Doppler Method Research Articles

TELARŞLI PUBERTE PREKOKS HASTALARINDA VASKÜLARİTENİN DOPPLER ULTRASONOGRAFI YÖNTEMLERİ İLE DEĞERLENDİRİLMESİ

OBJECTIVE: The aim of this study is to investigate the correlation between breast vascularity level and Tanner staging in the evaluation of thelarche, and to compare Doppler methods for demonstrating vascularity.MATERIAL AND METHODS: Girls aged 6–10 who were referred to the radiology clinic with a complaint of breast swelling and prediagnosed with precocious puberty between October and December 2017 were included in the study. Breast ultrasonography (US) and color doppler ultrasonography (CDUS) examinations were performed on all participants. Age, Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), Estradiol (E2), thelarche stage, both breast volumes were recorded for all participants. Vascular scores were measured for both breasts using imaging modalities such as color doppler (CD), Power US (PD), and superb microvascular imaging (SMI).RESULTS: We included 116 girls and 213 thelarche breasts in the study. A significant correlation was found between the depth and transverse and longitudinal diameter for each breast and breast volume and Tanner stages (rs = 0.762, rs = 0.830, rs = 0.774 rs = 0.824, respectively; p < 0.001). Although the highest correlation between Doppler methods was found in PD (PD rs =0.68, CD rs =: 0.61, SMI rs =:0.61, p<0.001), the methods did not have any superiority over each other (p>0.05). Vascularization with SMI was demonstrated in 30 of 65 breasts for which vascularization could not be demonstrated with power Doppler. Among these 30 cases, 90% (n = 27) were Tanner stage I and II.CONCLUSIONS: In conclusion, although SMI is as successful as conventional Doppler methods in the evaluation of thelarche vascularity, it can provide more data in some cases.

Quantitative Ultrasound: An Emerging Technology for Detecting, Diagnosing, Imaging, Evaluating, and Monitoring Disease.

Ultrasound has been a popular clinical imaging modality for decades. It is a well-established means of displaying the macroscopic anatomy of soft-tissue structures. While conventional ultrasound methods, i.e., B-mode and Doppler methods, are well proven and continue to advance technically in many ways, e.g., by extending into higher frequencies and taking advantage of harmonic phenomena in tissues, fundamentally new so-called quantitative ultrasound (QUS) technologies also are emerging and offer exciting promise for making significant improvements in clinical imaging and characterization of disease. These emerging quantitative methods include spectrum analysis, image statistics, elasticity imaging, contrast-agent methods, and flow-detection and -measurement techniques. Each provides independent information. When used alone, each can provide clinically valuable imaging capabilities; when combined with each other, their capabilities may be more powerful in many applications. Furthermore, all can be used fused with other imaging modalities, such as computed tomography (CT), magnetic-resonance (MR), positron-emission-tomography (PET), or single-photon emission computerized tomography (SPECT) imaging, to offer possibly even greater improvements in detecting, diagnosing, imaging, evaluating, and monitoring disease. This chapter focuses on QUS methods that are based on spectrum analysis and image statistics.

Transcranial Doppler as an early predictor of neurological outcome in mild and moderate traumatic brain injury: An observational study

Background: Traumatic brain injury (TBI) is a major cause of disability and mortality globaly. The transcranial Doppler (TCD) method may show low diastolic blood flow velocity (FVd) and high pulsatility index (PI) measurements brought on by high vascular bed resistance. This study aimed to assess the usefulness of the TCD-PI for the early detection of secondary neurological deterioration (SND) in mild and moderate TBI. Materials and Methods: This prospective study was carried out on 105 mild and moderate TBI patients, who had TCD measurements within 12 h of the initial trauma, and initial computerized tomography (CT) showed mild lesion or no detected abnormality. Results: Primary end point was assessed (SND) within 1st week post trauma. Of the 105 patients with mild and moderate TBI, 29 (27.6%) showed SND. We evaluated the value of our intervention (TCD) to predict SND after mild and moderate TBI in 1st week. PI could predict SND at cutoff 1.21 with good sensitivity of 96.5% and specificity of 94.7%, area under curve (AUC) value of 0.98, negative predictive value (NPV) of 98.6%, and positive predictive value (PPV) of 87.5%. To amplify our finding, we measured FVd, and at 25 cm/s it showed good sensitivity 86.2% and specificity 89.5% when AUC 0.93, NPV 94.4%, and PPV 75.8%. Conclusion: TCD on admission may provide a valuable tool of early prediction of neurological outcome for mild and moderate TBI patients. Closing the gap in poor prediction of commonly used evaluation by CT especially with mild lesion.

