Pulsed Doppler Research Articles

Range ambiguity suppression under high-resolution estimation using the MUSIC-AP algorithm for pulse-Doppler radar

Range ambiguity is a significant challenge in conventional pulse-Doppler radar systems with medium or high pulse repetition frequencies, greatly impacting radar detection and imaging capabilities. The classic approaches such as waveform diversity and compressed sensing are based on the isolation between pulses. However, these methods encounter issues like residual ambiguity and grid mismatch, resulting in poor range ambiguity suppression performance. In this paper, the multiple signal classification-alternating projection (MUSIC-AP) method is proposed to address these challenges and achieve high-resolution estimation. The proposed method converts the range-velocity estimate into a spectrum estimate, enabling the utilization of the MUSIC algorithm to solve the grid mismatch problem and improve echo reconstruction. Then, to mitigate the effect of ambiguous energy on reconstruction, the MUSIC reconstruction subprocess is embedded into the AP framework. Through iterative approximation, the method gradually suppresses ambiguous and noise energy, thereby further enhancing the echo reconstruction accuracy and range ambiguity suppression performance. Simulations demonstrate the effectiveness of the proposed method. Moreover, algorithm analysis is conducted, considering aspects such as resolution, robustness, and sparsity, which provides a basis for parameter selection and applicability conditions.

Echo Preprocessing-Based Smeared Spectrum Interference Suppression

Self-protection deceptive interferences (SPDI) are widely used in electronic countermeasures. Smeared spectrum (SMSP) interference, as a typical SPDI, can form a large number of dense false targets at the receiver output to affect effective target detection. Therefore, the suppression of SMSP interference is a compelling issue. The existing SMSP interference suppression methods inevitably result in energy loss of the target due to signal processing. This paper proposes a novel interference suppression method based on echo preprocessing to address this problem. Firstly, the pulse compression (PC) and the coherent integration (CI) characteristics of SMSP interference in the pulse Doppler radar are obtained through the derivation of formulas. Then, echo preprocessing is introduced, and the steps of interference suppression are listed in detail. Finally, the SMSP interference is suppressed because the preprocessed interference forms a center-shifting and range-scaling in the distance dimension after PC, and CI gain cannot be further obtained. The proposed method does not lose the energy of the true target because it does not involve filtering and reconstruction processing. Simulations show that the target detection probability of the proposed method can reach 100% via peak search after the interference suppression when the signal-to-noise ratio is greater than −10 dB and the jamming-to-signal ratio (JSR) is less than 35 dB. Compared with three representative methods in the recent literature, the proposed method has better robustness and higher JSR tolerance.

Systematic Approach of Basic Fetal Echocardiography in Normal and High Risk Pregnancy

Background Fetal echocardiography was initially used to identify congenital heart defects (CHD) and arrhythmias. Since then, technical advances have enabled a notable improvement in the assessment of cardiac structure and function. Objective to highlight the importance of a systematic approach of basic fetal echocardiography in normal and high risk pregnancy. Patients and Methods Normal and high risk pregnant females will be studied in this research using colour doppler ultrasound. Two-dimensional imaging is still the gold standard and commonly used in fetal echocardiography. Therefore, we present standard views of the normal fetal heart obtained during the second trimester by two-dimensional ultrasound, and color and pulsed wave Doppler. Study place: Ain Shams university hospitals. Sample size: 30 normal and 30 high risk pregnant female patients. Results we have provided reference values for cardiac morphometric parameters across second trimester of pregnancy in a low-risk and high risk population including the Right and left atria longitudinal diameters, right and left ventricular longitudinal diameters, cardiothoracic ratio and heart rate and correlate low to high risk values. All dimensions showed a progressive increase with gestational age, some of the parameters show significant difference between low risk and high risk including the LV diameter with p value of 0.023, cardiothoracic ratio with p value of 0.001 and heart rate with p value of 0.001 Conclusion Fetal Echocardiography at the second trimester of pregnancy is crucial for detection of any abnormality at the high risk group and their follow up along the whole pregnancy for a better outcome.

Safety of Ultrasound Exposure: Awareness of Ultrasound Bioeffects among Saudi Sonographers.

