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Objective: Despite the known poor outcomes of patients with hemorrhagic moyamoya disease (MMD), previous studies have not explored the entire population of hemorrhagic MMD, often excluding severely impaired patients due to the lack of imaging studies demonstrating cerebral angioarchitecture. Herein, we investigate the prevalence, location of intracerebral hematoma (ICH), and outcomes in patients with hemorrhagic MMD, including severely impaired individuals who underwent emergency computed tomography (CT) angiography (CTA) to identify secondary ICHs., Methods: We conducted a retrospective analysis of 2092 patients admitted to our hospital within 3 days of ICH onset from January 2010 to December 2022. CTA was performed for all patients with ICH, principally., Results: CTA was performed in 1645 (78.6%) patients. We diagnosed MMD in 40 patients (2.5%), making it the third leading cause of secondary ICH. Twenty patients had anterior-type hematomas, while the remaining twenty had posterior-type hematomas. At 90 days after onset, 19 patients (95%) with anterior-type hematomas had unfavorable outcomes (modified Rankin scale [mRS] scores of 3-6), compared to 11 patients (55%) with posterior-type hematomas. The number of unfavorable outcomes was significantly higher in the anterior-type group compared to the posterior-type group (p = 0.008)., Conclusion: This comprehensive study highlights that the majority of MMD cases with ICH result in unfavorable outcomes, especially when the ICH is located in the anterior circulation. While recent studies have focused on preventing bleeding from choroidal anastomosis in the posterior circulation, overall outcome improvement of hemorrhagic MMD necessitates a greater emphasis on addressing anterior circulation ICHs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Neonates with congenital heart disease (CHD) have smaller brain volume at birth. High rates of placental vascular malperfusion lesions may play a role in disrupted brain development., Methods: This is a single-center retrospective cohort study of infants born between 2010 and 2019 who were diagnosed with a major cardiac defect requiring surgery in the first year of life. Doppler ultrasound RI of the middle cerebral artery (MCA) and anterior cerebral artery were calculated within the first 72 hours of life. Placentas were evaluated using a standardized approach., Results: Over the study period, there were 52 patients with hypoplastic left heart syndrome (HLHS), 22 with single-ventricle right ventricular outflow tract obstruction (SV-RVOTO), 75 with a two-ventricle cardiac defect (2V), and 25 with transposition of the great arteries (TGA). MCA Doppler RI were significantly higher for all subgroups of CHD compared with control subjects (0.68 ± 0.11 in control subjects compared with 0.78 ± 0.13 in HLHS, P = 0.03; 0.77 ± 0.10 in SV-RVOTO, P = 0.002; 0.78 ± 0.13 in 2V, P = 0.03; and 0.80 ± 0.14 in TGA; P = 0.001) with the highest average MCA RI in the TGA group. In subgroup analyses, placental fetal vascular malperfusion in the 2V group was associated with higher MCA RI, but this relationship was not present in other subgroups, nor in regards to maternal vascular malperfusion., Conclusions: Major forms of CHD are associated with significantly higher cerebral artery RI postnatally, but placental vascular malperfusion lesions may not contribute to this hemodynamic adaptation., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: The clinical characteristics and mechanisms of stroke caused by anterior circulation atherosclerotic plaques (ACAPs) and posterior circulation atherosclerotic plaques (PCAPs) are distinct. We aimed to compare the differences in vulnerability, morphology, and distribution between ACAPs and PCAPs based on hign-resolution magnetic resonance imaging (HR-MRI)., Materials and Methods: The PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang database were retrieved from inception through May 2023. Meta-analysis was performed by R 4.2.1 software. The quality of the literature was assessed by the Agency for Healthcare Research and Quality (AHRQ). Subgroup analysis was conducted to explore the heterogeneity of the pooled results., Results: There were a total of 13 articles, including 1194 ACAPs and 1037 PCAPs. The pooled estimates demonstrated that the incidence of intraplaque hemorrhage in the PCAPs was higher (OR 1.72, 95%CI 1.35-2.18). The plaque length (SMD 0.23, 95%CI 0.06-0.39) and remodeling index (SMD 0.29, 95%CI 0.14-0.44) of PCAPs were larger than those in ACAPs. However, there were no evident differences in significant enhancement or stenosis degree between the two groups., Conclusion: There were more unstable features in PCAPs, highlighting an elevated risk of recurrent ischemic stroke in the posterior circulation. Furthermore, PCAPs were prone to developing penetrating artery disease due to their wider distribution. Nevertheless, posterior circulation arteries exhibited a greater propensity for outward remodeling, which may lead treatment team to miss the optimal intervention stage by being overlooked on angiographic detection., Competing Interests: Declaration of competing interest We hereby state that the study was carried out without any existing commercial or financial associations that might be perceived as potential conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background and Purpose: The circle of Willis (CoW) and leptomeningeal anastomoses play an important role in transforming infarct topography following middle cerebral artery occlusion. Their role in infarct topography following anterior cerebral artery occlusion is not well understood. The aim of this study was to evaluate the role of the CoW and leptomeningeal anastomoses in modifying regional variation in infarct topography following occlusion of the anterior cerebral artery and its branches., Methods: Perfusion and magnetic resonance imaging of patients with anterior cerebral artery stroke and evidence of vessel occlusion were segmented and manually registered to standard brain template for voxel-wise comparison. Next, a computer model of the cerebral arteries was formulated as network of nodes connected by cylindrical pipes. The experiments included occlusion of successive branches of the anterior cerebral artery while the configurations of the CoW were varied., Results: Forty-seven patients with a median age of 77.5 years (interquartile range, 68.0–84.5 years) were studied. The regions with the highest probabilities of infarction were the superior frontal gyrus (probability =0.26) and anterior cingulate gyrus (probability =0.24). The regions around the posterior cingulate gyrus (probability =0.08), paracentral lobule (probability =0.05), precuneus and superior parietal lobule (probability =0.03) had a low probability of infarction. Following occlusions distal to the anterior communicating artery, the computer model demonstrated an increase in flow (>30%) in neighboring cortical arteries with leptomeningeal anastomoses., Conclusions: Traditionally the CoW has been regarded as the primary collateral system. However, our computer model shows that the CoW is only helpful in redirecting flow following proximal vessel occlusions (pre-anterior communicating artery). More important are leptomeningeal anastomoses, which play an essential role in distal vessel occlusions, influencing motor outcome by modifying the posterolateral extent of infarct topography.

We analyzed interrelations between the cerebral blood flow, cardiac output, and condition of the brain substance in 530 patients with ischemic stroke. Dependencies between the linear blood flow velocities in all arteries supplying the brain, as well as between the total volume blood flow through the internal carotid arteries and left ventricular stroke volume were revealed. The severity of atrophy was maximum in the parietal lobes (median 1.5 (1.0; 2.0)) and minimum in the occipital lobes (median 0.5 (0; 1.0)). Temporal lobes cortical atrophy significantly correlated with changes in the limbic system and in the periventricular and deep white matter; a significant weak inverse correlation of this parameter with blood flow in the middle cerebral artery was also found. Changes in the periventricular white matter (but not in deep white matter) demonstrated a significant inverse correlation with blood flow in the middle and anterior cerebral arteries., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Inadequate cerebral perfusion is a risk factor for cerebral ischemia in patients with large artery steno-occlusion. We investigated whether prefrontal oxyhemoglobin oscillation (ΔHbO 2 , 0.6-2 Hz) was associated with decreased vascular reserve in patients with steno-occlusion in the large anterior circulation arteries. Thirty-six patients with steno-occlusion in the anterior circulation arteries (anterior cerebral artery, middle cerebral artery, and internal carotid artery) were included and compared to thirty-six control subjects. Patients were categorized into two groups (deteriorated vascular reserve vs. preserved vascular reserve) based on the results of Diamox single- photon emission computed tomography imaging. HbO 2 data were collected using functional near-infrared spectroscopy. The slope of ΔHbO 2 and the ipsilateral/contralateral slope ratio of ΔHbO 2 were analyzed. Among the included patients (n = 36), 25 (69.4%) had deteriorated vascular reserve. Patients with deteriorated vascular reserve had a significantly higher average slope of ΔHbO 2 on the ipsilateral side (5.01 ± 2.14) and a higher ipsilateral/contralateral ratio (1.44 ± 0.62) compared to those with preserved vascular reserve (3.17 ± 1.36, P = 0.014; 0.93 ± 0.33, P = 0.016, respectively) or the controls (3.82 ± 1.69, P = 0.019; 0.94 ± 0.29, P = 0.001). The ipsilateral/contralateral ΔHbO 2 ratio could be used as a surrogate for vascular reserve in patients with severe steno-occlusion in the anterior circulation arteries.