ISAR Imaging of Precession Target Based on Joint Constraints of Low Rank and Sparsity of Tensor

Precession is a typical form of micro-motion that can bring about complex and time-varying Doppler modulation. The range instantaneous Doppler (RID) method, which uses time-frequency analysis instead of the Fourier transform to describe the time-varying Doppler, is typically used to obtain the high-resolution inverse synthetic aperture radar (ISAR) image of a precession target. However, the observation time of a specific target is often non-uniform due to various interference and channel switching among multi-channel radars, which will lead to a sparse aperture. Sparse aperture can cause sidelobe interference in the ISAR image obtained by the RID method, making it difficult to focus well. To solve the problem whereby the RID method fails to image a precession target with sparse aperture, this paper proposes a new method based on the joint constraints of low-rank and sparsity of tensor, and uses the alternating direction method of multipliers to solve the problem. The low-rank can constrain the correlation among consecutive ISAR images, and sparsity can remove the impact of sparse aperture. This effectively eliminates the micro-Doppler interference and sidelobe interference in ISAR image, and enables the reconstruction of precession target in a sequence of ISAR images with sparse aperture. Experimental results under both simulations and darkroom measurements verify that the proposed method performs well on ISAR images of conic precession target with sparse aperture.

Oscillometric measurement of the ankle-brachial index and the estimated carotid-femoral pulse wave velocity improves the sensitivity of an automated device in screening peripheral artery disease.

To overcome the time and personnel constraints of the Doppler method, automated, four-limb blood pressure monitors were recently developed. Their additional functions, such as measuring the estimated carotid-femoral pulse wave velocity (ecfPWV), have been, thus far, less studied. We aimed to compare the sensitivity and specificity of different ankle-brachial index (ABI), toe-brachial index (TBI), and ecfPWV measurement methodologies to evaluate their contribution to peripheral artery disease (PAD) screening. Among 230 patients (mean age 64 ± 14 years), ABI measurements were performed using a Doppler device and a manual sphygmomanometer. The Doppler ABI was calculated by taking the higher, while the modified Doppler ABI by taking the lower systolic blood pressure of the two ankle arteries as the numerator, and the higher systolic blood pressure of both brachial arteries as the denominator. The automated ABI measurement was carried out using an automatic BOSO ABI-system 100 PWV device, which also measured ecfPWV. TBI was obtained using a laser Doppler fluxmeter (Periflux 5000) and a photoplethysmographic device (SysToe). To assess atherosclerotic and definitive PAD lesions, vascular imaging techniques were used, including ultrasound in 160, digital subtraction angiography in 66, and CT angiography in four cases. ROC analysis exhibited a sensitivity/specificity of 70.6%/98.1% for the Doppler ABI (area under the curve, AUC = 0.873), 84.0%/94.4% for the modified Doppler ABI (AUC = 0.923), and 61.5%/97.8% for the BOSO ABI (AUC = 0.882) at a cutoff of 0.9. Raising the cutoff to 1.0 increased the sensitivity of BOSO to 80.7%, with the specificity decreasing to 79.1%. The ecfPWV measurement (AUC = 0.896) demonstrated a 63.2%/100% sensitivity/specificity in predicting atherosclerotic lesions at a cutoff of 10 m/s. Combining BOSO ABI and ecfPWV measurements recognized 89.5% of all PAD limbs. The combined BOSO ABI and ecfPWV measurements may help select patients requiring further non-invasive diagnostic evaluation for PAD. The user-friendly feasibility may make it suitable for screening large populations.

EVALUATION OF DYNAMIC CHANGES IN THE MICROCIRCULATION OF THE MUCOSA IN THE ZONE OF DENTAL IMPLANTATION WITH IMMEDIATE INTRAOPERATIVE LOAD.

