Basilar Artery Diameters Research Articles

Anatomical study of variations in the configurations of the circle of Willis in relation to age, sex, and diameters of the components.

The circle of Willis (COW) refers to the anastomotic arterial network found on the brain base, tasked with provision of collateral circulation aimed at prevention of ischemia. The COW is of immense clinical importance especially with regard to the assessment of neurovascular diseases. Individuals portray significant variations in the COW's anatomical configuration. The present study seeks to evaluate the existing anatomical variations of the COW and within the anterior and posterior segments of the COW. Thus, the study seeks to evaluate the different anatomical variations of the COW and its segments and components within the study population. To attain the set objectives, the present study has utilized the angiographic images for studying the COW variants in patients who underwent cerebral angiography during assessment of different types of cerebral anomalies and conditions. Therefore, this study used conventional angiography as an important tool in the evaluation of the different variations in the COW, and is most appropriate for evaluation of smaller anatomical variations owing to its perfect spatial resolution and portrayal of COW anatomy. The study findings indicated the existence between age and sex, and anatomical variations of the COW, particularly with regard to diameters of COW components like basilar artery (BA), P1, and internal carotid arterys (ICAs). Males had bigger BA, P1 and ICA diameters than females, while individuals aged below 40 years had bigger BA, A1, posterior communicating artery, and ICA diameters than those aged above 40 years.

Brain artery diameters and risk of dementia and stroke.

We tested the association of brain artery diameters with dementia and stroke risk in three distinct population-based studies using conventional T2-weighted brain magnetic resonance imaging (MRI) images. We included 8420 adults> 40 years old from three longitudinal population-based studies with brain MRI scans. We estimated and meta-analyzed the hazard ratios (HRs) of the brain and carotids and basilar diameters associated with dementia and stroke. Overall and carotid artery diameters>95th percentile increased the risk for dementia by 1.74 (95% confidence interval [CI], 1.13-2.68) and 1.48 (95% CI, 1.12-1.96) fold, respectively. For stroke, meta-analyses yielded HRs of 1.59 (95% CI, 1.04-2.42) for overall arteries and 2.11 (95% CI, 1.45-3.08) for basilar artery diameters> 95th percentile. Individuals with dilated brain arteries are at higher risk for dementia and stroke, across distinct populations. Our findings underline the potential value of T2-weighted brain MRI-based brain diameter assessment in estimating the risk of dementia and stroke.

Abstract TMP67: Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy May Affect Large Cerebral Arteries

Introduction: CADASIL is the most common monogenic small-vessel disease (SVD) form. Large and small brain arteries are intimately related, but it is unclear whether people with CADASIL have changes in their large arteries as a result. We hypothesized that CADASIL patients have affected large arteries compared to controls. Methods: We conducted a comparative analysis by matching 37 CADASIL patients with 104 lacunar stroke patients from the NYP/ Columbia University Medical Center Stroke Registry Study matched by age +/-3 and sex. We measured the basilar and intracranial carotid artery diameters in both groups in T2 MRI images. We rated cervical artery tortuosity as 0 for no tortuosity, 1 for 45-90°, and 2 for >90°. We ran generalized linear models to compare cases and controls, adjusting for demographics and clinical variables. Results: Patients with CADASIL were less likely Hispanic\Latino (10.8% vs. 51.9%, p=<0.001), hypertensive (27% vs. 73.1%, p=<0.001), current smokers (5.4%vs. 22.1%, p=0.024), but more likely to have a prior stroke (56.8% vs. 24%, p=<0.001) than controls—Table 1. In the adjusted model, patients with CADASIL had larger basilar artery diameters (p=0.007) and a statistical trend for greater cervical carotid artery tortuosity—Table 2. Conclusions: Although traditionally considered an example of pure SVD, patients with CADASIL have a higher prevalence of cervical tortuosity and intracranial artery dilatation. Whether changes in large arteries result from small artery disease or part of the NOTCH3 mutation phenotype is uncertain. Further investigation is needed to determine if large artery involvement influences the clinical manifestations of CADASIL.

Prevalence of basilar artery dolichoectasia in patients with acute ischemic stroke or transient ischemic attack in a single center of Spain.