Ultrasound tends to produce biological effects on body tissues. Therefore, the application of ultrasound safety rules is needed in all ultrasound examinations to avoid bioeffects that may occur because of a high thermal index (TI) and mechanical index (MI). This study aimed to explore the Saudi sonographers' awareness of ultrasound safety and bioeffects. A descriptive cross-sectional study was conducted, and the data was collected using an online survey google forms questionnaire disseminated through social media (Telegram, WhatsApp, and Twitter) as an electronic link. A total of 70 participants responded to the survey directly, and then, the data was analyzed using SPSS (Statistical Package for Social Science). Regarding the awareness of TI and MI, 64.3% of the participants were aware of TI and 65.7% of MI as safety ultrasound indices; moreover, 74.3% of the participants were aware of the ALARA principle "As Low as Reasonably Achievable." Participants' knowledge concerning more heat production in pulsed Doppler ultrasound modes was poor (31.5%). Most of the sonographers, i.e., 77.1% were aware of the relationship between the risk of activation and MI, and 58.6% of the participants were acquainted with the current FDA output limits. In comparison, 58.6% of the participants were aware of the bioeffects of ultrasound contrast agents. There was no significant correlation between the educational level and the degree of awareness of ultrasound bioeffects and safety (P-value> 0.05). In this study, it was found that sonographers were aware of the theoretical principles of ultrasound safety indices and the ALARA principle, although they had poor knowledge of ultrasound bioeffects in Doppler mode.

The effect of bio-electro-magnetic-energy-regulation therapy on sleep duration and sleep quality among elite players in Norwegian women's football.

The current study investigated if physical loads peak on game days and if Bio-Electro-Magnetic-Energy-Regulation (BEMER) therapy is affecting sleep duration and sleep quality on nights related to game nights among elite players in Norwegian women's elite football. The sample included 21 female football players from an elite top series club with a mean age of ~24 years (± 2.8). Sleep was measured every day over a period of 273 consecutive days with a Somnofy sleep monitor based on ultra-wideband (IR-UWB) pulse radar and Doppler technology. The current study was conducted as a quasi-experiment, where each player was their own control based on a control period that lasted for 3 months, and an experimental period that lasted for 5 months. Accordantly, the time each player spent with BEMER therapy was used as a control variable. Multivariate analyses of variance using FFMANOVA and univariate ANOVA with False Discovery Rate adjusted p-values show that physical performance (total distance, distance per minute, sprint meters >22.5 kmh, accelerations and decelerations) significantly peak on game day compared with ordinary training days and days related to game days. The results also show that sleep quantity and quality are significantly reduced on game night, which indicate disturbed sleep caused by the peak in physical load. Most sleep variables significantly increased in the experiment period, where BEMER therapy was used, compared to the control period before the introduction of BEMER therapy. Further, the analyses show that players who spent BEMER therapy >440 h had the most positive effects on their sleep, and that these effects were significantly compared to the players who used BEMER therapy <440 h. The findings are discussed based on the function of sleep and the different sleep stages have on recovery.

Assessment of the Severity of Left Anterior Descending Coronary Artery Stenoses by Enhanced Transthoracic Doppler Echocardiography: Validation of a Method Based on the Continuity Equation.

To verify whether the severity of coronary stenosis could be non-invasively assessed by enhanced transthoracic coronary echo Doppler in convergent color Doppler mode (E-Doppler TTE) over a wide range of values (from mild to severe). Color-guided pulsed wave Doppler sampling in the left anterior descending coronary artery (LAD) was performed in 103 diseased LAD segments (corresponding to 94 patients examined) as assessed by quantitative coronary angiography (QCA) or intracoronary ultrasound (IVUS). The E-Doppler TTE examinations consisted of measuring the velocity (vel) at the stenosis site and a reference adjacent segment. Then the continuity equation (C-Eq) was applied to calculate the percent cross-sectional area reduction (%CSA) at the stenosis site. The applied formula was: %CSA = 100 × (1 - [TVIref × 0.5]/TVIs). TVI = the time velocity integral at the stenosis [s] and the reference site [ref], respectively); 0.5 = the correcting factor for a parabolic profile was used only when the % accelerated stenotic flow was >122% (AsF = diastolic peak vel at first site - diastolic peak vel at second site/diastolic peak vel at second site × 100). E-Doppler TTE feasibility was 100%. Doppler and QCA/IVUS-derived %CSA stenosis showed very good agreement over a large range of values (from mild to severe), with no significant bias; the maximum difference between QCA/IVUS and transthoracic Doppler %CSA was mostly around 20% with a few patients exceeding this limit (limits of agreement = -27.53 to 23.5%). The scattering was slightly larger for the non-significant stenoses. The correlation was strong (r = 0.89, p < 0.001). E-Doppler TTE is a feasible and reliable method for assessing the severity of LAD stenosis by applying the C-Eq.

Preeclampsia and risk of maternal pulmonary hypertension at high altitude in Bolivia.

