Measurement Of Blood Flow Velocity Research Articles

Ultrasound visualization and blood flow velocity measurements of the adrenal arteries in the fetus.

Detection and surveillance of fetal growth restriction (FGR) is well established, but there is still room for improvement. Animal studies indicate that compromised fetuses increase adrenal blood flow. Modern ultrasound equipment allows us to measure vascular impedance in the fetal adrenal arteries despite their modest size. However, extensive anatomical variance is a challenge to standardizing measurements. We set out to improve this. We included 75 low-risk pregnant women in a prospective cross-sectional study aiming to develop a reliable technique to visualize and measure flow velocity in human fetal adrenal arteries. We used commercially available ultrasound equipment: a GE Voluson 10 2019 with a C2-9 probe (GE Healthcare, Zipf, Austria), and a Philips Epiq Elite with a V9-2 probe (Philips Medical Systems International B.V., Best, The Netherlands), exploiting the modern sensitive power Doppler modes in both scanners to visualize small vessels. Among 72 fetuses, the inferior adrenal artery was the most consistently visualized and measured artery to the gland. Doppler velocimetry was achieved in 66 (92%) participants. We found the anatomical variation described previously but were able to develop visualization strategies to identify the common arteries and use a consistent Doppler technique for the second half of pregnancy. It is possible to visualize and measure flow velocity in the adrenal arteries of human fetuses. The success rate was highest for the inferior adrenal artery making this vessel a candidate for clinical studies.

Correlation between antihypertensive drugs and cerebral hemodynamic parameters: insights from observational findings using transcranial Doppler.

Antihypertensives (AHD) can influence cerebral autoregulation (CA) and attenuate hypertrophic concentric remodelling of arterioles. The aim of this study was to examine the associations between AHD, CA and structural and functional properties of cerebral arteries. In this observational, cross-sectional study 115 volunteers were divided in group 1 (non-hypertensive) [n = 30]; group 2 (hypertensive with systolic blood pressure [SBP] < 140 and diastolic blood pressure [DBP] < 90 mmHg) [n = 54]; group 3 (hypertensive with SBP ≥ 140 or DBP ≥ 90 mmHg) [n = 31] and simultaneous measurements of systemic blood pressure (BP) and middle cerebral artery blood flow velocity (CBFV) were obtained from digital plethysmography and transcranial Doppler. Beat-to-beat, critical closing pressure (CrCP), resistance-area product (RAP) and autoregulation index (ARI) values were extracted by linear regression analysis of instantaneous BP and CBFV waveforms using computerised analysis. Pulsatility index (PI) was calculated and CO2 reactivity was assessed by the breath-holding test. Despite their higher RAP (1.7 [±0.7], p < 0.001) compared to groups 1 and 2, uncontrolled hypertensive using diuretics (p = 0.047) and α2-agonists (p = 0.009) had significantly lower PI. Impaired CO2 reactivity was common between the two hypertensive groups (p = 0.008), however ARI, CrCP and CBFV did not differ between them and non-hypertensive individuals and also did not correlate with any AHD used. Unlike the RAP, PI does not seem to reflect the real cerebrovascular resistence resulting from chronic arterial remodelling. Despite impaired CO2 reactivity, hypertensivehavearterial tonus and CA comparable to non-hypertensive. Experimental studies involving an untreated hypertensive control group are required to robustly make definitive conclusions about these questions.

Optimizing Brain-Computer Interfaces for Methampetamine Use Disorder through Quantitative Electroencephalography (QEEG) and Transcranial Doppler Analysis: Article Review

