia, Aline Defaveri do Prado, Deise Marcela Piovesan, Markus Bredemeier, Inês Guimarães da Silveira, José Alexandre de Mendonça, and Henrique Luiz Staub. "Ultrasound resistive index, power Doppler, and clinical parameters in established rheumatoid arthritis." Clinical Rheumatology 36, no. 4 (December 19, 2016): 947–51. http://dx.doi.org/10.1007/s10067-016-3507-3.

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Tozaki, M., M. Toi, Y. Miyamoto, and K. Fukuda. "Power Doppler sonography of breast masses: correlation of Doppler spectral parameters with tumor angiogenesis and histologic growth pattern." Journal of Ultrasound in Medicine 19, no. 9 (September 2000): 593–600. http://dx.doi.org/10.7863/jum.2000.19.9.593.

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Thoman, John W., David W. Chandler, David H. Parker, and Maurice H. M. Janssen. "Two-dimensional Imaging of Photofragments." Laser Chemistry 9, no. 1-3 (January 1, 1988): 27–46. http://dx.doi.org/10.1155/lc.9.27.

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The technique of photofragment imaging is described, and several examples of the power of the technique are presented. Two-dimensional images of state-selected photofragments from the photodissociations of CD3I and H2S illustrate how photofragment imaging reveals β parameters, brancing ratios, Doppler profiles and vector correlations. Comparisons are made with Doppler profiling and one-dimensional time-of-flight techniques.

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Maxwell, Adam, Bryan W. Cunitz, Yak-Nam Wang, Christopher Hunter, Ga Won Kim, Stephanie Totten, Michael R. Bailey, and Wayne Kreider. "Power Doppler-based ultrasound detection of cavitation for burst wave lithotripsy." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A250. http://dx.doi.org/10.1121/10.0016172.

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Burst wave lithotripsy (BWL) is a noninvasive method to fragment urinary stones with pulsed focused ultrasound. Cavitation activity produced by ultrasound pulses in BWL can cause multiple effects including stone fragmentation, acoustic shielding, and tissue injury. Monitoring cavitation activity and spatial extent is therefore important to evaluating these effects and determining parameters that maximize effectiveness and safety. In vivo experiments in a porcine model were conducted using a Verasonics ultrasound system to detect the onset and spatial extent of cavitation through synchronized power Doppler ultrasound imaging during 350-kHz BWL exposures to stones and kidney tissue. Kidneys (n = 15) were exposed in vivo to transcutaneous BWL at multiple pressure levels, and cavitation in tissue was found to be detected as an increase in the measured Doppler power by an average of 28.6 dB (range 11–51 dB) over the background. Cavitation occurred at average levels between 5.8 and 8.0 MPa peak negative pressure, depending on targeting location, stone presence, and exposure parameters. Cavitation presence further correlated with gross observation of injury. These studies demonstrate suggest filtered power Doppler imaging can sensitively detect presence of sustained cavitation during burst wave lithotripsy exposures. [Work supported by NIDDK K01 DK104854 and P01 DK043881.]

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Fernandez, M. A., Simeon Bird, and Phoebe Upton Sanderbeck. "Effect of separate initial conditions on the lyman-α forest in simulations." Monthly Notices of the Royal Astronomical Society 503, no. 2 (February 26, 2021): 1668–79. http://dx.doi.org/10.1093/mnras/stab555.

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ABSTRACT Using a set of high resolution simulations, we quantify the effect of species-specific initial transfer functions on probes of the intergalactic medium (IGM) via the Lyman-α forest. We focus on redshifts 2–6, after H i reionization. We explore the effect of these initial conditions on measures of the thermal state of the low density IGM: the curvature, Doppler width cutoff, and Doppler width distribution. We also examine the matter and flux power spectrum, and potential consequences for constraints on warm dark matter models. We find that the curvature statistic is at most affected at the $\approx 2{{\ \rm per\ cent}}$ level at z = 6. The Doppler width cutoff parameters are affected by $\approx 5{{\ \rm per\ cent}}$ for the intercept, and $\approx 8{{\ \rm per\ cent}}$ for the fit slope, though this is subdominant to sample variation. The Doppler width distribution shows a $\approx 30{{\ \rm per\ cent}}$ effect at z = 3, however the distribution is not fully converged with simulation box size and resolution. The flux power spectrum is at most affected by $\approx 5{{\ \rm per\ cent}}$ at high redshift and small scales. We discuss numerical convergence with simulation parameters.

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Ctibor, Pavel, and Milan Hrabovský. "Dependence of Particle Parameters in Flight and Coating Character on Power of the Electric Supply at Plasma Spraying of TiO₂." Key Engineering Materials 434-435 (March 2010): 779–82. http://dx.doi.org/10.4028/www.scientific.net/kem.434-435.779.

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The influence of input power on the spayed powder and final coating was quantified for particular case of water-stabilized plasma spray torch (WSP®) and ceramic coating formed from titanium dioxide (TiO2). All other spray setup parameters were fixed during the experiment with electric supply power as the only variable factor. In-flight particles were characterized by Doppler particle velocimetry, microstructure of the coatings was observed by microscopic techniques and computer image analysis and phase composition was studied by X-ray diffraction. Various mechanical properties were measured – microhardness, surface roughness and wear resistance in a slurry. The results indicate that the higher power means better coating quality – its microstructure and mechanical performance. This substantial difference has the same trend for both power supplies utilized for the testing.

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Yang, Rong, Jie Zhang, Yan Ling He, and Yang Huang. "The Model and Algorithm of Doppler Radar Speed Measurement System ." Applied Mechanics and Materials 128-129 (October 2011): 1250–56. http://dx.doi.org/10.4028/www.scientific.net/amm.128-129.1250.

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Based on the measurement of train speed, this paper briefly describes the basic principle of Doppler speed measurement and the design of speed measurement system. By the analysis of test signal which simulates the actual speed signal and comparison of the simulation results, the AR power spectrum estimation algorithm is selected as the model of speed measurement system, and the Burg method is selected to evaluate the Doppler frequency. Then the effect of parameters such as sampling frequency, length of the input vector, FFT length and estimation order on power spectrum estimation are analyzed, the optimization principles of the parameters are defined. Finally, the determined method is simulated with a high-noise, multi-jamming signal and has good results. The accuracy, stability and immunity are proved by the simulation.

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Herlt, Catherine, Rosa Stark, Haukur Sigmarsson, and Johannes Kauffold. "Feasibility of transabdominal Doppler sonography for studying uterine blood flow characteristics in cycling gilts." Tierärztliche Praxis Ausgabe G: Großtiere / Nutztiere 46, no. 03 (June 2018): 154–63. http://dx.doi.org/10.15653/tpg-180369.