Basilar artery dolichoectasia (BADE) refers to abnormal enlargement or displacement of the basilar artery (BA). The previously reported prevalence of BADE among patients with stroke is 0.3 to 33.1%, however, it might vary among studied populations. We aim is to determine the prevalence of BADE in patients presenting with acute ischemic stroke (AIS) or transient ischemic attack (TIA) in a Stroke Unit in a single center in Spain. Patients 50 years old or older presenting with AIS or TIA were eligible for inclusion. Demographic and clinical data were prospectively collected. Two neuroradiologists, blind to each other, assessed BA morphology. Among 126 patients, 34.1% fulfilled the criteria for BADE (ectasia or dolichosis). BADE was associated with advanced age (p = 0.04). Patients with fetal-type circle of Willis presented smaller BA diameters (2.9 ± 0.1 vs. 3.5 ± 0.1; p < 0.001), whereas patients with lacunar strokes presented a greater diameter than other stroke subtypes (3.8 ± 0.3 mm vs. 3.3 ± 0.1 mm; p = 0.04). In this single-center study of patients presenting with AIS or TIA, the prevalence of BADE (ectasia or dolichosis) is high. Further studies focusing on Spaniards should confirm our results.

Association between vertebral artery dominance and basilar artery curvature in migraineurs: an anatomical magnetic resonance imaging study.

Numerous studies demonstrate a link between cerebrovascular alterations and migraine pathogenesis. We investigated the association between migraine and vertebral artery dominance (VAD), basilar artery (BA) curvature, and elongation. This cross-sectional MRI study included 74 migraine patients and 74 control subjects aged between 18 and 55 years. Diameters of the intracranial part of the vertebral artery (VA) and BA, height of the BA bifurcation, and total lateral displacement of the BA were measured. In addition, we investigated the directional relationship between VAD and BA curvature. There were no statistically significant differences between the groups regarding VA and BA diameters and total lateral displacement of the BA. The height of the BA bifurcation was found to be significantly higher in migraine patients compared to controls (p = 0.002). The left-side VAD was more frequent in migraine patients compared to control subjects (60.8% (45/74) vs 41.9% (31/74), p = 0.001). In migraine patients, particularly those with aura (MwA) patients, with left-side VAD, the rate of BA displacement to the right side is significantly higher than those with right-side VAD or non-VAD (p = 0.022). Also, we found that total lateral displacement of the BA is correlated with VA asymmetry in patients with MwA (r = 0.538, p = 0.007). VAD and its opposite-directional relationship with the lateral displacement of the BA may be associated with migraine pathophysiology. Together with aging, this association may contribute to changes in the vertebrobasilar system (VBS) geometry which may result in increased risk for posterior circulation infarction (PCI) in migraineurs.

Association of brain arterial diameters with demographic and anatomical factors in a multi-national pooled analysis of cohort studies.

Brain arterial diameters are markers of cerebrovascular disease. Demographic and anatomical factors may influence arterial diameters. We hypothesize that age, sex, height, total cranial volume (TCV), and persistent fetal posterior cerebral artery (fPCA) correlate with brain arterial diameters across populations. Participants had a time-of-flight MRA from nine international cohorts. Arterial diameters of the cavernous internal carotid arteries (ICA), middle cerebral arteries (MCA), and basilar artery (BA) were measured using LAVA software. Regression models assessed the association between exposures and brain arterial diameters. We included 6,518 participants (mean age: 70 ± 9 years; 41% men). Unilateral fPCA was present in 13.2% and bilateral in 3.2%. Larger ICA, MCA, and BA diameters correlated with older age (Weighted average [WA] per 10years: 0.18mm, 0.11mm, and 0.12mm), male sex (WA: 0.24mm, 0.13mm, and 0.21mm), and TCV (WA: for one TCV standard deviation: 0.24mm, 0.29mm, and 0.18mm). Unilateral and bilateral fPCAs showed a positive correlation with ICA diameters (WA: 0.39mm and 0.73mm) and negative correlation with BA diameters (WA: -0.88mm and -1.73mm). Regression models including age, sex, TCV, and fPCA explained on average 15%, 13%, and 25% of the ICA, MCA, and BA diameter interindividual variation, respectively. Using height instead of TCV as a surrogate of head size decreased the R-squared by 3% on average. Brain arterial diameters correlated with age, sex, TCV, and fPCA. These factors should be considered when defining abnormal diameter cutoffs across populations.