Background: There are no reports describing the surgical procedure for moyamoya disease (MMD) patients with severe cerebral ischemia in the territory of the posterior cerebral artery (PCA) at initial presentation. In this study, therefore, we describe their clinical and radiological features and clinical results of one-stage revascularization surgery for both anterior and posterior circulation., Methods: This study included 6 MMD patients who had severe cerebral ischemia in the PCA territory and underwent one-stage revascularization surgery for both anterior and posterior circulation. Of these, one patient underwent it on both sides. Their clinical and radiological data were precisely analyzed. Compared with usual procedure, craniotomy was extended towards the temporo-parietal area more widely. The parietal branch of superficial temporal artery (STA) was anastomosed to the angular or posterior temporal artery, while the frontal branch was anastomosed to the frontal branch of MCA. Ultimate indirect bypass was added. Their clinical and radiological outcomes were evaluated., Results: Their neurological symptoms included visual and speech disturbance as well as numbness of the extremities. Cerebral infarct was distributed in the posterior temporal, parietal, and/or occipital lobe. Cerebral hemodynamics and metabolism were also impaired in the same regions. These findings were completely different from those in MMD patients without PCA lesion. Postoperative course was uneventful, and none of them recurred stroke during a mean follow-up period of 10.5 years. Surgical collaterals widely provided blood flow to the entire hemispheres, including the occipital lobe. Cerebral hemodynamics and metabolism markedly improved after surgery., Conclusion: One-stage revascularization surgery for both anterior and posterior circulation is feasible and effective to prevent future stroke in MMD patients with severe cerebral ischemia in the PCA territory at initial presentation.

Purpose: To quantitatively estimate the influence of ductal shunt on cerebral blood flow and establish a new index of ultrasonography for estimating cerebral circulation without the influence of ductal shunt in newborn infants., Methods: We retrospectively examined the records of anterior cerebral artery (ACA) and left pulmonary artery (LPA) blood flow velocity curves recorded by pulsed Doppler ultrasonography within 6 h after birth in 123 newborn infants without asphyxia (normal group) and in 31 newborn infants with asphyxia (asphyxia group)., Results: In the normal group, the resistance index (RI) of the ACA showed a positive correlation with the ratio of LPA diastolic-to-systolic flow velocities (LPAD/LPAS) (P < 0.001, r = 0.58), and the estimated RI (eRI) of the ACA was calculated using the following formula: Y = 0.47X + 0.67 (Y estimated RI; X LPAD/LPAS). In the asphyxia group, the RI of the ACA showed a weak correlation to base excess (BE) (P < 0.05, r = 0.46). The eRI of the ACA was calculated by the LPAD/PLAS in the asphyxia group, and the difference between the RI and eRI showed a better correlation to BE than RI (P < 0.001, r = 0.64)., Conclusion: We determined the relation between cerebral blood flow RI and ductal shunt, and (RI - eRI) may be a new useful ultrasonographic index indicating cerebral circulation without the influence of ductal shunt in newborn infants.

Background and Objective: The temporal bone window (TBW) for transcranial Doppler (TCD) often fails to insonate the anterior cerebral artery (ACA). The frontal bone window (FBW) has never been evaluated in intensive care units (ICU). The main objective was to determine the ability of the FBW to assess ACA velocities in critically ill patients., Methods: A prospective study was conducted in two ICUs of the Montpellier University Hospital (France), between November 2014 and September 2016. Adult patients admitted to ICU for brain injury, with a Glasgow Coma Scale score ≤ 13, were enrolled within 3 days after admission. A first TCD examination was carried out bilaterally through the TBW and FBW by an intensivist expert in TCD, repeated by the same examiner, and 15 min later by an intensivist certified in TCD, designated as non-expert, blinded. The success of the FBW examinations was defined by the ability to measure the ACA velocities. Intra- and interobserver agreements were analyzed according to the Bland and Altman method., Results: A total of 147 patients were analyzed. The FBW succeeded in insonating the ACA in 66 patients [45%, CI (37-53)], 45 bilaterally and 21 unilaterally. For 16 patients (11%), the FBW was the only way to measure ACA velocities. By combining the two techniques, the ACA success rate increased from 62% CI (54-70) to 73% CI (65-79) (P = 0.05). Intra- and interobserver mean biases and 95% limits of agreement for ACA systolic velocity measurements through the FBW were 1 (- 33 to 35) and 2 (- 34 to 38) cm s -1 , respectively. For paired TBW and FBW measures of ACA velocities, mean biases (± SD) for ACA systolic, and mean and diastolic velocities were relatively close to zero, but negatives (- 7 ± 33, - 2 ± 19, - 1 ± 15 cm s -1 , respectively), highlighting that ACA velocities were lower with the FBW (A2 segment) than TBW (A1 segment). The correlation coefficient for ACA systolic velocities measured by the FBW and TBW was R = 0.47, CI (0.28-0.62). No risk factors for failure of the FBW were identified., Conclusions: In ICU, the FBW was able to insonate the ACA in 45% of patients admitted for brain injury, without the use of contrast agents. The FBW could improve the detection of ACA vasospasms.

Cerebral collateral circulation and age are critical factors in determining outcome from acute ischemic stroke. Aging may lead to rarefaction of cerebral collaterals, and thereby accelerate ischemic injury by reducing penumbral blood flow. Dynamic changes in pial collaterals after onset of cerebral ischemia may vary with age but have not been extensively studied. Here, laser speckle contrast imaging (LSCI) and two-photon laser scanning microscopy (TPLSM) were combined to monitor cerebral pial collaterals between the anterior cerebral artery (ACA) and the middle cerebral artery (MCA) in young adult and aged male Sprague Dawley rats during distal middle cerebral artery occlusion (dMCAo). Histological analysis showed that aged rats had significantly greater volumes of ischemic damage than young rats. LSCI showed that cerebral collateral perfusion declined over time after stroke in aged and young rats, and that this decline was significantly greater in aged rats. TPLSM demonstrated that pial arterioles narrowed faster after dMCAo in aged rats compared to young adult rats. Notably, while arteriole vessel narrowing was comparable 4.5 h after ischemic onset in aged and young adult rats, red blood cell velocity was stable in young adults but declined over time in aged rats. Overall, red blood cell flux through pial arterioles was significantly reduced at all time-points after 90 min post-dMCAo in aged rats relative to young adult rats. Thus, collateral failure is more severe in aged rats with significantly impaired pial collateral dynamics (reduced diameter, red blood cell velocity, and red blood cell flux) relative to young adult rats.

Background: We aimed to assess the correlation of lesion location and clinical outcome in patients with large hemispheric infarction (LHI)., Methods: We analyzed admission MRI data from the GAMES-RP trial, which enrolled patients with anterior circulation infarct volumes of 82-300 cm 3 within 10 hours of onset. Infarct lesions were segmented and co-registered onto MNI-152 brain space. Voxel-wise general linear models were applied to assess location-outcome correlations after correction for infarct volume as a co-variate., Results: We included 83 patients with known 3-month modified Rankin scale (mRS). In voxel-wise analysis, there was significant correlation between admission infarct lesions involving the anterior cerebral artery (ACA) territory and its middle cerebral artery (MCA) border zone with both higher 3-month mRS and post-stroke day 3 and 7 National Institutes of Health Stroke Scale (NIHSS) total score and arm/leg subscores. Higher NIHSS total scores from admission through poststroke day 2 correlated with left MCA infarcts. In multivariate analysis, ACA territory infarct volume (P = .001) and admission NIHSS (P = .005) were independent predictors of 3-month mRS. Moreover, in a subgroup of 36 patients with infarct lesions involving right MCA-ACA border zone, intravenous (IV) glibenclamide (BIIB093; glyburide) treatment was the only independent predictor of 3-month mRS in multivariate regression analysis (P = .016)., Conclusions: Anterior extension of LHI with involvement of ACA territory and ACA-MCA border zone is an independent predictor of poor functional outcome, likely due to impairment of arm/leg motor function. If confirmed in larger cohorts, infarct topology may potentially help triage LHI patients who may benefit from IV glibenclamide., Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01794182., (Copyright © 2019. Published by Elsevier Inc.)