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Summary Objective: To test for the feasibility of transabdominal Doppler sonography (color, power, pulse wave) to define uterine perfusion characteristics throughout the estrous cycle in gilts. Materials and methods: A total of 15 gilts were synchronized for estrus and scanned in their following spontaneous cycle while being restrained in a purpose-designed mobile crate. To define uterine perfusion characteristics, vessels in between and within uterine cross-sections were imaged and recorded as video sequences to be analyzed by PixelFlux® software for perfused area (Amix), blood flow velocity (vmix) and intensity (Imix) as well as resistance (RIvmix) and pulsatility index (PIvmix). Results: Color Doppler sonography proved to be the only feasible technique, as it was less affected by animal movements than power and pulse wave sonography. As determined by color Doppler sonography, all five parameters determined showed specific patterns through the estrous cycle, i. e. Amix, vmix, Imix were high in proestrus, decreased in estrus and remained low in midestrus and most parts of diestrus; RIvmix and PIvmix with inversely paralleled patterns. Conclusion and clinical relevance: This study has demonstrated that transabdominal color Doppler but not power and pulse wave Doppler sonography is feasible to be performed in crate-restrained gilts for studying uterine perfusion characteristics during the estrous cycle, and that changes of uterine perfusion over the course of the estrous cycle can be clearly followed by color Doppler sonography. Results encourage the use of color Doppler sonography for studying i. e. uterine capacity or uterus related infertility such as for cases of clinically unapparent endometritis.

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Bisi, Melissa Cláudia, Aline Defaveri do Prado, Deise Marcela Piovesan, Markus Bredemeier, Inês Guimarães da Silveira, José Alexandre Mendonça, and Henrique Luiz Staub. "Correction to: Ultrasound resistive index, power Doppler, and clinical parameters in established rheumatoid arthritis." Clinical Rheumatology 37, no. 3 (November 2, 2017): 855. http://dx.doi.org/10.1007/s10067-017-3882-4.

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Moreno, Mario. "Airborne GNSS reflectometry for coastal monitoring of sea state." Revista Cartográfica, no. 108 (May 8, 2024): 77–97. http://dx.doi.org/10.35424/rcarto.i108.4524.

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Sea level rise and sea state variability, resulting from climate change and global warming, are critical research areas. However, current techniques for observing and monitoring these phenomena have limitations in terms of spatial and temporal resolution, particularly in dynamic coastal zones. GNSS Reflectometry (GNSS-R) is an emerging bistatic radar-based technique that utilizes the GNSS direct (transmitter-receiver) and reflected (transmitter-reflection point-receiver) signals to extract properties of the reflecting surface. This study explores the potential of airborne GNSS-R as a means to monitor sea state in coastal areas by using the Doppler spread and reflectivity as observables. The paper aims to derive a sea state factor from the reflected signal power and the Doppler shift distribution to analyze its correlation with wind speed and significant wave height data obtained from the ERA5 model. The experiment involved four flights conducted along the coast between Calais and Boulogne-sur-Mer, France, in July 2019. A GNSS software receiver processes the direct and reflected signals, tracking and re-tracking the reflected signals with the aid of a specular reflection model. The resulting in-phase and quadrature components are analyzed in the spectral domain every minute to estimate the power, the surface reflectivity, and the relative Doppler shift. The findings reveal that the sea state factor and Doppler spreading are sensitive to sea state conditions, correlated with the ERA5 parameters, and influenced by the elevation angle of GNSS satellites. At low elevations (E<10°), the sea state factor demonstrates an inverse relationship (anti-correlation) with the wind speed and significant wave height, while the Doppler distribution shows a correlation with these parameters. Both correlations decrease with increasing elevation angle. This research underscores the potential of airborne GNSS-R for monitoring sea state variability in coastal areas enhancing our understanding of the relationships between GNSS-R measurements and sea state parameters.

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Bau, Santiago, Luis T. Mercé, and María J. Barco. "2D and 3D Power Doppler Ultrasound of Endometrium as Implantation Marker." Donald School Journal of Ultrasound in Obstetrics and Gynecology 2, no. 2 (2008): 1–11. http://dx.doi.org/10.5005/jp-journals-10009-1052.

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Abstract Transvaginal ultrasonography has an important role in assessing the endometrium. With 2DUS, a single measurement of endometrial thickness in the sagittal plane is widely used in assisted reproductive technology and in pregnancy prediction. Endometrial volume, measured with 3DUS, has been studied as a potentially more accurate parameter. The endometrial pattern was related to the likelihood of implantation. This pattern correlated in a positive fashion with subsequent implantation. 3D ultrasound and 3D power Doppler parameters have been applied to assisted reproductive techniques as outcome predictors, although studies are still scarce, they show very promising results.

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Höfling, Danilo Bianchini, Maria Cristina Chavantes, Adriana G. Juliano, Giovanni G. Cerri, Meyer Knobel, Elisabeth M. Yoshimura, and Maria Cristina Chammas. "Assessment of the Effects of Low-Level Laser Therapy on the Thyroid Vascularization of Patients with Autoimmune Hypothyroidism by Color Doppler Ultrasound." ISRN Endocrinology 2012 (December 17, 2012): 1–9. http://dx.doi.org/10.5402/2012/126720.

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Background. Chronic autoimmune thyroiditis (CAT) frequently alters thyroid vascularization, likely as a result of the autoimmune process. Objective. To evaluate the effects of low-level laser therapy (LLLT) on the thyroid vascularization of patients with hypothyroidism induced by CAT using color Doppler ultrasound parameters. Methods. In this randomized clinical trial, 43 patients who underwent levothyroxine replacement for CAT-induced hypothyroidism were randomly assigned to receive either 10 sessions of LLLT (L group, n=23) or 10 sessions of a placebo treatment (P group, n=20). Color Doppler ultrasounds were performed before and 30 days after interventions. To verify the vascularity of the thyroid parenchyma, power Doppler was performed. The systolic peak velocity (SPV) and resistance index (RI) in the superior (STA) and inferior thyroid arteries (ITAs) were measured by pulsed Doppler. Results. The frequency of normal vascularization of the thyroid lobes observed in the postintervention power Doppler examination was significantly higher in the L than in the P group (P=0.023). The pulsed Doppler examination revealed an increase in the SPV of the ITA in the L group compared with the P group (P=0.016). No significant differences in the SPV of the STA and in the RI were found between the groups. Conclusion. These results suggest that LLLT can ameliorate thyroid parenchyma vascularization and increase the SPV of the ITA of patients with hypothyroidism caused by CAT.

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Baker, Kenneth F., Ben Thompson, Dennis W. Lendrem, Adam Scadeng, Arthur G. Pratt, and John D. Isaacs. "Lack of association between clinical and ultrasound measures of disease activity in rheumatoid arthritis remission." Therapeutic Advances in Musculoskeletal Disease 12 (January 2020): 1759720X2091532. http://dx.doi.org/10.1177/1759720x20915322.

