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Blood Flow Velocity (blood + flow_velocity)
Kinds of Blood Flow Velocity Selected AbstractsRelationship between Slow Coronary Flow and Left Atrial Appendage Blood Flow VelocitiesECHOCARDIOGRAPHY, Issue 1 2007Recep Demirbag M.D. Aims: This study was undertaken to assess whether slow coronary flow (SCF)is related to low left atrial appendage (LAA) blood flow velocities. Methods: Study subjects consist of 44 patients with SCF and 11 volunteer subjects with normal coronary angiogram. The diagnosis of SCF was made using the TIMI frame count method. The blood flow velocities were obtained by placing a pulsed-wave Doppler sample volume inside the proximal third of the LAA. Results: The mean LAA emptying velocities (MEV)were significantly lower in patients than control subjects (34.5 ± 9.9 cm/sec vs 84.0 ± 12.1 cm/sec; P < 0.001). In bivariate analysis, significant correlation was found between MEV, and systolic pulmonary venous flow, mean TIMI frame count, deceleration time, and isovolumetric relaxation time (P < 0.05). By multiple linear regression analysis, mean TIMI frame count (ß=,0.865, P < 0.001) was identified as independent predictors of MEV. Conclusion: This study indicates that SCF phenomenon may be related to low LAA blood flows. [source] Noninvasive Assessment of Influence of Resistant Respiration on Blood Flow Velocities Across the Cardiac Valves in Humans,A Quantification Study by EchocardiographyECHOCARDIOGRAPHY, Issue 5 2004Lijun Yuan M.D. The aim of our study is to quantitatively investigate influence of the intrathoracic pressure change on the four cardiac valves' velocities and further verify a new proposal of the mechanism of respiratory influence on hemodynamics. Methods: Thirty healthy volunteers with no cardiopulmonary diseases were included. The intrathoracic pressure changes were measured with self-designed device. The velocity across the four cardiac valves during spontaneous respiration and with the intrathoracic pressure change at ,4, ,8, and ,12 mmHg, respectively, were recorded simultaneously with the electrocardiogram and respiratory curve. The respiratory variation indices (RVIs) were calculated. The average RVIs of mitral, aortic, tricuspid, and pulmonary valves were 12.54%, 13.19%; 6.23%, 8.27%; 20.27%, 24.36%; and 6.45%, 7.69% with intrathoracic pressure change at ,8 mmHg and ,12 mmHg, respectively. All the above parameters have a significant difference from those during spontaneous respiration (P < 0.01 or P < 0.001). We concluded that it might be the respiratory intrathoracic pressure change that causes the change of the velocity across the valves. (ECHOCARDIOGRAPHY, Volume 21, July 2004) [source] Biofeedback-Assisted Relaxation in Migraine Headache: Relationship to Cerebral Blood Flow Velocity in the Middle Cerebral ArteryHEADACHE, Issue 3 2003Sachinder Vasudeva MD Objective.,To determine if migraineurs with aura respond differently to biofeedback/relaxation than those without aura and, if so, whether the variability in outcome can be explained by blood flow velocity. Background.,The relationship between cerebral blood flow velocity and treatment response to biofeedback/relaxation in migraine with and without aura is uncertain. Method.,Twenty migraineurs underwent 12 sessions of biofeedback/relaxation therapy, while 20 controls simply were told to relax on their own. Cerebral blood flow velocity was measured bilaterally in the middle cerebral artery with transcranial Doppler. Results.,The biofeedback group showed significant (P < .05) reductions in pain, depression, and anxiety compared to the control group. Patients with and without aura did equally well. There were significant (P < .05) left to right blood flow velocity differences only in the migraine with aura group. Maximum blood flow velocities were significantly higher (P < .05) in the migraine with aura group than in the cohort without aura. There was an inverse correlation between indicators of anxiety and blood flow velocity, perhaps related to hyperventilation-induced constriction in the small vessels distal to the middle cerebral artery. Conclusion.,The positive treatment response to biofeedback/relaxation in migraine headache is not related to presence of aura, nor to changes in blood flow velocity, but may be associated with reduction in anxiety and depression. [source] Blood Flow Velocity and Pulsatility Index Differences in Patients With Unilateral MigraineHEADACHE, Issue 7 2001Oleg Y. Chernyshev MD Objective.,To evaluate blood flow velocity and pulsatility in unilateral migraine without aura during the headache-free period using transcranial Doppler (TCD) sonography. Methods.,Patients with unilateral headache were recruited during the headache-free period. Maximum mean flow velocity (MFV) and pulsatility index (PI) were measured in the middle cerebral (MCA) and basilar arteries. Controls were headache-free individuals without cerebrovascular disease. Results.,Twenty-five patients with right-sided migraine, 25 patients with left-sided migraine, and 19 controls were studied. The MCA PI was higher on the right headache side versus the left headache side (0.97 ± 0.2 versus 0.86 ± 0.1 cm/s, P = .02) and versus controls (0.9 ± 0.2 cm/s, NS). The basilar artery MFV was higher in patients with right-sided headache versus left-sided headache (39.5 ± 5.6 versus 34.7 ± 8.2 cm/s, P = .02) and versus controls (38.2 ± 8 cm/s, NS). No decrease in MFV with age was observed in patients with migraine. Conclusions.,Middle cerebral artery flow pulsatility and basilar artery velocity are higher in patients with right-sided migraine compared with left-sided migraineurs, during the headache-free period. Although these parameters were similar to controls, the differences found during the headache-free period in migraineurs may indicate vascular involvement predisposing to the unilateral headache recurrence. [source] Effect of Postconditioning on Coronary Blood Flow Velocity and Endothelial Function and LV Recovery After Myocardial InfarctionJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 5 2006XIAOJING MA Objective: Postconditioning is a novel approach to myocardial protection during ischemia reperfusion. Our study observed the effect of postconditioning on coronary blood flow velocity and endothelial