The aim: Study of the dynamics of changes in the average values of the index of mucosal microcirculation after dental implantation with immediate intraoperative prosthetics. Materials and methods: In clinical conditions, 55 patients aged from 29 to 60 years with a diagnosis of partial absence of teeth requiring orthopedic treatment using implants on the lower jaw were treated and examined. In the course of the latest achievements, the following methods were used: clinical protocol of immediate implantation with Solidum and Simplex implants of the «ART IMPLANT» system on the lower jaw by the one-stage implantation method, with immediate intraoperative loading and the manufacture of a temporary non-removable dental prosthesis, determination of the microcirculation index in dynamics using the laser Doppler method flowmetry, statistical analysis. Results: The obtained results indicate a pronounced reaction of microcirculation up to the 3rd day after surgery, an increase in blood perfusion of the mucous membrane by 2.7 times while maintaining vasomotor activity, which indicates adaptation to the injury and immediate loading of the denture in the postoperative period. 3 months after dental surgery and immediate intraoperative prosthetics, all indicators of microcirculation approach the initial values before surgery. Conclusions: With the help of laser Doppler flowmetry, the fact of a sharp restoration of microcirculation after dental implantation surgery with immediate intraoperative prosthetics is confirmed.

Fundamental validation of flow volume measurement by ultrasound pulse Doppler method using simulated circuit

Fundamental validation of flow volume measurement by ultrasound pulse Doppler method using simulated circuit

High-frequency ultrasound in the diagnosis and treatment of skin neoplasms.

High-frequency ultrasonography (HFUS) is a non-invasive and highly repetitive medical imaging method with a great and still rising value in the diagnostic process of skin tumours. It accompanies the physician's examination, dermoscopy, and biopsy; facilitates real-time assessment of locoregional staging and planning of surgical excision; and provides postoperative inspection of treatment results. The aim of this review article is to discuss HFUS application in common cutaneous malignant tumours while depicting the use of both the grayscale and colour Doppler methods.

Spatial Vibration and Displacement Measurement Through Single-Point Continuous and Interval Scanning Laser Doppler Vibrometer

The scanning laser Doppler vibrometer (SLDV) is an extremely valuable method for studying the dynamic properties of vibrating objects, such as those in industrial production, entomology research, and biomedical testing. The traditional SLDV method scans samples using an inclined laser, which ignores the three-dimensional (3-D) information of the sample, resulting in a relatively complicated calculation process. In industrial processes and scientific research, the measured target may have a known 3-D regular surface. When a structure with height information moves laterally, it causes a change in longitudinal information, which is of great benefit in the analysis of the 3-D vibration and displacement information of the target. In this article, continuous and interval scanning laser Doppler methods are proposed to expand the measuring capability of SLDV methods, based on the scanning of spherical structures. First, a spherical structure is introduced to simplify the solution to spiral vibrations. The high-precision displacement can also be calculated by fitting the circular scanning curve. Finally, the scanning method for 3-D displacement measurement is experimentally validated, and the theoretical errors are demonstrated. This work provides a new methodology to realize both periodic and nonperiodic displacements in all degrees of freedom (DOF) with high accuracy using a single-point SLDV, which is expected to have a long-term impact on industry vibration analysis and biological motion research. Most importantly, setting a reflector with a spherical surface on the end-effector of the micro–nano robot can realize the 3-D cross-scale repeated localization.

An intelligent method for pregnancy diagnosis in breeding sows according to ultrasonography algorithms.

Pig breeding management directly contributes to the profitability of pig farms, and pregnancy diagnosis is an important factor in breeding management. Therefore, the need to diagnose pregnancy in sows is emphasized, and various studies have been conducted in this area. We propose a computer-aided diagnosis system to assist livestock farmers to diagnose sow pregnancy through ultrasound. Methods for diagnosing pregnancy in sows through ultrasound include the Doppler method, which measures the heart rate and pulse status, and the echo method, which diagnoses by amplitude depth technique. We propose a method that uses deep learning algorithms on ultrasonography, which is part of the echo method. As deep learning-based classification algorithms, Inception-v4, Xception, and EfficientNetV2 were used and compared to find the optimal algorithm for pregnancy diagnosis in sows. Gaussian and speckle noises were added to the ultrasound images according to the characteristics of the ultrasonography, which is easily affected by noise from the surrounding environments. Both the original and noise added ultrasound images of sows were tested together to determine the suitability of the proposed method on farms. The pregnancy diagnosis performance on the original ultrasound images achieved 0.99 in accuracy in the highest case and on the ultrasound images with noises, the performance achieved 0.98 in accuracy. The diagnosis performance achieved 0.96 in accuracy even when the intensity of noise was strong, proving its robustness against noise.