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Objectives: The objective of this study was to assess the prevalence of ultrasound (US) abnormalities and association with clinical parameters in rheumatoid arthritis (RA) clinical remission. Methods: Patients with established RA in clinical remission (DAS28-CRP < 2.4) taking conventional synthetic disease-modifying anti-rheumatic drugs were recruited as part of the Biomarkers of Remission in Rheumatoid Arthritis (BioRRA) Study. In addition, patients from the Newcastle Early Arthritis Clinic (NEAC) with early active RA (DAS28-CRP > 2.4) or seronegative non-inflammatory arthralgia (NIA) were studied as positive and negative controls, respectively. The association between individual dependent variables (synovial power Doppler and greyscale, tenosynovial greyscale, and erosions) and clinical parameters was assessed by multivariate ordinal logistic regression, with adjustment for multiple testing. Results: A total of 294 patients were included: 66 RA in remission, 146 active RA, and 82 NIA. Within the active RA group, significant associations were observed between swollen joint count and higher total synovial greyscale score (OR 1.17 95% CI 1.08–1.26, p < 0.001) and higher total synovial power Doppler score (OR 1.20, 95% CI 1.12–1.30, p < 0.001). No significant associations were observed for the NIA group. In the RA remission group, US abnormalities were frequently observed and comparable for both DAS28-CRP and 2011 ACR/EULAR Boolean remission, with no significant association with clinical parameters identified. Conclusion: We observed widespread subclinical US findings in RA patients in clinical remission, even when remission is defined using the stringent ACR/EULAR Boolean criteria. In contrast to active disease, synovial power Doppler failed to show significant association with any of the clinical parameters in RA remission. Our results suggest that clinical and US examinations are non-overlapping in evaluating RA remission, challenging the proposition of US-driven management strategies in this setting.

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C, Raju, and Sreenivasulu Reddy T. "Sparse iterative covariance-based estimation approach for processing atmospheric radar data." International Journal of Engineering & Technology 7, no. 1.8 (March 1, 2018): 232. http://dx.doi.org/10.14419/ijet.v7i1.9215.

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The Doppler estimation is an important problem for Mesosphere–Stratosphere–Troposphere (MST) Radar data for detection and estimation of the weather parameters like turbulence intensity, mean radial velocity, humidity, temperature, wind speed. For Doppler estimation, one has to compute the Power Spectral Density (PSD). Various parametric and nonparametric methods have been developed. Recently, a new category of spectrum estimation method called Sparse Iterative Covariance Based Estimation (SPICE) is also developed. SPICE is a robust, user parameter-free, high resolution, iterative and globally convergent estimation algorithm. In this paper, the simple gradient approach is used for minimization of the weighted covariance estimation analyzing the data collected from the Indian MST radar at Gadanki (13.5°N, 79.2°E). The same method is applied for radar data to estimate the power spectrum and Doppler frequency. The zonal (U), meridional (V), wind speed (W) are calculated and the results have been validated using simultaneous Global Positioning System (GPS) Sonde data.

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NG, Ernest Hung Yu, and Pak Chung HO. "Ultrasound Assessment of Endometrial Receptivity in in vitro Fertilization Treatment." Donald School Journal of Ultrasound in Obstetrics and Gynecology 4, no. 2 (2010): 179–88. http://dx.doi.org/10.5005/jp-journals-10009-1141.

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Abstract Ultrasonography of the endometrium is a noninvasive way to evaluate the chance of successful implantation during in vitro fertilization treatment. Ultrasound parameters of endometrial receptivity include endometrial thickness, endometrial pattern, endometrial volume, Doppler studies of uterine vessels and the endometrium. Endometrial thickness, pattern and volume are not predictive of pregnancy. A good blood supply towards the endometrium is usually considered to be an essential requirement for implantation. Doppler study of uterine arteries does not reflect the actual blood flow to the endometrium. Endometrial and subendometrial vascularity can be more objectively measured with three-dimensional power Doppler ultrasound. However, the role of endometrial and subendometrial vascularity in predicting pregnancy of in vitro fertilization treatment remains controversial.

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Moliner, B., J. Llacer, F. Sellers, J. Ten, and R. Bernabeu. "P29.07: Cut-off values of 3D power Doppler parameters in relation to low ovarian response." Ultrasound in Obstetrics & Gynecology 44, S1 (September 2014): 354. http://dx.doi.org/10.1002/uog.14561.

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Jiang, Yaxuan, and Yipeng Ding. "A Target Localization Algorithm for a Single-Frequency Doppler Radar Based on an Improved Subtractive Average Optimizer." Remote Sensing 16, no. 12 (June 12, 2024): 2123. http://dx.doi.org/10.3390/rs16122123.

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A doppler radar holds promising prospects in the field of indoor target localization. However, traditional Doppler radar systems suffer from high power consumption, large size, and noticeable radio frequency interference issues when transmitting carriers of different frequencies. Therefore, an ISABO-based (improved subtraction-average-based optimizer) target localization algorithm for a single-frequency Doppler radar is proposed in this paper. Firstly, a mathematical model for target localization is established according to the spatial geometric relationships during the target movement and the Doppler frequency-shift information in the single-frequency echo signal. Then, the optimization function is constructed with the target motion error as the optimization goal. Finally, an improved subtraction-average-based optimizer algorithm is proposed to solve the optimal parameters and realize the target positioning. The experimental results show that the proposed method can achieve centimeter-level localization accuracy with a cost-effective system structure.

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Portnova, Galina V., Aleksandra V. Maslennikova, and Elena V. Proskurnina. "The Relationship between Carotid Doppler Ultrasound and EEG Metrics in Healthy Preschoolers and Adults." Brain Sciences 10, no. 10 (October 20, 2020): 755. http://dx.doi.org/10.3390/brainsci10100755.

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Despite widespread using electroencephalography (EEG) and Doppler ultrasound in pediatric neurology clinical practice, there are still no well-known correlations between these methods that could contribute to a better understanding of brain processes and development of neurological pathology. This study aims to reveal relationship between EEG and Doppler ultrasound methods. We compared two cohorts of adults and preschool children with no history of neurological or mental diseases. The data analysis included investigation of EEG and carotid blood flow indexes, which are significant in neurological diagnosis, as well as calculation of linear and non-linear EEG parameters and ratios between the systolic peak velocities of carotid arteries and carotid blood asymmetry. We have found age-dependent correlations between EEG and power Doppler ultrasound imaging (PDUI) data. Carotid blood flow asymmetry correlated with delta-rhythm power spectral density only in preschoolers. The ratios of blood flow velocities in the internal carotid arteries to those in the common carotid arteries correlated with higher peak alpha frequency and lower fractal dimension; moreover, they were associated with lower Epworth sleepiness scale scores. The study revealed significant correlations between EEG and PDUI imaging indexes, which are different for healthy children and adults. Despite the fact that the correlations were associated with non-clinical states such as overwork or stress, we assumed that the investigated parameters could be applicable for clinical trials.