Women with a history of preeclampsia (PE) have a greater risk of pulmonary arterial hypertension (PAH). In turn, pregnancy at high altitude is a risk factor for PE. However, whether women who develop PE during highland pregnancy are at risk of PAH before and after birth has not been investigated. We tested the hypothesis that during highland pregnancy, women who develop PE are at greater risk of PAH compared to women undergoing healthy highland pregnancies. The study was on 140 women in La Paz, Bolivia (3640m). Women undergoing healthy highland pregnancy were controls (C, n = 70; 29 ± 3.3 years old, mean±SD). Women diagnosed with PE were the experimental group (PE, n = 70, 31 ± 2 years old). Conventional (B- and M-mode, PW Doppler) and modern (pulsed wave tissue Doppler imaging) ultrasound were applied for cardiovascular íííassessment. Spirometry determined maternal lung function. Assessments occurred at 35 ± 4 weeks of pregnancy and 6 ± 0.3 weeks after birth. Relative to highland controls, highland PE women had enlarged right ventricular (RV) and right atrial chamber sizes, greater pulmonary artery dimensions and increased estimated RV contractility, pulmonary artery pressure and pulmonary vascular resistance. Highland PE women had lower values for peripheral oxygen saturation, forced expiratory flow and the bronchial permeability index. Differences remained 6 weeks after birth. Therefore, women who develop PE at high altitude are at greater risk of PAH before and long after birth. Hence, women with a history of PE at high altitude have an increased cardiovascular risk that transcends the systemic circulation to include the pulmonary vascular bed.

Assessment of High Frequency Imaging and Doppler System for the Measurements of the Radial Artery Flow-Mediated Dilation

Objectives: In the article we describe the new, high frequency, 20 MHz scanning/Doppler probe designed to measure the flow mediated dilation (FMD) and shear rate (SR) close to the radial artery wall. Methods: We compare two US scanning systems, standard vascular modality working below 12 MHz and high frequency 20 MHz system designed for FMD and SR measurements. Axial resolutions of both systems were compared by imaging of two closely spaced food plastic foils immersed in water and by measuring systolic/diastolic diameter changes in the radial artery. The sensitivities of Doppler modalities were also determined. The diagnostic potential of a high frequency system in measurements of FMD and SR was studied in vivo, in two groups of subjects, 12 healthy volunteers and 14 patients with stable coronary artery disease (CAD). Results: Over three times better axial resolution was demonstrated for a high frequency system. Also, the sensitivity of the external single transducer 20 MHz pulse Doppler proved to be over 20 dB better (in terms of a signal-to-noise ratio) than the pulse Doppler incorporated into the linear array. Statistically significant differences in FMD and FMD/SR values for healthy volunteers and CAD patients were confirmed, p-values < 0:05. The areas under Receiver Operating Characteristic (ROC) curves for FMD and FMD/SR for the prediction CAD had the values of 0.99 and 0.97, respectively. Conclusions: These results justify the usefulness of the designed high-frequency scanning system to determine the FMD and SR in the radial artery as predictors of coronary arterial disease.

The Forces Driving Streaming in the Presence of Scatterers Mimicking the Blood Cells and the Contrast Agents

Acoustical Driving Forces (ADF), induced by propagating waves in a homogeneous and inhomogeneous lossy fluid (suspension), are determined and compared depending on the concentration of suspended particles. Using integral equations of the scattering theory, the single particle (inclusion) ADF was calculated as the integral of the flux of the momentum density tensor components over the heterogeneity surface. The possibility of negative ADF was indicated. Originally derived, the total ADF acting on inclusions only, stochastically distributed in ambient fluid, was determined as a function of its concentration. The formula for the relative increase in ADF, resulting from increased concentration was derived. Numerical ADF calculations are presented. In experiments the streaming velocities in a blood-mimicking starch suspension (2 μm radius) in water and Bracco BR14 contrast agent (SF6 gas capsules, 1 μm radius) were measured as the function of different inclusions concentration. The source of the streaming and ADF was a plane 2 mm diameter 20 MHz ultrasonic transducer. Velocity was estimated from the averaged Doppler spectrum obtained from originally developed pulsed Doppler flowmeter. Numerical calculations of the theoretically derived formula showed very good agreement with the experimental results.

Atrial mechanical contraction and ambulatory atrioventricular synchrony: Predictors from the OPTIVALL study.