function in patients who underwent emergency percutaneous coronary intervention (PCI). Methods: Ninety-four patients with their first acute myocardial infarction who underwent revascularization within 12 hours of onset by primary PCI were recruited in the study. All the patients were randomized to two groups, IR group (PCI without postconditioning) and Postcond group (PCI with postconditioning). Corrected TIMI frame count (CTFC) was used to evaluate velocity of coronary blood after PCI. Creatine phosphokinase (CK), CK-MB, and malondialdehyde (MDA) were measured before and after PCI. Arterial endothelial function was studied noninvasively by examination of brachial artery responses to endothelium-dependent and endothelium-independent stimuli by echo Doppler technique. Wall motion score index (WMSI) was assessed by two-dimensional echocardiography before and 8 weeks after angioplasty. Results: There were no significant differences between the two groups with regard to age, sex, presence of angiographically visible collaterals, and elapsed time from the onset of symptoms until perfusion. Patients with postconditioning had much faster CTFC than patients without postconditioning (25.38 ± 5.35 vs 29.23 ± 5.54). After 8 weeks, the WMSI improved significantly in both groups, but the ,WMSI in Postcond group was significantly larger than that of IR group (1.20 ± 0.30 vs 1.04 ± 0.36, P < 0.05). There was a significant negative correlation between ,WMSI and CTFC in IR group and Postcond group (r =,0.9032, P < 0.01; r =,0.7884, P < 0.01). The peaks of CK and CK-MB of Postcond group were much lower than that of IR group (1236.57 ± 813.21 U/L vs 1697.36 ± 965.74 U/L; 116.92 ± 75.83 U/L vs 172.41 ± 92.64 U/L), and MDA-reactive products were significantly lower than that in the IR group at any same time after PCI. All patients with acute myocardial infarction had a depressed endothelium-dependent vasodilation function, while the endothelium-dependent vasodilation function was improved in Postcond group. Conclusion: Postconditioning is a simple, operative procedure for salvaging the coronary endothelial function and cardiomyocyte. It could be used widely in clinic and to better the prognosis of acute myocardial infarction. [source] Doppler measurement of blood flow velocities in extraocular orbital vessels in patients with obstructive sleep apnea syndromeJOURNAL OF CLINICAL ULTRASOUND, Issue 5 2003C. Zuhal Erdem MD Abstract Purpose. We used color Doppler sonography to determine blood flow velocities in the extraocular orbital vessels of patients with obstructive sleep apnea syndrome (OSAS) and compared the results with those of healthy control subjects without OSAS. Methods. Patients with OSAS were classified according to the apnea-hypopnea index (AHI) as having mild OSAS (AHI < 20) or severe OSAS (AHI , 20). The peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistance index were measured in the ophthalmic artery (OA), central retinal artery (CRA), lateral short posterior ciliary artery, and medial short posterior ciliary artery using color Doppler sonography. Only 1 eye was measured in each study participant, and right and left eyes were chosen randomly. The blood flow velocities of patients with OSAS and those of control subjects were compared with the Kruskal-Wallis test and Wilcoxon's rank-sum test. Results. The study comprised 30 patients (15 with mild and 15 with severe OSAS) and 20 healthy control subjects. Blood flow velocities were higher in most measured vessels in patients with OSAS than they were in the control subjects. Among patients with mild OSAS, the PSVs and EDVs in the posterior ciliary arteries were statistically significantly higher than those of the control group (p < 0.05), but those in the OA and CRA did not differ significantly between the mild OSAS group and the control group (p > 0.05). However, as the severity of OSAS increased, the PSVs and EDVs of the OA and CRA were also affected (p < 0.05). Conclusions. Color Doppler sonographic measurements of blood flow parameters in the orbital vessels may differ significantly between patients with OSAS and those without the syndrome. Therefore, OSAS should be considered in addition to other conditions when interpreting the results of color Doppler sonography of the extraocular orbital vessels if the clinical history points toward such a diagnosis. © 2003 Wiley Periodicals, Inc. 31:250,257, 2003 [source] Colour Doppler examination of early and late orbital haemodynamic changes in eyes with eyelid oedema due to blunt traumaACTA OPHTHALMOLOGICA, Issue 2 2006Mehmet Numan Alp Abstract. Purpose:,To evaluate the early and late alterations in orbital blood flow parameters in eyes with severe eyelid swelling due to blunt trauma by using colour Doppler ultrasonography (CDU). Methods:,Blood flow parameters in the ophthalmic artery (OA), central retinal artery (CRA), short posterior ciliary arteries (SPCAs) and central retinal vein (CRV) were examined by CDU in 62 eyes of 31 patients with unilateral blunt trauma and in 32 eyes of 32 normal subjects. Patients were examined within the first 5 days and at least 1 month after trauma. The traumatized eyes of patients were designated ,trauma eyes', non-traumatized fellow eyes were designated ,fellow eyes', and randomly chosen eyes of control subjects ,control eyes'. Results:,In the early phase, peak systolic velocity (PSV) and end diastolic velocity (EDV) in the OA in trauma eyes were statistically significantly higher than in both fellow eyes and control eyes: the p-values for the differences in PSV and EDV between trauma eyes and fellow eyes were p < 0.001 and p = 0.001, respectively, while the p-values for the differences in PSV and EDV between trauma eyes and control eyes were p = 0.002 and p = 0.019, respectively). No other blood flow parameters obtained at the first examination in all groups were statistically different. In the late phase, PSV in the OA in trauma eyes was found to be higher than that in both fellow eyes and control eyes, but the difference was significant only between trauma eyes and fellow eyes (p = 0.028). End diastolic velocity in the CRA was statistically significantly lower in fellow eyes than in control eyes (p = 0.046). No other blood flow parameters in any vessels examined in fellow eyes and control eyes were statistically