Vertebral Artery Blood Flow Research Articles

Characterization of the time course of the superior mesenteric, abdominal aorta, internal carotid and vertebral arteries blood flow response to the oral glucose challenge test using magnetic resonance imaging

Blood flow to the splanchnic circulation increases postprandially which may cause a reduction in systemic and cerebral perfusion leading to postprandial syncope in the elderly who lack adequate cardiovascular reserve. We used multi-station 2D phase contrast cine magnetic resonance imaging (PC-MRI) with the aim of characterizing the time course of the haemodynamic response to an oral glucose challenge test (OGCT) in the large arteries perfusing the splanchnic, systemic and cerebral circulations (superior mesenteric artery SMA, abdominal aorta AA, internal carotid arteries, ICA and vertebral arteries VA). In this study nine fasted healthy volunteers were studied. Separate cine PC-MRI scans were acquired in the neck and in the abdomen every 88 s, these two measurements being interleaved for ten baseline scans at each station with the scanner automatically moving the subject between the two stations. After ingestion of the OGCT, a further 30 cine PC-MRI scans were acquired at each station. Using this technique we were able to characterize with frequent sampling of volumetric blood flow the time course of blood flow response to the OGCT of the SMA, AA and both VA and ICA. We found a substantial variation between individuals in the amplitude and the time to the peak of the SMA blood flow response to the OGCT which correlated positively with body mass index. MRI provides a robust, non-invasive method of studying normal physiology that could be valuable in studies of diseases such as postprandial hypotension.

Atypical suboccipital vertebral artery blood flow in healthy subjects: Case studies using real-time ultrasound

Manual therapists and other professionals are using real-time ultrasound increasingly to visualize vessels and determine their diameter and blood flow. Four case studies are presented to show atypical ultrasound profiles of the suboccipital vertebral artery (VA3) in healthy, young individuals. VA3 diameters and blood flow velocities were measured with the subjects sitting, and the cervical spine in the neutral position then with active, full-range rotation to the left and right. None of the subjects reported any signs or symptoms of vertebrobasilar ischemia (VBI) during the measurement procedure, despite an absence of typical VA3 ultrasound profiles on one side in two of the individuals and a decreased unilateral VA3 blood flow in the other two subjects. Possible reasons for the atypical findings are proposed. Anatomical variations of VA3 and conditions such as obesity may give rise to atypical real-time ultrasound measurements of VA3 blood flow, particularly when associated with cervical spine rotation. The possibility of altered VA3 blood flow because of such factors, which may give rise to false-positive or false-negative findings in the standard VBI test, should be considered by manual therapists in pretreatment assessments and treatment programs in professional practice.

Vertebral Artery Blood flow Velocity Changes Associated with Cervical Spine rotation: A Meta-Analysis of the Evidence with implications for Professional Practice

Many studies of vertebral artery (VA) blood flow changes related to cervical spine rotation have been published, but the findings are controversial and the evidence unconvincing. Recent Doppler measurements suggest that contralateral VA blood flow is compromised on full rotation in both healthy subjects and patients. More rigorous research is needed, and it was the aim of this study to conduct a meta-analysis of published data to inform professional practice. A systematic literature search, including only Doppler studies of VA blood flow velocity associated with cervical spine rotation in adults, yielded nine reports with published data. Using weighted means of the pooled data, the magnitude of the effect size (Cohen's d) was calculated for differences between patients and subjects, sitting or lying supine for testing, the parts of the VA insonated, and the changes recorded after cervical spine rotation. From this meta-analysis, VA blood flow velocity was found to be compromised more in patients than healthy individuals, on contralateral rotation, with the subject sitting, and more in the intracranial compared to the cervical part of the VA. Possible reasons for these findings are suggested, and it is advised that sustained end-of-range rotation and quick-thrust rotational manipulations be avoided until there is a stronger evidence base for clinical practice.