The role that preprocedural factors have on atrioventricular synchrony (AVS) provided by leadless pacemakers requires investigation. We aimed to assess the correlation between mitral inflow echocardiographic parameters and p-wave morphology with the accelerometer A4 signal amplitude. We also sought to identify clinical and echocardiographic predictors of optimal ambulatory AVS (≥85% of cardiac cycles). Forty-three patients undergoing Micra AV implant from June 2020 to March 2023 were prospectively enrolled. Baseline echocardiogram and 12-lead resting ECG were performed. Device follow-up was scheduled at 24 h, 1, 3, and 6 months and yearly after the implant. Ambulatory AVS was studied with a 24 h Holter monitor performed at 3 months follow-up in 35 patients who remained in VDD mode. A4 signal amplitude at 1 month correlated to peak A wave velocity (r = .376; p = .024) at echocardiogram, but no relationship was found with peak A' wave velocity, E/A, or E'/A' ratio. P-wave amplitude in lead I and aVF correlated to A4 signal amplitude at 1- and 3-months follow-up, respectively. Median AVS during 24 h of daily activities was 85.6 ± 7.6% and remained stable up to 100 bpm. Twenty-three out of 35 patients (65.7%) reached optimal ambulatory AVS. There was no association between mitral inflow echocardiographic parameters and optimal AVS. Diabetes (OR: 0.05, 95% CI: 0.01-0.47; p = .009) and chronic obstructive pulmonary disease (COPD) (OR: 0.06, 95% CI: 0.01-0.63; p = .019) strongly predicted ambulatory AVS<85%. Diabetes and COPD should be considered when selecting candidates for Micra AV. Measurements of pulsed wave Doppler mitral inflow do not systematically reflect the behavior of the A4 signal amplitude.

Changes in blood flow in the dorsal scapular artery and relationship to shoulder joint function in rotator cuff tears

One of the pain-related factors in rotator cuff tears (RCTs) is abnormal scapular motion, which is thought to be related to the levator scapulae muscle activation. Additionally, attention has recently focused on the peak systolic velocity (PSV) as one of the causes of pain, but blood flow outside of the vessels supplying the rotator cuff has not been clarified. This study aimed to determine the difference in PSV in the dorsal scapular artery (DSA), which is the vessel that supplies the levator scapulae muscles, and the association between PSV and pain and shoulder function in patients with RCTs between the tear and nontear sides. This study included 31 patients with RCTs with tear and nontear sides. Magnetic resonance imaging and radiographic examinations included Cofield classification, Goutallier classification, thickening of the coracohumeral ligament, and measurement of the acromiohumeral interval. Clinical evaluation included an automatic range of motion (ROM) for flexion, abduction, and external rotation (ER), a visual analog scale, and the Shoulder36. PSV was evaluated using ultrasound pulsed Doppler mode to assess PSV of DSA. The PSV of DSA on the first rib was drawn in the medial aspect of the suprascapular angle in the long axis, and the maximum PSV waveform was measured three times. The average value was used for further analysis. The PSV in the DSA was significantly higher (P=.04, 95% confidence interval: 0.2-7.6) on the tear (22.6±7.4 cm/s) than the nontear sides (18.9±6.9 cm/s). In addition, a significant negative correlation (r=-0.46, P=.0087) was found between PSV in DSA and ER on the tear side. This study revealed a significantly increased PSV in the DSA on the tear side in RCTs and negatively correlated with ER ROM. The results suggest that increased PSV in the DSA may contribute to ER ROM limitation in the glenohumeral joint.

Atrial fibrillation in embolic stroke of undetermined source: role of advanced imaging of left atrial function.

Atrial fibrillation (AF) is detected in over 30% of patients following an embolic stroke of undetermined source (ESUS) when monitored with an implantable loop recorder (ILR). Identifying AF in ESUS survivors has significant therapeutic implications, and AF risk is essential to guide screening with long-term monitoring. The present study aimed to establish the role of left atrial (LA) function in subsequent AF identification and develop a risk model for AF in ESUS. We conducted a single-centre retrospective case-control study including all patients with ESUS referred to our institution for ILR implantation from December 2009 to September 2019. We recorded clinical variables at baseline and analysed transthoracic echocardiograms in sinus rhythm. Univariate and multivariable analyses were performed to inform variables associated with AF. Lasso regression analysis was used to develop a risk prediction model for AF. The risk model was internally validated using bootstrapping. Three hundred and twenty-three patients with ESUS underwent ILR implantation. In the ESUS population, 293 had a stroke, whereas 30 had suffered a transient ischaemic attack as adjudicated by a senior stroke physician. Atrial fibrillation of any duration was detected in 47.1%. The mean follow-up was 710 days. Following lasso regression with backwards elimination, we combined increasing lateral PA (the time interval from the beginning of the P wave on the surface electrocardiogram to the beginning of the A' wave on pulsed wave tissue Doppler of the lateral mitral annulus) [odds ratio (OR) 1.011], increasing Age (OR 1.035), higher Diastolic blood pressure (OR 1.027), and abnormal LA reservoir Strain (OR 0.973) into a new PADS score. The probability of identifying AF can be estimated using the formula. Model discrimination was good [area under the curve (AUC) 0.72]. The PADS score was internally validated using bootstrapping with 1000 samples of 150 patients showing consistent results with an AUC of 0.73. The novel PADS score can identify the risk of AF on prolonged monitoring with ILR following ESUS and should be considered a dedicated risk stratification tool for decision-making regarding the screening strategy for AF in stroke.

