Time-averaged Maximum Velocity Research Articles

Numerical study on the flow field characteristics of the new high-speed maglev train in open air

With the increasing demand of higher travelling speed, a new streamlined high-speed maglev train has been designed to reach a speed of 600 km/h. To better capture the flow field structures around the maglev train, an improved delayed detached eddy simulation (IDDES) is adopted to model the turbulence. Results show that the new maglev train has good aerodynamic load performance such as small drag coefficient contributing to energy conservation. The main frequencies of aerodynamic forces for each car have a scattered distribution. There are two pairs of counter-rotating large vortices in the non-streamlined part of the train that make the boundary layer thicker. Many high-intensity vortices are distributed in the narrow space between skirt plates or train floor and track. In the gap between the train floor and track (except near the tail car nose), the main frequency of vortex shedding remains constant and its strength increases exponentially in the streamwise direction. In the wake, the counter-rotating vortices gradually expand and reproduce some small vortices that move downward. The vortex has quite random and complex frequencydomain distribution characteristics in the wake. The maximum time-averaged velocity of the slipstream occurs near the nose of the head car, based on which, the track-side safety domain is divided.

Validation of a Sagittal Section Technique for Measuring Clitoral Blood Flow. Volume Flow: A New Parameter in Clitoral Artery Doppler

BackgroundClitoral artery Doppler has been used as an objective technique to measure changes in genital women response. However, the technique has not been fully validated, and arterial volume flow has never been used as an outcome measure. AimsTo validate the technique clitoral artery Doppler measured in a sagittal section and explore arterial volume flow as a new parameter in clitoral Doppler. MethodsWe examined 90 healthy volunteers by clitoral artery Doppler using the sagittal section approach described by Battaglia et al in 2008. We calculated intraobserver, interobserver, and intraobserver intersession variability and reliability for all Doppler parameters and described and validated arterial volume flow as a new parameter in clitoral artery Doppler. OutcomesWe calculated peak systolic velocity (PSV), time-averaged maximum velocity, time-averaged mean velocity, end-diastolic velocity, pulsatility index, resistance index, and volume flow (v-flow) in all groups. We conducted reliability analyses using the intraclass correlation coefficient for agreement. We explored differences between and within observers and calculated agreement limits using the Bland-Altman test. ResultsThe intraclass correlation coefficient analysis showed correlation values higher than 0.75 (good reliability) for most of the variables and higher than 0.60 (moderate reliability) for the remaining ones. There were statistically significant differences between PSV and time-averaged maximum velocity in the intraobserver intersession measurements. For the remaining groups and variables, no statistically significant differences were observed. Bland-Altman analyses showed that the limits of agreement were acceptable and the regressions were not significant. The v-flow parameter also showed good reliability and low variability between groups. Clinical ImplicationsWe found that PSV was not a good outcome measure because of its high intraobserver and intersession variability. Moreover, it is possible to measure v-flow in the clitoral artery using the sagittal technique described by Battaglia et al, and it seems that this measure is reliable and reproducible. This could be the best parameter to assess clinical changes. Strengths & LimitationsThis study provided full validation of the sagittal section approach and of a new parameter, v-flow, which could beuseful for assessing clitoral blood flow. The main limitation of the study is its retrospective nature for validating v-flow. ConclusionWe found that clitoral artery Doppler measured using a sagittal approach is a valid and reliable technique for studying clitoral blood flow in women. The v-flow variable is a promising and reliable parameter for measuring changes in clitoral blood flow.Pérez MF, Agís IF, La Calle Marcos P, et al. Validation of a Sagittal Section Technique for Measuring Clitoral Blood Flow: Volume Flow – A New Parameter in Clitoral Artery Doppler. J Sex Med 2020;17:1109–1117.

Pelvic floor muscle training: mechanisms of action for the improvement of genitourinary syndrome of menopause

Objective: This study aims to investigate the mechanism of action of pelvic floor muscle training (PFMT) for the improvement of the signs and symptoms of genitourinary syndrome of menopause (GSM) in postmenopausal women with GSM and urinary incontinence (UI).Methods: Twenty-nine women were included in the secondary analysis of a single-arm feasibility study. Using color Doppler ultrasound, the peak systolic velocity, time-averaged maximum velocity, and pulsatility index of the internal pudendal and dorsal clitoral arteries were measured at rest and after a pelvic floor muscle (PFM) contraction task. PFM function was assessed by dynamometry, and vulvovaginal tissue elasticity was measured using the Vaginal Atrophy Index.Results: PFMT significantly improved blood flow parameters in both arteries (p < 0.05) and significantly increased the speed of PFM relaxation after a contraction (p = 0.003). After the intervention, a marginally significant decrease in PFM tone was observed, as well as an increase in PFM strength (p = 0.060 and p = 0.051, respectively). Finally, improvements in skin elasticity and introitus width were observed as measured by the Vaginal Atrophy Index (p < 0.007).Conclusion: Our findings suggest that PFMT improves blood flow in vulvovaginal tissues, PFM relaxation capacity, and vulvovaginal tissue elasticity in postmenopausal women with GSM and UI.