402 A SIMPLIFIED ECHOCARDIOGRAPHIC FORMULA TO ESTIMATE CARDIAC INDEX IN THE INTENSIVE CARE UNIT

Abstract Background and aim Measurement of cardiac index (CI) is crucial in the hemodynamic assessment of critically ill patients in the intensive care unit (ICU). The most reliable trans-thoracic echocardiography (TTE) technique for CI estimation is the left ventricular outflow tract (LVOT) Doppler method that requires, among other parameters, the LVOT cross-sectional area (CSA) measurement. However, geometrical assumptions inherent limitations and practical disadvantages related to the ICU setting, hamper LVOT-CSA assessment. In this study, we aimed to validate a simplified formula, leveraging only on LVOT-velocity time integral (VTI) and heart rate (HR) variables, for the non-invasive estimation of CI in ICU patients. Methods and Results We prospectively enrolled 50 consecutive patients admitted to our ICU requiring PAC over a one-year period. For each patient we measured the CI by PAC (CIPAC) and TTE. The latter was obtained both with the “traditional formula” (traditional CITTE), requiring LVOT-CSA assessment, and our new “simplified formula” (simplified CITTE). The correlation between the simplified CITTE and CIPAC was strong (r = 0.81) and resulted significantly greater than the traditional CITTE and CIPAC correlation (r = 0.70; p < 0.05 for Pearson r coefficients comparison). Both TTE-based CI showed an acceptable agreement (+0.19±0.48 L/min/m2 for simplified CITTE and -0.18±0.58 L/min/m2 for traditional CITTE) with the reference CIPAC. Conclusion In this study, we propose an easy-to-use and practical approach, leveraging on TTE LVOT-VTI and HR only, for non-invasive estimation of CI in ICU patients.

Echocardiography in the Assessment of Valve Regurgitation- Incremental Role of Three Dimensional Echocardiography.

Echocardiography (Echo) has a primary role in the evaluation of cardiac valve regurgitation. Echo valve regurgitation assessment includes multiple qualitative and quantitative methods which require adequate image quality, comprehensive echocardiographic images and precise measurements to obtain accurate assessment. For patient management, it is also important to investigate the mechanism of valve regurgitation. Severity and mechanism of valve regurgitation determine whether continued medical follow up is optimal or surgical or percutaneous valve repair, or replacement option should be necessary. Transthoracic Echo (TTE) is the gold standard most commonly used for the assessment of valve leaflet anatomy, valve motion and regurgitation severity to determine primary versus secondary causes of valve regurgitation, however transesophageal echo (TEE) provides high resolution imaging of valve leaflets and supporting apparatus and oftentimes determines mechanism of valve regurgitation particularly for mitral and tricuspid valves when TTE is unable to determine the mechanism. By providing surgical type views in a moving heart under normal hemodynamic conditions, 3D TEE has greatly improved assessment of mechanism and etiology of valve regurgitation. Besides, TEE also allows quantitation of valve regurgitation severity by Doppler methods as well as direct 3D planimetry of valve area and regurgitant orifice area. Doppler methods are pre and afterload dependent whereas direct 3D planimetry allows assessment of location and severity of valve regurgitation irrespective of ventricular loading conditions. Pre or intraoperative 3D TEE assessment can provide valuable information for surgical planning of valve repair or replacement. This review discusses various valvular pathologies causing regurgitation and the role of TTE and TEE in improving this assessment as shown by several case examples.