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Macias-Perez, J. F., R. A. Watson, R. D. Davies, A. Wilkinson, J. A. Rubiño-Martin, C. M. Gutierrez, J. Gallegos, R. L. Rebolo, and R. J. Hoyland. "Tenerife Experiments: Galactic Contribution to CMB Observations at 1° angular scales." Symposium - International Astronomical Union 201 (2005): 484–85. http://dx.doi.org/10.1017/s0074180900216781.

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Cosmic Microwave Observations at 1° scales are extremely important on the understanding of modern Cosmology. At those angular scales the CMB power spectrum presents the first Doppler Peak. The position and amplitude of this peak provide strong constraints on cosmological parameters as H0 and Ω0. The JBO-IAC interferometer has observed those angular scales as well as the BOOMERANG and MAXIMA teams. The results from these groups show the existence of the first Doppler Peak. We present a detailed estimate of the galactic contribution to the JBO-IAC interferometer data set using data from the Tenerife and COSMOSOMAS experiments.

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Xian, Jinhong, Chao Lu, Xiaoling Lin, Honglong Yang, Ning Zhang, and Li Zhang. "Directly measuring the power-law exponent and kinetic energy of atmospheric turbulence using coherent Doppler wind lidar." Atmospheric Measurement Techniques 17, no. 6 (April 2, 2024): 1837–50. http://dx.doi.org/10.5194/amt-17-1837-2024.

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Abstract. Atmospheric turbulence parameters, such as turbulent kinetic energy and dissipation rate, are of great significance in weather prediction, meteorological disasters, and forecasting. Due to the lack of ideal direct detection methods, traditional structure function methods are mainly based on Kolmogorov's assumption of local isotropic turbulence and the well-known -5/3 power law within the inertial subrange, which limits their application. Here, we propose a method for directly measuring atmospheric turbulence parameters using coherent Doppler wind lidar, which can directly obtain atmospheric turbulence parameters and vertical structural features, breaking the limitations of traditional methods. The first published spatiotemporal distribution map of the power-law exponent of the inertial subrange is provided in this study, which indicates the heterogeneity of atmospheric turbulence at different altitudes and also indicates that the power-law exponent at high altitudes does not fully comply with the -5/3 power law, proving the superiority of our method. We analyze the results under different weather conditions, indicating that the method still holds. The turbulent kinetic energy and power-law index obtained by this method are continuously compared with the results obtained with an ultrasonic anemometer for a month-long period. The results of the two have high consistency and correlation, verifying the accuracy and applicability of the proposed method. The proposed method has great significance in studying the vertical structural characteristics of atmospheric turbulence.

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Nastrom, G. D., and T. Tsuda. "Anisotropy of Doppler spectral parameters in the VHF radar observations at MU and White Sands." Annales Geophysicae 19, no. 8 (August 31, 2001): 883–88. http://dx.doi.org/10.5194/angeo-19-883-2001.

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Abstract. Significant differences are found between the mean spectral widths from beams in the meridional plane and in the zonal plane at both the MU and the White Sands VHF radars. The spectral width in the beam directed perpendicular to the prevailing wind is greater than that in the beam parallel to the wind. The magnitudes of the differences in spectral width show a linear relationship with wind speed, with the greatest differences at the greatest wind speeds. The differences in spectral width show a positive correlation with the differences in backscattered power. The anisotropy in backscattered power is well-known and is usually attributed to aspect sensitivity effects. However, the anisotropy in spectral width does not appear to be due to the same mechanism, and while several hypotheses to account for this are considered, including finite range-volume effects, effects from the tilting of isentropic layers, and anisotropic turbulence effects, it is seen that each of these suggestions has its shortcomings.Key words. Meteorology and atmospheric dynamics (turbulence; instruments and techniques)

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Requena, Francisco, María Joana A. P. M. Campos, Andrés Luis Martínez Marín, Rocío Camacho, Rosa M. Giráldez-Pérez, and Estrella I. Agüera. "Assessment of Age Effects on Ovarian Hemodynamics Using Doppler Ultrasound and Progesterone Concentrations in Cycling Spanish Purebred Mares." Animals 11, no. 8 (August 8, 2021): 2339. http://dx.doi.org/10.3390/ani11082339.

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In equine reproduction, accurate and timely detection of the moment of ovulation is of great importance. Power Doppler ultrasound technology is a non-invasive method that enables to assess the morpho-echogenic features and blood flow changes during the estral cycle in mares. The objective of the present study was to evaluate the influence of age on ultrasonographic parameters (follicular diameter, follicular blood flow—FBF, corpus luteum (CL) area and corpus luteum blood flow—CLBF) and blood plasma progesterone concentrations in cycling Spanish Purebred mares (15 less than 8 years old and 15 equal o higher than 8 years old). The ultrasound images obtained were analyzed with the Image Colour Summarizer software, which allows the quantification of the pixels of each image. Young mares had significantly higher FBF, CLBF and plasma progesterone levels. Moreover, linear regression analysis showed that blood progesterone levels could be predicted in both groups from CLBF with moderate precision and accuracy. In conclusion, Power Doppler was useful to assess ovarian hemodynamics. Our results support that age is a factor that significantly influences FBF and CLBF as well as blood progesterone concentration in mares. More studies would be needed to develop high precision and accuracy predictive models of blood progesterone concentration from CLBF measured by Power Doppler.

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Póvoa, Ana, Alexandra Matias, Pedro Xavier, and Isaac Blickstein. "Can early ultrasonography explain the lower miscarriage rates in twin as compared to singleton pregnancies following assisted reproduction?" Journal of Perinatal Medicine 46, no. 7 (September 25, 2018): 760–63. http://dx.doi.org/10.1515/jpm-2017-0087.

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Abstract Objective: To compare first trimester 2D conventional and 3D power Doppler angiography measures in twins and singletons following assisted reproduction. Methods: We prospectively evaluated 50 singleton and 47 twin pregnancies that eventually ended in live births. Patients were recruited from a single assisted reproductive technology (ART) center with standard treatment protocols. Obstetric ultrasound was performed at 8–9 weeks +6 days. Intervillous flow, uteroplacental circulation and uterine artery pulsatility (PI) and resistance index (RI) using two-dimensional (2D) ultrasound examination were evaluated. Using three-dimensional (3D) power Doppler angiography, placental volume and the 3D power Doppler indices from the intervillous and uteroplacental circulation were calculated. Results: Demographic and cycle characteristics were similar in mothers of singletons and twins. Placental volume was significantly (1.6-fold) larger in twins. Vascular density and blood perfusion in the intervillous space were lower in twins. The comparison of the other parameters did not show significant differences between singletons and twins. Conclusion: The data confirm the larger placental volume in twins, denoting a probable higher production of placental hormones that would support an early twin pregnancy. The lower vascular density and blood perfusion in the intervillous space in twins may also confer a reproductive advantage to them.