Examination of jackass (Equus asinus) accessory sex glands by B-mode ultrasound and of testicular artery blood flow by colour pulsed-wave Doppler ultrasound: Correlations with semen production.

The accessory sex glands play a major role in the production of seminal plasma, and testicular artery blood flow seems to strongly influence testicular function. However, very little ultrasound imaging of these organs has been undertaken in donkeys. The present work reports the results of such examinations in five jackasses along the year. The accessory glands were inspected by B-mode ultrasound while the testicular artery blood flow was assessed by colour pulsed-wave Doppler ultrasound. The testicular artery was examined at pampiniform plexus (PPT), supratesticular area (ST) and capsular artery (CA). Values were recorded for the total arterial blood flow (TABF), peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI), pulsatility index (PI) and time average maximum velocity (TAMV). Semen was obtained and assessed for sperm concentration, viability, abnormalities and motility using a CASA system. The bulbourethral glands, prostate and ductus deferens ampullae were relatively larger than in the stallion. Bulbourethral glands and ampullae sizes were inversely correlated with sperm motility. An reduction in blood flow between the level the PPP and the CA was observed, helping to reduce testis temperature and oxygen pressure. Blood flow at the CA showed the strongest correlation with semen production. PI and RI were positively correlated with the CASA motility variable STR (p=.02, p=.06) and sperm viability (p=.01), while sperm concentration (p=.05) correlated inversely with PSV, EDV, TAMV and TABF. EDV also correlated negatively with the CASA variables VSL, LIN, STR and VAP (p≤.05). PI and RI were also negatively correlated with testis length (p=.0093, p=-.0438).

Stroke transcranial Doppler in children with human immunodeficiency virus.

To describe stroke syndromes and transcranial Doppler (TCD) findings in children with human immunodeficiency virus (HIV) and examine the associations between TCD and clinical and laboratory data. We enrolled 42 children (24 males, 18 females) with HIV (median age=7y 6mo; 2y 7mo-15y 6mo), with and without stroke who underwent a TCD examination of the anterior and posterior circulations to derive time-averaged maximum mean velocity (TAMMV) measurements for comparison with previous studies. Clinical and laboratory variables were extracted from the medical records. Of the 42 children with HIV, five had right-sided hemiparesis, three had chronic lung disease, two occurred post-varicella infection, one after herpetic oral ulceration, and one had a poorly functioning left ventricle. Neuroimaging showed middle cerebral artery (MCA) TAMMV greater than 200cm/s, moyamoya-like arteriopathy, left basal ganglia infarction with ipsilateral stenosis, hygroma consistent with venous thrombosis, and a hyperdense left MCA. Eight neurologically asymptomatic children had atypical TCD. The CD4 cell count was non-significantly lower in 6 out of 30 children with atypical TCD (median=21.5; interquartile range=16.1-26.5) compared with the remainder (median=29; interquartile range=21.3-35.0; p=0.09). A variety of stroke syndromes occur in children with HIV. TCD suggests atypical intracranial vessels and/or haemodynamics in some children with HIV infection, consistent with vasculopathy, possibly related directly to immunodeficiency and/or infection. A range of stroke syndromes are found in children with human immunodeficiency virus (HIV). Transcranial Doppler (TCD) velocities in HIV are commonly outside the range for typically developing children. TCD and neuroimaging data in children with HIV suggest intracranial vasculopathy as one mechanism for stroke. CD4 cell count is non-significantly lower in children with HIV and atypical TCD.

Correlation of Maternal BMI with Foetal Liver Blood Flow and Neonatal Adiposity in Normal Pregnancies and Pregnancies Complicated by Gestational Diabetes Mellitus and Foetal Growth Restriction