Two-Dimensional Wavenumber Analysis Implemented in Ultrasonic Vector Doppler Method with Focused Transmit Beams

The multi-angle Doppler method was introduced for the estimation of velocity vectors by measuring axial velocities from multiple directions. We have recently reported that the autocorrelation-based velocity vector estimation could be ameliorated significantly by estimating the wavenumbers in two dimensions. Since two-dimensional wavenumber estimation requires a snapshot of an ultrasonic field, the method was first implemented in plane wave imaging. Although plane wave imaging is predominantly useful for examining blood flows at an extremely high temporal resolution, it was reported that the contrast in a B-mode image obtained with a few plane wave emissions was lower than that obtained with focused beams. In this study, the two-dimensional wavenumber analysis was first implemented in a framework with focused transmit beams. The simulations showed that the proposed method achieved an accuracy in velocity estimation comparable to that of the method with plane wave imaging. Furthermore, the performances of the methods implemented in focused beam and plane wave imaging were compared by measuring human common carotid arteries in vivo. Image contrasts were analyzed in normal and clutter-filtered B-mode images. The method with focused beam imaging achieved a better contrast in normal B-mode imaging, and similar velocity magnitudes and angles were obtained by both the methods with focused beam and plane wave imaging. In contrast, the method with plane wave imaging gave a better contrast in a clutter-filtered B-mode image and smaller variances in velocity magnitudes than those with focused beams.

A simplified echocardiographic formula to estimate cardiac index in the intensive care unit

Background and aimMeasurement of cardiac index (CI) is crucial in the hemodynamic assessment of critically ill patients in the intensive care unit (ICU). The most reliable trans-thoracic echocardiography (TTE) technique for CI estimation is the left ventricular outflow tract (LVOT) Doppler method that requires, among other parameters, the LVOT cross-sectional area (CSA) measurement. However, inherent and practical disadvantages, mostly related to the ICU setting, hamper LVOT-CSA assessment. In this study, we aimed to validate a simplified formula, leveraging on LVOT-velocity time integral (VTI) and heart rate (HR) only, for non-invasive estimation of CI in ICU patients. Methods and resultsWe prospectively enrolled 50 consecutive patients admitted to our ICU requiring pulmonary artery catheterization (PAC) over a one-year period. For each patient we measured the CI by PAC (CIPAC) and TTE. The latter was obtained both with the “traditional formula” (traditional CITTE), requiring LVOT-CSA assessment, and our new “simplified formula” (simplified CITTE). The correlation between the simplified CITTE and CIPAC was strong (r = 0.81) and resulted significantly greater than the traditional CITTE and CIPAC correlation (r = 0.70; p < 0.05 for Pearson r coefficients comparison). Both TTE-based CI showed an acceptable agreement (+0.19 ± 0.48 L/min/m2 for simplified CITTE and − 0.18 ± 0.58 L/min/m2 for traditional CITTE) with the reference CIPAC. ConclusionIn this study, we validated a practical approach, leveraging on TTE LVOT-VTI and HR only, for non-invasive estimation of CI in ICU patients.

Echocardiography strain: why is it used more and more?

In the last decade, speckle tracking echocardiography (STE) has acquired a fundamental role in the evaluation of the systolic function of the left ventricle, with several advantages over the Doppler method, including angle independence, greater reproducibility, and rapidity of image acquisition. Speckle tracking finds application in various pathologies, ranging from ischaemic heart disease, to cardiomyopathies, to heart failure, both with reduced and preserved ejection fraction (EF), in which the EF is not a reliable prognostic marker and the estimate of left ventricular function by means of 'strain' is of crucial utility. In addition, the strain of the left atrium finds application in many clinical contexts as an early index of diastolic dysfunction and left ventricular filling pressures. Finally, the strain of the right ventricle is of particular prognostic importance in the evaluation of heart failure, particularly in its advanced form, becoming an indispensable index in the evaluation of patients who are candidates for advanced therapeutic strategies. This document aims to describe the various fields of clinical application of STE, with particular emphasis on its diagnostic and prognostic role, so much that it is now integrated into the algorithms for managing multiple pathologies in daily clinical practice.