A Brain-Computer Interface (BCI) is a system that allows a person to control external devices using only their brain activity. It works by translating brain signals into commands that can be understood by a computer. Several lines of evidence demonstrated the deleterious effect of methamphetamine (MA) on neurological and psychological functions. The use of amphetamines, such as MA, is associated with cerebrovascular complications such as cerebrovascular accidents (CVA) ,hemorrhage, hypoxic damage and vasculitis. Interestingly, while changes to cerebral blood flow (CBF) in response to acute amphetamine exposure have been reported. Transcranial Color Doppler (TCCD) is a non-invasive medical imaging technique that uses ultrasound waves to measure blood flow velocity in the major arteries of the brain, specifically within the circle of Willis. The research paper you referenced explores the use of TCCD as a potential measurement modality for BCIs. Quantitative electroencephalogram (qEEG) is a powerful tool for understanding brain function qEEG can reveal specific brain wave patterns associated with drug addiction, potentially providing insights into the neurobiological mechanisms underlying cravings, withdrawal symptoms, and relapse risk in Methamphetamine User Disorder (MUD). There is growing research interest in using Transcranial dopller as a measurement modality for BCIs.Here are some of the key considerations for using Transcranial doppler in BCIs: Mental Tasks, signal processing and classification, accuracy and reliability. Transcranial doppler provides information about blood flow in specific arteries but lacks detailed spatial information about brain activity. These patterns could vary depending on the type of drug, the severity of addiction, and individual differences. Transcranial doppler in measuring middle cerebral artery (MCA) blood flow velocity parameters (peak systolic velocity (PSV) and mean flow velocity (MFV)). qEEG can help researchers investigate the complex interplay between addiction and other brain disorders, like depression or anxiety. Characteristic qEEG in drugs addiction Increased Theta (4-8 Hz) and delta (1-4 Hz) brain waves are often associated with sleep and relaxation. However, research has shown that individuals with drug addiction may have increased theta and delta activity, particularly in the frontal and temporal regions of the brain. Altered Beta (13-30 Hz) brain waves are generally associated with wakefulness, alertness, and cognitive processing. Studies have observed both increases and decreases in beta activity in individuals with drug addiction, depending on the type of drug, the stage of addiction, and the specific brain regions being examined. The results of this research have important practical implications for building an diagnostic and functional assement with a better understanding of an using technology.

Physics-Informed Graph Neural Networks to solve 1-D equations of blood flow

Background and Objective:Computational models of hemodynamics can contribute to optimizing surgical plans, and improve our understanding of cardiovascular diseases. Recently, machine learning methods have become essential to reduce the computational cost of these models. In this study, we propose a method that integrates 1-D blood flow equations with Physics-Informed Graph Neural Networks (PIGNNs) to estimate the propagation of blood flow velocity and lumen area pulse waves along arteries. Methods:Our methodology involves the creation of a graph based on arterial topology, where each 1-D line represents edges and nodes in the blood flow analysis. The innovation lies in decoding the mathematical data connecting the nodes, where each node has velocity and lumen area pulse waveform outputs. The training protocol for PIGNNs involves measurement data, specifically velocity waves measured from inlet and outlet vessels and diastolic lumen area measurements from each vessel. To optimize the learning process, our approach incorporates fundamental physical principles directly into the loss function. This comprehensive training strategy not only harnesses the power of machine learning but also ensures that PIGNNs respect fundamental laws governing fluid dynamics. Results:The accuracy was validated in silico with different arterial networks, where PIGNNs achieved a coefficient of determination (R2) consistently above 0.99, comparable to numerical methods like the discontinuous Galerkin scheme. Moreover, with in vivo data, the prediction reached R2 values greater than 0.80, demonstrating the method’s effectiveness in predicting flow and lumen dynamics using minimal data. Conclusions:This study showcased the ability to calculate lumen area and blood flow rate in blood vessels within a given topology by seamlessly integrating 1-D blood flow with PIGNNs, using only blood flow velocity measurements. Moreover, this study is the first to compare the PIGNNs method with other classic Physics-Informed Neural Network (PINNs) approaches for blood flow simulation. Our findings highlight the potential to use this cost-effective and proficient tool to estimate real-time arterial pulse waves.