significantly different during the study period. Conclusion:,Blood flow velocities detected by CDU are increased in the OA in eyes with eyelid oedema due to blunt trauma and some of these changes may persist for up to 1 month. This effect seems to be a consequence of trauma-induced hyperaemia in the orbital soft tissues rather than an expression of traumatic choroidal vasculopathy. [source] Altered free radical metabolism in acute mountain sickness: implications for dynamic cerebral autoregulation and blood,brain barrier functionTHE JOURNAL OF PHYSIOLOGY, Issue 1 2009D. M. Bailey We tested the hypothesis that dynamic cerebral autoregulation (CA) and blood,brain barrier (BBB) function would be compromised in acute mountain sickness (AMS) subsequent to a hypoxia-mediated alteration in systemic free radical metabolism. Eighteen male lowlanders were examined in normoxia (21% O2) and following 6 h passive exposure to hypoxia (12% O2). Blood flow velocity in the middle cerebral artery (MCAv) and mean arterial blood pressure (MAP) were measured for determination of CA following calculation of transfer function analysis and rate of regulation (RoR). Nine subjects developed clinical AMS (AMS+) and were more hypoxaemic relative to subjects without AMS (AMS,). A more marked increase in the venous concentration of the ascorbate radical (A,,), lipid hydroperoxides (LOOH) and increased susceptibility of low-density lipoprotein (LDL) to oxidation was observed during hypoxia in AMS+ (P < 0.05 versus AMS,). Despite a general decline in total nitric oxide (NO) in hypoxia (P < 0.05 versus normoxia), the normoxic baseline plasma and red blood cell (RBC) NO metabolite pool was lower in AMS+ with normalization observed during hypoxia (P < 0.05 versus AMS,). CA was selectively impaired in AMS+ as indicated both by an increase in the low-frequency (0.07,0.20Hz) transfer function gain and decrease in RoR (P < 0.05 versus AMS,). However, there was no evidence for cerebral hyper-perfusion, BBB disruption or neuronal,parenchymal damage as indicated by a lack of change in MCAv, S100, and neuron-specific enolase. In conclusion, these findings suggest that AMS is associated with altered redox homeostasis and disordered CA independent of barrier disruption. [source] Probing events with single molecule sensitivity in zebrafish and Drosophila embryos by fluorescence correlation spectroscopyDEVELOPMENTAL DYNAMICS, Issue 12 2009Xianke Shi Abstract Zebrafish and Drosophila are animal models widely used in developmental biology. High-resolution microscopy and live imaging techniques have allowed the investigation of biological processes down to the cellular level in these models. Here, using fluorescence correlation spectroscopy (FCS), we show that even processes on a molecular level can be studied in these embryos. The two animal models provide different advantages and challenges. We first characterize their autofluorescence pattern and determine usable penetration depth for FCS especially in the case of zebrafish, where tissue thickness is an issue. Next, the applicability of FCS to study molecular processes is shown by the determination of blood flow velocities with high spatial resolution and the determination of diffusion coefficients of cytosolic and membrane-bound enhanced green fluorescent protein,labeled proteins in different cell types. This work provides an approach to study molecular processes in vivo and opens up the possibility to relate these molecular processes to developmental biology questions. Developmental Dynamics 238:3156,3167, 2009. © 2009 Wiley-Liss, Inc. [source] Relationship between Slow Coronary Flow and Left Atrial Appendage Blood Flow VelocitiesECHOCARDIOGRAPHY, Issue 1 2007Recep Demirbag M.D. Aims: This study was undertaken to assess whether slow coronary flow (SCF)is related to low left atrial appendage (LAA) blood flow velocities. Methods: Study subjects consist of 44 patients with SCF and 11 volunteer subjects with normal coronary angiogram. The diagnosis of SCF was made using the TIMI frame count method. The blood flow velocities were obtained by placing a pulsed-wave Doppler sample volume inside the proximal third of the LAA. Results: The mean LAA emptying velocities (MEV)were significantly lower in patients than control subjects (34.5 ± 9.9 cm/sec vs 84.0 ± 12.1 cm/sec; P < 0.001). In bivariate analysis, significant correlation was found between MEV, and systolic pulmonary venous flow, mean TIMI frame count, deceleration time, and isovolumetric relaxation time (P < 0.05). By multiple linear regression analysis, mean TIMI frame count (ß=,0.865, P < 0.001) was identified as independent predictors of MEV. Conclusion: This study indicates that SCF phenomenon may be related to low LAA blood flows. [source] Long-term follow-up of patients with asymptomatic occlusion of the internal carotid artery with good and impaired cerebral vasomotor reactivityEUROPEAN JOURNAL OF NEUROLOGY, Issue 10 2010I. Kimiagar Background:, Cerebral hemodynamic status might be prognostic for either the symptomatic or asymptomatic course of carotid occlusive disease. It is determined by evaluating cerebral vasomotor reactivity (VMR). We assessed VMR in asymptomatic patients with total occlusion of the internal carotid artery (ICA) and followed them to evaluate the role of impaired VMR in predicting ischaemic stroke (IS). Methods:, Thirty-five patients (21 men, mean age ± SD 68 ± 7.5 years) with unilateral asymptomatic ICA occlusion were studied by transcranial Doppler and the Diamox test (intravenous 1.0 g acetazolamide) and followed for 48 months or until reaching the end-points of IS, transient ischaemic attack, or vascular death. VMR% was evaluated by recording the percent differences in peak systolic blood flow velocities in each middle cerebral artery at baseline and after Diamox administration. Results:, Based on VMR% calculations, 14 (40%) patients had good VMRs and 21 (60%) had impaired VMRs. The global annual risk of ipsilateral ischaemic events was 5.7%. The annual ipsilateral ischaemic event risk was 1.8% in patients with good VMRs, whilst it was 7.1% in patients with impaired VMRs. An impaired VMR was significantly correlated with ipsilateral IS (Kaplan,Meier log rank statistic, P = 0.04). Conclusions:, Our results support the value of VMR assessment for