Basilar artery diameter as neuroimaging biomarker in Chinese Fabry disease patients

BackgroundFabry disease (FD) is an X-linked lysosomal storage disease resulting from mutations of α-galactosidase A gene, and has been emphasized as one of the etiologies of young stroke and leukoencephalopathy. Vertebrobasilar dolichoectasia (VBD) is a highlighted finding in FD. We aim to examine the utility of VBD in Chinese FD by comparing the differences in basilar artery (BA) diameter of Chinese FD patients against age-matched controls with and without stroke.MethodsThis was a matched case-control study involving 37 Chinese FD patients. The BA diameters were evaluated on axial T2-weighted magnetic resonance imaging and compared to two age-and-gender matched control groups, one with stroke and one without. The association between BA diameter and stroke occurrences and white matter hyperintensities (WMH) were analyzed among all FD patients.ResultsPatients with FD had significantly increased BA diameter compared to controls with and without stroke (p < 0.001). A BA diameter of 4.16 mm could distinguish FD from controls in the stroke subgroup (ROC AUC 0.870, p = 0.001, sensitivity 80% specificity 100%), and with a cut-off of 3.21 mm in the non-stroke subgroup (ROC AUC 0.846, p < 0.001, sensitivity 77.8% specificity 88.9%). Larger BA diameter had more stroke occurrences and was moderately associated with heavier WMH load in terms of higher total FAZEKAS scores. (Spearman’s rho = 0.423, p = 0.011).ConclusionVBD was also present in Chinese FD patients. BA diameter has high diagnostic utility in identifying FD from a mixed cohort of stroke and normal controls, and carried predictive value in evaluating neurological complications of FD.

Association of Brain Arterial Elongation With Risk of Stroke and Death in Stroke-Free Individuals: Results From NOMAS.

Brain arterial dilation and elongation characterize dolichoectasia, an arteriopathy associated with risk of stroke and death. We aim to determine whether brain arterial elongation increases the risk of stroke and death independent of brain arterial diameters. We analyzed 1210 stroke-free participants (mean age 71±9 years, 41% men, 65% Hispanic) with available time-of-flight magnetic resonance angiogram from the Northern Manhattan Study, a population-based cohort study across a multiethnic urban community. We obtained baseline middle cerebral artery M1-segment (MCA-M1) and basilar artery (BA) mean lengths and diameters using a semi-automated software. Cox proportional hazards models adjusted for brain arterial diameters and potential confounders yielded adjusted hazards ratios with 95% CIs for the primary outcomes of incident stroke and all-cause mortality, as well as secondary outcomes including noncardioembolic stroke, vascular death, and any vascular event. Neither MCA-M1 nor BA lengths correlated with incident stroke or all-cause mortality. Both MCA-M1 and BA larger diameters correlated with all-cause mortality (MCA-M1 aHR, 1.52 [95% CI, 1.03-2.23], BA aHR, 1.28 [95% CI, 1.02-1.61]), as well as larger MCA-M1 diameters with vascular death (aHR, 1.84 [95% CI, 1.02-3.31]). Larger MCA-M1 and BA diameters did not correlate with incident stroke. However, larger BA diameters were associated with posterior circulation noncardioembolic stroke (aHR, 2.93 [95% CI, 1.07-8.04]). There were no statistical interactions between brain arterial lengths and diameters in relation to study outcomes. In a multiethnic cohort of stroke-free adults, brain arterial elongation did not correlate with risk of stroke or death, nor influenced the significant association between brain arterial dilation and vascular risk.

Abstract TMP64: Association Of Brain Arterial Diameters With Demographic And Anatomical Factors In A Multi-national Pooled Analysis Of Cohort Studies

Objectives: Brain arterial dilation is an increasingly recognized cerebrovascular disease marker. However, demographic and anatomical factors may influence brain arterial diameters within the normal spectrum. We hypothesize that age, sex, height, total cranial volume (TCV) and fetal posterior cerebral arteries (fPCA) presence correlate with brain arterial diameters across diverse populations. Methods: We included participants with available time-of-flight MRA from 9 cohort studies across the United States (4), Ecuador (1), Venezuela (1), South Africa (1) and Singapore (2). Arterial diameters of the basilar artery (BA), cavernous internal carotid arteries (ICAs) and middle cerebral arteries (MCAs) were measured using LKEB Automated Vessel Analysis (LAVA) software. Linear regression models were fitted to assess the association between brain arterial diameters and exposures. The R-squared was calculated to assess the extent of brain arterial diameter variation explained by the variables studied. Results: The sample included 6,269 participants (mean age 68 years; 42% men). Unilateral fPCA was found in 12.6% and bilateral fPCAs in 3.0%. Older age, male sex and TCV were uniformly correlated with larger BA, ICA and MCA diameters (Table). Unilateral and bilateral fPCAs showed a negative correlation with BA diameter and a positive correlation with ICA diameters in a dose-dependent manner. Models fitted for age, sex, TCV, and fPCA presence explained on average 24, 16 and 12 % of the BA, ICAs and MCA diameter interindividual variation, respectively. Using height instead of TCV decreased the R-squared by 2% on average. Conclusions: In this pooled analysis of cohort studies, we found brain arterial diameters consistently correlate with age, sex, TCV and fPCA presence. These factors should be considered to define abnormal arterial diameter cut-offs across populations. If resources are limited or if bedside applicability is desired, height could be used instead of TCV.