Flow-Mediated Dilatation: Learning Curve Study with a Novice Operator

BackgroundPerforming reproducible flow-mediated dilatation (FMD) measurements can be challenging, especially among inexperienced operators. Our aim was to present the detailed learning curve of a novice operator.MethodsFollowing a one-week basic training period, the operator performed duplicate measurements on 6–8 individuals per week, for six weeks. The operator followed the recommendations of the most recent guideline. Duplex ultrasound was used for the simultaneous and continuous measurement of brachial artery diameter and local blood flow velocity. Following a 1-min recording of baseline diameter (D), FMD was measured after a 5-min period of occlusion of the proximal forearm vessels. Inter-session coefficient of variation (CV) values for D and FMD were calculated for each week.ResultsThe number of volunteers assessed each week were the following: 8, 7, 7, 6, 7, 7 individuals. CV values for both D and FMD exhibited a decreasing trend over the training period, ending at 1.73% for D and 14.24% for FMD at week 6. These CV values are within the range outlined in the most recent FMD guideline for proficiency.ConclusionWithin a reasonable timeframe, and with careful adherence to measurement guidelines, the attainment of sound reproducibility in FMD measurements by a novice operator is feasible.

Measurement of retinal blood flow precision in the human eye with multimodal adaptive optics imaging.

Impaired retinal blood flow (RBF) autoregulation plays a key role in the development and progression of several ocular diseases, including glaucoma and diabetic retinopathy. Clinically, reproducible RBF quantitation could significantly improve early diagnosis and disease management. Several non-invasive techniques have been developed but are limited for retinal microvasculature flow measurements due to their low signal-to-noise ratio and poor lateral resolution. In this study, we demonstrate reproducible vessel caliber and retinal blood flow velocity measurements in healthy human volunteers using a high-resolution (spatial and temporal) multimodal adaptive optics system with scanning laser ophthalmoscopy and optical coherence tomography.

Ergodic speckle contrast optical coherence tomography velocimetry of rapid blood flow.

Visualizing a 3D blood flow velocity field through noninvasive imaging is crucial for analyzing hemodynamic mechanisms in areas prone to disorders. However, traditional correlation-based optical coherence tomography (OCT) velocimetry techniques have a maximum measurable flow velocity depending on the A-line rate. We presented the ergodic speckle contrast OCT (ESCOCT) to break the bottleneck in measuring the rapid blood flow velocity. It achieved a measurement of blood flow velocity ranging from 9.5 to 280 mm/s using a 100 kHz swept-source (SS) OCT based on 100 A-repeats scanning mode. Addressing the non-ergodic problem of temporal OCT signals by integrating more consecutive A-scans, ESCOCT can enable the estimation for lower velocity flows by increasing A-repeats. ESCOCT provided a wide dynamic range with no upper limit on measuring blood flow velocity with an adequate signal-to-noise ratio and improved the sensitivity and accuracy of the hemodynamic assessment.

Ultrasound in Microsurgery: Current Applications and New Frontiers.

Ultrasound has revolutionized reconstructive microsurgery, offering real-time imaging and enhanced precision allowing for preoperative flap planning, recipient vessel identification and selection, postoperative flap monitoring, and lymphatic surgery. This narrative review of the literature provides an updated evidence-based overlook on the current applications and emerging frontiers of ultrasound in microsurgery, focusing on free tissue transfer and lymphatic surgery. Color duplex ultrasound (CDU) plays a pivotal role in preoperative flap planning and design, providing real-time imaging that enables detailed perforator mapping, perforator suitability assessment, blood flow velocity measurement, and, ultimately, flap design optimization. Ultrasound also aids in recipient vessel selection by providing assessment of caliber, patency, location, and flow velocity of recipient vessels. Postoperatively, ultrasound enables real-time monitoring of flap perfusion, providing early detection of potential flap compromise and improved flap survival rates. In lymphatic surgery, ultra-high frequency ultrasound (UHFUS) offers precise mapping and evaluation of lymphatic vessels, improving efficacy and efficiency by targeting larger dilated vessels. Integrating ultrasound into reconstructive microsurgery represents a significant advancement in the utilization of imaging in the field. With growing accessibility of devices, improved training, and technological advancements, using ultrasound as a key imaging tool offers substantial potential for the evolution of reconstructive microsurgery.