Cerebral hemodynamics in vertebrobasilar pathology, as for the issue of vertebrobasilar insufficiency

A study of the functional state of cerebral hemodynamics (blood flow velocity and hemodynamic reserve in the basilar artery) using transcranial Doppler with nitroglycerine test has been carried out in 18 patients with ischemic stroke in vertebrobasilar circulation and 20 patients with and/or symptoms suggestive of posterior circulation disease. Significant decrease of the parameters of cerebral hemodynamic reserve was shown in patients with a history of ischemic stroke and also in patients with atherosclerotic obstructive lesions of the vertebral arteries. On the other hand in patients with the anomalies of the vertebral arteries (kinking, hypoplasia) blood flow in vertebrobasilar circulation was normal. Therefore these patients need not of the surgical preventive treatment

Wisconsin awards $600,000 for ethanol research

The purpose of this study was to determine the within-session and between-sessions reliability of measuring the vertebral artery blood flow velocities in people with cervicogenic dizziness using Doppler ultrasound at both upper and lower cervical levels.Outcome measures were taken on 2 occasions 3 weeks apart with no active treatment provided in between the assessments on 12 participants. Pulsed-wave Doppler ultrasound was used to quantify time-averaged mean velocities through the vertebral artery at upper cervical (C0-1) and lower cervical vertebrae (C5-6). The clinical outcome measures were also recorded in people with cervicogenic dizziness. The intraclass correlation coefficient (ICC) was used to determine the within-session and between-session repeatability. Paired t test was used to determine the differences in the time-averaged mean velocities of blood flow at the same site of the vertebral artery and the clinical outcome measures in 2 sessions 3 weeks apart.In people with cervicogenic dizziness, there was no significant change in both clinical outcome measures and the time-averaged mean velocities when the patients were measured 3 weeks apart (P > .05). This study identified good within-session (ICC: 0.903-0.967) and between-session (ICC: 0.922-0.984) repeatability in measuring the vertical blood flow velocities in patients with cervicogenic dizziness when the clinical outcome measures were unchanged.This study supports the use of Doppler ultrasound to identify changes in mean vertebral arterial blood flow velocities before and after intervention in people with cervicogenic dizziness in future studies.

Forty-six Cases of Vertebrobasilar Insufficiency Treated by Acupuncture plus Intravenous Infusion of Ligustrazine

To observe the therapeutic effect of acupuncture plus Ligustrazine on vertebrobasilar insufficiency (VBI) by transcranial Doppler (TCD) sonography. 86 VBI patients including 56 cases of low flow rate velocity type (LFVT) and 30 cases of high flow velocity type (HFVT) were randomly divided into Ligustrazine group (26 LFRT and 14 HFVT) and acupuncture plus Ligustrazine group (30 LFVT and 16 HFVT). The blood flow velocity (BFV) of vertebral artery (VA) and basilar artery (BA) in systole before and after treatment was measured with TCD and therapeutic effects were evaluated after 10 days' treatment in the two groups. In the acupuncture plus Ligustrazine group, the total effective rate was 93.3% and 88.5% in cases of LFVT and HFVT respectively, and BFV of VA and BA increased in LFVT patients while that in HFVT patients decreased significantly (P<0.05 or P<0.01). Owing to its dual regulation on blood flow of VA and BA, the therapeutic effect of acupuncture plus Ligustrazine was better than that of simple Ligustrazine.

Validity of the Doppler velocimeter in examination of vertebral artery blood flow and its use in pre-manipulative screening of the neck

Pre-existing compromise of one or both vertebral arteries is considered a contraindication to neck manipulation. Current pre-manipulative screening tests may not adequately identify individuals with such compromise. It has been proposed that using a continuous wave ultrasound device (Doppler velocimeter) may assist in identifying patients presenting with flow abnormalities. The aim of this study was to determine the validity and reliability of the use of a velocimeter in detecting altered vertebral artery blood flow. Blood flow in the atlanto-axial segment of seated healthy adult volunteers ( n = 60) was examined in the neutral and end-range contralateral rotation positions. Duplex ultrasound scans were performed ( n = 58) and identified 17 volunteers (29.3%) with abnormal flow according to pre-determined criteria. Three trained physiotherapists blinded to the duplex examination results used a velocimeter to examine the vertebral arteries of the volunteers. The specificity of the velocimeter examination to detect abnormal flow identified by the duplex examination was fair to good (range 0.78–0.88). However, its sensitivity was poor (range 0.25–0.38) and the inter-examiner reliability was poor ( κ ranged from 0.15 to 0.26). This study suggests that the velocimeter may be neither a valid or reliable tool for the detection of abnormal blood flow in the vertebral arteries.