Introduction: The foetus exhibits a wide array of structural and functional adaptations in response to intrauterine conditions, towards protection of vital organs and maintaining the supply of essential nutrients. When oxygen is limited, foetal adaptations prioritise brain growth, irrespective of whether other essential nutrients are limited or not. The hypothesis for this study was that fatty acid synthesis occurs in foetal liver therefore if adaptive changes occur in the hepatic and umbilical flow it will affect fat deposition which will manifest as neonatal adiposity. Aim: Correlation of maternal Basal Metabolic Index (BMI) with Foetal liver blood flow and neonatal adiposity in normal pregnancies and pregnancies complicated by Gestational Diabetes Mellitus (GDM) and Foetal Growth Restriction (FGR) .Materials and Methods: An observational pilot study was carried out in a tertiary care referral hospital of Northern India. Antenatal women were recruited in three groups of singleton uncomplicated pregnancies (40), Women with GDM (31) and women with FGR (29). Maternal characteristics including pre-pregnancy BMI and obstetric ultrasound doppler study were recorded at 35 weeks gestation. The time-averaged maximum velocity (TAMX) was calculated for Umbilical Vein (UV) and Ductus Venosus (DV) as (Vmax) UV and (Vmax) DV. Blood flow (Q) was calculated as Q=h×(D/2)2×p×TAMX. The neonatal biometry and Skin Fold Thickness (SFT) was measured. Statistical techniques used were t-tests for analyses of dichotomous outcomes, Pearson’s correlation (r) and multivariate regression. Results: In mothers with higher DV shunting neonatal adiposity was significantly lower in the FGR group. In the uncomplicated group about 46% of variation in adiposity was explained by all the study variables and overall regression equation was statistically significant (p=0.004). Conclusion: Mothers with low BMI and normal umbilical and middle cerebral doppler flow had higher foetal hepatic flow to improve substrate deposition. DV shunting was significantly higher in hypoxic foetuses with reduced hepatic flow.

An Educational Study Promoting the Delivery of Transcranial Doppler Ultrasound Screening in Paediatric Sickle Cell Disease: A European Multi-Centre Perspective.

Background: Effective stroke prevention in sickle cell disease (SCD) is recommended for children with sickle cell anaemia. Effective implementation relies on the correct stratification of stroke risk using Transcranial Doppler Ultrasound (TCD), prior to committing children to long-term treatment with transfusion. Nevertheless, less than 50% of children with SCD in Europe receive annual TCD—one of the reasons being a lack of trained personnel. The present European multi-centre study was designed to promote the standardisation and delivery of effective screening. Methods: Fifty-five practitioners from differing professional backgrounds were recruited to the TCD training program. The impact of the training programme was evaluated in three European haematology clinics by comparing stroke risk classification and middle cerebral artery time-averaged maximum velocity (TAMMV) obtained from a cohort of 555 patients, before and after training. Results: 42% (23/55) of trainees successfully completed the program. The TAMMV, used to predict stroke risk at each Centre, demonstrated the highest values in Centre 3 (p < 0.0001) before training. The imaging-TCD TAMMV was also higher in Centre 3 (p < 0.001). Following training, the TAMMV showed closer agreement between centres for both imaging-TCD and non-imaging TCD. The stroke risk distribution of children at each centre varied significantly before training (p < 0.001), but improved after training (Fisher’s Exact: no treatment = 5.6, p = 0.41, treatment = 13.8, p < 0.01). The same consistency in stroke risk distribution following training was demonstrated with both non-imaging and imaging-TCD data. Conclusion: The attainment of competency in stroke screening using transcranial Doppler scanning (TCD) in sickle cell disease is more feasible for professionals with an ultrasound imaging background. A quality assurance (QA) system is required to ensure that standards are maintained. Further work is in progress to develop an achievable and reproducible QA program.

Testicular Morphological and Ultrasonographic Characterization of Male Gray Brocket Deers (Mazama gouazoubira) in Different Reproductive Status

Background: Gray brocket deer (Mazama gouazoubira) populations have been declining due to human intervention. Yet, only a few studies have assessed ultrasonographic testicular characteristics in cervids. Considering the relevance of monitoring testicular size, blood flow, and parenchyma, the present study aims to establish baseline information on scrotal circumference, testicular volume, and spectral Doppler parameters, to describe differences among adult male gray brocket deer in different reproductive status, and to correlate ultrasound parameters with testes size measurements.Materials, Methods &amp; Results: Six adult male gray brocket deers were used in the study. Scrotal circumference and testicular volume were measured. B mode ultrasound images of testes (longitudinal and cross-sectional views) and epididymes were subjected to computer-assisted analysis, obtaining the numerical pixel values (NPV) and pixel standard deviation (PSD). Using spectral Doppler, supratesticular artery blood flow velocities (peak systolic velocity - PSV, end diastolic velocity - EDV, time-average maximum velocity - TAMAX, resistivity - RI and pulsatility indices - PI) were obtained. Semen was analyzed through total motility, vigor, and concentration tests. Three animals were normospermic (F+ group) and three were oligo/azoospermic (F- group). Groups were compared using were compared using a one-way ANOVA or Kruskal-Wallis followed by Student-Newman-Keuls (SNK) test. Ultrasound parameters were correlated to testes size parameters using Pearson’s correlation for parametric variables and Spearman’s correlation for non-parametric variables. F+ group presented significantly higher scrotal circumference (14.57 ± 1.19 cm), testicular volume (26.18 ± 4.94 cm3), and testes cross-sectional NPV (69.88 ± 24.00) and PSD (10.78 ± 3.42) than group F- (NPV: 28.26 ± 13.75, PSD: 6.70 ± 1.84). No significant differences were observed between the groups regarding the spectral Doppler ultrasound parameters. Significant correlations were observed between scrotal circumference and longitudinal (r = 0.76) and cross-sectional testes NPV (r = 0.89), and testicular volume was correlated with longitudinal (r = 0.78) and cross-sectional testes NPV (r = 0.91) and with cross-sectional testes PSD (ρ = 0.82).Discussion: Increased testicular echogenicity (higher NPV) has been positively associated with improved testicular growth, cell population expansion, inner and outer seminiferous tubules diameter, spermatids percentages and testis weight. In addition, more heterogenous testes (higher PSD) were associated with higher sperm output. It was suggested that the animals in group F- had compromised testicular development and spermatogenesis. The correlation observed between testes NPV and scrotal circumference was proposed to be associated with seminiferous tubules impairment. The F- group showed lower testicular volume, NPVs and PSDs in cross-sectional testicular images, suggesting higher protein levels and lower lipid contents were present in their parenchyma, influencing in testicular echogenicity and echotexture. No differences in spectral Doppler parameters were observed between the two groups. Also observed in stallions. However, PSV, EDV, TAMAX could be potential infertility indicators in other mammalians. These different results may be due to different locations of the evaluated vessel, species and techniques, age, ambient temperature, pathological conditions, and anaesthesia. Thus, it is suggested that scrotal circumference, testicular volume, and testes NPV are good indicators of male reproductive health in gray brocket deer and may help with better male selection in the species.