Studying the imaging features and infarction mechanism of vertebrobasilar dolichoectasia with high-resolution magnetic resonance imaging.

The mechanisms underlying ischemic infarction in patients with vertebrobasilar dolichoectasia (VBD) remain unclear. In this study, we retrospectively analyzed the imaging characteristics of high-resolution magnetic resonance imaging (HR-MRI) in patients with VBD to explore the possible mechanisms of ischemic stroke (IS) in patients with VBD. Patients with VBD were recruited from the HR-MRI database between July 2017 and June 2021. HR-MRI was used to evaluate the diameter, bifurcation height, laterality, arterial dissection, and atherosclerotic plaques of the basilar artery (BA). Transcranial Doppler was used to measure the vertebrobasilar mean velocity (Vm), peak systolic velocity (Vs), end-diastolic velocity (Vd), and pulsatile index. Twenty-six patients with VBD were enrolled, of which 15 had IS and 11 did not. The incidence of classical vascular risk factors, including age, sex, hypertension, diabetes, and hypercholesterolemia, did not differ significantly between the two groups. The BA diameters of the stroke group were significantly higher than that of the nonstroke group (6.57 ± 1.00 mm vs. 5.06 ± 0.50 mm, p=0.000). The height of the BA bifurcation in the stroke and nonstroke groups was statistically significant (p=0.002). Compared with the nonstroke group, the Vm, Vs, and Vd of the BA in the stroke group were lower, but the difference was not significant. In the 16 patients with atherosclerotic stenosis, 30 atherosclerotic plaques were found in the BA, 18 (60%) in the greater curvature, and 12 (40%) in the lesser curvature. In addition, one artery dissection (on the lesser curvature) and two dissecting aneurysms (on the greater curvature) were found in the BA of three patients, respectively. The BA diameter and bifurcation height are factors related to IS in patients with VBD. The mechanism of stroke in patients with VBD may involve abnormal hemodynamics, artery dissection, and atherosclerosis. HR-MRI is a useful method for evaluating the risk and underlying mechanism of stroke in patients with VBD.

Aerobic exercise increases brain vessel lumen size and blood flow in young adults with elevated blood pressure. Secondary analysis of the TEPHRA randomized clinical trial

ImportanceCerebrovascular changes are already evident in young adults with hypertension and exercise is recommended to reduce cardiovascular risk. To what extent exercise benefits the cerebrovasculature at an early stage of the disease remains unclear. ObjectiveTo investigate whether structured aerobic exercise increases brain vessel lumen diameter or cerebral blood flow (CBF) and whether lumen diameter is associated with CBF. DesignOpen, parallel, two-arm superiority randomized controlled (1:1) trial in the TEPHRA study on an intention-to-treat basis. The MRI sub-study was an optional part of the protocol. The outcome assessors remained blinded until the data lock. SettingSingle-centre trial in Oxford, UK. ParticipantsParticipants were physically inactive (<150 min/week moderate to vigorous physical activity), 18 to 35 years old, 24-hour ambulatory blood pressure 115/75 mmHg-159/99 mmHg, body mass index below 35 kg/m2 and never been on prescribed hypertension medications. Out of 203 randomized participants, 135 participated in the MRI sub-study. Randomisation was stratified for sex, age (<24, 24–29, 30–35 years) and gestational age at birth (<32, 32–37, >37 weeks). InterventionStudy participants were randomised to a 16 week aerobic exercise intervention targeting 3×60 min sessions per week at 60 to 80 % peak heart rate. Main outcomes and Measurescerebral blood flow (CBF) maps from ASL MRI scans, internal carotid artery (ICA), middle cerebral artery (MCA) M1 and M2 segments, anterior cerebral artery (ACA), basilar artery (BA), and posterior cerebral artery (PCA) diameters extracted from TOF MRI scans. ResultsOf the 135 randomized participants (median age 28 years, 58 % women) who had high quality baseline MRI data available, 93 participants also had high quality follow-up data available. The exercise group showed an increase in ICA (0.1 cm, 95 % CI 0.01 to 0.18, p =.03) and MCA M1 (0.05 cm, 95 % CI 0.01 to 0.10, p =.03) vessel diameter compared to the control group. Differences in the MCA M2 (0.03 cm, 95 % CI 0.0 to 0.06, p =.08), ACA (0.04 cm, 95 % CI 0.0 to 0.08, p =.06), BA (0.02 cm, 95 % CI −0.04 to 0.09, p =.48), and PCA (0.03 cm, 95 % CI −0.01 to 0.06, p =.17) diameters or CBF were not statistically significant. The increase in ICA vessel diameter in the exercise group was associated with local increases in CBF. Conclusions and RelevanceAerobic exercise induces positive cerebrovascular remodelling in young people with early hypertension, independent of blood pressure. The long-term benefit of these changes requires further study. Trial RegistrationClinicaltrials.gov NCT02723552, 30 March 2016

