3,514 results match your criteria Circle of Willis

Visit-to-Visit Blood Pressure Variability, Neuropathology, and Cognitive Function.

Neurology 2021 Apr 26. Epub 2021 Apr 26.

Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, USA.

Objective: Large systolic blood pressure (SBP) variability has been proposed as a novel risk factor for dementia above and beyond SBP levels, but the underlying neuropathology is largely unknown. We investigated the relationship among visit-to-visit SBP variability, cognitive deterioration and underlying neuropathological changes.

Methods: We used longitudinal data (between 2005 and 2019) from the National Alzheimer's Coordinating Center. Read More

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Silent Moyamoya disease - A rare case report.

Radiol Case Rep 2021 Jun 9;16(6):1368-1373. Epub 2021 Apr 9.

University Clinical Center, Clinic of Radiology, University For Business and Technology -Radiology, Pristina, Kosovo.

Moyamoya is a rare cerebrovascular disorder marked by chronic, gradual blockage of the circle of Willis arteries, leading to characteristic collateral vessels, specifically cerebral angiography. The disease can develop in children and adults, although there are different clinical characteristics. Moyamoya disease occurs mainly in Japanese people but has been reported in all races of varying age distributions and clinical features. Read More

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Bilateral Vertebral Artery Hypoplasia and Fetal-Type Variants of the Posterior Cerebral Artery in Acute Ischemic Stroke.

Front Neurol 2021 8;12:582149. Epub 2021 Apr 8.

Department of Neurology, Chung Shan Medical University Hospital, Taichung, Taiwan.

Unilateral vertebral artery hypoplasia is considered a risk factor for posterior circulation infarction. Despite the increasing attention on unilateral vertebral artery hypoplasia, few studies have discussed bilateral vertebral artery hypoplasia, its influence on stroke, or its collateral supply from the circle of Willis. We aimed to identify its characteristics, stroke pattern, and unique ultrasonographic and brain imaging findings. Read More

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Study on the correlation between the circle of Willis structure and collateral circulation in bilateral carotid artery occlusion.

Neurol Sci 2021 Apr 23. Epub 2021 Apr 23.

Department of Nucleus Radiation-related Injury Treatment, PLA Rocket Force Characteristic Medical Center, No.16 Xinjiekouwai Street, Xicheng District, Beijing, 100088, China.

Background And Purpose: Bilateral carotid artery occlusion (CAO) is a rare condition and the collateral circulation is more complicated than in unilateral CAO. The circle of Willis (CoW) is the most important collateral circulation compensation pathway in CAO. However, the specific role of CoW in the collateral circulation compensation pathway of CAO has not been fully elucidated. Read More

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Cerebral Aneurysms with Internal Carotid Artery Agenesis: A Unique Case Similar to Moyamoya Disease and Literature Review.

Neurol Med Chir (Tokyo) 2021 Apr 15. Epub 2021 Apr 15.

Department of Neurosurgery, Kashiwaba Neurosurgical Hospital.

Internal carotid artery (ICA) agenesis/aplasia is occasionally accompanied with cerebral aneurysms caused by hemodynamic stress. If the aneurysms are located around the circle of Willis, they are managed with clipping or coil embolization. Herein, we report a case of ICA agenesis with perforating artery aneurysms treated successfully with revascularization. Read More

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Internal Carotid Artery Agenesis in a Trauma Patient with Ipsilateral Neck GSWs.

Ann Vasc Surg 2021 Apr 6. Epub 2021 Apr 6.

Division of Vascular Surgery, Department of Surgery, Louisiana State University Medical Center, New Orleans, LA, USA.

A 38-year-old man presented to the emergency room in the trauma bay for multiple ballistic injuries to the right neck. He was hemodynamically stable, protecting his airway, and neurologically intact. Computed tomography angiography (CTA) revealed absent filling the right internal carotid artery from its origin to the circle of Willis, which was intact, as well as absent petrous carotid canal on the right. Read More

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Cerebral venous steal equation for intracranial segmental perfusion pressure predicts and quantifies reversible intracranial to extracranial flow diversion.

Sci Rep 2021 Apr 8;11(1):7711. Epub 2021 Apr 8.

Department of Anesthesiology, New York-Presbyterian/Queens, New York, NY, USA.