Background: Accurate assessment of the frequency of large vessel occlusion (LVO) is important to determine needs for neurointerventionists and thrombectomy-capable stroke facilities. Current estimates vary from 13% to 52%, depending on acute ischemic stroke (AIS) definition and methods for AIS and LVO determination. We sought to estimate LVO prevalence among confirmed and suspected AIS patients at 2 comprehensive US stroke centers using a broad occlusion site definition: internal carotid artery (ICA), first and second segments of the middle cerebral artery (MCA M1,M2), the anterior cerebral artery, vertebral artery, basilar artery, or the proximal posterior cerebral artery., Methods: We analyzed prospectively maintained stroke databases of patients presenting to the centers between January and December 2017. ICD-10 coding was used to determine the number of patients discharged with an AIS diagnosis. Computed tomography angiography (CTA) or magnetic resonance angiography (MRA) was reviewed to determine LVO presence and site. Percentages of patients with LVO among the confirmed AIS population were reported., Results: Among 2245 patients with an AIS discharge diagnosis, 418 (18.6%:95% confidence interval [CI] 17.3%-20.0%) had LVO documented on CTA or MRA. Most common occlusion site was M1 (n=139 [33.3%]), followed by M2 (n=114 [27.3%]), ICA (n=69[16.5%]), and tandem ICA-MCA lesions (n=44 [10.5%]). Presentation National Institutes of Health Stroke Scale scores were significantly different for different occlusion sites (P=.02)., Conclusions: The LVO prevalence in our large series of consecutive AIS patients was 18.6% (95% CI 17.3%-20.0%). Despite the use of a broad definition, this estimate is less than that reported in most previous studies., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction and Objectives: The anterior communicating complex is one the most common locations for aneurysm development. It receives blood from both carotid circulations and the effect of synchrony on the arrival of blood flow has not been previously studied. The objective of this study was to compare the asynchrony conditions of the A1 pulse and its effects on the haemodynamic conditions of anterior communicating artery (ACoA) aneurysms., Materials and Methods: From 2008 to 2017, 54 anterior communicating artery aneurysms treated at our centre were included in the study. Computational fluid dynamics (CFD) techniques were employed and simulations consisted of complete conditions of synchrony and introducing a delay of 0.2s in the non-dominant A1 artery. Time-averaged wall shear stress (TAWSS), low shear area (LSA), A1 diameter and ACoA angles were measured., Results: The difference in the LSA in conditions of synchrony and asynchrony resulted in a broad range of positive and negative values. The symmetry index (p=0.04) and A1/A2 angle on the dominant artery (p=0.04) were associated with changes in LSA., Conclusions: In asynchrony, LSA increased in the absence of A1 asymmetry and low A1/A2 angles, potentially increasing the risk of aneurysm rupture in this location., (Copyright © 2019 Sociedad Española de Neurocirugía. Publicado por Elsevier España, S.L.U. All rights reserved.)

Purpose: To determine the impact of vessel variation and anatomical features on technical and clinical success., Materials and Methods: In vitro blood clots (n=100) were introduced into a silicon carotid-T flow model of 2, 3 or 4mm. The ICA/M1angle varied at 45°, 90°, 135° and 180°. Peripheral embolism was measured. In vivo 50 pat. (73.5 yrs.,±15) with MCA occlusion were examined for siphon variation, ICA morphology, vessel diameter and angles. The patients were divided according to the clinical success (mRS): group A: mRS≤2 after 90 day and group B: mRS≥3. Furthermore the technical success (TICI) and number of retrieval (n) were analysed., Results: In vitro with larger vessel diameter the migrated thrombus load decreased (P=.001). The steeper the M1/ICA angles, the higher thrombus weighs (180°: 2.94mg; 135°: 6.32mg; 90°: 8.65mg, 45°: 10.69mg; P<.001). In vivo patients with mRS≤2 had significantly lower NIHSS (16.5 vs 20, P=.009) and higher ASPECTS (9 vs 6, P<.05). TICI≥2b was more often achieved (86.6 vs 40% P=.002). The procedure time was lower (45 vs. 80min, P<.05) with smaller number of retrieval (1.5 vs 4, P<05). Proximal ICA stenosis offers a trend to unfavourable outcome (P=.073). Siphon variation "D" is associated with less retrieval manoeuvre., Conclusion: While in vitro there is a close correlation between embolism and vascular anatomy, in vivo carotid artery stenosis and siphon variation influence clinical and technical success., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Background: The Pipeline embolization device (PED) is commonly used for the treatment of distal internal carotid artery (ICA) aneurysms, which often require placing the stent across the origin of the precommunicating segment of the anterior cerebral artery (ACA-A1). We sought to characterize the clinical and angiographic consequences of this maneuver., Methods: We performed a retrospective review of a prospectively collected database of patients treated with the PED at a single academic center from 2011 to 2017 to find patients for whom the PED was extended across the origin of the ACA-A1. The patient demographic data, pretreatment angiographic imaging findings, sizing of the bilateral A1 and ipsilateral M1 segment of the middle cerebral artery (MCA-M1), and follow-up angiographic and clinical imaging findings were recorded., Results: A total of 27 patients were included in the present study (8 men and 19 women; age, 52 ± 14.9 years). Follow-up angiography was conducted at a median of 9.2 months (interquartile range, 6; range, 5-84). The covered A1 segment was patent in 17 patients (63%). The covered ACA-A1/ipsilateral MCA-M1 ratio was 1.43 times greater for the patent ACA-A1 segments than those that were occluded (P = 0.0006). Similarly, the covered ACA-A1/contralateral ACA-A1 ratio was significantly larger statistically (1.64; P < 0.0001) for the patent ACA-A1 segments than that for those that were occluded. None of the patients developed clinical or radiographic signs of ACA stroke. The modified Rankin scale worsened for 1 patient during follow-up owing to a further decline of presenting vision loss., Conclusions: The PED can be used to treat aneurysms with deployment from the MCA-M1 to the ICA without resulting in ACA stroke. Ipsilateral A1 segment dominance might be predictive of continued blood flow into the ACA after deployment at this location., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: The pathogenesis of cerebral aneurysms in patients with internal carotid artery (ICA) occlusion is hypothesized to be hemodynamic. For the first time, the authors quantify the hemodynamic characteristics associated with aneurysm formation in patients with ICA occlusion., Methods: Records of patients with unilateral ICA stenosis or occlusion ≥ 90% who underwent hemodynamic assessment before treatment using quantitative MR angiography were retrospectively reviewed. The patients were classified into 2 groups based on the presence or absence of aneurysms. The hemodynamic parameters of flow volume rate, flow velocity, and wall shear stress (WSS) were measured in each vessel supplying collateral flow-bilateral A1 segments and bilateral posterior communicating arteries-and then compared between the groups., Results: A total of 36 patients were included (8 with and 28 without aneurysms). The mean flow (72.3 vs 48.9 ml/min, p = 0.10), flow velocity (21.1 vs 12.7 cm/sec, p = 0.006), and WSS (22.0 vs 12.3 dynes/cm2, p = 0.003) were higher in the A1 segment contralateral to the side of the patent ICA in patients with versus without aneurysms. All de novo or growing aneurysms in our cohort were located on the anterior communicating artery (ACoA) or P1 segment., Conclusions: Flow velocity and WSS are significantly higher across the ACoA in patients who harbor an aneurysm, and de novo or growing aneurysms are often located on collateral vessels. Thus, robust primary collaterals after ICA occlusion may be a contributing factor in cerebral aneurysm formation.