Cerebral blood flow dynamics during cardiac surgery in infants.

In this pilot study, we investigated continuous cerebral blood flow velocity measurements to explore cerebrovascular hemodynamics in infants with congenital heart disease undergoing cardiac surgery. A non-invasive transfontanellar cerebral Doppler monitor (NeoDoppler) was used to monitor 15 infants (aged eight days to nine months) during cardiac surgery with cardiopulmonary bypass. Numerical and visual analyses were conducted to assess trends and events in Doppler measurements together with standard monitoring equipment. The mean flow index, calculated as the moving Pearson correlation between mean arterial pressure and time averaged velocity, was utilized to evaluate dynamic autoregulation. Two levels of impaired autoregulation were defined (Mean flow index >0.3/0.45), and percentage of time above these limits were calculated. High quality recordings were achieved during 90.6% of the monitoring period. There was a significant reduction in time averaged velocity in all periods of cardiopulmonary bypass. All patients showed a high percentage of time with impaired dynamic autoregulation, with Mean flow index >0.3 and 0.45: 73.71% ± 9.06% and 65.16% ± 11.27% respectively. Additionally, the system promptly detected hemodynamic events. Continuous transfontanellar cerebral Doppler monitoring could become an additional tool in enhancing cerebral monitoring in infants during cardiac surgery. This pilot study demonstrates the feasibility of continuous transfontanellar Doppler monitoring of cerebral blood flow velocities during cardiac surgery in infants. It also demonstrates a high proportion of time with impaired cerebral autoregulation during cardiac surgery based on the Mean flow index. Continuous transfontanellar Doppler could become a useful tool to improve cerebral monitoring and provide new pathophysiological insight.

The Relation between Vascular Risk Factors and Flow in Cerebral Perforating Arteries: A 7 Tesla MRI Study

Introduction: Cerebral perforating arteries provide blood supply to the deep regions of the brain. Recently, it became possible to measure blood flow velocity and pulsatility in these small arteries. It is unknown if vascular risk factors are related to these measures. Methods: We measured perforating artery flow with 2D phase-contrast 7 Tesla MRI at the level of the centrum semiovale (CSO) and the basal ganglia (BG) in seventy participants from the Heart Brain Connection study with carotid occlusive disease (COD), vascular cognitive impairment (VCI), or no actual cerebrovascular disease. Vascular risk factors included hypertension, diabetes, hyperlipidemia, and smoking. Results: No consistent relations were found between any of the vascular risk factors and either flow velocity or flow pulsatility, although there was a relation between lower diastolic blood pressure and higher pulse pressure and higher cerebral perforator pulsatility (p = 0.045 and p = 0.044, respectively) at the BG level. Results were similar in stratified analyses for patients with and without a history of cardiovascular disease, or only COD or VCI. Conclusion: We conclude that, cross-sectionally, cerebral perforating artery flow velocity and pulsatility are largely independent of the presence of common vascular risk factors in a population with a mixed vascular burden.

TinyProbe: A Wearable 32-channel Multi-Modal Wireless Ultrasound Probe.

The need for continuous monitoring of cardiorespiratory activity, blood pressure, bladder, muscle motion analysis, and more, is pushing for research and development of wearable ultrasound devices. In this context, there is a critical need for highly configurable, energy-efficient wearable ultrasound systems with wireless access to raw data and long battery life. Previous exploratory works have primarily relied on bulky commercial research systems or custom-built prototypes with limited and narrowly-focused field applicability. This paper presents TINYPROBE, a novel multi-modal wearable ultrasound platform. TINYPROBE integrates a 32-channel ultrasound RX/TX frontend, including TX beamforming (64 Vpp excitations, 16 delay profiles) and analog-to-digital conversion (up to 30 Msps, 10 bit), with a WiFi link (21.6 Mbps, UDP), for wireless raw data access, all in a compact (57 × 35 × 20 mm) and lightweight (35 g) design. Employing advanced power-saving techniques and optimized electronics design, TINYPROBE achieves a power consumption of < 1W for imaging modes (32 ch., 33 Hz) and < 1.3W for high-PRF Doppler mode (2 ch., 1400 Hz). This results in a state-of-the-art power efficiency of 44.9 mW/Mbps for wireless US systems, ensuring multi-hour operation with a compact 500 mAh Li-Po battery. We validate TINYPROBE as a versatile, general-purpose wearable platform in multiple in-vivo imaging scenarios, including muscle and bladder imaging, and blood flow velocity measurements.