Cerebral blood flow dynamic in foetuses with hypoplastic left heart syndrome: Incremental value of the first segment of the anterior cerebral artery over the middle cerebral artery?

To investigate the blood flow Doppler parameters of the anterior cerebral artery (ACA) in foetuses with hypoplastic left heart syndrome (HLHS). Doppler parameters (peak systolic velocity [PSV], end-diastolic velocity [EDV], time-averaged maximum velocity [TAMXV] and pulsatility index [PI]) and biometric parameters were measured in two anatomical segments of the ACA (S1 and S2) and in the middle cerebral artery (MCA) in 35 HLHS foetuses and 73 gestational age-matched normal foetuses. Correlations between the cerebral artery PIs and head circumference (HC) were assessed. Both EDV and TAMXV of the ACA and MCA in the HLHS group were significantly higher than in the normal group (P < .05). The PI of the ACA and MCA in the HLHS group were significantly lower than in the normal group (P < .05). ACAS1PI and ACAS2PI in the HLHS foetuses with retrograde blood flow in the aortic isthmus (AoI) were significantly lower than those of HLHS foetuses without retrograde blood flow in the AoI (P < .05). ACAS2PI was significantly lower than ACAS1PI in the HLHS foetuses with retrograde blood flow in the AoI (P = .047). The abnormal rates of ACAS1 and ACAS2 were significantly higher than that of the MCA (P < .05) in the HLHS group. The HC and biparietal diameter were significantly lower in the HLHS group than in the control group (P < .05). HC was correlated with the PIs of ACAS1, ACAS2 and the MCA in the HLHS group (P < .05). A redistribution of foetal cerebral blood flow appeared in HLHS, and the measurement of ACA PI might provide early information on brain hypoxia.

Noninvasive determination of the fetal cardiac interatrial pressure gradients by Doppler ultrasonography: preliminary results

Objective In 2000, Johnson et al. measured the atrial pressures puncturing the atria invasively in 19 fetuses that will be terminated. In this study, it is aimed to define the fetal cardiac interatrial pressure gradient noninvasively. The pressure gradients were calculated using the ductus venosus (DV) and pulmonary vein (PV) blood flow velocities and Bernoulli equation for flowing fluids. Methods “S,” “a,” and the time-averaged maximum velocities in both veins of 246 fetuses were used in the simplified Bernoulli equation; Δp =4 (). Additionally, the umbilical vein maximum velocity is measured in order to calculate ducto-umbilical pressure gradient. Results The average interatrial pressure gradient was biggest in the ventricular systole and the least gradient was in the atrial systole of a cardiac cycle. The pressure gradient changes throughout the second and the third trimester have four periods with two increases and two decreases. Conclusions The interatrial and ducto-umbilical pressure gradients can be measured noninvasively in order to follow the hemodynamic of the fetal circulatory system.