Cerebral perfusion is determined by segmental perfusion pressure for the intracranial compartment (SPP), which is lower than cerebral perfusion pressure (CPP) because of extracranial stenosis. We used the Thevenin model of Starling resistors to represent the intra-extra-cranial compartments, with outflow pressures ICP and Pe, to express SPP = Pd-ICP = FFR*CPP-Ge(1 - FFR)(ICP-Pe). Here Pd is intracranial inflow pressure in the circle of Willis, ICP-intracranial pressure; FFR = Pd/Pa is fractional flow reserve (Pd scaled to the systemic pressure Pa), Ge-relative extracranial conductance. Read More

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The discovery of the circle of Willis as a result of using the scientific method in anatomical dissection.

Rom J Morphol Embryol 2020 Jul-Sep;61(3):959-965

Department of Ophthalmology, Faculty of Medicine, Grigore T. Popa University of Medicine and Pharmacy, Iaşi, Romania; 2nd Neurosurgery Clinic, Prof. Dr. Nicolae Oblu Emergency Clinical Hospital, Iaşi, Romania;

There are numerous articles on the discovery of this arterial polygon, its history being quite long, beginning with the Antiquity and up to the Modern Era. Making an analysis of the primary and secondary sources on this topic, the purpose of this article is to identify the significant moments of the discovery of this arterial polygon, which is an anatomical structure with great importance for neurologists and neurosurgeons. We will present the contributions to this topic from Renaissance and early Modern Era anatomists, such as Andreas Vesalius, Jean Fernel, Gabriel Fallopius, Giulio Cesare Casseri, Adriaan van den Spiegel, Johann Vesling, and Johann Jakob Wepfer von Schaffhausen. Read More

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Challenges in hemodynamics assessment in complex neurovascular geometries using computational fluid dynamics and benchtop flow simulation in 3D printed patient specific phantoms.

Proc SPIE Int Soc Opt Eng 2021 Feb 15;11600. Epub 2021 Feb 15.

University Dept. of Biomedical Engineering, University at Buffalo, Buffalo, NY.

Purpose: Complex hemodynamics assessments, as those related to carotid stenosis, are not always easily straightforward due to multifaceted challenges presented by the collateral flow in the Circle of Willis (CoW) and brain flow autoregulation. Advanced computational and benchtop methods to investigate hemodynamics aspects related to such complex flows are often used, however both have limitations and could lead to results which may diverge. In this study we investigated these aspects by performing correlated computational fluid dynamics (CFD) simulations and benchtop experiments in patient specific 3D printed phantoms. Read More

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February 2021

Which Acute Ischemic Stroke Patients Are Fast Progressors?: Results From the ESCAPE Trial Control Arm.

Stroke 2021 May 5;52(5):1847-1850. Epub 2021 Apr 5.

Clinical Neurosciences (J.M.O., M.D.H., A.M.D., B.K.M., A.M., M.G.), University of Calgary, Canada.

Background And Purpose: Fast infarct progression in acute ischemic stroke has a severe impact on patient prognosis and benefit of endovascular thrombectomy. In this post hoc analysis of the ESCAPE trial (Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke), we identified acute ischemic stroke patients with rapid infarct growth and investigated their baseline clinical and imaging characteristics.

Methods: Control arm patients were included if they had follow-up imaging at 2-8 hours without substantial recanalization, and if their baseline Alberta Stroke Program Early CT Score was ≥9. Read More

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3D Printing of Rapid, Low-Cost and Patient-Specific Models of Brain Vasculature for Use in Preoperative Planning in Clipping of Intracranial Aneurysms.

J Clin Med 2021 Mar 13;10(6). Epub 2021 Mar 13.

Department of Neurosurgery, Spine and Peripheral Nerves Surgery, Medical University of Łódź, 90-549 Łódź, Poland.

We developed a practical and cost-effective method of production of a 3D-printed model of the arterial Circle of Willis of patients treated because of an intracranial aneurysm. We present and explain the steps necessary to produce a 3D model from medical image data, and express the significant value such models have in patient-specific pre-operative planning as well as education. A Digital Imaging and Communications in Medicine (DICOM) viewer is used to create 3D visualization from a patient's Computed Tomography Angiography (CTA) images. Read More

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Variants of the circle of Willis in ischemic stroke patients.