Objectives: The study aimed to determine which hemodynamic parameters independently characterize anterior communicating artery (AcomA) aneurysm formation and explore the threshold of wall shear stress (WSS) of the parent artery to better illustrate the correlation between the magnitude of WSS and AcomA aneurysm formation., Methods: Eighty-one patients with AcomA aneurysms and 118 patients without intracranial aneurysms (control population), as confirmed by digital subtraction angiography (DSA) from January 2014 to May 2017, were included in this cross-sectional study. Three-dimensional-DSA was performed to evaluate the morphologic characteristics of AcomA aneurysms. Local hemodynamic parameters were obtained using transcranial color-coded duplex (TCCD). Multivariate logistic regression and a two-piecewise linear regression model were used to determine which hemodynamic parameters are independent predictors of AcomA aneurysm formation and identify the threshold effect of WSS of the parent artery with respect to AcomA aneurysm formation., Results: Univariate analyses showed that the WSS (p < 0.0001), angle between the A1 and A2 segments of the anterior cerebral artery (ACA) (p < 0.001), hypertension (grade II) (p = 0.007), fasting blood glucose (FBG; > 6.0 mmol/L) (p = 0.005), and dominant A1 (p < 0.001) were the significant parameters. Multivariate analyses showed a significant association between WSS of the parent artery and AcomA aneurysm formation (p = 0.0001). WSS of the parent artery (7.8-12.3 dyne/cm 2 ) had a significant association between WSS and aneurysm formation (HR 2.0, 95% CI 1.3-2.8, p < 0.001)., Conclusions: WSS ranging between 7.8 and 12.3 dyne/cm 2 independently characterizes AcomA aneurysm formation. With each additional unit of WSS, there was a one-fold increase in the risk of AcomA aneurysm formation., Key Points: • Multivariate analyses and a two-piecewise linear regression model were used to evaluate the risk factors for AcomA aneurysm formation and the threshold effect of WSS on AcomA aneurysm formation. • WSS ranging between 7.8 and 12.3 dyne/cm 2 was shown to be a reliable hemodynamic parameter in the formation of AcomA aneurysms. The probability of AcomA aneurysm formation increased one-fold for each additional unit of WSS. • An ultrasound-based TCCD technique is a simple and accessible noninvasive method for detecting WSS in vivo; thus, it can be applied as a screening tool for evaluating the probability of aneurysm formation in primary care facilities and community hospitals because of the relatively low resource intensity.

Background: There are a variety of collateral routes to compensate persistent cerebral ischemia in moyamoya disease. However, there is no report presenting the persistent primitive olfactory artery (POA) as a spontaneous collateral route to the anterior cerebral artery (ACA) in moyamoya disease., Methods: We precisely examined cerebral angiography in 84 patients with moyamoya disease to identify the collateral channel through the persistent POA. Its anatomy was evaluated on pre- and postoperative angiography., Results: Of 84 patients, four (4.8%) had spontaneous collateral channel through the persistent POA. All of these four hemispheres were categorized into Stage 5. In all four patients, the collateral blood flow arose from the ophthalmic artery and run to the persistent POA through the ethmoidal moyamoya. The persistent POA provided collateral blood flow from the ophthalmic artery to the ACA in all four patients. Superficial temporal artery to middle cerebral artery anastomosis and encephalo-duro-myo-arterio-pericranial synangiosis was performed in three of four patients. After surgery, the collateral channel through the persistent POA completely disappeared or markedly regressed, suggesting a significant improvement of cerebral hemodynamics in the territory of not only the MCA but also the ACA., Conclusion: The persistent POA can potentially provide collateral blood flow to the ACA in about 5% of patients with moyamoya disease, and should be recognized as a novel collateral channel in moyamoya disease. The persistent POA may be useful to evaluate therapeutic effects of surgical revascularization on the ACA territory., (Copyright © 2018. Published by Elsevier Inc.)

Objective: To investigate hemodynamic stresses on anterior cerebral artery bifurcation apex and possible mechanism of the optimality principle in protecting bifurcation wall from supercharged hemodynamic stresses., Methods: Three-dimensional angiographic datasets of 122 patients with anterior communicating artery (Acom) aneurysms, 21 patients with non-Acom aneurysms, and 220 control subjects with no aneurysms were used. Radii of parent (r 0 ) and daughter branches (r 1 and r 2 ) were measured, and bifurcations obeying the optimality principle required optimal caliber control of r 0 n  = r 1 n  + r 2 n , with the junction exponent n approximating 3. Radius ratio = r 0 3 /(r 1 3  + r 2 3 ) and n were compared between aneurysmal and control bifurcations. Blood flow was simulated for analysis of hemodynamic stresses., Results: Acom bifurcations in subjects without Acom aneurysms displayed optimal caliber radius, with mean radius ratio of 0.99 and n of 3.25, whereas Acom aneurysmal bifurcations had significantly lower radius ratio, 0.62 (P < 0.05), but higher n, 4.23 (P < 0.05). Peak wall shear stress and corresponding total pressure were significantly smaller for bifurcations obeying than disobeying the optimality principle (P < 0.001 and P < 0.05, respectively). Total pressures in the direct impinging center, peak wall shear stress distance, and anterior cerebral artery bifurcation angle all were significantly smaller for bifurcations obeying than disobeying the optimality principle (P < 0.05 and P < 0.001, respectively)., Conclusions: Normal anterior cerebral artery bifurcations obey the optimality principle whereas bifurcations with Acom aneurysms do not. Disobeying the optimality principle presents significantly enhanced hemodynamic stresses to possibly damage the bifurcation wall for aneurysm initiation., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Introduction: Internal carotid artery termination (ICAT) and proximal A1 aneurysms can be challenging for open surgical clipping or endovascular coiling. Treatment with flow diversion covering the middle cerebral artery (MCA), an end vessel supplying a terminal circulation, has not been reported., Methods: A prospective, Institutional Review Board-approved database was analysed for patients with pipeline embolisation device (PED) placement from the anterior cerebral artery (ACA) to the ICA during cerebral aneurysm treatment., Results: Nine cases were identified, including five proximal A1, three posterior communicating artery and one ICAT aneurysm locations. Average aneurysm size was 8.3 mm (range 3-17), with 67% saccular and 78% right-sided. Primary indication for treatment was significant dome irregularity (44%), recurrence or enlargement (33%), underlying collagen vascular disorder (11%) and traumatic pseudoaneurysm (11%). Preservation of the ipsilateral ACA (with PED placed in A1) was performed when the anterior communicating artery (67%) or contralateral A1 (33%) were absent on angiography. Adjunctive coiling was done in four cases (44%). There was one major stroke leading to mortality (11%) and one minor stroke (11%). Clinical follow-up was 27 months on average. Follow-up digital subtraction angiography (average interval 15 months) showed complete aneurysm obliteration (88%) or dome occlusion with entry remnant (12%). The jailed MCA showed minimal or mild delay (primarily anterograde flow) in 75% of cases and significant delay (reliance primarily on ACA and external carotid artery collaterals) in 25%., Conclusions: Covering the MCA with a flow diverting stent should be reserved for select rare cases. Strict attention to blood pressure augmentation during the periprocedural period is necessary to minimise potential ischaemic compromise., Competing Interests: Competing interests: ALC is a consultant for InNeuroCo, a consultant and proctor for Medtronic Neurovascular, MicroVention-Terumo and Stryker Neurovascular. L-ML is a proctor for Medtronic Neurovascular, consultant for Stryker Neurovascular and Cerenovus. GPC is a consultant for Stryker Neurovascular. The other authors have no conflict of interest., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To investigate the relationship of anterior cerebral artery (ACA) bifurcation angles with hemodynamic stresses for aneurysm initiation., Methods: Forty patients with or without anterior communicating artery aneurysms were enrolled, and 3 patients with ACA bifurcation angles of 169.0°, 136.9°, and 73.2°, respectively, were entered into computational fluid dynamics analysis for hemodynamic stresses., Results: Larger bifurcation angles had a larger direct flow impinging zone and larger peak pressure area. In the direct flow impinging center, the total pressure was the highest, whereas the other stresses were the lowest. As blood flowed distally, the total pressure decreased rapidly, whereas all other parameters increased quickly to their peaks. The hemodynamic peak distance was decreased as the bifurcation angle became narrower. The total pressure summit and the peak hemodynamic stresses all decreased with the decrease of bifurcation angles. The distance between the hemodynamic peaks was the smallest at 73.2° compared with larger angles. A significant (P < 0.01) positive linear correlation existed in the ACA bifurcation angle with the distance between hemodynamic stress peaks or in the ACA branch diameter with the distance from the direct impinging center to the ipsilateral hemodynamic stress peak. The hemodynamic stresses on the aneurysm dome were significantly (P < 0.001) smaller than at the aneurysm initiation site., Conclusions: Larger bifurcation angles may lead to abnormally enhanced hemodynamic stresses, enlarged zones of direct flow impingement, and increased distance between hemodynamic stress peaks to damage the vascular wall for aneurysm initiation on the bifurcation apex wall., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Competing Interests: Competing interests: We have read and understood BMJ policy on declaration of interests and have no relevant interests to declare.