identifying asymptomatic patients with carotid occlusion who belong to a high-risk subgroup for IS. New trials using extracranial-to-intracranial bypass surgery in patients with asymptomatic ICA occlusion and impaired VMRs are warranted. [source] Biofeedback-Assisted Relaxation in Migraine Headache: Relationship to Cerebral Blood Flow Velocity in the Middle Cerebral ArteryHEADACHE, Issue 3 2003Sachinder Vasudeva MD Objective.,To determine if migraineurs with aura respond differently to biofeedback/relaxation than those without aura and, if so, whether the variability in outcome can be explained by blood flow velocity. Background.,The relationship between cerebral blood flow velocity and treatment response to biofeedback/relaxation in migraine with and without aura is uncertain. Method.,Twenty migraineurs underwent 12 sessions of biofeedback/relaxation therapy, while 20 controls simply were told to relax on their own. Cerebral blood flow velocity was measured bilaterally in the middle cerebral artery with transcranial Doppler. Results.,The biofeedback group showed significant (P < .05) reductions in pain, depression, and anxiety compared to the control group. Patients with and without aura did equally well. There were significant (P < .05) left to right blood flow velocity differences only in the migraine with aura group. Maximum blood flow velocities were significantly higher (P < .05) in the migraine with aura group than in the cohort without aura. There was an inverse correlation between indicators of anxiety and blood flow velocity, perhaps related to hyperventilation-induced constriction in the small vessels distal to the middle cerebral artery. Conclusion.,The positive treatment response to biofeedback/relaxation in migraine headache is not related to presence of aura, nor to changes in blood flow velocity, but may be associated with reduction in anxiety and depression. [source] Orbital blood flow velocities in patients with rheumatoid arthritisJOURNAL OF CLINICAL ULTRASOUND, Issue 7 2007Besir Erdogmus MD Abstract Purpose. To assess orbital blood flow changes in patients with rheumatoid arthritis using Doppler sonography. Patients and Methods. The study comprised 35 patients who were diagnosed with RA and were treated at the Department of Physical Therapy and Rehabilitation at Duzce Medical School. A control group consisted of 35 healthy volunteers. Color Doppler imaging was used to measure peak systolic velocity (PSV) and end diastolic velocity (EDV), from which the resistance index (RI) was calculated in the ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary arteries (PCAs). Results. In the OA, PSV, EDV, and RI were, respectively, 36.7 ± 0.6 cm/sec, 9.7 ± 0.2 cm/sec, and 0.73 in the control group versus 34.7 ± 3.0 cm/sec, 9.1 ± 1.1 cm/sec, and 0.74 in the patient group. In the CRA, they were, respectively, 11.8 ± 1.7 cm/sec, 3.6 ± 0.7 cm/sec, and 0.66 in the control group versus 11.1 ± 1.7 cm/sec, 3.4 ± 0.7 cm/sec, and 0.68 in the patient group. In the PCAs, they were, respectively, 13.2 ± 1.2 cm/sec, 4.7 ± 0.6 cm/sec, and 0.65 in the control group versus 12.4 ± 1.2 cm/sec, 4.2 ± 0.6 cm/sec, and 0.66 in the PCAs. PSV, EDV, and RI of the PCAs and OA and RI of the CRA were significantly different between patients and controls, whereas there was no difference in the serum levels of glucose, triglyceride, low-density lipoprotein cholesterol, and total cholesterol. In the patient group, there was a significant correlation between orbital blood flow and duration of disease. Conclusion. Ocular blood flow appears to be slightly lower in RA patients than in healthy controls, suggesting that RA is a systemic inflammatory disease that may also involve ocular vessels. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007 [source] Color Doppler sonography of orbital and vertebral arteries in migraineurs without auraJOURNAL OF CLINICAL ULTRASOUND, Issue 6 2003Simay Altan Kara MD Abstract Purpose The objective of this study was to investigate whether the retrobulbar hemodynamics in the ophthalmic (OA), posterior ciliary (PCA), central retinal (CRA), and vertebral (VA) arteries are affected in migraineurs without aura. Methods The eyes of migraineurs without aura and those of healthy control subjects were evaluated during both headache and headache-free periods. Retrobulbar and vertebral blood flow velocities in the OA, PCA, CRA, and the extracranial part of the VA were measured bilaterally using color Doppler sonography. The peak systolic and end-diastolic flow velocities and the pulsatility (PI) and resistance (RI) indices were determined for all arteries. Results In total, we enrolled 30 migraineurs and 31 healthy control subjects. Statistically significant differences between headache-free migraineurs and control subjects were observed in the PI and RI of both right and left PCAs and in the RI of both right and left CRAs. The PI and RI of the left VA of the migraineurs were significantly lower during both headache and headache-free periods than were those of the control subjects. Among the migraineurs, the peak systolic and end-diastolic velocities of the left VA were increased during headache periods relative to those found during the headache-free periods. Conclusions The retrobulbar circulation and flow hemodynamics in the left VA may be altered in both headache and headache-free periods in migraineurs without aura. The differences found between migraineurs and control subjects may implicate autonomic dysfunction in migraineurs. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:308,314, 2003 [source] Doppler measurement of blood flow velocities in extraocular orbital vessels in patients with obstructive sleep apnea syndromeJOURNAL OF CLINICAL ULTRASOUND, Issue 5 2003C. Zuhal Erdem MD Abstract Purpose. We used color Doppler sonography to determine blood flow velocities in the extraocular orbital vessels of patients with obstructive sleep apnea syndrome (OSAS) and compared the results with those of healthy control subjects without OSAS. Methods. Patients with OSAS were classified according to the apnea-hypopnea index (AHI) as having mild OSAS (AHI < 20) or severe OSAS (AHI , 20). The peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistance index were measured in the ophthalmic artery (OA), central retinal artery (CRA), lateral short posterior ciliary artery, and medial short posterior ciliary artery using color Doppler sonography. Only 1 eye was measured in each study participant, and right and left eyes were chosen randomly. The blood flow velocities of patients with OSAS and those of control subjects were compared with the Kruskal-Wallis test and Wilcoxon's rank-sum test. Results. The study comprised 30 patients (15 with mild and 15 with severe OSAS) and 20 healthy control subjects. Blood flow velocities were higher in most measured vessels in patients with OSAS than they were in the control subjects. Among patients with mild OSAS, the PSVs and EDVs in the posterior ciliary arteries were statistically significantly higher than those of the control group (p < 0.05), but those in the OA and CRA did not differ significantly between the mild OSAS group and the control group (p > 0.05). However, as the severity of OSAS increased, the PSVs and EDVs of the OA and CRA were also affected (p < 0.05). Conclusions. Color Doppler sonographic measurements of blood flow parameters in the orbital vessels may differ significantly between patients with OSAS and those without the syndrome. Therefore, OSAS should be considered in addition to other conditions when interpreting the results of color Doppler sonography of the extraocular orbital vessels if the clinical history points toward such a diagnosis. © 2003 Wiley Periodicals, Inc. 31:250,257, 2003 [source] Cerebral Vasospasm in Childhood Migraine During the Intermigrainous PeriodJOURNAL OF NEUROIMAGING, Issue 2 2004Lauren E. Boasso ABSTRACT Background and Purpose. The aims of this study were to evaluate the changes in intracranial hemodynamics and assess the presence of vasospasm in children with migraine during the intermigrainous period. Methods. Transcranial Doppler (TCD) sonography findings, clinical examinations, and the vasospastic index of Lindegaard were analyzed for children who fulfilled the criteria for childhood migraine. The significance of the presence of vasospasm and abnormal hemodynamics were statistically analyzed using the normal approximation to the binomial test method. TCD sonography was performed using the standard published techniques for children. Results. Sixty-two patients between the ages of 5 and 17 years who had undergone at least one TCD sonographic examination were selected for this study. A total of 113 TCD sonographic examinations were performed on the patients. Elevated mean blood flow velocities were found in 23 of 62 patients (37%) (P< .001). Early vasospasm was found in 4 of 62 patients (6.5%) (P< .001). Bruits were noted in 35 of 62 patients (56%). Conclusions. This study raises the possibility of cerebral vasospasm in the intermigrainous period in childhood migraine. Further studies are needed to elaborate on the pathophysiology of cerebrovascular behavior during this period. These findings may have a significant impact on the current clinical treatment of childhood migraine. [source] High-resolution blood flow velocity measurements in the human fingerMAGNETIC RESONANCE IN MEDICINE, Issue 4 2001M. Klarhöfer Abstract MR phase contrast blood flow velocity measurements in the human index finger were performed with triggered, nontriggered, and cine acquisition schemes. A strong (Gmax = 200 mT/m), small bore (inner diameter 12 cm) gradient system inserted in a whole body 3 Tesla MR scanner allowed high-resolution imaging at short echo times, which decreases partial volume effects and flow artifacts. Arterial blood flow velocities ranging from 4.9,19 cm/sec were measured, while venous blood flow was significantly slower at 1.5,7.1 cm/sec. Taking into account the corresponding vessel diameters ranging from 800 ,m to 1.8 mm, blood flow rates of 3.0,26 ml/min in arteries and 1.2,4.8 ml/min in veins are obtained. The results were compared to ultrasound measurements, resulting in comparable blood flow velocities in the same subjects. Magn Reson Med 45:716,719, 2001. © 2001 Wiley-Liss, Inc. [source] Cardiocirculatory effects of patent ductus arteriosus in extremely low-birth-weight infants with respiratory distress syndromePEDIATRICS INTERNATIONAL, Issue 3 2003Senji Shimada Abstract Background:,Cardiocirculatory effects of hemodynamically significant patent ductus arteriosus (hsPDA) have not been systematically studied in extremely low-birth-weight (ELBW) infants with respiratory distress syndrome (RDS). The objective of the present study was to evaluate the effects of hsPDA on the left ventricular output (LVO) and organ blood flows in ELBW infants with RDS. Methods:,Extremely low-birth-weight infants (birth-weight <1000 g) treated with surfactant for RDS were studied by serial Doppler flow examinations. Doppler flow variables in 19 infants in whom hsPDA developed (hsPDA group) were compared with those in 19 infants without hsPDA matched for gestational age, birth-weight, and postnatal age (non-hsPDA group). All infants in the hsPDA group had pharmacologic closure of ductus arteriosus when hsPDA developed. Results:,Before pharmacological closure of PDA, the hsPDA group had significantly higher LVO, lower blood flow volume of the abdominal aorta, and lower mean blood flow velocities in the celiac artery, superior mesenteric artery, and renal artery than the non-hsPDA group. These alterations in the hsPDA group reverted to the levels in the non-hsPDA group after the closure of PDA and had no deleterious effects on the cardiorespiratory status. No significant differences between the groups were found in mean blood flow velocities of the anterior cerebral artery throughout the study period. Conclusion:,These results indicate that although LVO is increased, the splanchnic and renal blood flows are decreased when hsPDA develops in ELBW infants with RDS. The effects of these alterations of LVO and organ blood flows on the cardiorespiratory course seem to be minor when early pharmacologic closure of PDA is done. [source] Fetal tricuspid valve Doppler at 11,13 weeks and 6 days: reference values and reproducibilityPRENATAL DIAGNOSIS, Issue 8 2010Milena Almeida Prado Ninno Abstract Objective To determine normal blood flow velocities across the fetal tricuspid valve (TV) at 11,13 weeks and 6 days of gestation and to examine the reproducibility of these measurements. Methods A prospective study involving 166 