Basilar artery dilatation relates to Alzheimer dementia, particularly among APOE4 non‐carriers

AbstractBackgroundBrain arterial dilatation has been associated with higher risk of dementia and cognitive decline in population‐based studies. Whether the association is related to brain amyloid or tau, pathological hallmarks of Alzheimer disease, is uncertain.MethodWe analyzed existing and de novo data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) regarding participants’ demographics, hypertension, dementia status, APOE4 genotype. We used composite PET measures of gray matter regions of beta amyloid (AV‐45) and neurofibrillary tangles (AV‐1451). We obtain de novo cross‐sectional carotid and basilar artery diameters using axial T2 MRI sequences. For cognitive outcomes, we used the Alzheimer's Disease Assessment Scale–Cognitive Subscale (ADAS‐Cog) and clinical dementia rating (ordinal CDR) scores. All models were adjusted for age, sex, years of education, APOE4 carrier status and hypertensionResultWe included 478 ADNI participants (56% men, mean age 77±7, 36% cognitively normal, 48 with mild cognitive impartment and 16% with dementia). Combined carotid and basilar artery diameters were not associated with ADAS‐13 cog score (B=0.07 per SD, P=0.46), ordinal CDR (B=0.13, P=0.32), amyloid (B=‐0.001, P=0.57) or tau (B=0.02, P=0.45). Stratifying by anterior versus posterior circulation artery showed that basilar artery diameters, but not carotid diameters, were associated with a higher ADAS‐13 cog score (B=0.17, P=0.01), higher CDR (0.25, P=0.009), but not with amyloid (B=0.01, P=0.46). The association between basilar artery diameters and CDR was stronger among APOE4 non‐carriers (B=0.37, P=0.004) than in carriers (B=0.05, P=0.70, P for the interaction 0.12).ConclusionBrain arterial dilatation is associated with poorer cognitive outcomes, and the association is stronger among APOE4 negative participants. Investigation of how brain arterial dilatation relates to dementia and whether such relationship interacts with amyloid and/or tau may reveal novel aspects of the vascular contributions to dementia.

What is the restorative effect of VEGF inhibitor bevacuzimab against subarachnoid hemorrhage in an experimental model?

This study investigated the effect of vascular endothelial growth factor (VEGF) inhibitor bevacuzimab (BVZ) on the rabbit basilar artery using an experimental subarachnoid hemorrhage (SAH) model. Eighteen adult male New-Zealand white rabbits were randomly divided into three groups: a control group (n = 6), SAH group (n = 6), and SAH+BVZ group (n = 6). Experimental SAH was created by injecting autologous arterial blood into the cisterna magna. In the treatment group, the subjects were administered a daily dose of 10 mg/kg, intravenous BVZ for 2 days after the SAH. Basilar artery diameters were measured with magnetic resonance angiography (MRA) 72 h after the SAH in all groups. After 72 h, whole brains, including the upper cervical region, were obtained from all the animals after perfusion and fixation of the animal. The wall thickness, luminal area, and the apoptosis at the basilar arteries were evaluated in all groups. BVZ significantly prevented SAH-induced vasospasm confirmed in vivo with MRA imaging with additional suppression of apoptosis on basilar artery wall. VEGF inhibition with BVZ has shown to have a vasospasm and apoptosis attenuating effect on basilar artery in a SAH model.