To observe Doppler changes in the three main cerebral arteries in fetuses with congenital heart defects (CHDs). The pulsatility index (PI) values of the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA) were prospectively compared in 78 CHD fetuses and 78 normal control fetuses. Correlations between the cerebral artery PIs and the neurodevelopment scores (psychomotor development index [PDI] and mental development index [MDI]) were assessed. The MCA-PI was decreased significantly in fetuses with hypoplastic left heart syndrome (HLHS). The ACA-PI was reduced significantly in fetuses with HLHS, fetuses with left-sided obstructive lesions (LSOLs) and fetuses with transposition of the great arteries. The PCA-PI was significantly smaller in fetuses with HLHS and fetuses with LSOLs. More fetuses presented signs of cerebral vasodilatation of the ACA than the MCA for certain types of CHD (P < 0.05). The ACA-PI was positively correlated with the PDI and MDI scores in fetuses with CHDs (r 2  = 0.26, 0.20, P < 0.01). The MCA-PI was only positively correlated with the PDI scores (r 2  = 0.15, P < 0.01). The ACA exhibited signs of vasodilatation more frequently and severely than the MCA. The ACA-PI appears to be more sensitive for predicting abnormal neurodevelopmental outcomes than the MCA-PI.

The anterior choroidal artery (AChA) is a critical artery in brain physiology and function. The AChA is involved in many diseases, including aneurysm, brain infarct, Moyamoya disease (MMD), brain tumor, arteriovenous malformation (AVM), etc. The AChA is vulnerable to damage during the treatment of these diseases and is thus a very important vessel. However, a comprehensive systematic review of the importance of the AChA is currently lacking. In this study, we used the PUBMED database to perform a literature review of the AChA to increase our understanding of its role in neurophysiology. Although the AChA is a small thin artery, it supplies an extremely important region of the brain. The AChA consists of cisternal and plexal segments, and the point of entry into the choroidal plexus is known as the plexal point. During treatment for aneurysms, tumors, AVM or AVF, the AChA cisternal segments should be preserved as a pathway to prevent the infarction of the AChA target region in the brain. In MMD, a dilated AChA provides collateral flow for posterior circulation. In brain infarcts, rapid treatment is necessary to prevent brain damage. In Parkinson disease (PD), the role of the AChA is unclear. In trauma, the AChA can tear and result in intracranial hematoma. In addition, both chronic and non-chronic branch vessel occlusions in the AChA are clinically silent and should not deter aneurysm treatment with flow diversion. Based on the data available, the AChA is a highly essential vessel., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

Arterial aneurysms of the A2 segment are very rare (<1%) peripheral aneurysms of the anterior cerebral artery (ACA) territory. Usually, these are saccular aneurysms; there are single reports of fusiform aneurysms of this location. Surgical treatment of these aneurysms involves both microsurgical and endovascular interventions. In the presented case, we used deconstructive surgery (proximal clipping of the aneurysm) with intraoperative awakening of the patient, which verified sufficient collateral blood flow. In the case of focal deficit development, we planned to simultaneously perform an interarterial anastomosis between the A3 segments of the right and left ACAs.

Background and Purpose: Proximal large vessel occlusion (LVO) is present in up to 30% of minor strokes. The effectiveness of mechanical thrombectomy (MT) in the subgroup of minor stroke with LVO in the anterior circulation is still open to debate. Data about MT in this subgroup of patients are sparse, and their optimal management has not yet been defined. The purpose of this multicenter cohort study was to evaluate the effectiveness of MT in patients experiencing acute ischemic stroke (AIS) because of LVO in the anterior circulation, presenting with minor-to-mild stroke symptoms (National Institutes of Health Stroke Scale score of <8)., Methods: Multicenter cohort study involving 4 comprehensive stroke centers having 2 therapeutic approaches (urgent thrombectomy associated with best medical treatment [BMT] versus BMT first and MT if worsening occurs) about management of patients with minor and mild acute ischemic stroke harboring LVO in the anterior circulation. An intention-to-treat analysis was conducted. The primary end point was the rate of excellent outcome defined as the achievement of a modified Rankin Scale score of 0 to 1 at 3 months., Results: Three hundred one patients were included, 170 with urgent MT associated with BMT, and 131 with BMT alone as first-line treatment. Patients treated with MT were younger, more often received intravenous thrombolysis, and had shorter time to imaging. Twenty-four patients (18.0%) in the medical group had rescue MT because of neurological worsening. Overall, excellent outcome was achieved in 64.5% of patients, with no difference between the 2 groups. Stratified analysis according to key subgroups did not find heterogeneity in the treatment effect size., Conclusions: Minor-to-mild stroke patients with LVO achieved excellent and favorable functional outcomes at 3 months in similar proportions between urgent MT versus delayed MT associated with BMT. There is thus an urgent need for randomized trials to define the effectiveness of MT in this patient subgroup., (© 2017 American Heart Association, Inc.)

Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Background: Intracranial atherosclerosis of the anterior circulation (anterior ICAS) and intracranial atherosclerosis of the posterior circulation (posterior ICAS) are thought to involve different pathogeneses and risk factors. Recently, we identified a genetic variant that has a significant association with ICAS. The variant was ring finger protein 213 (RNF213) c.14576G>A (rs112735431), which was originally identified as a susceptibility genetic variant for moyamoya disease (MMD). The present study investigated the association of RNF213 c.14576G>A with anterior and posterior ICAS., Materials and Methods: A total of 221 study participants (43 with anterior ICAS, 61 with posterior ICAS, 12 with extracranial carotid atherosclerosis [ECAS], 5 with MMD, and 100 control subjects) were recruited from April 2015 to October 2015. A genetic analysis of RNF213 c.14576G>A and an association study with these cerebrovascular diseases were performed., Results: RNF213 c.14576G>A was present in 10 of 43 patients in the anterior ICAS group and 4 of 5 patients in the MMD group, but was not present in the patients in the posterior ICAS and ECAS groups. c.14576G>A was found in 2 of 100 patients in the control group. RNF213 c.14576G>A showed a significant association with anterior ICAS (allele count: P = 3.9 × 10 -5 , odds ratio [OR] = 13.0, 95% confidence interval [CI] = 2.8-60.8; prevalence of carriers of c.14576G>A: P = 2.6 × 10 -5 , OR = 14.8, 95% CI = 3.1-71.3). However, RNF213 c.14576G>A showed no association with posterior ICAS. RNF213 c.14576G>A also had a significant association with MMD and had no association with ECAS., Conclusions: The genetic variant RNF213 c.14576G>A is significantly associated with anterior ICAS but not with posterior ICAS. The present findings may indicate factors involved in the pathogenesis of ICAS-related stroke., (Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Anterior cerebral artery (ACA) flow diversion (FD), defined as ipsilateral mean velocity (MV) of at least 30% greater than the contralateral artery, could be seen an indirect sign of leptomeningeal collateralization in the setting of middle cerebral artery occlusion. The purpose of the study was to evaluate the association between dynamic FD and functional outcome in acute anterior stroke patients with large artery occlusion. Acute middle cerebral artery (MCA) or internal carotid artery (ICA) occlusive stroke patients within 12h were recruited. Transcranial Doppler ultrasound was done at baseline, 24h and 7d after onset and velocities of MCA and ACA were recorded. FD ratio was calculated by dividing the ipsilateral ACA MV by the contralateral ACA MV. FD was determined positive when FD ratio ≥1.3. Outcome was assessed by 90-day modified Rankin's Scale (mRS). The association between FD at different time points and functional outcome were analyzed. 16 patients (median age of 67 and 75% were male) were recruited. FD ratio showed a trend of decline but did not reach statistical significance (p=0.056). The proportion of FD at baseline (p=0.026), 24h (p=0.001) and 7d (p=0.044) was significantly higher in patients with favorable outcome. Higher FD ratio at baseline (p=0.02) and 24h (p=0.003) were significantly associated with favorable outcome. These results suggested that FD ratio showed a trend of decline after stroke onset. Presence of FD within 7days was associated with favorable functional outcome in acute MCA/ICA occlusive stroke patients., (Copyright © 2017. Published by Elsevier Ltd.)