Aortic Pseudoaneurysm Caused by Migration of a Swallowed Sewing Needle

A white 64-year-old woman who made dresses for her livelihood was admitted to the emergency department for evaluation of acute chest pain and respiratory distress. Physical examination was unremarkable except for low arterial blood pressure (90 mm Hg systolic, 65 mm Hg diastolic), whereas ECG showed left atrial enlargement, possible previous septal myocardial infarction, negative T waves in the inferior leads, and no evidence of acute ischemia (Figure 1). Myocardial enzyme levels, including Troponin I, were within normal values after serial determination. Figure 1. ECG shows sinusal rhythm with 98 bpm, left atrial enlargement, possible previous septal myocardial infarction, and negative T waves in inferior leads. Chest x-ray was performed and showed a thin radiopaque foreign body at the 5° body of the thoracic vertebra level, near the trachea (Figure 2). When questioned specifically, the patient mentioned the possible accidental ingestion of …

Real‐time ultrasound measurements of changes in suboccipital vertebral artery diameter and blood flow velocity associated with cervical spine rotation

The vulnerability of the vertebral artery (VA) to distortion with sustained, full-range cervical spine rotation, resulting in compromised blood flow and possible vertebrobasilar ischaemia, is well recognized. However, few studies have measured such blood flow changes in the parts of the VA downstream from the region of maximum cervical spine rotation: the suboccipital (VA3) and intracranial vertebral arteries. The purpose of this experimental study was to visualize the VA3 and record the changes in its blood flow associated with cervical spine rotation. VA3 diameters and blood flow velocities were measured in the neutral cervical spine position and with active full-range rotation to the left and right, in 35 healthy female subjects, using colour-coded real-time ultrasound. Both left and right VA3 diameters and blood flow velocities decreased significantly on ipsilateral rotation. These values increased non-significantly in the left VA3 and decreased non-significantly in the right VA3 on contralateral rotation. The results of this study suggest that the distortion or compression of VA3 demonstrated by the reduction in diameter on ipsilateral cervical spine rotation, particularly, was sufficient to result in compromised blood flow. A significant stretching effect of VA3, on contralateral rotation, was not demonstrated in these subjects. Nevertheless, these findings add evidence to support the recommendation that sustained, full-range cervical spine rotation should be avoided in professional practice.

Analiza kliniczna chorych z zawrotami głowy pochodzenia szyjnego w materiale własnym

The aim of this work was a clinical analysis of patients suffering from vertigoes of neck origin, conducted within the own study. The study covered a group of 120 patients, including 76 females and 44 males, aged 20-85, who were diagnosed and treated due to vertigoes of neck origin in the Clinic of Otolaryngology and Laryngological Oncology the Medical University of Łódź between 2005-2006. Criteria for all the patients treated for vertigoes of neck origin include: an interview, subject otolaryngological treatment, complete audiological tests, laboratory tests, computerized tomography of the head or classical and functional x-ray of the cervical spine, blood flow in vertebral arteries and the basilar artery due to the Doppler method (using Transport-TCD apparatus, 2 Mhz head through the great foramen and using the torsion of the neck test). The electronystagmographic examination (ENG) covered registration of: position nystagmus detected in five classical positions according to Nylen, neck nystagmus in the torsion of the neck test. All the patients suffering form vertigoes of neck origin were treated with physical therapy and kinesitherapeutic exercises. The major part of the studied material of the patients with vertigoes of neck origin constituted: office workers (56.76%), aged 41-60 (59.16%), smoking (50.83%), suffering from hypercholesterolemia (35.29%), with abnormal x-ray of the cervical spine (93.37%) and injuries in this segment (13.33%), using non-steroid anti-inflammatory (69.17%) and vascular (52.59%) drugs, thus not young people with some additional pathological history. On the grounds of the obtained results it is claimed that the registration of the neck nystagmus in the torsion of the neck test as well as the position nystagmus examination according to Rose were most useful in this study, which facilitated reliable diagnostics of the vertigoes of the neck origin and monitoring of their intensity after applied treatment.