J Neurol 2021 Mar 30. Epub 2021 Mar 30.

UOSD Stroke Unit, Department of Clinical and Experimental Medicine, University of Messina, 98125, Messina, Italy.

Purpose: We aim to provide prevalence and pattern of anatomical variants of circle of Willis in over one thousand ischemic stroke patients compared to an age- and sex-matched control group, and to determine their role in the severity and in-hospital prognosis.

Methods: Two groups of neuroradiologists evaluated all vascular images of ischemic stroke patients and controls to identify anatomical variants using a preexisted classification. We collected data concerning patient characteristics, stroke severity on admission and discharge, in-hospital mortality, hemorrhagic transformation, acute treatment performed, and etiology. Read More

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Carotid Stump Pressure and Contralateral Internal Carotid Stenosis Ratio During Carotid Endarterectomies: 1D-0D Hemodynamic Simulation of Cerebral Perfusion.

Ann Vasc Dis 2021 Mar;14(1):39-45

Division of Vascular Surgery, Department of Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.

We selectively place carotid shunting when ipsilateral mean stump pressure is less than 40 mmHg during carotid endarterectomy (CEA). This study aimed to assess the validity of our selective shunting criterion by 1D-0D hemodynamic simulation technology. We retrospectively reviewed 88 patients (95 cases) of CEA and divided them into two groups based on the degree of contralateral internal carotid artery (ICA) stenosis ratio, which was determined as severe when the peak systolic velocity ratio of the ICA to the common carotid artery was ≥4 by carotid duplex ultrasonography. Read More

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Utility of minimum intensity projection images based on three-dimensional CUBE weighted imaging for evaluating middle cerebral artery stenosis.

Br J Radiol 2021 May 25;94(1121):20210145. Epub 2021 Mar 25.

China Medical University, Shenyang, Liaoning, China 110032.

Objective: This study investigated the diagnostic performance of MinIP images based on three-dimensional variable-flip-angle turbo spin echo weighted imaging (3D CUBE WI) from high-resolution vessel wall magnetic resonance imaging for detecting middle cerebral artery (MCA) stenosis.

Methods: A total of 63 consecutive patients were included in this study. MinIP images were reconstructed using 3D CUBE WI as the source images. Read More

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Maximizing the catheter-to-vessel size optimizes distal flow control resulting in improved revascularization in vitro for aspiration thrombectomy.

J Neurointerv Surg 2021 Mar 15. Epub 2021 Mar 15.

Department of Physiology, National University of Ireland Galway, Galway, Ireland

Background: Balloon guide catheters (BGCs) achieve proximal flow control during thrombectomy but antegrade intracranial flow often persists via the Circle of Willis. Closely sizing an aspiration catheter to the target vessel might achieve greater flow control and improve technical performance. Our objective was to measure the impact of aspiration catheter size on distal flow control and flow reversal with and without the use of BGCs. Read More

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Management of carotid stenosis for primary and secondary prevention of stroke: state-of-the-art 2020: a critical review.

Eur Heart J Suppl 2020 Nov 6;22(Suppl M):M35-M42. Epub 2020 Dec 6.

Department of Cardiology, Dupuytren University Hospital, INSERM 1094 & IRD, Limoges, France.

Carotid atherosclerotic plaque is encountered frequently in patients at high cardiovascular risk, especially in the elderly. When plaque reaches 50% of carotid lumen, it induces haemodynamically significant carotid stenosis, for which management is currently at a turning point. Improved control of blood pressure, smoking ban campaigns, and the widespread use of statins have reduced the risk of cerebral infarction to <1% per year. Read More

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November 2020

Thomas Willis: physician who described the circle of Willis, the arterial anastomosis at the base of the brain.

Harold Ellis

Br J Hosp Med (Lond) 2021 Feb 22;82(2):1-2. Epub 2021 Feb 22.

c/o British Journal of Hospital Medicine, London, UK.

Thomas Willis is known for the discovery and description of the circle of Willis, but his contributions to the development of medicine were much broader, including the first use of the term 'neurology'. Read More

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February 2021

An in vitro study of pressure increases during contrast injections in diagnostic cerebral angiography.