Primary Prevention of Strokes in Nigerian Children with Sickle Cell Disease (SPIN Trial): Final Results

Introduction: In children with sickle cell anemia (SCA) living in high-income settings, the routine use of transcranial Doppler (TCD) measurements, coupled with regular blood transfusion therapy for those with abnormal velocities (&amp;gt; 200 cm/sec) dramatically decreased the rate of strokes. Despite evidence of its beneficial effects in preventing strokes, regular blood transfusion therapy is not feasible for 99% of the children that are born with SCA living in low- and middle-income countries. To address this gap in care, we tested the hypothesis that moderate fixed dose of hydroxyurea (20 mg/kg/day) for primary stroke prevention was feasible in a low-income setting, Kano, Nigeria. Specifically, we previously demonstrated that families were willing to enroll at a 92% recruitment rate and were adherent to the study protocol with no missed monthly research visits (603 of 603 visits). We have extended the trial for approximately five years to test the hypotheses that moderate fixed dose hydroxyurea will: 1) not result in excess incidence rate of severe adverse events (death or stroke) when compared to a group of children with SCA and TCD measurements less than 200 cm/sec; 2) decrease the incidence rate of strokes to the level of children receiving regular blood transfusion for primary stroke prevention in the STOP Trial. We report the final results of the primary Stroke Prevention Feasibility Trial in Nigeria (SPIN Trial (NCT01801423). Methods: At trial entry, all eligible participants were screened with non imaging TCD to determine increased stroke risk; defined as two independent measurements of time-averaged maximum velocity (TAMV) ≥ 200cm/sec in the middle cerebral artery (MCA) or one measurement &amp;gt;219cm/sec. Families were offered moderate fixed dose hydroxyurea (~20mg/kg/day). The comparison group included individuals with SCA that have a TCD measurement less than 200 cm/sec and agreed to be followed as routine medical care. Serious adverse events including death or stroke in the treatment and comparison groups were defined based on WHO criteria. Results: A total of 29 children treated with hydroxyurea for primary stroke prevention, and 206 children in the comparison group, were included. The median age for the treatment and comparison groups were 7.0 and 8.2 years, respectively. No statistically significant difference was observed in age, sex, ethnicity, height and weight of the treatment and comparison groups. Table 1 The median time on therapy (follow up time) was 4.9years (IQR- 4.60, 5.2). After 3 months of starting hydroxyurea therapy, 65.5% of the participants had a drop in TCD measurement to below 200cm/sec, which was sustained through 12months of therapy (61.5% had a TCD measurement below 200cm/sec at 12 months). Figure 1 The stroke incidence rate among the participants on hydroxyurea was 0.76 per 100 person-years (95% confidence interval 0.11 to 5.24), which was not significantly different from the incidence rate of 0.32 per 100 person-years (95% confidence interval 0.10 to 0.99) for participants in the comparison arm (P = 0.489), and significantly lower than the reported rate of stroke in the standard care group for the STOP study (10.7 per 100 person-years, total of 102 patient years). A total of 20 deaths occurred, with no death in the treatment group. One death occurred in a child that was originally in the treatment group, but after the patient was withdrawn from the trial due to progressive renal disease unrelated to treatment. The death rate in the comparison group was 2.05 per 100 patient-years. There was no statistically significant difference in the death rate between treatment and comparison group (p = 0.082). The leading cause of death was suspected malaria occurring in 79% (15 of 19). As expected, we found a statistically significant higher incidence rate of pain in the comparison group (30.04 per 100 person-years) compared to the treatment group (15.28 per 100 person-years) (P &amp;lt;0.001). No difference in incidence rates of anemia, infection, malaria and transfusion rates between the two groups. Conclusion: The extended results of the SPIN trial provide clear evidence that initial treatment with fixed moderate dose hydroxyurea (20 mg/kg/day) will prevent strokes in children with abnormal TCD measurements in a low-resource setting. The results of the extended SPIN trial have established the first evidence based stand care strategy for primary stroke prevention for children with SCA in Africa. Disclosures No relevant conflicts of interest to declare.

Helical Blood Flow in Hemodynamically Significant Carotid Stenosis.

To define helical blood flow (HBF) characteristics in hemodynamically significant atherosclerotic stenosis of the internal carotid artery (ICA) by means of duplex scanning. Twenty-five hemodynamically significant (65.0% [range, 63.0%-69.0%]) carotid stenoses were examined in 23 patients. The severity of the stenosis was calculated by the European Carotid Surgery Trial grading method by transverse section scanning in the B-mode. Rotational components were estimated in color flow mapping by transverse-section scanning of a vessel at the most narrowed site, as well as in the prestenotic and poststenotic segments. A quantitative evaluation of HBF was performed on the basis of pulsed wave Doppler imaging of longitudinal and transverse sections of the arterial lumen. Helical blood flow was most often (68%) registered in the poststenotic segment of the ICA as a single vortex (52%) or double vortices (16%). At the most narrowed site, HBF was registered in 48% of the cases (44% single vortex and 4% double vortices), whereas in the prestenotic segment of the blood vessel, it was registered in only 16% of the cases (8% single vortex and 8% double vortices). The time-averaged maximum blood flow velocities at the most narrowed site were 88.5 cm/s (25th-75th percentiles, 73.8-127.8 cm/s) for the axial component and 33.1 cm/s (22.7-40.9 cm/s) for the rotational component. The calculated summary velocity of motion of the blood particles in helical paths was 92.2 cm/s (75.7-144.2 cm/s). It has been shown that HBF can be registered by Doppler ultrasound in atherosclerotic stenosis, and its registration rate increases while passing through the narrowed segment of the ICA.