The inability to quantify cerebral blood flow and changes in macrocirculation cross-sectional area in all brain regions impedes robust insight into hypoxic cerebral blood flow control. We applied four-dimensional flow magnetic resonance imaging to quantify cerebral blood flow (ml • min -1 ) and cross-sectional area (mm 2 ) simultaneously in 11 arteries. In healthy adults, blood pressure, O 2 Saturation (SpO 2 ), and end-tidal CO 2 were measured at baseline and steady-state hypoxia (FiO 2 = 0.11). We investigated left and right: internal carotid, vertebral, middle, anterior, posterior cerebral arteries, and basilar artery. Hypoxia (SpO 2 = 80±2%) increased total cerebral blood flow from 621±38 to 742±50 ml • min -1 ( p < 0.05). Hypoxia increased cerebral blood flow, except in the right posterior cerebral arteries. Hypoxia increased cross-sectional area in the anterior arteries (left and right internal carotid arteries, left and right middle, p < 0.05; left and right anterior p = 0.08) but only the right vertebral artery of the posterior circulation. Nonetheless, relative cerebral blood flow distribution and vascular reactivity (Δ%cerebral blood flow • ΔSpO 2 -1 ) were not different between arteries. Collectively, moderate hypoxia: (1) increased cerebral blood flow, but relative distribution remains similar to normoxia, (2) evokes similar vascular reactivity between 11 arteries, and (3) increased cross-sectional area primarily in the anterior arteries. This study provides the first wide-ranging, quantitative, functional and structural data regarding intracranial arteries during hypoxia in humans, highlighting cerebral blood flow regulation of microcirculation and macrocirculation differs between anterior and posterior circulation.

Purpose: To evaluate the relationship between anterior cerebral artery (ACA) velocities (and ancillary parameters) and ACA infarction following aneurysmal subarachnoid hemorrhage (aSAH), and to examine the factors that influence velocities., Methods: Retrospective investigation of 500 consecutive aSAH patients. ACA mean velocities (Vm) were evaluated by daily transcranial ultrasound during the early (days 1-4) and late (days 5-20) periods posthemorrhage. Presence and timing of acute ACA infarctions were identified by serial retrospective review of cerebral computerized tomography (CT) scans. Predictors of ACA velocities were identified and compared to predictors of vasospasm and infarction from the literature., Results: Decreased velocities on the day of infarction were observed in infarct-positive vessels when compared to infarct-negative vessels. ACA velocity increases, ipsilateral/contralateral ACA velocity ratios, and ACA velocity ranges, were inaccurate in anticipating infarction. Decreased ACA index velocities were moderately accurate in anticipating ACA infarction during the early [Vm<60cms/s], late [Vm<70cms/s] and overall [Vm<70cms/s] time periods. Decreased index velocities also independently predicted infarction during all time periods. ACA velocities were most consistently predicted by age, race, hemorrhage quantity on CT, and ACA/ACom (anterior communicating artery) aneurysm location., Conclusions: ACA velocity increases and ancillary parameters do not relate to the development of infarction, whereas velocity decreases are moderately accurate in anticipating infarction. Predictors of velocity increases generally coincide with those of vasospasm, whereas predictors of velocity decreases coincide more with those of infarction following aSAH., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Objective To examine patency of the cerebral anterior and posterior communicating arteries in patients with ischaemic stroke with or without diabetes mellitus. Methods This retrospective study included patients with acute ischaemic stroke treated between July 2011 and May 2016. Cerebral infarction was evaluated by magnetic resonance imaging. Anterior and posterior communicating-artery patency was determined using magnetic resonance angiography. Vessels were defined as patent or occluded. Results Out of 1 406 patients, incidence of vertebral basilar artery brain infarction and posterior cerebral artery brain infarction were significantly higher in patients with diabetes versus those without diabetes (35.5% versus 22.3% and 11.7% versus 6.8%, respectively). Among patients with posterior cerebral artery brain infarction, anterior and posterior communicating-artery patency rates were higher in patients with diabetes versus those without diabetes (66.7 versus 23.5% and 33.3% versus 5.9% [bilateral], respectively). Among patients with vertebral basilar artery infarction and posterior cerebral artery P1 segment infarction, patency rate of the anterior communicating artery was higher in patients with diabetes versus those without diabetes (55.7% versus 45.9%). Conclusion Among patients with ischaemic stroke, patency rate of the circle of Willis may be higher in patients with diabetes than those without diabetes.

Background: Patients with moyamoya disease are frequently encountered with improved symptoms related to anterior cerebral artery territory (ACAt) and middle cerebral artery territory (MCAt) after bypass surgery at MCAt., Objective: To evaluate hemodynamic changes in MCAt and ACAt after bypass surgery in adult moyamoya disease., Methods: Combined bypass surgery was performed on 140 hemispheres in 126 patients with MCAt symptoms. Among them, 87 hemispheres (62.1%) accompanied preoperative ACAt symptoms. Clinical, hemodynamic, and angiographic states were evaluated preoperatively and approximately 6 months after surgery., Results: Preoperative symptoms resolved in 127 MCAt (90.7%) and 82 ACAt (94.3%). Hemodynamic analysis of total patients showed a significant improvement in MCAt basal perfusion and reservoir capacity ( P < .001 and P = .002, respectively) and ACAt basal perfusion ( P = .001). In a subgroup analysis, 82 hemispheres that completely recovered from preoperative ACAt symptoms showed a significant improvement in MCAt basal perfusion and reservoir capacity ( P < .001 and P = .05, respectively) and ACAt basal perfusion ( P = .04). Meanwhile, 53 hemispheres that had never experienced ACAt symptoms significantly improved MCAt basal perfusion and reservoir capacity ( P < .001 and P = .05, respectively); however, no ACAt changes were observed. A qualitative angiographic analysis demonstrated a higher trend of leptomeningeal formation from MCAt to ACAt in the former subgroup ( P = .05). During follow-up, no ACAt infarctions were observed., Conclusion: Combined bypass surgery at MCAt resulted in hemodynamic improvements in ACAt and MCAt, especially in patients with preoperative ACAt symptoms., (Copyright © 2017 by the Congress of Neurological Surgeons)

Objectives: Atherosclerosis is an important cause of stroke and remains a challenge for stroke prevention. Risk factors involved in atherosclerotic stroke and anterior and posterior circulation strokes (ACS and PCS, respectively) are different. The purpose of this study is to investigate differences in risk factors between intracranial and extracranial atherosclerosis (ICAS and ECAS), ACS and PCS, and ICAS/ECAS with ACS/PCS in a Chinese acute ischaemic stroke population., Methods: We analysed 551 ischaemic stroke patients who had been enrolled between August 2005 and July 2008. First, risk factors were compared between non-atherosclerosis, ICAS, ECAS, and combined ICAS and ECAS groups. ICAS and ECAS were assessed with transcranial Doppler and carotid colour Doppler ultrasound, respectively. Second, risk factors were compared between ACS and PCS groups. Stroke lesion was assessed with magnetic resonance imaging. Third, risk factors were compared in ICAS/ECAS associated with ACS/PCS., Results: The risk factor for ICAS was high diastolic blood pressure (OR, 1.075; 95% CI, 1.016-1.138; p = 0.013), and the risk factors for ECAS were age (OR, 1.113; 95% CI, 1.046-1.183; p = 0.001) and low density lipoprotein (OR, 1.450; 95% CI, 1.087-1.935; p = 0.012). Hypertension (OR, 1.090; 95% CI, 1.001-1.109; p = 0.027) was associated with PCS. Age (OR, 1.026; 95% CI, 1.011-1.128; p = 0.003), male gender (OR, 2.278; 95% CI, 1.481-3.258; p = 0.003) and age (OR, 1.067; 95% CI, 1.013-1.123; p = 0.014), scores of NIHSS (OR, 1.069; 95% CI, 1.012-1.130; p = 0.018) were risk factors for ICAS and ECAS with ACS, respectively., Conclusion: Risk factors are different between ICAS and ECAS, ACS and PCS, and ICAS/ECAS with ACS/PCS. Thus, targeted strategies are needed to consider these differences to prevent, treat and manage these diseases.

Intracranial dissecting aneurysms have been frequently reported to present with fairly challenging and time-variable imaging findings that can be mostly explained by the pathological mechanisms that underline the dissection. We present two cases of spontaneous dissecting aneurysm of the supraclinoid ICA, both clinically presenting with SAH, but characterized by different progression of clinical symptoms and imaging. However, in both cases an outpouch and a mild fusiform dilation of the supraclinoid ICA was present in the initial CTA performed after the occurrence of symptoms. These findings were well depicted by the MPR reformats performed retrospectively. We postulate that this finding may represent the point of initial transmural dissection and we recommend that careful analysis of the CTA MRP reformatted images should be performed in order to detect this finding promptly., (© The Author(s) 2016.)