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Frehlich, Rod, and Robert Sharman. "Maximum Likelihood Estimates of Vortex Parameters from Simulated Coherent Doppler Lidar Data." Journal of Atmospheric and Oceanic Technology 22, no. 2 (February 1, 2005): 117–30. http://dx.doi.org/10.1175/jtech-1695.1.

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Abstract The performance of pulsed coherent Doppler lidar in estimating aircraft trailing wake vortices by scanning across the aircraft flight track is evaluated using Monte Carlo lidar simulations of a simple vortex pair in both a nonturbulent and turbulent environment. The performance estimates are based on maximum likelihood estimates of aircraft wake vortex parameters and provide a measure of the ability of the lidar to detect and track wake vortices under the best possible conditions. Two aircraft types are considered: the Boeing 737 and the Boeing 747. Rigorous error analyses are produced by comparing the estimated parameters from numerical simulations of raw lidar data with the known input parameters of the simulation. It is shown that the probability density functions for the estimates are approximately Gaussian and the bias is very small. The main source of the bias was determined to be the movement of the vortex during the lidar scan. The estimation error is increased by the effects of a background turbulent velocity field. The trade-off between lidar pulse energy and pulse repetition frequency for the standard condition of constant laser power is also presented. It is shown that these maximum likelihood estimates provide accurate detection and tracking of the key vortex parameters for a simple vortex model, with and without background turbulence.

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Kyritsis, Alexandros, Rodoula Makri, and Nikolaos Uzunoglu. "Detection of Low RCS Unmanned Air Systems Using K-Band Continuous Wave Doppler Radar." Journal of Electrical and Computer Engineering 2023 (February 4, 2023): 1–13. http://dx.doi.org/10.1155/2023/5683661.

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UASs (Unmanned Air Systems) are universally used in many activities, spanning from leisure-commercial to military applications. Accordingly, as the number of UASs operating in the sky increases, so does the need to detect and identify them, in order to ensure their legitimate use. This paper introduces a continuous wave (CW) Doppler radar implementation that can be used to provide early warning for flying-by small UASs. By applying Fast Fourier Transform (FFT) to the returned signal’s Doppler frequency, estimations can be made regarding the presence of aerial bodies inside an Area of Interest (AoI). Achieving reliable detection with a low false alarm rate (FAR) while keeping the size and power demands of the system to minimum was a challenge that was successfully met. The proposed system was extensively tested in outdoor environments; measurement results are presented and parameters such as radar power, antenna gain, and noise are discussed.

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Turkyilmaz, B., D. Mansuroglu, and I. U. Uzun-Kaymak. "Characterization of high microwave power atmospheric pressure plasma torch." Canadian Journal of Physics 96, no. 7 (July 2018): 851–54. http://dx.doi.org/10.1139/cjp-2017-0751.

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An atmospheric pressure microwave plasma torch operating at 2.45 GHz frequency using a surfaguide waveguide fed by argon gas at a constant rate is characterized at various microwave power settings. Coarse optical emission spectroscopy technique is used to diagnose the plasma parameters. The Boltzmann plot method is implemented to measure the electron temperature. Using the Doppler shift of the strong argon atomic spectral lines, the plasma velocity is determined. These results are in good agreement with earlier studies conducted on similar microwave plasma torches at a lower power setting. In this study, we exceed the previous power limitations observed in earlier studies and scan the microwave power in increments up to 2 kW.

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Zeng, Hong-Cheng, Jie Chen, Peng-Bo Wang, Wei Yang, and Wei Liu. "2-D Coherent Integration Processing and Detecting of Aircrafts Using GNSS-Based Passive Radar." Remote Sensing 10, no. 7 (July 23, 2018): 1164. http://dx.doi.org/10.3390/rs10071164.

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Long time coherent integration is a vital method for improving the detection ability of global navigation satellite system (GNSS)-based passive radar, because the GNSS signal is not radar-designed and its power level is very low. For aircraft detection, the large range cell migration (RCM) and Doppler frequency migration (DFM) will seriously affect the coherent processing of azimuth signals, and the traditional range match filter will also be mismatched due to the Doppler-intolerant characteristic of GNSS signals. Accordingly, the energy loss of 2-dimensional (2-D) coherent processing is inevitable in traditional methods. In this paper, a novel 2-D coherent integration processing and algorithm for aircraft target detection is proposed. For azimuth processing, a modified Radon Fourier Transform (RFT) with range-walk removal and Doppler rate estimation is performed. In respect to range compression, a modified matched filter with a shifting Doppler is applied. As a result, the signal will be accurately focused in the range-Doppler domain, and a sufficiently high SNR can be obtained for aircraft detection with a moving target detector. Numerical simulations demonstrate that the range-Doppler parameters of an aircraft target can be obtained, and the position and velocity of the aircraft can be estimated accurately by multiple observation geometries due to abundant GNSS resources. The experimental results also illustrate that the blind Doppler sidelobe is suppressed effectively and the proposed algorithm has a good performance even in the presence of Doppler ambiguity.

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Cherniakov, M., Rajesh Saini, Michael Antoniou, Rui Zuo, and Eleftherios Plakidis. "Experiences Gained during the Development of a Passive BSAR with GNSS Transmitters of Opportunity." International Journal of Navigation and Observation 2008 (July 8, 2008): 1–12. http://dx.doi.org/10.1155/2008/807958.

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This paper presents an overview of the research conducted at University of Birmingham. It highlights and briefly discusses various systems parameters (e.g., resolution, power budget), problems (e.g., interference, heterodyne channel Doppler compensation), and signal processing algorithms (imaging, synchronization) required for successfully obtaining an image. The GLONASS satellite is used for experiential confirmation of the main results. All these results are presented and briefly discussed.

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Ahmed, Naeem, Boyu Hua, Qiuming Zhu, Kai Mao, and Junwei Bao. "A Novel GBSM for Non-Stationary V2V Channels Allowing 3D Velocity Variations." Sensors 21, no. 9 (May 10, 2021): 3271. http://dx.doi.org/10.3390/s21093271.

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A new non-stationary (NS) geometry-based stochastic model (GBSM) is presented for developing and testing the communication systems of vehicle-to-vehicle (V2V) applications, which considers the three-dimensional (3D) scattering environments and allows 3D velocity as well. In this paper, the proposed GBSM for NS V2V channels allowed 3D velocity variations and was more suitable for actual V2V communications because it provided smoother transitions between the consecutive channel segments. The time-variant channel coefficient and the channel parameters, i.e., Doppler frequencies, path delay and power, angle of arrival (AoA), and angle of departure (AoD), were analyzed and derived. Likewise, the theoretical statistical properties as the probability density function (PDF), the auto-correlation function (ACF), and Doppler power spectral density (DPSD) were also analyzed and derived under the von Mises–Fisher (VMF) distribution. Finally, the theoretical and measured results were well coordinated alongside the implemented results, which confirmed the feasibility of the introduced model along with the theoretical expressions.