Hemodynamic changes detected by Doppler ultrasonography in the ovaries of cattle during early development of cystic ovarian disease

A common reproductive disease in dairy cattle is Cystic Ovarian Disease. To study its development, there was use of an experimental model of follicular persistence to detect hemodynamic changes occurring in ovaries by using Doppler ultrasonography. After estrous synchronization, control cows received no additional treatment and were evaluated at proestrus (CG), whereas treated cows (PG) received sub-luteal doses of progesterone for 15 days and were evaluated at proestrus, and after 0, 5, 10 and 15 days of follicular persistence. Spectral Doppler was used to evaluate blood flow in the ovarian artery, and power Doppler for evaluation of blood flow in the ovarian parenchyma and follicular wall of persistent and dominant preovulatory follicles. Findings using power Doppler signals indicated there were no differences between groups in the parenchyma of both right (P = 0.455) and left (P = 0.762) ovaries. In contrast, power Doppler signals of blood flow were less in walls of persistent follicles from day 0 to 15 when there was follicular persistence than in dominant follicles of the CG (P < 0.001). Blood flow in ovarian arteries was less (P < 0.05) in diastolic velocity and time averaged maximum velocity in all PG groups than in the CG. Peak systolic velocity was less (P < 0.05) in all PG than in the CG, with the exception of P15 (P > 0.05). These findings indicate there are marked changes in blood irrigation area of walls of persistent follicles during the 15 days of follicular persistence.

Uterine hemodynamics during a short-term progesterone synchronization protocol in ewes.

Twenty-eight pluriparous and non-lactating Santa Inês sheep were synchronized with vaginal sponge and an intramuscular (IM) injection of 37.5μg of cloprostenol on random days of the estrous cycle (D0); day 6 (D6), at 7:00am, the devices were removed, and after 24h (D7), GnRH analog (25μg of lecirelin) was administrated. Fixed-time artificial insemination (FTAI) with cervical traction by the transcervical route was performed 52 to 58h after sponge removal. Doppler velocimetry of both uterine arteries was performed on D0, D2, D4, and the morning of D6 (every 48h), and then every 12h from D6 to D8 (7:00a.m. and 7:00p.m.). We analyzed the peak systolic velocity (PSV), end-diastolic velocity (EVD), time-averaged maximum and mean velocity (TAMAX, TAMEAN), pulsatility index (PI), resistance index (RI), systolic/diastolic ratio (S/D), arterial diameter (AD), and blood flow volume (BFV), with the objective of evaluating the hemodynamic behavior of blood flow velocity parameters of the uterine artery during a short-term progesterone synchronization protocol in ewes. With respect to phases, we noted increases in the means of TAMAX and TAMEAN and decreases of EDV, PI, and RI (P < 0.05). S/D, EDV, TAMEAN, PI, RI, SD, AD, and BFV showed differences between the time of progesterone insertion and the estimated time of ovulation (which was considered the last evaluation) (P < 0.05). The PI and RI values were different when comparing the times of insertion and withdrawal of the progesterone device (PI 2.53-1.54 and RI 0.76-0.68) (P < 0.05). The PI was different with respect to side (P < 0.001), but no side effect was seen in the RI. In conclusion, the two uterine arteries behave differently under the effect of progesterone (intravaginal sponges) and the effect of estradiol during the follicular phase, and estrous phase was responsible for increasing uterine blood flow.

Doppler sonography of uterine blood flow at mid-oestrus during different degree of clinical endometritis in dairy cows.