Vertebral Artery Stenoses Contribute to the Development of Diffuse Plaques in the Basilar Artery.

Vertebral artery (VA) stenosis is relevant to a high early risk of recurrent stroke and basilar artery (BA) is the most common intracranial site of atherosclerotic lesions. It is important to show predictive risk factors for transient ischemic attack (TIA) or posterior infarctions. The aim of the study is to investigate morphometry and hemodynamics in intracranial vertebral and basilar arteries of health and diseased patients to enhance the risk assessment. Based on the geometrical model reconstructed from CTA images in 343 patients, a transient three-dimensional computational model was used to determine the hemodynamics. Patients were classified in symmetric, asymmetric, hypoplastic, and stenotic groups while patients in the stenotic group were divided into unilateral, bilateral, bifurcation, and tandem stenotic sub-groups. Patients in bilateral, bifurcation, and tandem stenotic sub-groups had significantly lower basilar artery diameters than other groups. Patients in the stenotic group had significantly higher surface area ratio (SAR) of high time-averaged wall shear stress gradient (TAWSSG) and higher incidence of TIAs or posterior infarctions than other groups while patients in the tandem stenotic sub-group had the highest values (SAR-TAWSSG of 57 ± 22% and TIAs or posterior infarction incidence of 54%). The high SAR-TAWSSG is predisposed to induce TIAs or posterior infarction.

Basilar Artery Tortuosity Is Associated With White Matter Hyperintensities by TIMP-1.

Background and PurposeTo test the hypothesis that the imbalance between matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) may play a potential role in bridging vertebrobasilar dolichoectasia (VBD) with lacunar infarction (LI) and white matter hyperintensities (WMH).MethodsWe studied 212 patients with vertigo who underwent multimodal magnetic resonance imaging (MRI) tests for VBD, LI, and WMH identification. We investigated biomarkers of VBD with magnetic resonance angiography (MRA) via various physical characteristics of the vertebrobasilar arteries (VBAs). Similarly, LI and WMH biomarkers were extracted using T2-weighted and fluid attenuated inversion recovery (FLAIR) images. We first determined which of these neuroimaging markers were significant identifiers of VBD, LI and the different grades of WMH. We then sought to draw potential mechanistic conclusions from these MRI-derived parameters, by associating the aforementioned biomarkers with MMP and TIMP serum levels in patient blood samples using non-parametric statistical tests.ResultsMMP-9 serum level was significantly higher in vertigo patients with VBAs dilation and basilar artery (BA) elongation compared to those with healthy arterial size, and the ratio of MMP-9/TIMP-1 level were higher in those patients. TIMP-1 level was also markedly higher in vertigo patients with BA tortuosity than those without BA tortuosity. The bending length (BL) of the BA was positively correlated with TIMP-1. The length, BL, and tortuosity index of the BA, as well as serum levels of TIMP-1 were greater in patients with higher WMH grades compared to those with low WMH grades. The vertebral artery and BA diameters, and the levels of MMP-2, -3, -9, TIMP-2 and cathepsin L were similar in patients with different WMH grades.ConclusionIn vertigo patients, we found various probably associations between MMP-9 and TIMP-1 with arterial alterations linked to both VBD and WMH that may help with the diagnosis and treatment of such diseases in the future.

Endovascular Ultraviolet Laser-Facilitated Reversal of Vasospasm Induced by Subarachnoid Hemorrhage in Canines.