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Rao, I. Srinivasa, V. K. Anandan, and M. Shravan Kumar. "Multifrequency Decoding of a Phased Array Doppler Sodar." Journal of Atmospheric and Oceanic Technology 26, no. 4 (April 1, 2009): 759–68. http://dx.doi.org/10.1175/2008jtecha1166.1.

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Abstract Doppler sodar is being used for studying the lower part of atmospheric boundary layer (ABL) and wind profiling. To obtain maximum altitude coverage multifrequency transmission has been used along with more transmitted power. In this article, the implementation of multifrequency transmission of a Doppler sodar and its decoding to extract the atmospheric parameters are presented. This article also shows the advantage of profiling using multifrequency sodar operation. The range of frequency used for transmission is between 1700 and 2100 Hz. The decoded Doppler spectra have shown significant improvement in signal-to-noise ratio (SNR) as well as higher altitude coverage compared to single-frequency transmission and reception. Wind profiles obtained from sodar have been compared with data obtained from high-resolution GPS sonde balloons, which were launched from a place close to the sodar system. The authors observed that 30% more wind data height coverage in when transmission is in multifrequency mode; the consistency in wind estimate is also improved compared to the single-frequency transmission.

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Childs, Charmaine, Harriet Nwaizu, Elizabeth Bullivant, Jon Willmott, Matthew Davies, Karen Ousey, Hora Soltani, and Richard Jacques. "Cutaneous Perfusion Dynamics of the Lower Abdomen in Healthy Normal Weight, Overweight and Obese Women: Methods Development Using Infrared Thermography with Applications for Future Wound Management after Caesarean Section." International Journal of Environmental Research and Public Health 20, no. 6 (March 14, 2023): 5100. http://dx.doi.org/10.3390/ijerph20065100.

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Background: Evidence has shown an association between obesity and an increased risk of wound infection after caesarean section. This study was designed to examine if abdominal subcutaneous adiposity impacts upon cutaneous perfusion dynamics. Methods: Mild cool challenge, followed by real-time video thermography, was developed to map the appearance of abdominal ‘hot spots’. Correspondence of marked ‘spots’ with audible Doppler and colour and power Doppler ultrasound was performed. Results: 60 healthy, afebrile, women (20–68 years; BMI 18.5–44 kg/m2) were recruited. Hot spot appearance consistently corresponded with audible Doppler sounds. Colour and power Doppler ultrasound revealed vessels at depths of 3–22 mm. No statistically significant interactions for BMI, abdominal circumference or environmental parameters were observed for hot spot count. The temperature of cold stimulus was significant for effects on spot count, but only for the first minute (p = 0.001). Thereafter, effects on spot numbers were not significant. Conclusions: Cutaneous ‘perforator’ mapping of the abdomen (via hot spot appearance) in healthy women, as a potential and future method for risk of perfusion-dependent wound healing complications, reveals that bedside mapping of skin perfusion is feasible over a short interval. Hot spot number was not influenced by BMI or indicators of central fat distribution (abdominal circumference) indicating variability in an individual’s vascular anatomy. This study provides the underpinning methodology for personalised perfusion assessment after incisional surgery which may be a more reliable indicator of potential healing complications than body habitus as is currently the norm.

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Zuhair, Zuhair, Wahid Luthfi, R. Andika Putra Dwijayanto, and Suwoto Suwoto. "STUDY ON CRITICALITY AND NEUTRONIC SAFETY PARAMETERS OF NUSCALE FUEL ASSEMBLY." Urania : Jurnal Ilmiah Daur Bahan Bakar Nuklir 27, no. 3 (October 29, 2021): 165. http://dx.doi.org/10.17146/urania.2021.27.3.6509.

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STUDY ON CRITICALITY AND NEUTRONIC SAFETY PARAMETERS OF NUSCALE FUEL ASSEMBLY. NuScale, a typical Pressurized Water Reactor (PWR) Small Modular Reactors (SMRs), offers a new opportunity for the future of nuclear industry. With 160 MW thermal power, NuScale has several advantages such as flexibility due to its modularity in construction. This work is focused on the study of criticality and neutronic safety parameters of NuScale fuel assembly using MCNP6 code and ENDF/B-VII library. The calculation results shows that criticality of fuel assembly type D is the highest among other assembly types because it has a fuel pin with pure UO2 without Gd2O3 concentration. The Doppler temperature coefficient (DTC) of fuel assembly type C is the most negative among other assemblies due to Doppler broadening effect on resonance region of capture cross section of 238U which is the highest concentration. The moderator temperature coefficient (MTC) of fuel assembly type D is the most negative among the other assembly types. The effective delayed neutron fraction (βeff) does not reflect a consistent trend among fuel assembly types. Fuel assembly type D shows the highest prompt neutron lifetime (ℓ) while the highest neutron generation time (Ʌ) is shown in assembly type C. It can be concluded that this study provides adequate results that can be used as a first step to carry out the neutronic computation and analysis of the NuScale full core.Keywords: Criticality, safety parameters, NuScale fuel assembly, MCNP6, ENDF/B-VII.

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Wu, Shi Long, Jing Qing Luo, and Hua Xing Wang. "Single Channel Signal Separation of GMSK Signals Based on MLP." Applied Mechanics and Materials 347-350 (August 2013): 1705–10. http://dx.doi.org/10.4028/www.scientific.net/amm.347-350.1705.

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In according to the issue of multi-signal jamming in communication reconnaissance, single channel signal separation for multi-GMSK signals has been studied with a method based on MLP. With parameters of Doppler-shift, time-delay, amplitude and coding sequences efficiently estimated, signals could be restructured, and then be separated. Simulations have proved well separation results can be obtained with the method for unequal power signals with certain SNRs.

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Mayer, Richard Bernhard, Thomas Ebner, Christoph Weiss, Christina Allerstorfer, Reinhard Altmann, Peter Oppelt, and Omar Shebl. "The Role of Endometrial Volume and Endometrial and Subendometrial Vascularization Parameters in a Frozen Embryo Transfer Cycle." Reproductive Sciences 26, no. 7 (November 12, 2018): 1013–18. http://dx.doi.org/10.1177/1933719118804421.