Interv Neuroradiol 2021 Feb 25:1591019921996099. Epub 2021 Feb 25.

Department of Neurosurgery, Stony Brook University Medical Center, Stony Brook, NY, USA.

Background: During diagnostic cerebral angiography, the contrast bolus injected into a vessel can cause substantial changes in baseline pressures and flows. One potential, and serious complication is the re-rupture of aneurysms due to these injections. The goals of this in vitro study were to evaluate the effect of injection conditions on intraneurysmal pressure changes during angiography. Read More

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February 2021

Vascular Lesions, APOE ε4, and Tau Pathology in Alzheimer Disease.

J Neuropathol Exp Neurol 2021 Feb;80(3):240-246

Banner Sun Health Research Institute, Sun City, Arizona, USA.

We sought to determine the associations among cerebral amyloid angiopathy (CAA), white matter rarefaction (WMR), circle of Willis atherosclerosis (CWA), and total microinfarct number with Braak neurofibrillary stage in postmortem individuals with and without Alzheimer disease (AD). Data from 355 cases of autopsied individuals with Braak stage I-VI who had antemortem consensus diagnoses of cognitively unimpaired (n = 183), amnestic mild cognitive impairment (n = 31), and AD dementia (n = 141) were used. The association between Braak stage and vascular lesions were individually assessed using multivariable linear regression that adjusted for age at death, APOE ε4 carrier status, sex, education, and neuritic plaque density. Read More

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February 2021

Mathematical synthesis of the cortical circulation for the whole mouse brain-part II: Microcirculatory closure.

Microcirculation 2021 Feb 21:e12687. Epub 2021 Feb 21.

Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA.

Recent advancements in multiphoton imaging and vascular reconstruction algorithms have increased the amount of data on cerebrovascular circulation for statistical analysis and hemodynamic simulations. Experimental observations offer fundamental insights into capillary network topology but mainly within a narrow field of view typically spanning a small fraction of the cortical surface (less than 2%). In contrast, larger-resolution imaging modalities, such as computed tomography (CT) or magnetic resonance imaging (MRI), have whole-brain coverage but capture only larger blood vessels, overlooking the microscopic capillary bed. Read More

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February 2021

Cerebral hypoperfusion necessitating additional bypass following hunterian ligation of the internal carotid artery despite reassuring intraoperative challenges: Video case report.

Surg Neurol Int 2021 20;12:22. Epub 2021 Jan 20.

Department of Neurosurgery, University at Buffalo, Buffalo, New York, United States.

Background: Hunterian ligation has been adapted for complex intracranial aneurysm repair when other, more modern techniques are insufficient. Before drastic alteration of cerebral blood flow dynamics, intraoperative challenges and consideration of blood flow dynamics must be completed to ensure adequate perfusion postligation. On satisfaction, ligation may proceed; however, subtle changes related to hypoperfusion may not be immediately observed during intraoperative challenge under general anesthesia and/or before onset of the vasospasm window. Read More

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January 2021

Cerebral arterial architectonics and CFD simulation in mice with type 1 diabetes mellitus of different duration.

Sci Rep 2021 Feb 17;11(1):3969. Epub 2021 Feb 17.

Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.

Type 1 diabetes is a chronic autoimmune disease that affects tens of millions of people. Diabetes mellitus is one of the strongest factors in the development of cerebrovascular diseases. In this study we used NOD. Read More

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February 2021

Collateral flow at circle of Willis in healthy condition.

Perfusion 2021 Feb 17:267659120987550. Epub 2021 Feb 17.

School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran.

Experimental simulation of cerebrovascular system would be very beneficial tool to evaluate millions of human body cascade sequence. The Circle of Willis (CoW) recently named Cerebral Arterial Circle (CAC) is a main loop structure of cerebral circulatory system which positioned at the cranium base. In this research, we investigate cerebral artery flow pattern in cerebral arteries including afferent, Willisian, and efferent arteries of CAC emphasizing on communicating and connecting arteries which are main routes in CAC and as a risky sites when autoregulation is occurred in terminal parts of middle cerebral arteries (MCAs) by PMMA (Polymethyl methacrylate) chip and high quality camera which depict Sequential images. Read More

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February 2021

Automatic segmentation, feature extraction and comparison of healthy and stroke cerebral vasculature.