Because treatments for cerebral arterial spasm-a delayed consequence of subarachnoid hemorrhage (SAH)-are clinically inconsistent, we describe here a new method for reversal of arterial spasm, possibly extensible to nitric oxide (NO)-sensitive microvasculature. We subjected dogs to the intracisternal double-hemorrhage model of SAH (autologous blood injection on days 1 and 3) and began endovascular treatment of the spasmed basilar artery (BA) on Day 4. A conical-tip fused silica optical fiber was introduced via a microcatheter (inserted femorally) into the proximal vicinity of the spasmed BA. After local saline flushing of blood, an ultraviolet (UV) pulsed laser beam (355 nm Nd:YAG) was focused into the optical fiber and converted into a concentric ring beam, which facilitated endovascular irradiation for 30s at intensities of 12-20W/cm2. BA diameters were measured angiographically using a semiautomated routine over the entire BA length as well as the proximal, medial, and distal segments. On Day 4 the BAs had constricted by 21±11%. After UV laser irradiation on Day 4, the constricted BAs dilated to 93±15% of their normal diameters within minutes, and the dilation (91±12%) persisted on Day 5. Most BA segments recovered to their respective baselines after UV irradiation, even when the UV beam was located considerably proximal to the BA origin. At days 4 and 5, the percent BA dilation normalized to Day 4 pre-treatment decreased linearly (by scatter plot, p<0.02) over a range of about 60 mm from the UV irradiation site. We conjecture that the vasodilator nitric oxide, produced at high local concentration from its vascular storage forms (chiefly nitrites) by UV laser-induced photoscission, stimulates a wave of arterial dilation, possibly by longitudinal propagation of transnitrosation reactions in the arterial wall, which reverses cerebral vasospasm semi-locally and thus avoids the deleterious effects of systemic treatment.

Abstract TMP52: Basilar Artery Tortuosity and Elongation and Risk of Ischemic Stroke and Death: The Northern Manhattan Study

Background: Basilar artery (BA) dolichoectasia is defined as dilatation, tortuosity, and/or elongation of the basilar artery. Hospital-based studies have demonstrated an association between BA dilatation and risk of death and stroke. We hypothesized that BA tortuosity and elongation increase risk of death and stroke independent of BA dilatation. Methods: We included stroke-free participants in the Northern Manhattan Study, a population-based prospective cohort study, with an available time of flight MRA. BA tortuosity was defined as BA localization lateral to margin of the clivus, and BA elongation as BA tip distal to margin of the sella. BA diameters were obtained with semi-automated in-house software. Primary outcomes were any death and ischemic stroke. Cox proportional hazards models were used to obtain hazards ratios [HR] and 95% confidence intervals [CI] after adjusting for demographics and vascular risks. Results: Participants (N=1032, mean age 70.7 years, 39.5% men, 65.7% Hispanic) were followed on average for 10.4 ± 3.1 years after their MRA. Among these, 97 (9.4%) had BA tortuosity, 294 (28.5%) had BA elongation, and 98 (9.5%) had both tortuosity and elongation. Participants with BA tortuosity were more likely men, and participants with BA elongation were older, more likely women, non-Hispanic white and were more likely hypertensive. There was no association between BA tortuosity (HR 0.89; 95% CI 0.73 – 1.09, P=0.27), BA elongation (HR 1.12; 0.96 – 1.31, P=0.14), or BA dilatation (HR 1.03; 95% CI 0.84 – 1.27, P=0.76) and risk of death. There was an interaction between BA tortuosity and elongation (P for interaction=0.02); BA elongation was associated with an increased risk of death only among those with BA tortuosity (HR 2.06; 1.29 – 3.29; P=0.002). Adjusting for BA dilatation attenuated the association (HR 1.66; 0.99 – 2.81, P=0.05). We found no association between BA tortuosity (HR 0.92; 95% CI 0.77 – 1.10) or elongation (HR 1.07; 95% CI 0.92 – 1.23), or their combination, and ischemic stroke. Conclusion: Stroke-free individuals with both basilar elongation and tortuosity may have a higher risk of death, but not stroke. Further studies of vasculopathy seen in dolichoectasia and its relationship to systemic vascular disease and mortality are warranted.

Variation in Calibre of Arteries of Circle of Willis with Age: An MRA Based Study

Objective: To establish reference range for the diameters of arteries forming the Circle of Willis (CoW) and to correlate it with age.&#x0D; Methods: This cross-sectional study was conducted at the Radiology Department from January to July 2018. It comprises of patients referred for MR imaging of brain without any manifestation of cere- brovascular diseases. Patients who were claustrophobic or had a history of atherosclerosis, vasculi- tis, thrombus, aneurysm, arteriovenous malformation (AVM), intracranial tumour, diabetes and hypertension were excluded. 300 individuals comprising both males and females with mean age of 45 ± 11.6 (years) were recruited via non-probability sampling technique. Three-dimensional Time of Flight (TOF) Magnetic Resonance Angiography (MRA) was performed. Diameters of all component vessels forming the Circle of Willis were measured.&#x0D; Results: The diameter of the anterior cerebral, anterior communicating, internal carotid, posterior communicating, posterior cerebral and basilar arteries were found to be 1.51 ± 0.28 mm, 1.05 ± 0.37 mm, 3.69 ± 0.23 mm, 1.10 ± 0.11 mm, 1.85 ± 0.23 mm, 3.00 ± 0.11 mm respectively. Spearman correlation demonstrated that the diameters of the arteries were significantly correlated with age in different ways. Significant moderate positive correlations of internal carotid and basilar artery diameters were seen with age. Significant weak negative correlations were seen in anterior and posterior cerebral arteries. Significant very weak negative correlations were seen in anterior and posterior commu- nicating artery diameters and age.&#x0D; Conclusion: The normal reference values for vessels diameter of CoW were determined in general population living in Karachi. Diameter of the arteries showed statistically significant correlation with age in different ways. Knowledge of calibre of the arteries is helpful in cerebrovascular surgeries and radiological neuro interventions.