The present study was aimed at analysing the mid-oestrous uterine blood flow parameters during varying degree of endometritis in dairy cows. Degree of clinical endometritis was adjudged on the basis of visual examination of uterine discharge collected from cows at mid-oestrus, that is mild (slightly turbid; n=13), moderate (turbid with pus flakes; n=14) and severe (milky; n=13). Pulsatility and resistance indices (PI and RI), time average mean velocity (TAMEAN), time average maximum velocity (TAMAX), diameter of the artery, volume of blood flow, Doppler pulse duration (DPD) and systolic upstroke/acceleration time (AT) were measured to study the spectral waveforms at mid-oestrus. Significantly higher (p<.01) PI and RI were found in cows diagnosed with mild degree in comparison with cows diagnosed with moderate and severe degrees of clinical endometritis. There was significantly higher (p<.01) velocity (TAMEAN and TAMAX), volume of blood flow (BFV-TAMEAN, BFV-TAMAX) and DPD in both the middle uterine arteries during moderate and severe degrees of clinical endometritis as compared to mild endometritis. However, significantly higher (p<.01) AT was recorded in cows diagnosed with mild degree as compared to moderate and severe degrees of clinical endometritis. Pearson's correlation analysis has shown that RI was positively correlated with PI and AT in all the groups under study (mild degree, r=.72 and .49; moderate degree, r=.54 and .38; severe degree, r=.90 and .42; p<.05). However, there found significantly negative correlation (p<.05) with other parameters in all the cows irrespective of degree of inflammation. Therefore, it may be deducted that assessment of uterine inflammation can be done with a non-invasive technique known as Doppler sonography which can be useful in adjudging the hemodynamic changes inside uterus and future fertility of dairy cows.

Mid-estrus uterine blood flow in endometritic and non-endometritic dairy cows using transrectal Doppler ultrasonography

ABSTRACT The objective of the present study was to derive the comparative quantification of various blood flow parameters in endometritic and non-endometritic dairy cows at mid-estrus. Uterine perfusion was investigated by performing the transrectal Doppler ultrasonography of both the middle uterine arteries in Jersey cows diagnosed with clear uterine discharge and clinical endometritis at mid-estrus. Pulsatility and Resistance indices (PI and RI), Time average mean velocity (TAMEAN), Time average maximum velocity (TAMAX), diameter of the artery and volume of blood flow were measured to study the waveforms. Significantly lower (p < 0.05) PI and RI were found in cows diagnosed with clinical endometritis in comparison to non-endometritic cows. There was significantly higher (p < 0.01) volume and velocity of blood flow (TAMEAN, TAMAX, Blood flow volume (BFV)-TAMEAN and BFV-TAMAX) in both the middle uterine arteries during endometritis as compared to non-endometritic cows. Also, significantly higher (p < 0.05) blood flow velocity and volume (TAMEAN, BFV-TAMEAN and BFV-TAMAX) were recorded in middle uterine artery ipsilateral to dominant follicle as compared to contralateral one in non-endometritic cows. The PI value was positively correlated with RI in endometritic (r = 0.88; p < 0.01) and non-endometritic cows (r = 0.81; p < 0.01) but negatively correlated with other parameters in all the cows irrespective of inflammatory state of uterus.

Quantitative evaluation of primary retinitis pigmentosa patients using colour Doppler flow imaging and optical coherence tomography angiography.

To find the potential relation between changes in retinal large vessels and terminal vessels using colour Doppler flow imaging (CDFI) and optical coherence tomography angiography (OCTA) and to compare the respective advantages of CDFI and OCTA in evaluating vascular changes in retinitis pigmentosa (RP) patients. A prospective series of case study was conducted to enrol RP patients and age-matched controls, who were, respectively, imaged by CDFI and OCTA. Repeatability and reproducibility of both CDFI and OCTA were performed among healthy volunteers. The central retinal artery (CRA) was detected by CDFI analysis to provide parameters of peak systolic velocity (PSV), end-diastolic velocity (EDV) and time-averaged maximum velocity (TAMV). Retinal parameters were evaluated from OCTA images, including vascular area density (VAD) of the superficial vascular layer, the fovea avascular zone (FAZ) area and retinal thickness. RP patients were separated into a high-vision group and a low-vision group, according to median vision (0.3, LogMAR 0.5). Multiple comparisons were used to analyse the data between groups. A correlation analysis was used to determine the correlation between CDFI and OCTA parameters. Twenty RP patients (40 eyes) and thirteen normal volunteers (26 eyes) were enrolled in this study. Repeatability and reproducibility of the measurements by CDFI had higher CVs, from 4.5% to 15.4%, than those measurements by OCTA (<5%). All the CDFI and OCTA parameters examined had significant reductions in RP patients compared to those in the controls (p<0.01). Compared to the high-vision group, the low-vision group exhibited a statistically significant decrease in vascular parameters of the FAZ area, fovea VAD and parafovea nasal side VAD (p<0.05); as well as in the parameters of the fovea thickness, and the parafovea nasal, superior and inferior side thickness (p<0.05). From the correlation analysis, a significant association was found between the vision and CDFI parameters (PSV and time-averaged maximum velocity (TAMX), p<0.05), and the vision and OCTA parameters (FAZ area, fovea and nasal side VAD, retinal thickness in all sides, p<0.05). PSV and TAMX of the CRA were closely related to the OCTA superficial VAD in all sides, whereas the CDFI parameters showed poor correlation with retinal thickness. Colour Doppler flow imaging (CDFI) and OCTA parameters revealed a significant reduction in RP patients when compared to the controls. OCTA can detect vision-related microvascular and thickness changes around the macula between high- and low-vision groups, which happen earlier than the changes in large vessels. In addition to good repeatability and reproducibility, OCTA may have significant utility in the diagnosis and monitoring of disease progression in RP patients.