A Submillimeter-Wave FMCW Pulse-Doppler Radar to Characterize the Dynamics of Particle Clouds

This work presents a 340-GHz frequency-modulated continuous-wave (FMCW) pulse-Doppler radar. The radar system is based on a transceiver module with about one milli-Watt output power and more than 30-GHz bandwidth. The front-end optics consists of an off-axis parabola fed by a horn antenna from the transceiver unit, resulting in a collimated radar beam. The digital radar waveform generation allows for coherent and arbitrary FMCW pulse waveforms. The performance in terms of sensitivity and resolution (range/cross-range/velocity) is demonstrated, and the system's ability to detect and map single particles (0.1-10 mm diameter), as well as clouds of particles, at a 5-m distance, is presented. A range resolution of 1 cm and a cross-range resolution of a few centimeters (3-dB beam-width) allow for the characterization of the dynamics of particle clouds with a measurement voxel size of a few cubic centimeters. The monitoring of particle dynamics is of interest in several industrial applications, such as in the manufacturing of pharmaceuticals and the control/analysis of fluidized bed combustion reactors.

Evaluation of fetal adrenal artery Doppler velocimetry and fetal adrenal gland size in pregnancies after recovery from COVID-19.

Assessment of the fetal adrenal gland (FAG) size and middle adrenal artery (MAA) Doppler parameters in pregnancy recovered from Coronavirus Disease (COVID-19) and comparison of the values with the healthy control group. Thirty-eight pregnant women who had recovered from COVID-19 infection and 76 healthy control group between 33 and 35 weeks of gestation were involved in this case-control study. Fetuses were examined for fetal biometry, fetal well-being, adrenal gland dimensions, and Doppler parameters 4-6 weeks after the diagnosis of COVID 19 infection. FAG dimensions were measured in two planes and MAA blood flow velocity was evaluated with pulsed Doppler. Pregnant women with COVID-19 infection were grouped according to the National Institutes of Health for the severity of the disease, and those with mild and moderate infections were examined in the study. The total adrenal gland (TAG) height, fetal zone (FZ) length and width, and MAA-Peak Systolic Velocity (MAA-PSV) were significantly higher, and the MAA-Pulsatility Index (MAA-PI) was significantly lower in the COVID-19 group (p < 0.05). The lower in MAA-PI and the higher in MAA-PSV, the width of the FZ, and width of the TAG were found to be significant in the moderate group compared to the mild groups (p < 0.05). COVID-19 pregnancies might cause early maturation of the FAG and its vasculature depends on the intrauterine stress due to the hyper-inflammation, so fetuses exposed to maternal COVID-19 suggested to have an increase in blood flow to the adrenal gland and fetal adrenal size.