On the association between abdominal aorta and basilar artery diameters: a population-based study in community-dwelling older adults.

Information on the relationship between the diameters of the abdominal aorta (AA) and the basilar artery (BA) is limited. Using the Atahualpa Project cohort, we aimed to assess this association in Atahualpa residents aged ≥ 60years. Atahualpa residents aged ≥ 60years underwent abdominal ultrasound and MRA of intracranial vessels. The independent association between both arterial diameters was estimated in a generalized linear model adjusted for demographics, cardiovascular risk factors, the presence of a fetal-type Circle of Willis, and severity of white matter hyperintensities. Fractional polynomials were fitted to model the relationship between AA and BA diameters. The mean age of 277 participants was 69.5 ± 7.7years (61% women). The mean AA diameter was 19.8 ± 3.3mm, and the mean BA diameter was 3.1 ± 0.7mm. The mean diameters of both arteries were significantly higher in men than in women. Locally weighted scatterplot smoothing showed a non-linear relationship between both arterial diameters. Fractional polynomial models showed that AA and BA diameters had a significant non-linear association in men (p = 0.005), but not in women (p = 0.315). When sex was excluded from a generalized linear model, the relationship between both arterial diameters became significant (p = 0.017). In this population of community-dwelling older adults, the relationship between AA and BA diameters was confined to men. The finding of a large AA diameter in men should prompt the investigation of the intracranial vasculature because of the possibility of BA ectasia.

Basilar Artery Lateral Displacement May Be Associated with Migraine with Aura.

The objective of this study is to determine whether structural features of the vertebrobasilar arterial system are related to migraine. Alterations in cerebral vascular structure and function have been associated with migraine, possibly mediated by hypoperfusion and/or endothelial dysfunction triggering cortical spreading depression. Vessel tortuosity, in particular, has been associated with both altered hemodynamics and endothelial function. Symptoms of migraine with aura (MWA) often localize to the occipital cortex, and evidence supports the localization of a migraine generator to the brain stem, suggesting that the vertebrobasilar system may be of particular relevance. We performed a post hoc exploratory analysis of data collected in a prospective, observational, case-control study enrolling MWA, migraine without aura (MwoA), and control subjects in a 1:1:1 ratio. 3 T high-resolution MR angiography was used to assess vascular structure, and arterial spin-labeled perfusion MRI to measure interictal cerebral blood flow (CBF). White matter lesions were assessed using T2/FLAIR. Vertebral and basilar artery (BA) diameters and BA total lateral displacement were measured. 162 subjects were included (52 control/52 MWA/58 MwoA). Mean age was 33 ± 6 years, and 78% were female. BA diameter was similar across groups (3.6 ± 0.6 mm in all 3 groups). BA displacement was similar in MwoA (5.1 ± 3.0 mm) and controls (4.9 ± 3.1 mm), but tended to be greater in MWA (6.3 ± 3.8 mm, p = 0.055 vs. controls). BA displacement increased with age (p < 0.001) was greater in men vs. women (6.6 ± 4.2 vs. 5.1 ± 3.0, p = 0.02) and with increased migraine frequency (p = 0.03). In multivariate analysis, BA displacement was significantly greater in MWA subjects (p = 0.02), with older age (p = 0.003), and in men (p = 0.046). In regression analysis adjusted for age and sex, BA displacement remained significantly greater with increasing migraine frequency (p = 0.02). There was no association between BA displacement and interictal posterior cerebral artery territory CBF or overall white matter lesions. BA lateral displacement may be associated with MWA as well as headache frequency. This association does not appear to be mediated by cerebral hypoperfusion.