Ischemic cerebrovascular diseases are one of the most common vascular diseases in aged people and CT perfusion (CTP) is a very popular tool to detect the ischemic changes in brain vascular. The present study aims to establish a novel intracranial hemodynamic model to simulate anterior cerebral artery blood flow, and compare the actual and simulated hemodynamic parameters of healthy people and patients with carotid stenosis or occlusion.A mathematical model of the intracranial hemodynamic was generated using MATLAB software, and data from patients with or without infarct disease (57 and 44 cases, respectively) were retrospectively collected to test the new model. The actual time-density curve (TDC) of anterior cerebral artery was obtained from the original intracranial CTP data, and simulated TDC was calculated from our intracranial hemodynamic model. All model parameters were adjusted according to patients' sex, height, and weight. Time to peak enhancement (TTP), maximum enhancement (ME), and mean transit time (MTT) were selected to evaluate the status of hemodynamics.In healthy people, there were no significant differences of TTP and ME between actual and simulated curves. For patients with infarct symptoms, ME was significantly decreased in actual data compared with simulated curve, while there was no obvious difference of TTP between actual and simulated data. Moreover, MTT was delayed in infarct patients compared with healthy people.Our group generated a computer-based, physiologic model to simulate intracranial hemodynamics. The model successfully simulated anterior cerebral artery hemodynamics in normal healthy people and showed noncompliant ME and MTT in infarct patients, reflecting their abnormal cerebral hemodynamic status. The digital model is reliable and may help optimize the protocol of contrast medium enhancement in intracranial CT, and provide a solid tool to study intracranial hemodynamics., Competing Interests: The authors have no conflicts of interest to disclose,

Background/objective: We sought to assess the different patterns of cerebral hemodynamic changes in staged carotid angioplasty and stenting (CAS)., Methods: We prospectively recruited a cohort of patients with regular angioplasty or staged angioplasty from October 2013 to August 2015. The hemodynamic changes, including peak systolic, end-diastolic, and mean flow velocities in the ipsilateral middle cerebral artery (MCA) and the contralateral anterior cerebral artery (ACA), were recorded by transcranial Doppler ultrasound., Results: Between October 2013 to August 2015, 25 patients (age range from 48 to 78 years, 96% male) with CAS were recruited, of whom 13 patients received staged angioplasty and 12 patients received regular angioplasty. Patients in the staged angioplasty group showed a higher degree of stenosis in the internal carotid artery. After the procedure, the peak systolic, diastolic, and mean flow velocities in the ipsilateral MCA in the staged angioplasty group were significantly higher than those in the regular angioplasty group (P = .028, .036, and .027, respectively). In the staged angioplasty group, first, the peak systolic, end-diastolic, and mean flow velocities in the contralateral ACA decreased significantly soon after balloon dilation in stage I (P = .042, .033, and .034, respectively). Second, the peak systolic, diastolic, and mean flow velocities in the ipsilateral MCA increased after stent placement in stage II (P = .006, .042, and .003, respectively)., Conclusions: Two-stage hemodynamic changes were observed in staged angioplasty. The velocities in the ipsilateral MCA started to increase significantly after the collateral flow diminished., (Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Objectives: The purpose of this study was to determine the value of resistive index (RI) variability in predicting cerebrovascular complications during extracorporeal membrane oxygenation (ECMO)., Methods: This retrospective study included 36 infants treated by ECMO. The RI was measured on daily transfontanellar duplex sonography, obtained first without fontanel compression and then after gentle compression with the transducer. The age at ECMO cannulation, sex, gestational age at birth, method of delivery, indication, and type and duration of ECMO were recorded., Results: There was a statistically significant difference in RI variability in infants who developed cerebrovascular complications as opposed to those who did not (P = .002). Resistive index variability of 10% or greater on any day was associated with an increased risk for cerebrovascular complications (P = .0482; χ 2 = 3.9). Variability in the first 5 days was significantly higher than on following days (P < .0001). The age at ECMO cannulation showed a significant difference, with mean ± SD values of 1.1 ± 0.9 days in the complications group and 2.7 ± 2.2 days in the no-complications group (P = .043)., Conclusions: Resistive index variability of 10% or greater on any day had a statistically significant risk of cerebrovascular complication development. Extracorporeal membrane oxygenation cannulation at younger than 3 days conferred an increased risk of cerebrovascular complications., (© 2016 by the American Institute of Ultrasound in Medicine.)

Background and Purpose: Reversible cerebral vasoconstriction syndrome is characterized by thunderclap headache and diffuse segmental vasoconstriction that resolves spontaneously within 3 months. Previous reports have proposed that vasoconstriction first involves small distal arteries and then progresses toward major vessels at the time of thunderclap headache remission. The purpose of this study was to confirm centripetal propagation of vasoconstriction on MRA at the time of thunderclap headache remission compared with MRA at the time of reversible cerebral vasoconstriction syndrome onset., Materials and Methods: Of the 39 patients diagnosed with reversible cerebral vasoconstriction syndrome at our hospital during the study period, participants comprised the 16 patients who underwent MR imaging, including MRA, within 72 hours of reversible cerebral vasoconstriction syndrome onset (initial MRA) and within 48 hours of thunderclap headache remission., Results: In 14 of the 16 patients (87.5%), centripetal propagation of vasoconstriction occurred from the initial MRA to remission of thunderclap headache, with typical segmental vasoconstriction of major vessels. These mainly involved the M1 portion of the MCA (10 cases), P1 portion of the posterior cerebral artery (10 cases), and A1 portion of the anterior cerebral artery (5 cases)., Conclusions: This study found evidence of centripetal propagation of vasoconstriction on MRA obtained at the time of thunderclap headache remission, compared with MRA obtained at the time of reversible cerebral vasoconstriction syndrome onset. If clinicians remain unsure of the diagnosis during early-stage reversible cerebral vasoconstriction syndrome, this time point represents the best opportunity to diagnose reversible cerebral vasoconstriction syndrome with confidence., (© 2016 by American Journal of Neuroradiology.)

Introduction: Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiologic syndrome not yet fully understood and characterized by transient neurologic symptoms in addition to typical radiological findings. There are only a few articles that describe the clinical differences between patients with PRES that involve carotid and vertebrobasilar circulations. Our study aims to further evaluate the differences between predominantly anterior and posterior circulation PRES., Methods: We review 54 patients who had received the diagnosis of PRES from 2009 to 2015. The patients were divided into 2 groups: (1) exclusively in posterior zones; and (2) anterior plus posterior zones or exclusively anterior zones. Several clinical characteristics were evaluated, including the following: age, sex, previous diseases, the neurologic manifestations, the highest blood pressure in the first 48 hours of presentation, highest creatinine level during symptoms, and the neuroimaging alterations in brain magnetic resonance imaging., Results: Mean age at diagnosis was 28.5 years old (9 men and 45 women) and mean systolic blood pressure among patients with lesions only in posterior zones was 162.1 mmHg compared to 179.2 mmHg in the anterior circulation. The most common symptoms in the 2 groups were headache and visual disturbances., Discussion: PRES may have several radiological features. A higher blood pressure seems to be 1 of the factors responsible for developing widespread PRES, with involvement of carotid vascular territory. This clinical-radiological difference probably occurs because of the larger number of autonomic receptors in the carotid artery in comparison to the vertebral-basilar system., (Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Background: To investigate the possible role of fluid mechanical factors in thromboembolism that occurs at a high rate in the human middle cerebral artery (MCA)., Methods: Isolated transparent cerebral arterial trees containing the terminal bifurcation of the internal carotid artery (ICA), where the ICA bifurcated into the MCA and the anterior cerebral artery, were prepared from human cadavers. The flow behavior and distribution of embolus-model polystyrene particles in dilute suspensions at the bifurcation were studied in detail by means of flow visualization and high-speed cinemicrographic techniques., Results: Large particles in suspensions flowing through the ICA migrated radially away from the vessel wall toward the axis of the ICA. It became more remarkable by increasing the flow rate in the ICA (Q0), flow rate ratio of Q1 to Q0 (MCA/ICA), and particle diameter. As a result, redistribution of particles flowing in the ICA occurred at the bifurcation. The particles >1 mm in diameter (≈1/4 of vessel diameter) selectively entered the MCA, even when the flow rate ratio of Q1 to Q0 was decreased to as low as 0.34. In contrast, the particles whose diameters were <0.3 mm (≈1/10 of vessel diameter) and that did not show radial migration entered the MCA at the same rate as the flow rate ratio of Q1 to Q0., Conclusions: Due to the flow-dependent migration of particles away from the vessel wall toward the axis of the ICA, large particles selectively enter the MCA to which the core flow of the ICA is generally directed. This might explain why the incidence of thromboembolism is higher in the MCA than in the anterior cerebral artery in humans., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: Many numerical studies have been published with respect to about flow structures around cerebral aneurysm assuming to be rigid. Furthermore, there is little experimental research concerning aneurysm with elastic wall. Wall shear stress in elastic wall comparing with rigid wall should be clarified in experimental approach and verified in CFD., Objective: We have experimentally realized elastic aneurysm model accompanying with wall deformation. Wall shear stress was examined for both rigid and elastic aneurysm models in pulsatile flow., Methods: Effect of elasticity on wall shear stress inside aneurysm induced at the apex of anterior cerebral artery was experimentally examined by particle image velocimetry in vitro. In order to adjust the wall deformation, the pressure adjustment chamber was specially equipped outside the aneurysm wall., Results: Effect of elasticity on wall shear stress was noticed on the comparison with that of rigidity. Wall elasticity reduced the peak magnitude, the spatial and temporal averaged wall shear stress comparing with those of wall rigidity experimentally. These reductions were endorsed by fluid-structure interaction simulation., Conclusion: Elastic wall comparing with rigid wall would reduce the peak magnitude, the spatial and temporal averaged wall shear stress acting on vascular wall.