Evaluation of the Effects of Sildenafil Citrate (Viagra) on Vertebral Artery Blood Flow in Patients with Vertebro-Basilar Insufficiency

ObjectiveTo investigate the effects of sildenafil citrate (Viagra) on the vertebral artery blood flow of patients with vertebro-basilar insufficiency (VBI) using color duplex sonography (CDS).Materials and MethodsThe study included 21 patients with VBI (aged 31-76; mean 61.0 ± 10.5 yrs). We administered a 50 mg oral dose of sildenafil citrate to all patients. Next, we measured the peak systolic velocity (Vmax), end diastolic velocity (Vmin), resistive index (RI), pulsatility index (PI), diameter, area, and flow volume (FV) of vertebral arteries using CDS before the administration of sildenafil citrate; 45 minutes after, and 75 minutes after administration. Statistical testing was performed using SPSS for windows version 11.0. The statistical test used to determine the outcome of the analysis was the repeated measures analysis of variance (ANOVA) test.ResultsCompared to the baseline values, the vertebral artery diameter, area, and FV increased significantly following the administration of sildenafil citrate. The diameter, area and FV increased from 3.39 mm at 45 minutes to 3.64 mm at 75 minutes, 9.43 cm2 to 10.80 cm2 at 45 minutes and 10.81 cm2 at 75 minutes, as well as from 0.07 L/min at baseline to 0.09 L/min at 45 minutes and unchanged at 75 minutes, respectively.ConclusionSildenafil citrate elicited a significant effect on vertebral artery diameter, area and FVs.

Doppler insonation of vertebral artery blood flow changes associated with cervical spine rotation: Implications for manual therapists

The controversy related to changes in vertebral artery (VA) blood flow associated with rotation of the cervical spine and the implications for professional practice is still of concern to manual therapists. The aim of this review of the literature is, first, to assess current evidence of altered VA blood flow following cervical spine rotation in persons with and without signs and symptoms of vertebrobasilar ischemia/insufficiency (VBI). Second, any reported, related alterations in blood flow that may have consequences for the individual will be discussed to assist manual therapists in pretreatment risk assessment of patients. The most commonly used noninvasive, in vivo technique for measuring blood flow is Doppler ultrasonography. Of the 88 relevant papers retrieved by a systematic literature search covering the past 50 years, 20 studies reported measurement of VA blood flow related to cervical spine rotation. A critical analysis of these reports revealed that there is no standardization of methods used (heterogeneous samples, small sample sizes, various measurement positions and instruments, and different parts of the VA measured); no consensus of findings (no change, and a significant reduction in contralateral VA blood flow, with or without VBI); and no correlations found between rotation, blood flow, and VBI. Nevertheless, this review is of value in increasing our knowledge of the possible mechanisms and consequences of repeated minor arterial trauma and of blood flow changes related to rotational movements used in cervical manual therapy. It highlights, too, the need for caution in the interpretation of pretreatment risk assessment outcome measures.

Cerebral blood stream status observation of cervical dizziness treatmen with traction and heating acupuncture

目的 探讨牵引配合温针治疗颈性眩晕对脑血流状态的改善作用.方法 对53例颈性眩晕患者在牵引配合温针治疗20次前后的经颅多普勒(TCD)检测结果进行对比分析.结果 治疗后与治疗前比较,除左侧大脑前动脉外,双侧大脑中、大脑后及右侧大脑前动脉平均血流速度均显著降低(P＜0.01);双侧椎动脉均较治疗前的平均血流速度有明显提高(P＜0.01).结论 牵引配合温针治疗可双向调整颅内动脉异常的血流速度,从而达到改善和治疗颈性眩晕之目的 。

Doppler sonography evaluation of flow velocity and volume of the extracranial internal carotid and vertebral arteries in healthy adults