normal singleton pregnancies examined at 11,13 weeks and 6 days was carried out. Descriptive analysis of E- and A-waves' maximum velocities, E/A ratio, duration of the cardiac cycle (C) and diastole (D) and D/C ratio were calculated. Intraobserver and interobserver agreement analysis was performed in a subgroup of 12 cases. Results Average ( ± SD) flow velocities were: E-wave, 25.0 ( ± 4.6) cm/s; A-wave, 42.9 ( ± 5.9) cm/s; E/A, 0.58 ( ± 0.07); cardiac cycle, 390 ( ± 21.1) ms; diastole, 147 ( ± 18) ms and D/C, 0.38 ( ± 0.04). Significant correlation was observed between all parameters (except A-wave) and gestational age but not with nuchal translucency (NT). Intraclass correlation coefficients (interobserver, intraobsever examiner 1 and intraobserver examiner 2) were: E-wave, 0.53, 0.53 and 0.64; A-wave, 0.45, 0.46 and 0.49; cardiac cycle, 0.70, 0.79 and 0.84 and diastole, 0.63, 0.85 and 0.82, respectively. Conclusions The present study establishes normal Doppler parameters for blood flow across the TV at 11,13 weeks and 6 days and demonstrates that these parameters do not correlate with NT measurement and have good/moderate reproducibility. Copyright © 2010 John Wiley & Sons, Ltd. [source] Reference ranges for umbilical vein blood flow in the second half of pregnancy based on longitudinal dataPRENATAL DIAGNOSIS, Issue 2 2005Ganesh Acharya Abstract Objectives To construct new reference ranges for serial measurements of umbilical vein (UV) blood flow. Methods Prospective longitudinal study of blood flow velocities and diameter of the UV measured at four-weekly intervals during 19 to 42 weeks' gestation in 130 low-risk singleton pregnancies. Regression models and multilevel modeling were used to construct the reference ranges. Results On the basis of 511 sets of longitudinal observations, we established new reference percentiles of UV diameter, blood flow velocities, volume flow, and blood flow normalized for fetal weight and abdominal circumference. They reflected some of the developmental patterns of previous cross-sectional studies, but with important differences, particularly near term. The UV blood flow showed a continuous increase until term, whereas the flow normalized per unit fetal weight, a corresponding reduction. Calculating the blood flow on the basis of intensity-weighted mean velocity or 0.5 of the maximum velocity gave almost interchangeable results for most fetuses. Conclusion New reference ranges for UV blood flow based on longitudinal observations appear slightly different from cross-sectional studies, and should be more appropriate for serial evaluation of fetal circulation. Copyright © 2005 John Wiley & Sons, Ltd. [source] Haemoglobin oxygen saturation is a determinant of cerebral artery blood flow velocity in children with sickle cell anaemiaBRITISH JOURNAL OF HAEMATOLOGY, Issue 4 2009Charles T. Quinn Summary Steady-state haemoglobin (Hb) desaturation is a common finding in sickle cell anaemia (Hb SS) that could predispose to stroke by limiting oxygen delivery to the brain. To determine its association with the risk of overt stroke, we examined the relationship between daytime Hb saturation measured by pulse oximetry (SpO2) and cerebral artery blood flow velocity measured by transcranial Doppler ultrasonography (TCD), an established risk factor for overt stroke in Hb SS. We studied 181 children using multivariate models to control for known determinants of TCD velocity, including age, haematocrit, and a measure of stenosis. We found that SpO2 correlated significantly and inversely with TCD velocity in both the right and left middle cerebral arteries. Hb desaturation was associated with increased cerebral artery blood flow velocities and increased odds of abnormal TCD velocities, hence increased risk of stroke. About 5% of the variation in TCD velocity could be ascribed to Hb saturation while controlling for other determinants of TCD velocity. In conclusion, Hb saturation is a determinant of TCD velocity and a risk factor for stroke in children with Hb SS. [source] Ultrasound assessment of short-term ocular vascular effects of intravitreal injection of bevacizumab (Avastin®) in neovascular age-related macular degenerationACTA OPHTHALMOLOGICA, Issue 6 2010Philippe Bonnin Acta Ophthalmol. 2010: 88: 641,645 Abstract. Purpose:, Angiogenic inhibitors, alone or combined with other therapies, are believed to represent a promising treatment for neovascularization in age-related macular degeneration (wet AMD). They can maintain or improve visual acuity (VA), at least for the first 2 years. However, evolution to retinal atrophy cannot be ruled out and it may be useful to assess the effects of antiangiogenic therapy on retinal and choroidal circulation. Methods:, We carried out a pilot study in 15 patients with wet AMD. Time-averaged mean blood flow velocities (BFVs) in the central retinal, temporal posterior ciliary and ophthalmic arteries (CRA, TPCA and OA) were measured by ultrasound imaging before and 4 weeks after a single intravitreal injection of 1.25 mg bevacizumab in 0.05 ml. Patients underwent two ophthalmic examinations, before and 4 weeks after injection, including VA measurement and optical coherence tomography (OCT3) examination. Results:, In treated eyes, bevacizumab injection was followed by a significant improvement in VA (from 20/125 to 20/80; p = 0.0214), and a decrease in mean central macular thickness (from 392 ± 96 ,m to 271 ± 50 ,m; p = 0.0038). Mean BFV decreased by 10% in the CRA (p = 0.0226), 20% in the TPCA (p = 0.0026) and 20% in the OA (p = 0.0003). No effect was observed in fellow eyes. Conclusions:, Intravitreal bevacizumab acutely improved VA and reduced central macular thickness in wet AMD. Ultrasound imaging revealed that BFVs decreased in all retrobulbar arteries, suggesting that after local diffusion, bevacizumab exerts a short-term regional effect. Bevacizumab might therefore induce hypoperfusion of the whole eye, which may correspond to a vascular side-effect. [source] 3254: Neurovascular coupling in the retrobulbar ciliary circulationACTA OPHTHALMOLOGICA, Issue 2010O ZEITZ Purpose Perfusion of the retina is adapted to the metabolic demand by neurovascular coupling. Neurovascular coupling has shown to be present in the retinal vasculature, but not in vessels supplying the optic nerve. The present