Objectives: Ruptured anterior communicating artery (ACoA) aneurysms occur more frequently in men. The purpose of the study was to investigate sex difference in aneurysm morphologies and clinical outcomes in patients with ruptured ACoA aneurysms., Setting: A tertiary referral hospital., Participants: A total of 574 consecutive patients with ACoA aneurysms were admitted to our hospital from December 2007 to February 2015. In all, 474 patients (257 men and 217 women) with ruptured ACoA aneurysms were included in the study., Main Outcome Measures: Aneurysm morphologies were measured using computed tomographic angiography and clinical outcomes were measured with Glasgow coma score at discharge., Results: The aneurysm sizes (p=0.001), aneurysm heights (p=0.011), size ratios (p<0.001), flow angles (p=0.047) and vessel angles (p=0.046) were larger in the male patients than in the females. The female patients more often had larger vessel sizes (p=0.002). Multivariate logistic analysis revealed that significant differences in aneurysm morphologies between men and women were aneurysm size (OR 1.1, 95% CI 1.0 to 1.3; p=0.036), aneurysm height (OR 0.8, 95% CI 0. to 0.9; p=0.006) and size ratio (OR 1.4, 95% CI 0.5 to 1.7; p=0.001). There were no statistically significant differences in the outcomes between men and women (OR 1.0, 95% CI 0.6 to 1.7, p=0.857)., Conclusions: The men were independently associated with larger aneurysm sizes, greater aneurysm heights and larger size ratios. Sex was not a risk factor for poor outcome in patients with ruptured ACoA aneurysms., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

The effect of a simple bare metal stent on repression of wall shear stress inside a model cerebral aneurysm was experimentally investigated by two-dimensional particle image velocimetry in vitro. The flow model simulated a cerebral aneurysm induced at the apex of bifurcation between the anterior cerebral artery and the anterior communicating artery. Wall shear stress was investigated using both stented and non-stented models to assess the simple stent characteristics. The flow behavior inside the stented aneurysm sac was unusual and wall shear stress was much smaller inside the aneurysm sac. Stent placement effectively repressed the temporal and spatial variations and the magnitude of wall shear stress. Hence, there is an effective possibility that would retard the progress of cerebral aneurysms by even simple stent.

Background: In patients with cerebral infarction, identifying the distribution of infarction and the relevant artery is essential for ascertaining the underlying vascular pathophysiological mechanisms and preventing subsequent stroke. However, visualization of the basal perforating arteries (BPAs) has had limited success, and simultaneous viewing of background anatomical structures has only rarely been attempted in living human brains. Our study aimed at identifying the BPAs with 7T MRI and evaluating their distribution in the subcortical structures, thereby showing the clinical significance of the technique., Methods: Twenty healthy subjects and 1 patient with cerebral infarction involving the posterior limb of the internal capsule (ICpost) and thalamus underwent 3-dimensional fast spoiled gradient-echo sequence as time-of-flight magnetic resonance angiography (MRA) at 7T with a submillimeter resolution. The MRA was modified to detect inflow signals from BPAs, while preserving the background anatomical signals. BPA stems and branches in the subcortical structures and their origins were identified on images, using partial maximum intensity projection in 3 dimensions., Results: A branch of the left posterior cerebral artery (PCA) in the patient ran through both the infarcted thalamus and ICpost and was clearly the relevant artery. In 40 intact hemispheres in healthy subjects, 571 stems and 1,421 branches of BPAs were detected in the subcortical structures. No significant differences in the numbers of stems and branches were observed between the intact hemispheres. The numbers deviated even less across subjects. The distribution analysis showed that the subcortical structures of the telencephalon, such as the caudate nucleus, anterior limb of the internal capsule, and lenticular nucleus, were predominantly supplied by BPAs from the anterior circulation. In contrast, the thalamus, belonging to the diencephalon, was mostly fed by BPAs from the posterior circulation. However, compared with other subcortical structures, the ICpost, which marks the anatomical boundary between the telencephalon and the diencephalon, was supplied by BPAs with significantly more diverse origins. These BPAs originated from the internal carotid artery (23.1%), middle cerebral artery (38.5%), PCA (17.3%), and the posterior communicating artery (21.1%)., Conclusions: The modified MRI method allowed the detection of the relevant BPA within the infarcted area in the stroke survivor as well as the BPAs in the subcortical structures of living human brains. Based on in vivo BPA distribution analyses, the ICpost is the transitional zone of the anterior and posterior cerebral circulations., (© 2016 S. Karger AG, Basel.)

The clinical management of a patent ductus arteriosus (PDA) in preterm newborns is a controversial topic, and despite nearly three decades of research, varying opinions remain. This dilemma stems from uncertain causal linkage between PDA and neonatal comorbidities, as well as the lack of clear evidence showing that benefits of treatment outweigh risks. There has been a general shift in the management of PDA in preterm newborns from early and aggressive closure to a more conservative approach of watchful waiting and spontaneous closure. However, a firm recommendation cannot be made due to a lack of randomized controlled trials validating either treatment strategies. Although cyclooxygenase inhibitors, namely indomethacin and ibuprofen, are approved pharmacological treatments for PDA, there is a need to explore alternative medical therapies in view of lack of clinical response in many newborns and concerns over adverse effects. One such recent interest is the use of acetaminophen as a pharmacological agent. This present review tries to address the questions at hand, integrate the current evidence, highlight the principles of PDA management in preterm newborns, and suggest areas for possible future research.

Brain retraction is required during many intracranial procedures to provide more working space. However, it is difficult to avoid brain retraction injury. Here, we report on retractorless surgery for anterior circulation aneurysms via a pterional keyhole approach. All patients undergoing a minimally invasive pterional keyhole approach within 3 days after hemorrhage by the same surgeon were included in the study. Patients were randomly assigned into group I (with the retractorless technique) and group II (with fixed retractors). Data on adequate clipping level, intraoperative ischemia induced by retraction, operation time, brain retraction injury, intraoperative blood loss, intraoperative aneurysm rupture, and modified Rankin Scale were collected for the 2 groups. A consecutive series of 47 patients (21 patients in group I, 26 patients in group II) successfully underwent a minimally invasive pterional keyhole approach. Statistical analysis revealed no significant between-group differences with regard to sex, age, Hunt-Hess grade, adequate clipping level, operation time, intraoperative blood loss, and aneurysm rupture (P > 0.05). However, no intraoperative ischemia was detected in group I, whereas 23.1% (6 of 26) of patients in group II had reversible ischemia. Furthermore, the proportion of brain retraction injuries in group I (5.3%) was lower than that in group II (34.6%). In addition, a better prognosis was obtained in patients who underwent retractorless surgery. With the careful and accurate use of a handheld suction device and operating instruments, the retractorless technique can replace fixed retraction, reduce brain retraction injury, and is applicable to surgeries on anterior circulation aneurysms via pterional keyhole approaches., (Copyright © 2015 Elsevier Inc. All rights reserved.)