To measure with Doppler sonography the velocity and volume of blood flow in the extracranial internal carotid artery (ICA) and vertebral artery (VA) of healthy adults and to calculate total cerebral blood flow volume (tCBFV). Bilateral ICA and VA were examined sonographically in 180 healthy adults. Angle-corrected peak systolic (Vps), end-diastolic (Ved), and time-averaged maximum blood flow velocity (TAV) were measured in pulsed Doppler mode, and the resistance index (RI) and pulsatility index (PI) were calculated. The cross-sectional area (A) was measured on gray-scale images. Volume flow was calculated as FV = TAV x A, and tCBFV was calculated as the sum of the right and left ICA and VA volume flow. tCBFV was 651 +/- 96 ml/min for the entire population. There was a significant decrease in Vps, Ved, TAV, and tCBFV with age in all arteries. RI and PI values initially declined and then increased with age. Cross-sectional area increased with age in ICA but not in VA. PI and RI were higher in men than in women. Blood flow velocity and volume were higher, and RI was lower in the left than in the right VA. The Doppler sonographic assessment of extracranial ICA and VA blood flow volume may be useful for the study of cerebral hemodynamic changes in patients with cerebrovascular disorders. Age-dependent changes should be considered, for instance, in the management of intensive care patients with impaired cerebral perfusion.

Cerebral vasomotor reactivity in Parkinson's disease, multiple system atrophy and pure autonomic failure

Parkinson's disease (PD), multiple system atrophy (MSA) and pure autonomic failure (PAF) are neurodegenerative disorders frequently associated with orthostatic hypotension and syncope, though with different underlying mechanisms. Cerebral hemodynamic responses in these three neurodegenerative diseases are still incompletely studied and it is possible that they would be differentially affected. We measured blood flow velocity (BFV) in the middle cerebral artery (MCA) and vertebral artery (VA) in patients with these disorders and investigated whether cerebral vasomotor reactivity (VMR) differs in these three disorders. Twenty-four patients (9 with PD, 10 with MSA and 5 with PAF) were studied. VMR was assessed in the MCA and VA, using transcranial Doppler (TCD) and Diamox test (injection of 1 g acetazolamide i.v.) with the patients in a recumbent position. The percent difference between BFV before and after acetazolamide injection was defined as VMR% and the results were compared by ANOVA. The mean MCA and VA blood flow velocities were similar in the three disorders and within normal limits for our laboratory. The mean MCA VMR values were 37.5 ± 24.0%, 27.9 ± 28.0% and 38.0 ± 33.9% in PD, MSA and PAF, respectively. The VA VMR values were 22.9 ± 23.6%, 32.4 ± 38.0% and 18.9 ± 18.3%, respectively, with no significant differences between the groups. We conclude that BFV is normal in PD, MSA and PAF and that the VMR, as investigated by TCD and the Diamox test, did not disclose differences in cerebral vasomotor responses between these conditions.

Rotational vertebral artery occlusion

Rotational vertebral artery occlusion (RVAO), also known as bow hunter’s syndrome, is rare but clinically important: it carries a risk of impending stroke but can be treated by surgical decompression. Most patients who experience RVAO exhibit a stenosis or vessel malformation (e.g., hypoplasia or termination in the posterior inferior cerebellar artery) of the vertebral artery on the same side as the precipitating horizontal head rotation. This movement compresses the dominant vertebral artery (opposite to the head rotation) and thus interrupts the major blood supply to the vertebrobasilar artery territory. A rotational contralateral vertebral artery occlusion was originally considered physiologic after Toole and Tucker1 found compromised blood flow in vertebral arteries due to head rotation in hemodynamic studies of cadavers. However, this was not supported by vertebral angiography of 39 patients in both the neutral head position and …