Metabolic Vasoreactivity in the Middle Cerebral Artery of Heart Failure Patients with and without Continuous-Flow Left Ventricular Support

Purpose In advanced heart failure (HF) patients, a normal cardiac output is restored after continuous-flow left ventricular assist device (CF-LVAD) implantation. Previous studies have suggested that cerebral autoregulation is preserved. However, it is not known whether CF-LVAD therapy affects the cerebrovascular reactivity to a metabolic challenge. Hypothesis CF-LVAD patients will have a similar cerebrovascular response to a CO2-retention challenge compared with HF patients and healthy controls. Methods Angle-corrected Doppler ultrasound images of the middle cerebral artery (MCA) were recorded immediately before and at the end of a 30s breathhold in 10 healthy controls, 4 HF and 7 CF-LVAD (HM II) patients. Time-averaged maximum blood velocity (TAMAX), peak flow velocity (Vmax), Pulsatility Index (PI) and Resistance Index (RI) were determined by tracing of the blood velocity envelope. Statistical differences were determined with 2-way ANOVA (% change is illustrated graphically). Results In the MCA, significant baseline differences in TAMAX, Vmax, PI and RI existed between groups (all P Conclusion A metabolic challenge has a differential impact on cerebrovascular hemodynamics of HF and CF-LVAD patients compared with healthy controls. The pilot data suggest that cerebrovascular reserve may be altered already in HF and not further modulated after CF-LVAD implantation.

Asymmetric Dimethylarginine Levels and Its Correlation to Cerebral Blood Flow in Children with Sickle Cell Anemia.

Asymmetric dimethylarginine (ADMA) level may play a role in the pathogenesis of cerebrovascular stroke in Children with Sickle Cell Anemia (SCA). To assess the plasma level of ADMA in children with SCA and its correlation to cerebral blood flow. This is a cross sectional study was carried out on 30 children with homozygous SCA under follow up in the Out Patients Clinic, Pediatric Department at Tanta University Hospital and 30 healthy children as a control group. Both groups had undergone the following investigations: Complete blood count, lactate dehydrogenase enzyme, and plasma level of ADMA by a commercial ADMA ELISA Kit. Trans-cranial Doppler were done for both groups. ADMA plasma level was significantly higher in-patient group in comparison to the control group (p < 0.001), with a mean value 1.43 ± 0.20μmol/l, 0.48 ± 0.16μmol/l respectively. The time-averaged mean maximum velocities for middle cerebral artery, anterior cerebral artery, inferior cerebral artery and posterior cerebral artery were significantly different between patient and control group, p < 0.05. Trans-cranial Doppler data revealed that, 86.7% of patients have low velocity (< 70cm/s) and 13.3% having very low velocity (< 10cm/s) while control group have normal velocity. There was a significant negative correlation between ADMA plasma levels and cerebral blood flow. Elevated ADMA levels may have a role in the pathogenesis of the decreased cerebral blood flow in children with SCA.

Changes in Vertebral Artery Hemodynamics Associated With McKenzie Therapeutic Cervical Movements: An Exploration Using Duplex Ultrasound Imaging

ObjectiveThe purpose of this study was to explore vertebral artery hemodynamic changes associated with McKenzie therapeutic cervical movements in healthy individuals. MethodsA single-group repeated-measure design was used to examine 20 healthy participants aged 22.05 (1.69) years, mean (standard deviation). Vertebral artery volume flow, diameter, resistive index, time-averaged maximum velocity, and pulsatility index were measured using Duplex ultrasound. Vertebral artery hemodynamics were measured at cervical neutral positions then compared against vertebral artery hemodynamics measured during end-range loading and after repeated McKenzie therapeutic movements. Wilcoxon signed rank tests were used for comparisons, and standardized mean differences (SMDs) were calculated to quantify the changes in size. ResultsRepeated retraction with extension in a sitting position and end-range retraction with extension in supine position were significantly associated with an increase in vertebral artery volume flow, P ≤ .01, and the SMD suggests small-medium changes in size. Statistical significant vertebral artery dilation was observed in the sitting position with protraction, combined retraction with extension, and flexion, P ≤ .01, yet the SMD suggested small changes in size. End-range flexion was significantly associated with a reduction in vertebral artery pulsatility index, and the SMD suggested large changes in size. Repeated retraction with extension in supine position was significantly associated with an increase in vertebral artery time-averaged maximum velocity, yet the SMD revealed no clinically important difference. ConclusionFor the healthy participants in this study, McKenzie cervical movements were mostly associated with an increase in vertebral artery hemodynamics.