Auto left atrial strain by speckle tracking echocardiography and auto left atrial volumes by 3D transthoracic echocardiography after electrical cardioversion for atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Introduction We have evidence that left atrial dysfunction and stunning occur after electric cardioversion for atrial fibrillation (CAF). Additionally, after successful cardioversion to sinus rhythm, a dissociation between electrical and mechanical recovery may be observed. Traditional pulsed Doppler and tissue Doppler imaging parameters demonstrate reduced atrial contractility immediately after cardioversion. Improvement in atrial function occurs within the first 4 weeks after sinus rhythm is restored. Recent advances in the assessment of myocardial function have facilitated the direct measurement of auto left atrial strain using speckle tracking echocardiography, and auto left atrial volumes measurements using dynamic heart model modern 3D transthoracic echo logistics. Purpose Aim of this study was to determine whether auto left atrial strain (auto LAs) by speckle tracking echocardiography, and auto left atrial volumes measurements, auto left atrial volume indices calculations (auto LAVI), could be used to evaluate global left atrial function and when a main improvement occurs after electrical cardioversion for CAF. Methods Auto LAs was measured from transthoracic echocardiography in 25 patients with CAF who had been cardioverted to sinus rhythm and followed up for 4 weeks, and in a cohort of 25 healthy individuals. Left atrial contractile strain (LACTS), conduit strain (LACDS) and reservoir strain (LARSS) were measured. Conventional measures of atrial function derived from transmitral pulsed wave doppler (PW) and tissue doppler imaging (TDI) of lateral mitral annulus were included, such as A wave velocity, A wave velocity time integral, A' wave velocity and A' velocity time integral. Results Immediately after cardioversion all PW, TDI and all three auto LAs parameters were significantly lower than in controls. On the other hand, auto LAVI was significantly higher in patients compared to controls immediately after cardioversion Atrial function was improved over time with maximal change observed 4 weeks after cardioversion and restoration to sinus rhythm. Auto LAs parameters were significantly higher in the group of patients. Auto LA volumes and auto LAVI with dynamic heart model logistics were lower in the same group, but with no statistical significance. Three patients with the lowest auto LAs values immediately after cardioversion, suffered recurrence of atrial fibrillation during the 4 weeks follow up. Conclusions Although left atrial electrical function is immediately restored after cardioversion in CAF patients, a persistent degree of atrial dysfunction remains for up to 4 weeks. This difference could explain the increased propensity for these patients to develop recurrent atrial fibrillation. Additional this dysfunction could indicate the longer-term use of antiarrhythmic and antithrombotic medication in the CAF cohort.

Novel handheld ultrasound with spectral Doppler modality allows for reliable valvular blood flow velocity assessment

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Handheld Ultrasonographs (HUD) have soldified their position as a entry-level echocardiographic tool tailored for introducing non-invasive imaging diagnostics to everyday clinical practice. Current approach to valve assessment with the use of HUD could only involve qualitative method based on the visual detection of morphologic abnormalities and color Doppler assessment. It was not until recently that, Quantitative analysis was enabled with the implementation of spectral doppler to the HUD. Purpose To assess if HUD featured with spectral Doppler modality enables for reliable evaluation of the valvular flow velocity. Methods 102 consecutive patients reporting to the cardiological emergency room underwent HUD examination involving both the measurement of mitral valvular flow velocity with the pulsed wave Doppler and aortic valvular flow with continuous wave Doppler. Subsequently, the same parameters were measured with the high end stationary workstation, and acquired results were treated as reference. Mitral valvular blood velocity &amp;gt; 1,3 m/s and atrial valvular blood flow velocity &amp;gt;2,0 m/s. were considered as abnormal values. Results The correlation between the measurements of maximum velocity through mitral valve obtained with the HUD and standard echocardiography was high (r=0,85; p&amp;lt;0,0001; 95% CI 0,78–0,89). The Bland-Altman plot showed no clinically relevant bias (mean difference 0,06 m/sec, upper limits of agreement 0,2 m/sec lower limit of agreement 0,32 m/s). Accelerated valvular blood flow (present in 4 pts) was detected with HUD with sensitivity of 75 % (95% CI: 19%-99%), specificity of % (95% CI: 96%-100%), positive predictive value of 100% (95% CI: 29%-100%), negative predictive value of 99% (95% CI: 95%-100%). Corresponding assessment of aortic valve showed the following correlation: r=0,87; p&amp;lt;0,0001; 95% CI 0,81–0,91). The Bland-Altman plot analysis indicated small underestimation bias of −0,17 m/sec (P &amp;lt; .001), upper limits of agreement of 0,47 m/sec, lower limit of agreement −0,81. Accelerated valvular blood flow (found in 7pts): sensitivity of 57% (95% CI: 19%-90%), specificity of 100% (95% CI: 96%-100%), positive predictive value of 100% (95% CI: 40%- 100%), negative predictive value of 97% (95% CI: 91%-99%). Conclusion Correlations calculated between the results of valvular blood flow measured with HUD and conventional workstation proved to be very strong. HUD examination enables for detection of accelerated blood flow through mitral and aortic valves with high positive and negative predictive value.