study investigated the presence of neurovascular coupling in the anterior part of the optic nerve in healthy and glaucoma subjects. Methods Retrobulbar blood flow velocities were determined by color Doppler imaging (CDI). A Siemens Elegra ultrasound system with a 7.5L40 transducer was used. Peak-systolic and end-diastolic velocities (PSV and EDV) in the central retinal artery (CRA) or the short posterior ciliary artery (SPCA) were the primary readout. CDI measurements were performed shortly before, during, immediately after, 60 s after, and 120 s after a 10-Hz flicker stimulation of the retina. Results Thirty-five glaucoma patients and 44 healthy control subjects were included in the study. In the SPCA of healthy controls, flicker stimulation led to a rise of PSV from 9.7±0.8 to 12.5±0.8 cm/s (P<0.001; N=24) and of EDV from 2.4±0.3 to 3.6±0.3 cm/s (P<0.001; N=24). This effect was not detectable in glaucoma patients. In the CRA, flicker light led to an increase of EDV from 2.1±0.2 to 3.0±0.3 cm/s (P=0.002; N=20) in healthy volunteers and from 1.3±0.2 to 2.0±0.2 cm/s in glaucoma patients (P=0.004; N=15). PSV was affected by flicker stimulation in neither the healthy volunteers nor glaucoma patients. Conclusion The data indicate the presence of neurovascular coupling in the vascular bed supplied by the paraoptic SPCA. The response pattern to the flicker stimulus differs between healthy and glaucoma subjects. [source] Colour Doppler imaging evaluation of blood flow parameters in the ophthalmic artery in acute and chronic phases of optic neuritis in multiple sclerosisACTA OPHTHALMOLOGICA, Issue 1 2009Pavel Hradílek Abstract. Purpose:, Optic neuritis (ON) is a common manifestation of multiple sclerosis (MS). It is caused by the immune-mediated inflammation of the optic nerve. Some vascular factors that may influence blood flow in the ophthalmic artery (OA) have also been suggested as factors in the pathogenesis of ON. The purpose of our study was to evaluate blood flow velocities and resistance (RI) and pulsatile (PI) indices in the OA in both orbits in patients in the acute and chronic phases of unilateral ON and to compare these with equivalent findings in healthy control subjects. Methods:, Orbital colour Doppler imaging (CDI) was performed in 40 consecutive MS patients during acute unilateral ON prior to corticosteroid treatment. Optic neuritis was diagnosed on the basis of clinical presentation and facultative assessment of visual evoked potentials (VEPs). The peak systolic (PSV) and end-diastolic (EDV) velocities and RI and PI were measured in the OA in both eyes. We compared results from affected and unaffected orbits using the paired t -test. The same measurements were performed in 114 MS patients with a history of acute unilateral ON that occurred > 1 year prior to ultrasound examination. We also measured the same parameters in the middle cerebral arteries (MCAs) on both sides in all subjects in both groups. The same measurements were obtained in healthy controls. Results:, The PSV (p < 0.0001), RI (p < 0.0001) and PI (p < 0.0001) in the OA in the eye affected with acute ON were significantly higher than in the unaffected eye. There was no difference in EDV in the OA between affected and unaffected eyes (p > 0.05) in the group with acute ON. We did not observe any significant differences between eyes in either blood flow velocities or the RI or PI (p > 0.05) in the group in the chronic phase of ON or in the control group. All the parameters in the MCAs on both sides were normal in both the acute and chronic groups, as well as in the control group. Conclusions:, Pathophysiological changes during acute unilateral ON influence orbital haemodynamics, as is indicated by increased PSV, RI and PI in the OA in eyes affected with ON. However, these changes do not persist over longer periods. [source] Ophthalmic artery blood flow velocity changes in diabetic patients as a manifestation of macroangiopathyACTA OPHTHALMOLOGICA, Issue 2 2000Masanori Ino-ue ABSTRACT. Purpose: The hemodynamic characteristics of ophthalmic artery (OA) blood flow velocity in diabetic patients with ocular involvement were evaluated. Methods: Changes in OA blood flow of eyes with background diabetic retinopathy (BDR), proliferative retinopathy (PDR) and ocular ischemic syndrome (OIS) were ananalyzed by Color Doppler imaging. Results: Patients with BDR and PDR had significantly lower diastolic and mean blood flow velocities and higher pulsatility indices compared to controls. Diabetic patients with OIS had significantly lower systolic, diastolic and mean anterograde OA blood flow velocities than the controls. Pulsatility indices were higher in anterograde OA blood flow measurements compared to controls. Systolic blood flow velocities in rubeotic eyes with OIS were significantly lower than in rubeotic eyes with PDR. Conclusion: OA blood flow measurements by color doppler imaging may detect macroangiopathies in diabetic patients as manifested by carotid atheromas and arterio- and arterosclerosis of the OA and its branches. [source] Childhood cardiac function after twin-to-twin transfusion syndrome , a 10-year follow upACTA PAEDIATRICA, Issue 9 2009CP Halvorsen Abstract Aim:, To perform a 10-year follow up of cardiac structure and function after twin-to-twin transfusion syndrome (TTTS) , a severe foetal circulatory complication associated with myocardial hypertrophy in the recipient twin. Methods:, Cardiac dimensions, systolic and diastolic function as assessed by echocardiography including flow and tissue Doppler velocimetry in 22 healthy survivors of TTTS with a mean age of 9.6 (7.2,11.8) years. Results:, The donor and recipient twin did not show any differences in end-diastolic ventricular size, interventricular septum thickness, diameter of right ventricular outflow tract, cardiac valves, coronary arteries or in systolic blood flow velocities. However, compared with the donors, the recipients had significantly lower E/A ratios because of lower E-waves in both mitral (,0.15 ± 0.10, p < 0.01) and tricuspid (,0.09 ± 0.07, p < 0.01) valves, indicating reduced early diastolic ventricular fillings compared with donors. Conclusion:, At school age, twins surviving TTTS had a cardiac structure and function within normal range. There were no differences in heart structure or