Comparison of diffuse correlation spectroscopy analytical models for measuring cerebral blood flow in adults.

Although multilayer analytical models have been proposed to enhance brain sensitivity of diffuse correlation spectroscopy (DCS) measurements of cerebral blood flow, the traditional homogeneous model remains dominant in clinical applications. Rigorous in vivo comparison of these analytical models is lacking. We compare the performance of different analytical models to estimate a cerebral blood flow index (CBFi) with DCS in adults. Resting-state data were obtained on a cohort of 20 adult patients with subarachnoid hemorrhage. Data at 1 and 2.5cm source-detector separations were analyzed with the homogenous, two-layer, and three-layer models to estimate scalp blood flow index and CBFi. The performance of each model was quantified via fitting convergence, fit stability, brain-to-scalp flow ratio (BSR), and correlation with transcranial Doppler ultrasound (TCD) measurements of cerebral blood flow velocity in the middle cerebral artery (MCA). The homogeneous model has the highest pass rate (100%), lowest coefficient of variation (CV) at rest (median [IQR] at 1Hz of 0.18 [0.13, 0.22]), and most significant correlation with MCA blood flow velocities (, ) compared with both the two- and three-layer models. The multilayer model pass rate was significantly correlated with extracerebral layer thicknesses. Discarding datasets with non-physiological BSRs increased the correlation between DCS measured CBFi and TCD measured MCA velocities for all models. We found that the homogeneous model has the highest pass rate, lowest CV at rest, and most significant correlation with MCA blood flow velocities. Results from the multilayer models should be taken with caution because they suffer from lower pass rates and higher coefficients of variation at rest and can converge to non-physiological values for CBFi. Future work is needed to validate these models in vivo, and novel approaches are merited to improve the performance of the multimodel models.

Study of the blood flow structure in personalized models of graft branch from the femoral artery

The paper presents the methodology and results of calculating the pulsating flow of blood-mimicking fluid in three personalized models of proximal anastomosis of the femo-ral artery after femoral popliteal bypass surgery performed using synthetic grafts. Per-sonalized models were built based on computed tomography data and ultrasound meas-urements of blood flow velocity in the common femoral artery and in the graft. The char-acteristics of the pulsating flow of blood-mimicking fluid were calculated by numerically solving the three-dimensional unsteady Navier-Stokes equations. Comparison of the calculated velocity field obtained for one of the personalized models with clinical meas-urement data using ultrasonic high-speed vector imaging (applying the V Flow technol-ogy implemented in the Mindray scanner) showed satisfactory agreement of the results. A comparative analysis of the flow structure in two personalized models built for the sec-ond patient one and seven months after surgery is given. It was established that the nar-rowing of the flow sections of the vascular bed, detected after seven months, due to the growth of neointima in the common femoral artery (immediately before the anastomosis) and in the initial section of the graft, led to a significant increase in gradients of the ve-locity field and the time-averaged wall shear stress (TAWSS) in the area of the anastomo-sis; at the same time, the value of the oscillatory shear index (OSI) on the wall throughout the entire anastomosis area decreased. It was also revealed that at a distance of several calibers from the anastomosis, a single-vortex, weakly swirling flow is formed in the graft, the direction of swirl in which is determined by the individual geometry of the anastomo-sis area.