EVALUATION OF CEREBRAL BLOOD FLOW VOLUME USING COLOR DUPLEX SONOGRAPHY IN PATIENTS WITH POLYCYSTIC OVARY SYNDROME

Aim: Polycystic ovary syndrome (PCOS), one of the commonest endocrinopathies in the human, is known to be associated with risk factors for cerebrovascular disease. The aim of this study was to determine whether there was a change in cerebral blood flow volume in PCOS. Methods: We reported 30 women with PCOS and 20 healthy women as control group. We detected internal carotid (ICA), vertebral artery (VA) and cerebral blood flow (CBF) volumes using color duplex sonography. Results: There were no significant differences between patients with PCOS and control group in CBF volumes or the bilateral sum of flow volumes in the ICA and VA. There was also no statistically significant correlation between sum of bilateral VA, ICA and CBFV with age in both groups. However bilateral mean velocity of VA was significantly lower in patients with PCOS compared to control group. Conclusion: It seems that although endocrine and metabolic abnormalities occur in patients with PCOS there are no abnormality of CBF volume in young patients. However, a further study with a wider age range is required.

Doppler Sonographic Evaluation of Cerebral Blood Flow in Anemia Resulting From Chronic Renal Failure

This study was undertaken to describe Doppler sonographic measurement of cerebral blood flow in anemia secondary to chronic renal failure and to compare the results with data gathered from healthy control subjects. We also aimed to compare vertebral and internal carotid artery blood flows to see whether any alteration of dominance in cerebral blood supply would occur. We studied 27 predialytic patients with chronic anemia resulting from chronic renal failure and 20 healthy control subjects by means of extracranial Doppler sonography. In these patients, blood flows of bilateral internal carotid and vertebral arteries were measured, and net vertebral artery, net internal carotid artery, and total cerebral blood flows were estimated. Statistical significance was observed between groups, and the data were correlated with hemoglobin level. Variation of the difference of the Doppler measurements between case and control groups by side (left or right) or disease status (patient or control subject) was analyzed. From the assessed Doppler parameters, only cerebral blood flow and right and net vertebral artery blood flows had a significant difference between groups (P < .05) and showed a negative correlation with hemoglobin level. Vertebral artery blood flow was found to have significant interactions with disease status (P = .009) and side (P = .054). Right vertebral artery blood flow is most prone to increase in chronic anemia of chronic renal failure. This effect also appears as increasing net vertebral artery blood flow and cerebral blood flow.

Hemodynamic influence of arteria vertebralis type cervical spondylosis treated by needling Yuzhen (BL 9) and Fengchi (GB 20)

To observe the curative effect and the hemodynamic change of cervical vertigo treated by acupuncture, 66 patients were randomly divided into two groups: group A in which acupoints Yuzhen (BL 9) and Fengchi (GB 20) were used and Group B in which Cervical Jiaji points (C4–6) were used. Before and after treatment, the symptom of the cervical vertigo and the grade variety of function and the change of Color Doppler Flow Imaging (CDFI) of vertebral artery were observed. After treatment, the grade in two groups increased, there was a remarkable difference between two groups (P<0.05); after treatment, the grade of vertigo degree increased, there was a remarkable difference between two groups (P<0.05); needling Yuzhen (BL 9) and Fengchi (GB 20) can remarkably improve the symptom of cervical vertigo and vertebral artery blood flow rate, and the curative effect was superior to needling Jiaji points.

The vertebral artery: a review of anatomical, histopathological and functional factors influencing blood flow to the hindbrain

An uncompromised blood flow to the brain is essential for normal neurological function. If the blood supply to the hindbrain, via the paired vertebral arteries, is reduced sufficiently, signs and symptoms of vertebrobasilar ischaemia may result. There are several factors that may cause a reduction in vertebral artery blood flow. These include exostoses, such as the retroarticular canal and lateral bridge of the atlas vertebra that may cause compression of the related part of the vertebral artery; or atherosclerosis of the artery wall occluding the vessel lumen. Functional factors, such as sustained end-of-range rotation of the cervical spine, may cause distortion of the vertebral artery in the suboccipital region, which may be reflected as decreased blood flow in the suboccipital and intracranial parts of the artery. A combination of such factors is likely to cause reduced blood flow to the hindbrain. It is the purpose of this review to highlight some of the factors that may compromise vertebral artery blood flow and, therefore, to provide some evidence on which to base our professional practice.