systolic ventricular function between twins but, compared with the donor twin, we found a reduced early diastolic function in the recipient. [source] Hyperoxia-induced arterial compliance decrease in healthy manCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 1 2005Pascal Rossi Summary Introduction:, Oxygen therapy is commonly used in emergency department and intensive care units without careful evaluation of its effects, especially on the haemodynamics and artery characteristics. Materials and methods:, A prospective laboratory study evaluated brachial circulatory effects of normobaric hyperoxia using ultrasonography-Doppler. The study was set in a hospital research laboratory. The subjects were thirteen healthy volunteers. Investigations were performed under normal air ventilation and after 20 min of hyperoxic mixture ventilation using a high concentration mask. Two dimensional images and brachial blood flow velocities were recorded using ultrasonography and pulsed Doppler to study changes in cross sectional area, blood flow, resistance index, and cross-sectional compliance coefficient. Results:, During hyperoxic exposure, mean PaO2 was 372 ± 21 mmHg. A significant decrease of heart rate was observed. Arterial pressures (systolic and diastolic arterial pressures) were not modified. A decrease of cross sectional areas at end diastole and end systole was observed. Pulsed Doppler study showed a decrease of brachial artery blood flow and an increase of the resistance index. Furthermore, a decrease of the cross-sectional compliance coefficient was observed during hyperoxic exposure in all subjects. Conclusion:, This study using two-dimensional ultrasonography and pulsed Doppler could demonstrate an increase in brachial arterial tone and a decrease in brachial blood flow under normobaric hyperoxia. [source] Transcranial Doppler Blood Flow Assessment in Patients With Mild Heart Failure: Correlates With Neuroimaging and Cognitive PerformanceCONGESTIVE HEART FAILURE, Issue 2 2008Raymond L. C. Vogels MD Cardiac output and cerebral perfusion are reduced in patients with advanced stages of heart failure. Our aim was to determine whether cerebral blood flow velocity measured by transcranial Doppler ultrasonography was reduced in outpatients with mild heart failure in comparison to controls and, if so, whether this reduction was related to cognitive performance and abnormalities of the brain diagnosed by magnetic resonance imaging. [source] Cerebral oxygenation decreases during exercise in humans with beta-adrenergic blockadeACTA PHYSIOLOGICA, Issue 3 2009T. Seifert Abstract Aim:, Beta-blockers reduce exercise capacity by attenuated increase in cardiac output, but it remains unknown whether performance also relates to attenuated cerebral oxygenation. Methods:, Acting as their own controls, eight healthy subjects performed a continuous incremental cycle test to exhaustion with or without administration of the non-selective beta-blocker propranolol. Changes in cerebral blood flow velocity were measured with transcranial Doppler ultrasound and those in cerebral oxygenation were evaluated using near-infrared spectroscopy and the calculated cerebral mitochondrial oxygen tension derived from arterial to internal jugular venous concentration differences. Results:, Arterial lactate and cardiac output increased to 15.3 ± 4.2 mm and 20.8 ± 1.5 L min,1 respectively (mean ± SD). Frontal lobe oxygenation remained unaffected but the calculated cerebral mitochondrial oxygen tension decreased by 29 ± 7 mmHg (P < 0.05). Propranolol reduced resting heart rate (58 ± 6 vs. 69 ± 8 beats min,1) and at exercise exhaustion, cardiac output (16.6 ± 3.6 L min,1) and arterial lactate (9.4 ± 3.7 mm) were attenuated with a reduction in exercise capacity from 239 ± 42 to 209 ± 31 W (all P < 0.05). Propranolol also attenuated the increase in cerebral blood flow velocity and frontal lobe oxygenation (P < 0.05) whereas the cerebral mitochondrial oxygen tension decreased to a similar degree as during control exercise (delta 28 ± 10 mmHg; P < 0.05). Conclusion:, Propranolol attenuated the increase in cardiac output of consequence for cerebral perfusion and oxygenation. We suggest that a decrease in cerebral oxygenation limits exercise capacity. [source] Twenty-four-hour non-invasive monitoring of systemic haemodynamics and cerebral blood flow velocity in healthy humansACTA PHYSIOLOGICA, Issue 1 2002M. DIAMANT ABSTRACT Acute short-term changes in blood pressure (BP) and cardiac output (CO) affect cerebral blood flow (CBF) in healthy subjects. As yet, however, we do not know how spontaneous fluctuations in BP and CO influence cerebral circulation throughout 24 h. We performed simultaneous monitoring of BP, systemic haemodynamic parameters and blood flow velocity in the middle cerebral artery (MCAV) in seven healthy subjects during a 24-h period. Finger BP was recorded continuously during 24 h by Portapres and bilateral MCAV was measured by transcranial Doppler (TCD) during the first 15 min of every hour. The subjects remained supine during TCD recordings and during the night, otherwise they were seated upright in bed. Stroke volume (SV), CO and total peripheral resistance (TPR) were determined by Modelflow analysis. The 15 min mean value of each parameter was assumed to represent the mean of the corresponding hour. There were no significant differences between right vs. left, nor between mean daytime vs. night time MCAV. Intrasubject comparison of the twenty-four 15-min MCAV recordings showed marked variations (P < 0.001). Within each single 15-min recording period, however, MCAV was stable whereas BP showed significant short-term variations (P < 0.01). A day,night difference in BP was only observed when daytime BP was evaluated from recordings in the seated position (P < 0.02), not in supine recordings. Throughout 24 h, MCAV was associated with SV and CO (P < 0.001), to a lesser extent with mean arterial pressure (MAP; P < 0.005), not with heart rate (HR) or TPR. These results indicate that in healthy subjects MCAV remains stable when measured under constant supine conditions but shows significant variations throughout 24 h because of activity. Moreover, changes in SV and CO, and to a lesser extent BP variations, affect MCAV throughout 24 h. [source] | |||||||||||||||||||||||||||||||