#2875 CONGESTION PHENOTYPES AND DECONGESTION PATTERNS ASSESSED BY POCUS IN HAEMODIALYSIS PATIENTS: A PILOT STUDY

Abstract Background and Aims Despite the evolution of hemodialysis (HD) in recent years, cardiovascular diseases continue to be the main cause of death in this group of patients. Congestion is one of the factors associated with the highest morbidity and mortality. Unfortunately, there is no gold standard for the proper assessment of dry weight; in fact, physical examination, and even newer techniques such as bioimpedance have poor sensitivity, are difficult to interpret in some cases and fail to discriminate between tissular and vascular congestion. Recently, the use of Point-of-care Ultrasonography (PoCUS) has emerged as the fifth pillar of the conventional physical examination that allows dynamic assessment of congestion and enables congestion to be phenotyped. The aims of the present study were: 1. to phenotype congestion in HD patients and 2. to establish patterns of decongestion according to changes in phenotypes over the course of a HD session. Method Descriptive study carried out in HD units of two tertiary hospitals. Patients with more than three months on HD were included. Excluding patients with short life expectancy or who had an acute complication. In addition to the congestive composite score (CCS), a PoCUS evaluation was performed at the beginning and the end of the HD session on long dialysis interval. Tissular congestion was assessed by lung ultrasound and vascular congestion was assessed by evaluation of the inferior vena cava diameter and portal vein pulsation by pulsed Doppler. Four phenotypes of congestion were established: phenotype A: no congestion, phenotype B: predominance of tissue congestion, phenotype C: predominance of vascular congestion and phenotype D: mixed congestion. In addition, 4 patterns of decongestion were established: pattern 1: absence of congestion at the beginning and end of the HD session, pattern 2: change of phenotype from B, C or D to A, pattern 3: change in congestion phenotype and pattern 4: persistence in the same congestion phenotype as at the beginning. Results 20 patients were included, mean age: 70.5±11.3 years, 14 (70%) were male, CCS: 3 (1.5 – 7.5), interdialysis weight gain: 2.93±0.95 kg and mean UF: 2,570±868mL. 75% of patients reached the prescribed dry weight. At the beginning of the session the distribution of phenotypes was: phenotype A: 35%, phenotype B: 25%, phenotype C: 25% and phenotype D: 15%. At the end of the HD session: phenotype A: 55%, phenotype B: 30%, phenotype C: 10% and phenotype D: 5%. At the end of the HD session 45% of the patients persisted with ultrasound congestion. As for the patterns of decongestion: pattern 1: 35% of patients, pattern 2: 10%, pattern 3: 10% and pattern 4: 35%. 45% of patients persisted with some phenotype of congestion at the end of the session. An inverse correlation was found between age and phenotype at baseline (Rho: -0.506; p = 0.023). No correlation was found between dry weight and UF with decongestion patterns. Conclusion These results show the persistence of echographic congestion at the end of the HD session in a significant number of patients, suggesting that subclinical congestion is more frequent than clinically observed. Further studies are warranted to confirm these results.