Monolithic Integration of Ultraslim Flow Sensor and Medical Guidewire by Laser Filament Scanning Sintering for In Vivo Diagnostics of Cardiovascular Diseases.

In this study, an ultraslim thermal flow sensor system integrated onto a 340 μm diameter medical guidewire was developed using a laser filament scanning sintering method for the early diagnosis of cardiovascular diseases. The proposed system is a calorimetric-based micro thermal flow sensor comprising a microheater and two thermistors. Prior to fabrication, the sensor design was optimized through flow simulation, and the patterned sensor was successfully implemented on a thin and curved surface of the medical guidewire using a laser patterning method with Ag nanoparticles. The performance of the ultraslim thermal flow sensor-on-guidewire system (SoW) was evaluated under pulsatile flow by using an artificial heartbeat simulator with differentially induced fluid flow velocities of up to 60 cm/s. The resulting electrical signals generated by the temperature difference between the two thermistors caused by the fluid flow were measured across different velocity ranges. Based on the obtained data, a calibration curve was derived to establish the relationship between the fluid velocity and the sensor output voltage. Furthermore, the SoW was tested on living animals, whereby the measured blood flow velocities were 60-90 cm/s in the left coronary artery of pigs. This research demonstrates the potential of ultraslim microsensors, such as the developed thermal flow sensor system, for various industries, particularly in the medical field.

Application of an automated analysis framework for pulsed-wave Doppler cardiac ultrasound measurements to generate reference data in adult zebrafish.

High-frequency cardiac ultrasound is the only well-established method to characterize in vivo cardiovascular function in adult zebrafish noninvasively. Pulsed-wave Doppler imaging allows measurements of blood flow velocities at well-defined anatomical positions, but the measurements and results obtained using this technique need to be analyzed carefully, taking into account the substantial baseline variability within one recording and the possibility for operator bias. To address these issues and to increase throughput by limiting hands-on analysis time, we have developed a fully automated processing pipeline. This framework enables the fast, unbiased analysis of all cardiac cycles in a zebrafish pulsed-wave Doppler recording of both atrioventricular valve flow as well as aortic valve flow without operator-dependent inputs. Applying this automated pipeline to a large number of recordings from wild-type zebrafish shows a strong agreement between the automated results and manual annotations performed by an experienced operator. The reference data obtained from this analysis showed that the early wave peak during ventricular inflow is lower for female compared with male zebrafish. We also found that the peaks of the ventricular inflow and outflow waves as well as the peaks of the regurgitation waves are all correlated positively with body surface area. In general, the presented reference data, as well as the automated Doppler measurement processing tools developed and validated in this study will facilitate future (high-throughput) cardiovascular phenotyping studies in adult zebrafish ultimately leading to a more comprehensive understanding of human (genetic) cardiovascular diseases.

Association between resistivity index of central retinal artery and severity of diabetic retinopathy.

Diabetic retinopathy (DR) is a leading cause of ocular morbidity. Its progression depends mainly on retinal vasculature and ocular blood flow. Color Doppler imaging (CDI) is a noninvasive imaging technique that measures blood flow velocity. The resistivity index (RI), calculated by the CDI, reflects the vascular resistance distal to the measuring location. RI is independent of the doppler angle and position of the patient, making it a reliable and reproducible parameter. To the best of our knowledge, there is only one study in literature studying the association between resistivity index (RI) of the central retinal artery (CRA) and severity of DR. To determine the association between RI of CRA and severity of DR. To determine the association between RI of CRA and spectral-domain optical coherence tomography (SD-OCT) biomarkers for DR. Type II diabetics visiting our OPD underwent DR screening and were graded into three categories according to ETDRS classification which include Group A-No diabetic retinopathy (No DR), Group B-Nonproliferative diabetic retinopathy (Moderate-Severe-Very Severe NPDR), and Group C-Proliferative diabetic retinopathy (PDR). SD-OCT was performed. Ultrasonic color doppler imaging was done. RI of the CRA was noted. It was compared between the three groups and its association with severity of DR and OCT biomarkers (central subfield thickness, cube average thickness and ellipsoid zone disruption) was studied. 56 eyes of 28 patients were included in our study with 20 in Group A,14 in Group B, and 22 in Group C. RI of CRA compared within groups showed statistically significant association with severity of DR (P < 0.001). The presenting BCVA (LogMar) showed positive correlation with RI in all groups. OCT biomarker central subfield thickness showed a positive correlation with RI in Groups A (P < 0.001) and B. Ellipsoid zone (EZ) disruption showed a statistically significant association with RI in Group C (P < 0.001). The RI of CRA is a reliable biomarker for the assessment of the severity of DR. Patients with high RI of CRA had higher chances of EZ disruption and presented with poor visual acuity.