Exercise-induced pulmonary hypertension assessed by echocardiography in patients with chronic thromboembolic pulmonary disease

Abstract Background Many patients with chronic thromboembolic pulmonary disease (CTEPD) without pulmonary hypertension (PH) at rest suffer from exercise intolerance. Exercise echocardiography, which is a noninvasive examination, may have potential to discover exercise-induced PH in these patients, however, its role is scarcely explored in this population. Purpose To determine the occurrence of abnormal pulmonary pressure during rest and by exercise echocardiography in patients with CTEPD. Methods In total, 24 patients with CTEPD, all diagnosed after pulmonary embolism, underwent exercise echocardiography with dynamic supine leg exercise using a cycle ergometer. In addition, all participants underwent a modified incremental shuttle walk test (mISWT), pulmonary function tests and measurement of NT pro-BNP. Systolic pulmonary arterial pressure (sPAP) &amp;gt;50 mmHg by echocardiography during exercise was chosen as cutoff to define exercise-induced pulmonary hypertension (EIPH). Left ventricular diastolic dysfunction during stress was defined according to the American Society of Cardiology guidelines from 2016. Mean pulmonary artery pressure was estimated by sPAP measurements using the Chemla formula (0.61 x sPAP + 2 mmHg), and pulmonary vascular resistance (PVR) by the Doppler method (5.19 x TRV2/TVI RVOT − 0.4) proposed by Abbas et al. [1]. Subjects with heart failure with reduced or preserved ejection fraction, significant valvular heart disease, chronic pulmonary disease and chronic thromboembolic pulmonary hypertension were excluded. Results 11 (46%) of the patients had EIPH at peak exercise (range 50 to 89 mmHg). PVR at peak exercise ranged from 2.6 to 5.9 WU, whereas 10 had PVR &amp;gt;3.0 WU. None had unmasked left ventricular diastolic dysfunction during exercise, resting tricuspid regurgitation peak velocity (TR V max) &amp;gt;3.4m/s, or a high probability of PH at rest. Three patients had TR V max between 2.9 and 3.4m/s or intermediate probability of PH. All patients had normal biventricular systolic function at rest and during exercise (Table 2). Conclusion Patients with CTEPD had normal pulmonary pressures at rest. However, approximately half of the patients showed abnormal rise in pulmonary pressure during exercise, which may explain or contribute to the exercise intolerance in these patients. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Ostfold Hospital Trust

Novel Method for Fetal and Maternal Heart Rate Measurements Using 2-D Ultrasound Color Doppler Flow Images.

Fetal heart rate (FHR) and maternal heart rate (MHR) are important indicators of fetal well-being during pregnancy. A common method in clinical examination is to estimate the FHR using the Doppler shift of echoes from umbilical artery blood flow based on an ultrasound pulsed-wave (PW) Doppler technique. Similarly, a sampling gate can be located at the maternal blood flow to measure MHR using PW Doppler. Ultrasound color Doppler flow imaging (CDFI) is one of the most commonly used imaging modes for clinical fetal examinations. Color coding is employed to display the blood flow velocity and direction in color grades according to the Doppler shift. Continuous CDF images contain dynamic changes characteristics of the blood flow. The periodic characteristics can be used to obtain heart rate information. Therefore, here we propose a novel method to measure FHR and MHR simultaneously using CDF images. The proposed method calculates the histogram of color similarity of CDF images to initially extract the periodic characteristics of the CDF image sequence. The histogram of color similarity function is then processed by a bandpass filter and autocorrelation operation to reduce noise and enhance periodicity. Finally, peak detection is performed on the processed signal to obtain the period and estimate the heart rate. The proposed method can measure the FHR and MHR in parallel after selecting two regions containing the umbilical artery and maternal blood flow, respectively. Thus, the method has high computational efficiency. The proposed method was evaluated on a Doppler flow phantom and clinical CDF images and then compared with the PW Doppler method. The correlation analysis and Bland-Altman plots reveal that the proposed method agrees well with the PW Doppler. It is a sanity check method for real-time clinical FHR and MHR measurements.