#3406 CARDIOPROTECTIVE EFFECT OF SOY PROTEIN ON LONG-TERM HIGH-SALT DIET IN CYNOMOLGUS MONKEYS

Abstract Background and Aims A high salt content in the diet is one of the reasons for the increase in blood pressure (BP) and the development of cardiovascular disorders. However, high intake of sodium chloride does not always lead to an increase in blood pressure, but causes endothelial dysfunction and cardiac remodeling. It has been established that the introduction of soy products into the diet can have a nephro- and cardioprotective effect in chronic kidney disease. At the same time, it is not clear whether the damaging effect of a high-salt diet on the cardiovascular system can be offset by other dietary interventions, in particular, soy proteins. In this regard, the aim of the study was to study the effect of long-term use of diets with different content of sodium chloride and soy protein on myocardial remodeling in cynomolgus monkeys. Method A total of 18 cynomolgus male monkeys with age 6–8 years were studied. The animals were divided into three groups (six in each group). The first (control) group received the standard diet. The second group received the diet rich in common salt (8 g of NaCl/kg), and the third, the high salt diet in combination with soy protein SUPRO 760 (200 g/kg; Protеin Tеchnology Intеrnational, USA). Systolic (BP) and diastolic (BPd) blood pressure (BP) in monkeys was recorded by oscillometric method on a veterinary tonometer ML-410 VET (Microlux, Russia) under anesthesia. After registration of blood pressure, an echocardiographic study (EchoCG) was performed with a sector sensor with a frequency of 3-5 MHz on an ultrasound system Chison SonoTouch 60 (China). Echocardiography was performed in B-mode (two-dimensional scanning), M-mode (one-dimensional scanning), as well as in pulsed and tissue Doppler modes. Echocardiography and blood pressure measurements were performed at baseline, after 4 and 12 months of follow-up. Results BP values (group 1 - BPs: 109±10.09, BPd: 60±7.42; group 2 - BPs: 109±25.14, BPd: 57±11.86; group 3 - BPs: 101±8, 59, BPd: 57±6.92 mm Hg, all p&amp;gt;0.05) and heart rate (group 1 - 77±12.61, group 2 - 81±18.07, group 3-80±19.9 beats/min, all p&amp;gt;0.05) in macaques did not undergo significant changes over 12 months of the experiment in any of the groups. In group 1, there were also no significant changes in echocardiographic parameters. Group 2 monkeys showed no early changes in LV shortening fraction (FU) and ejection fraction (EF). However, after 12 months, FU decreased by an average of 26.6%, and EF by 12.8% compared with the indicator for a period of 4 months. In addition, the speed of the transmitral flow in early diastole (E) decreased by 19.1% compared with the baseline. Long-term intake of soy proteins prevented a decrease in LV FU in macaques on a high-salt diet. Its value was 25.1% greater than in group 2. In group 3 monkeys, after 12 months, the magnitude of systolic excursion of the mitral annulus plane and the maximum rate of excursion of the fibrous annulus of the mitral valve in early diastole (e') increased, the thickness of the interventricular septum in diastole decreased, and E/e' ratio. In group 3, the thickness of the posterior wall of the left ventricle decreased in systole (0.57±0.056 mm), the mass of the LV myocardium (14.9±2.94 g/m2), the average diameter of the base of the right ventricle (1.20±0.115 mm) compared with group 2 (0.69±0.040 mm, 19.6±2.83 g/m2, 1.40±0.111 mm, respectively; all p&amp;lt;0.01). Conclusion The obtained results can be considered as confirmation of the hypothesis that high consumption of sodium chloride leads to adverse structural and functional changes in the heart and blood vessels, not associated with an increase in blood pressure. The inclusion of isolated soy proteins in the diet is likely to reduce the effects of this negative impact. The specific mechanisms of this cardioprotective effect remain to be explored. Statistical analysis used One-way analysis of variance for unrelated samples when comparing the data of 3 studied groups and one-way analysis of variance for related samples when studying the dynamics of the indicator in each of the groups during 12 months of observation. Results are presented as mean ± standard deviation (M ± SD). Differences were considered significant at p&amp;lt;0.05.

Evaluation of Fetal Cardiac Functions in Preeclampsia: Does the Severity or Proteinuria Affect Fetal Cardiac Functions?

To compare the fetal cardiac functions in preeclampsia and control group, and determine whether the severity or amount of proteinuria affects fetal cardiac functions. This prospective case-control study involves 48 pregnant women with preeclampsia and 48 healthy women. Pulsed wave Doppler, M-mode, and tissue Doppler imaging were used to measure the cardiac function between the 32 and 34 gestational weeks in each group. All Doppler indices and cardiac function parameters were also compared in subgroups with mild and severe preeclampsia and between subgroups with proteinuria >3 g/24 hours and <3 g/24 hours. Decreased diastolic function (decreased E, A, E', and A' values in mitral/tricuspid valves and increased isovolumetric relaxation time) and decreased systolic functions (decreased mitral and tricuspid annular plane systolic excursion and S' value in mitral/tricuspid valves) were detected in the preeclampsia group. Decreased tricuspid E value in severe preeclampsia compared with mild preeclampsia was shown in the present study. Preeclampsia may cause changes in systolic and diastolic functions in the fetal heart. Subclinical functional changes of these fetuses can be detected earlier and more sensitively with the help of tissue Doppler imaging. Biventricular diastolic functional changes are more prominent in preeclamptic cases with proteinuria >3 g/24 hours.

A 94 GHz Pulse Doppler Solid-State Millimeter-Wave Cloud Radar

A 94 GHz pulse Doppler solid-state millimeter-wave cloud radar (MMCR), Tianjian-II (TJ-II), has been developed. It reduces the size and cost using a solid-state power amplifier (SSPA) and a single antenna. This paper describes the system design, including hardware and signal processing components. Pulse compression, segmented pulse, and dual pulse repetition frequency (PRF) technologies are employed to overcome the limitations imposed by the low power of the SSPA and the high frequency of 94 GHz. The TJ-II also features a dual-polarization, high-gain antenna for linear depolarization ratio detection and a time-division receive channel to improve channel consistency and save on costs. To achieve high flexibility and low interference in signal transmission and reception, the TJ-II uses software-defined radio technology, including direct digital synthesis, digital downconversion, and bandpass sampling. A series of Doppler power spectrum processing methods are proposed for detecting weak cloud signals and improving scene adaptability.