Exploring the effects of resveratrol supplementation on cerebrovascular function in hormonal migraineurs: A pilot study

BackgroundPast research suggests that hormonal migraineurs may have poorer cerebrovascular function than women who do not suffer from migraine. Resveratrol, a vasoactive phytoestrogen, has been shown to improve cerebrovascular function in several populations but has never been tested in hormonal migraineurs. AimTo investigate the effects of 3-month resveratrol supplementation on the cerebrovascular function of hormonal migraineurs. MethodsWe conducted a randomised, double-blind, placebo-controlled, crossover intervention pilot study with resveratrol (150 mg/d for 3 months) in ten hormonal migraineurs (mean age: 37.2 ± 2.6 years). Participants visited the University of Newcastle’s Clinical Nutrition Research Centre where quality of life and disability, and cerebrovascular function were assessed. Quality of life and disability were examined using Migraine-Specific Quality of Life, Headache Impact Test-6 and the Migraine Disability Assessment. Cerebrovascular function was determined using transcranial Doppler ultrasound to bilaterally measure blood flow velocity in the middle and posterior cerebral arteries at rest and in response to a hypercapnic stimulus. Cerebrovascular responsiveness to a cognitive task battery was also measured bilaterally in the middle cerebral arteries. ResultsCompared to placebo, blood flow velocity in the right posterior cerebral artery was significantly higher (P = 0.041) following resveratrol supplementation. No other significant differences in cerebrovascular function between resveratrol and placebo treatments were observed. Baseline correlation analyses revealed higher blood flow velocities in the middle and posterior cerebral arteries were associated with better quality of life and less disability. However, higher cerebrovascular responsiveness to hypercapnia in the posterior circulation was associated with higher migraine-related disability and poorer migraine-related quality of life. ConclusionIn this pilot we found evidence that resveratrol may increase blood flow velocity in the right posterior cerebral artery in hormonal migraineurs. Larger cohorts are required confirm this effect and its potential relationship to migraine in premenopausal women.

Impact of maternal dietary folic acid or choline dietary deficiencies on vascular function in young and middle-aged female mouse offspring after ischemic stroke.

Adequate maternal dietary levels of one-carbon metabolites, such as folic acid and choline, play an important role in the closure of the neural tube in utero; however, the impact of deficiencies in one-carbon (1C) metabolism on offspring neurological function after birth remain undefined. Stroke is one of the leading causes of death and disability globally. The aim of our study was to determine the impact of maternal 1C nutritional deficiencies on cerebral and peripheral blood flow after ischemic stroke in adult female offspring. In this study, female mice were placed on either control (CD)-, folic acid (FADD)-, or choline (ChDD)-deficient diets before pregnancy. Female offspring were weaned onto a CD for the duration of the study. Ischemic stroke was induced in offspring and after 6 wk cerebral and peripheral blood flow velocity was measured using ultrasound imaging. Our data showed that 11.5-mo-old female offspring from ChDD mothers had reduced blood flow in the posterior cerebral artery compared with controls. In peripheral blood flow velocity measurements, we report an aging effect. These results emphasize the importance of maternal 1C diet in early life neuro-programming on long-term vasculature health.NEW & NOTEWORTHY We demonstrate that a maternal dietary deficiency in one-carbon (1C) metabolites result in reduced cerebral blood flow in adult female offspring after ischemic stroke, but the long-term effects are not present. This result points to the key role of the maternal diet in early life neuroprogramming, while emphasizing its effects on both fetal development and long-term cerebrovascular health.