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The role of three-dimensional power Doppler ultrasonography of the endometrium in assisted reproduction is still far from clear. In this retrospective cohort study, transvaginal three-dimensional power Doppler examinations were performed 30 min before frozen–thawed embryo transfer. After pregnancy tests, two cohorts were established: P (pregnant, n = 31) and NP (nonpregnant, n = 31). The study only included nullipara with no uterine abnormalities who were undergoing infertility treatment at the Department of Gynecology, Obstetrics and Gynecological Endocrinology, Kepler University Hospital, Linz, Austria. The main outcome measures were the vascularization flow index (VFI), flow index (FI), and vascularization index (VI) in the endometrium/subendometrium, assessed using Virtual Organ Computer-aided AnaLysis (VOCAL™), and the endometrial volume. A total of 62 patients were enrolled in the study, forming two cohorts (pregnant, P; nonpregnant, NP). There were no significant differences between the two cohorts with regard to demographic data, numbers of embryos transferred, or embryo grading, but there was a significant difference in endometrial volume (cohort P, 3.17 ± 0.84 mL; cohort NP, 2.36 ± 0.9 mL; P = 0.001) and the pregnancy rate rises with larger volume. No differences were observed in the vascularization parameters FI, VFI, and VI in the endometrium and subendometrium. In the cohort of pregnant patients, there were 26 (41.9%) live births, with 21 term deliveries (80.8%). The endometrial volume was larger in the cohort of pregnant patients. Measurements were performed 30 min before embryo transfer, and no differences were observed in vascularization parameters in the subendometrium and endometrium.

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Bakhshaee, Mehdi, Yasamin Davoudi, Mostafa Mehrabi, Parvin Layegh, Saadat Mirsadaee, Masoud Pezeshki Rad, and Parvaneh Leyegh. "Vascular Pattern and Spectral Parameters of Power Doppler Ultrasound as Predictors of Malignancy Risk in Thyroid Nodules." Laryngoscope 118, no. 12 (December 2008): 2182–86. http://dx.doi.org/10.1097/mlg.0b013e3181864ae7.

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Sakamoto, Hideo, Masakazu Nagata, Katsuyuki Saito, Taisuke Okumura, and Hideki Yoshida. "Anatomic variations of cavernous arteries and their effect on measurement of hemodynamic parameters: a power Doppler study." Urology 63, no. 3 (March 2004): 539–44. http://dx.doi.org/10.1016/j.urology.2003.10.024.

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Jalencas, G., R. De Diego Burillo, L. Fiores, J. Sabria, A. Vela, and J. Lailla. "OC09.05: Volume and three-dimensional power Doppler cervical parameters in threatened preterm labour and short cervix pregnancies." Ultrasound in Obstetrics & Gynecology 40, S1 (September 2012): 19. http://dx.doi.org/10.1002/uog.11282.

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Song, Hongwei, Ming Li, Chaoquan Wu, Qingchuan Wang, Shunke Wei, Mingxing Wang, and Wenhui Ma. "Data-Driven Methodology for the Prediction of Fluid Flow in Ultrasonic Production Logging Data Processing." Geofluids 2022 (March 15, 2022): 1–15. http://dx.doi.org/10.1155/2022/5637971.

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A new method for the determination of oil and water flow rates in vertical upward oil-water two-phase pipe flows has been proposed. This method consists of an application of machine learning techniques on the probability density function (PDF) and the power spectral density (PSD) of the power spectrum output of an ultrasonic Doppler sensor in the pipe. The power spectrum characteristic parameters of the two-phase flow are first determined by the probability density function (PDF) method. Then, the transducer signal is preprocessed by distance correlation analysis (DCA), and independent features are extracted by principal component analysis (PCA). The extracted features are used as input to a least-squares fit, which gave the oil flow rates as output. In the same way, the transducer signal is also preprocessed by partial correlation analysis (PCA), and independent features were extracted using independent component analysis (ICA). The extracted features were used as inputs to multilayer back-propagation neural networks, which water cuts as output. The present method was used to calibrate an ultrasonic Doppler sensor to estimate the flow rates of both phases in oil–water flow in a vertical pipe of diameter 159 mm. Predictions of the present method were in good agreement with direct flow rate measurements. Compared to previously used methods of feature extraction from the ultrasonic Doppler power spectrum signals, the present method provides a theoretical basis for the interpretation of ultrasonic multiphase flow logging data. Ultrasonic multiphase flow logging has potential application value in the production profile logging and interpretation evaluation of production wells with low fluid production and high water cut.

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Wu, Yi-Cheng, Ching-Hsuan Chen, Hsin-Tzu Lu, Yu-Li Lee, Pi-Yu Chen, Ting-Yu Wu, Ming-Hsun Tien, et al. "Fetal Aortic Blood Flow Velocity and Power Doppler Profiles in the First Trimester: A Comprehensive Study Using High-Definition Flow Imaging." Bioengineering 11, no. 4 (April 15, 2024): 378. http://dx.doi.org/10.3390/bioengineering11040378.

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Objectives: This study aimed to establish reference values for fetal aortic isthmus blood flow velocity and associated indices during the first trimester, utilizing a novel ultrasonographic technique known as high-definition flow imaging (HDFI). Additionally, the correlation between Doppler profiles of aortic blood flow and key fetal parameters, including nuchal thickness (NT), crown-rump length (CRL), and fetal heartbeat (FHB), was investigated. Methods: A total of 262 fetuses were included in the analysis between December 2022 and December 2023. Utilizing 2D power Doppler ultrasound images, aortic blood flow parameters were assessed, including aortic peak systolic velocity (PS), aortic end-diastolic velocity (ED), aortic time average maximal velocity (TAMV), and various indices such as aortic systolic velocity/diastolic velocity (S/D), aortic pulsatile index (PI), aortic resistance index (RI), aortic isthmus flow velocity index (IFI), and aortic isthmic systolic index (ISI). Concurrently, fetal FHB, NT, and CRL were evaluated during early trimester Down syndrome screening. Results: Significant findings include a positive correlation between gestational age (GA) and PS (PS = 3.75 × (GA) − 15.4, r2 = 0.13, p < 0.01), ED (ED = 0.42 × (GA) − 0.61, r2 = 0.04, p < 0.01), PI (PI = 0.07 × (GA) + 1.03, r2 = 0.04, p < 0.01), and TAMV (TAMV = 1.23 × (GA) − 1.66, r2 = 0.08, p < 0.01). In contrast, aortic ISI demonstrated a significant decrease (ISI = −0.03 × (GA) + 0.57, r2 = 0.05, p < 0.05) with gestational age. No significant correlation was observed for aortic RI (p = 0.33), S/D (p = 0.39), and IFI (p = 0.29) with gestational age. Aortic PS exhibited positive correlations with NT (0.217, p = 0.001) and CRL (0.360, p = 0.000) but a negative correlation with FHB (−0.214, p = 0.001). Aortic PI demonstrated positive correlations with CRL (0.208, p = 0.001) and negative correlations with FHB (−0.176, p = 0.005). Aortic TAMV showed positive correlations with NT (0.233, p = 0.000) and CRL (0.290, p = 0.000) while exhibiting a negative correlation with FHB (−0.141, p = 0.026). Aortic ISI demonstrated negative correlations with NT (−0.128, p = 0.045) and CRL (−0.218, p = 0.001) but a positive correlation with FHB (0.163, p = 0.010). Conclusions: Power Doppler angiography with Doppler ultrasound demonstrates the ability to establish accurate reference values for fetal aortic blood flow during the first trimester of pregnancy. Notably, aortic PS, TAMV, and ISI exhibit significant correlations with NT, CRL, and FHB, with ISI appearing more relevant than IFI, PS, TAMV, and FHB. The utilization of HDFI technology proves advantageous in efficiently detecting the site of the aortic isthmus compared to traditional color Doppler mode in early second trimesters.