Passive and active Doppler methods and metrics to quantify inertial cavitation induced by pulsed focused ultrasound

Inertial cavitation induced by pulses of nonlinearly distorted focused ultrasound (FUS) at moderate intensity can result in mild mechanical disruption of tissue, short of its complete mechanical disintegration—histotripsy. This effect can be used to enhance diffusion of subsequently systemically administered drugs or biologics. Previously, single-element passive cavitation detection (PCD) of broadband noise emissions was successfully used to quantify tissue disruption and enhancement in drug concentration. This metric, however, has limitations: minimal spatial resolution and challenges with calibration when used at large depths in acoustically variable tissue. To address this, we developed a combination of passive and active Doppler-based methods that relied on relative, rather than absolute signal metrics. Specifically, destructive cavitation behaviors were previously linked to substantial motion of the bubbles during the FUS pulse due to acoustic radiation force and shock scattering. This was reflected in the backscattered FUS harmonics as Doppler shift and measurable from PCD. The bubbles were observed to dissolve within milliseconds following each FUS pulse, thus their distribution could be visualized as an area of rapid change via fast plane wave Doppler ensemble following the FUS pulse. The Doppler power distribution was spatially correlated with the area of tissue disruption in the in vivo experiments. [Work supported by NIH R01CA154451, R01EB025187, and R01EB23910.]

Anatomy and Physiology of Right Heart Adaptation to Pulmonary Arterial Hypertension Along with Treatment

Background: Right ventricular (RV) performance is directly correlated with staying alive in individuals with the pulmonary arterial hypertension (PAH). There is still large degree of heterogeneity in the RV's response to pulmonary hypertension, despite the fact that the load of pulmonary i.e. lung, is a key factor in determining RV systolic performance in PAH. Objective: The main reason why this study was conducted to find out the normal differential function, interrelationships, and response to pulmonary arterial hypertension apical, right ventricular (RV) input and outflow compartments (PAH). Methods:40 individuals were examined using echocardiography which was 2-dimensional (2D) and also 3-dimensional (3D) in addition to traditional Doppler methods, including 15 controls, with the number of patients with left-sided heart failure was 25, 13 without secondary PAH which was named group-1 (G1) and 12 with secondary PAH was calledgroup-2 (G2). Results: The apical ejection percent was lower in controls than in patients for example the ejection of control was p≤0.01 and p≤0.01, for G1 it was: p≤0.05 and p≤0.01 and the ejection fraction forG2 was: p≤0.05 and p≤0.01, as well as in patients. The Inflow was decreased i.e.: p≤0.001 for both, same in the case of the apical: p≤0.01 for both, and again also in outflow tract: p≤0.05 for both patients showed decreased ejection percent. In G2, however, the inflow compartment achieved the minimal volume simultaneously with the outflow and apex, as opposed to controls where it took 20 ms for it to do so. In patients (in G1: the apical ejection percent was p=0.02 and p=0.01 and forG2 it was: p=0.01 for both), the times for both isovolumic contraction and that of relaxation were lengthened. In controls, volumetric outflow rate decline and the peak RV ejection time were associated (r=0.6, p0.05), however G2's peak RV ejection time was connected with the apex. Conclusion: The inflow of the right side ventricular, apical, and also the outflow tract compartments each have distinctive characteristics and share to the total combined systolic function to varying degrees. The ventricle of the right side becomes one non synchronous compartment in PAH, that can lead to a long-term impact on systemic cardiac dysfunction.

Evaluation of the performance of GNSS-based velocity estimation algorithms

Global Navigation Satellite System (GNSS) based velocity estimation is one of the most cost-effective and widely used methods in determining velocity in geodesy and transport applications. Highly accurate and reliable velocity measurements can be obtained by exploiting the raw Doppler, carrier phase, and pseudorange measurements with a GNSS receiver. There are several approaches to GNSS-based velocity determination. This paper investigates the characteristics of the approaches which are currently popular and applicable to the observations of Global Positioning System (GPS), BeiDou Navigation Satellite System (BDS), and their combination (GPS/BDS). Specifically, it evaluates the performance of the velocity estimated based on the Raw Doppler method, the Time-Differenced Pseudorange method, the Time-Differenced Carrier Phase method, and the Double-Differenced Carrier Phase method, in both static and dynamic modes and in open and urban scenarios. The experiments show that BDS has the advantages in delivering accurate velocity determinations over GPS in the Asia–Pacific region, and the effectiveness of the GPS/BDS in improving the overall accuracy of velocity determination in complex urban scenarios.