Ultra-fast ultrasound blood flow velocimetry for carotid artery with deep learning

Accurate measurement of blood flow velocity is important for the prevention and early diagnosis of atherosclerosis. However, due to the uncertainty of parameter settings, the autocorrelation velocimetry methods based on clutter filtering are prone to incorrectly filter out the near-wall blood flow signal, resulting in poor velocimetric accuracy. In addition, the Doppler coherent compounding acts as a low-pass filter, which also leads to low values of blood flow velocity estimated by the above methods. Motivated by this status quo, here we propose a deep learning estimator that combines clutter filtering and blood flow velocimetry based on the adaptive property of one-dimensional convolutional neural network (1DCNN). The estimator is operated by first extracting the blood flow signal from the original Doppler echo signal through an affine transformation of the 1D convolution, and then converting the extracted signal into the desired blood flow velocity using a linear transformation function. The effectiveness of the proposed method is verified by simulation as well as in vivo carotid artery data. Compared with typical velocimetry methods such as high-pass filtering (HPF) and singular value decomposition (SVD), the results show that the normalized root means square error (NRMSE) obtained by 1DCNN is reduced by 54.99 % and 53.50 % for forward blood flow velocimetry, and 70.99 % and 69.50 % for reverse blood flow velocimetry, respectively. Consistently, the in vivo measurements demonstrate that the goodness-of-fit of the proposed estimator is improved by 8.72 % and 4.74 % for five subjects. Moreover, the estimation time consumed by 1DCNN is greatly reduced, which costs only 2.91 % of the time of HPF and 12.83 % of the time of SVD. In conclusion, the proposed estimator is a better alternative to the current blood flow velocimetry, and is capable of providing more accurate diagnosis information for vascular diseases in clinical applications.

Hyper-acute effects of sub-concussive soccer headers on brain function and hemodynamics.

Sub-concussive head impacts in soccer are drawing increasing research attention regarding their acute and long-term effects as players may experience thousands of headers in a single season. During these impacts, the head experiences rapid acceleration similar to what occurs during a concussion, but without the clinical implications. The physical mechanism and response to repetitive impacts are not completely understood. The objective of this work was to examine the immediate functional outcomes of sub-concussive level impacts from soccer heading in a natural, non-laboratory environment. Twenty university level soccer athletes were instrumented with sensor-mounted bite bars to record impacts from 10 consecutive soccer headers. Pre- and post-header measurements were collected to determine hyper-acute changes, i.e., within minutes after exposure. This included measuring blood flow velocity using transcranial Doppler (TCD) ultrasound, oxyhemoglobin concentration using functional near infrared spectroscopy imaging (fNIRS), and upper extremity dual-task (UEF) neurocognitive testing. On average, the athletes experienced 30.7 ± 8.9 g peak linear acceleration and 7.2 ± 3.1 rad/s peak angular velocity, respectively. Results from fNIRS measurements showed an increase in the brain oxygenation for the left prefrontal cortex (PC) (p = 0.002), and the left motor cortex (MC) (p = 0.007) following the soccer headers. Additional analysis of the fNIRS time series demonstrates increased sample entropy of the signal after the headers in the right PC (p = 0.02), right MC (p = 0.004), and left MC (p = 0.04). These combined results reveal some variations in brain oxygenation immediately detected after repetitive headers. Significant changes in balance and neurocognitive function were not observed in this study, indicating a mild level of head impacts. This is the first study to observe hemodynamic changes immediately after sub-concussive impacts using non-invasive portable imaging technology. In combination with head kinematic measurements, this information can give new insights and a framework for immediate monitoring of sub-concussive impacts on the head.