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Carvalho, Camila Franco de, Jéssica Ribeiro Magalhães, Andreia Moreira Martins, Kyrla Cartynalle das Dores Silva Guimarães, Reiner Silveira de Moraes, Daniel Bartoli de Sousa, and Andréia Vitor Couto do Amaral. "Pulsed-wave doppler ultrasound in canine reproductive system – Part 1: technical aspects." Research, Society and Development 10, no. 5 (May 15, 2021): e52510515348. http://dx.doi.org/10.33448/rsd-v10i5.15348.

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The purpose of this article is to review the literature on the essential technical aspects of implementing the pulsed Doppler, as part of the teachings to their use in the diagnosis of changes in the canine reproductive system. A narrative review was carried out, using scientific articles, monographs, theses and dissertations published and available in online databases: Periodical Capes (Coordination for the Improvement of Higher Education Personnel), SciELO (Scientific Electronic Library Online) and Google Scholar, in addition to specific books on the topic. Two-dimensional ultrasound has been widely used in medicine since 1942, leading to advancements in disease identification and subsequent prognosis. In terms of vascular assessment, Doppler ultrasound is used to evaluate the blood flow inside the vessel, its direction, and hemodynamic pattern. Among all types of Doppler ultrasound, the Color Doppler (CD), Power Doppler (PD), and the Pulsed-wave Doppler (PW) are commonly used in the identification of abnormalities through ultrasound flow imaging and the analysis of hemodynamic indices: peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI), and pulsatility index (PI). To accurately estimate these hemodynamic indices, however, it is essential to know the technical adjustments and parameters such as the pulse repetition frequency (PRF), size of the sample volume (Gate), angle of insonation, gain, baseline, and wall filter, which need to be corrected to avoid technician derive artifacts such as aliasing, signal absence, and mirror imaging. In medicine, the use of Doppler Mode in reproductive functions is already well established, but its use in veterinary medicine is still a subject of recent studies.

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Li, Ko-Jen, Huan-Chen Lin, Chiao-Feng Cheng, Tiffany Ting-Fang Shih, Cheng-Hsun Lu, Peemongkon Wattananon, Wen-Shiang Chen, and Hsing-Kuo Wang. "Ultrasound characteristics of soft tissues near sacroiliac joints and in the lumbar region of patients with ankylosing spondylitis." Medical Ultrasonography 25, no. 3 (September 29, 2023): 279. http://dx.doi.org/10.11152/mu-3973.

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Aims: To investigate the musculoskeletal morphomechanical properties (i.e., the thickness and elastic modulus) and the total count of power Doppler signals near the sacroiliac joints in patients with ankylosing spondylitis (AS) and non-AS individuals.Material and methods: Twenty participants with AS [median age (interquartile range): 31.7 (11.04) years] and 19 controls [36.3 (10.5) years] with no AS history were recruited. Bilateral ultrasound image acquisition was performed, including the short posterior sacroiliac ligament, interosseous sacroiliac ligament, long posterior sacroiliac ligament, iliolumbar ligament, proximal piriformis muscle, and sacrotuberous ligament. The intraclass correlation coefficients (ICC) of ultrasound parameters, laboratory test results of human leukocyte antigen B27, C-reactive protein, and erythrocyte sedimentation rate, and self-reported physical and disease activity scores were also obtained.Results: The ligaments and piriformis muscle were thicker and stiffer (greater elastic modulus) in participants with AS than in non-AS participants (all p<0.01). The measurements showed good or excellent reliability (all ICC(3,1) >0.85). The numbers of power Doppler signals detected in the iliolumbar ligament, proximal piriformis muscle, and sacrotuberous ligament were higher in participants with AS than in non-AS participants (all p<0.001). A correlation was identified between disease duration and the elastic modulus of the piriformis muscle (r=0.640, p=0.003).Conclusion: We conclude that the ligaments and proximal piriformis muscle of AS participants have increased thickness, elastic modulus, and power Doppler signal than those of non-AS individuals. These reliable findings may serve as potential markers for the early diagnosis of AS and for assessing medication effects.

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Conz, Livia, Rodrigo Menezes Jales, Maira Teixeira Dória, Isabelle Melloni, Carla Andries Cres Lyrio, Carlos Menossi, Sophie Derchain, and Luís Otávio Sarian. "Predictive value of ultrasound doppler parameters in neoadjuvant chemotherapy response of breast cancer: Prospective comparison with magnetic resonance and mammography." PLOS ONE 19, no. 6 (June 4, 2024): e0302527. http://dx.doi.org/10.1371/journal.pone.0302527.

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Background Neoadjuvant chemotherapy (NACT) is a treatment option for breast cancer patients that allows for the assessment of tumor response during treatment. This information can be used to adjust treatment and improve outcomes. However, the optimal imaging modalities and parameters for assessing tumor response to NACT are not well established. Methods This study included 173 breast cancer patients who underwent NACT. Patients were imaged with ultrasound (US), mammography (MMG), and magnetic resonance imaging (MRI) at baseline, after two cycles of NACT, and before breast surgery. US parameters included lesion morphology, Doppler variables, and elastography measurements. MMG and MRI were evaluated for the presence of nodules and tumor dimensions. The pathological response to NACT was determined using the residual cancer burden (RCB) classification. Results The US parameter with the highest power for predicting pathological complete response (pCR) was shear wave elastography (SWE) maximum speed inside the tumor at baseline. For nonluminal tumors, the end diastolic velocity measured by US after two cycles of NACT showed the highest predictive value for pCR. Similarly, SWE maximum speed after two cycles of NACT had the highest discriminating power for predicting RCB-III in luminal tumors, while the same parameter measured at baseline was most predictive for nonluminal tumors. Conclusions This study provides evidence that mid-treatment Doppler US and other imaging modalities can be used to predict the response to NACT in breast cancer patients. Functional parameters, such as blood flow velocities and SWE measurements, demonstrated superior predictive value for pCR, while morphological parameters had limited value. These findings have implications for personalized treatment strategies and may contribute to improved outcomes in the management of breast cancer.

Journal articles on the topic 'Power Doppler parameters'

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