Neuroimage Clin 2021 Jan 26;30:102573. Epub 2021 Jan 26.

Department of Biomedical Engineering, University of Arizona, United States; Department of Aerospace and Mechanical Engineering, University of Arizona, United States. Electronic address:

Accurate segmentation of cerebral vasculature and a quantitative assessment of its morphology is critical to various diagnostic and therapeutic purposes and is pertinent to studying brain health and disease. However, this is still a challenging task due to the complexity of the vascular imaging data. We propose an automated method for cerebral vascular segmentation without the need of any manual intervention as well as a method to skeletonize the binary segmented map to extract vascular geometric features and characterize vessel structure. Read More

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January 2021

Two cases of combined anatomical variations: maxillofacial trunk, vertebral, posterior communicating and anterior cerebral atresia, linguofacial and labiomental trunks.

Folia Morphol (Warsz) 2021 Feb 9. Epub 2021 Feb 9.

Department of Functional Sciences, Discipline of Public Health, Faculty of Medicine, "Victor Babes" University of Medicine and Pharmacy, Timisoara, Romania.

Background: Commonly, arterial anatomic variants are reported as single entities. However, different such variants can occur in a single patient.

Materials And Methods: During a retrospective study of computed tomography angiograms of 52 adult patients, two cases were found with unilateral maxillofacial trunks. Read More

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February 2021

Eponyms in Vascular Neurosurgery: Comprehensive Review of 11 Arteries.

World Neurosurg 2021 Feb 4. Epub 2021 Feb 4.

Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA. Electronic address:

Objective: Anatomic knowledge and insight depend on the cumulative contributions of anatomists over time, and eponyms pay homage to some of these individuals.

Methods: A PubMed literature review identified 11 eponymous arteries of the brain and spinal cord.

Results: The 11 eponyms include the artery of Adamkiewicz, the artery of Bernasconi and Cassinari, the artery of Davidoff and Schechter, the recurrent artery of Heubner, McConnell's capsular arteries, the artery of Percheron, the artery of Salmon, the Vidian artery, the arteria termatica of Wilder, the circle of Willis, and the artery of Wollschlaeger and Wollschlaeger. Read More

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February 2021

Hypertension and Alzheimer's disease: indirect effects through circle of Willis atherosclerosis.

Brain Commun 2020 21;2(2):fcaa114. Epub 2020 Jul 21.

Veteran Affairs San Diego Healthcare System, San Diego, CA 92161, USA.

Hypertension is common among older adults and is believed to increase susceptibility to Alzheimer's disease, but mechanisms underlying this relationship are unclear. Hypertension also promotes circle of Willis atherosclerosis, which contributes to cerebral hypoperfusion and arterial wall stiffening, two potential mechanisms linking hypertension to Alzheimer's disease. To examine the role of circle of Willis atherosclerosis in the association between hypertension and Alzheimer's disease neuropathology, we analysed post-mortem neuropathological data on 2198 decedents from the National Alzheimer's Coordinating Center database [mean (standard deviation) age at last visit 80. Read More

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Moyamoya disease: a spectrum of clinical and radiological findings in a series of eight paediatric patients.

Acta Neurol Belg 2021 Feb 4. Epub 2021 Feb 4.

Department of Neurology, Bangur Institute of Neurosciences, Institute of Post Graduate Medical Education and Research, 52 1/A Sambhu Nath Pandit Street, Gokhale Road, Bhowanipore, Kolkata, 700020, West Bengal, India.

Moyamoya disease (MMD) is a progressive steno-occlusive vasculopathy at the circle of Willis, characteristically involving the supra-clinoid segment of internal carotid arteries and their proximal branches with prominent collateral artery formation. Here we present, a series of imaging findings and varied clinical presentation of eight cases (n = 8) of MMD in the pediatric population (aged 0-18 years) after a retrospective review and detailed clinical evaluation. Detailed clinical history and examination were performed of eight pediatric patients of MMD with varied presentations. Read More

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February 2021

Metagenomics Analysis of Thrombus Samples Retrieved from Mechanical Thrombectomy.

Neurointervention 2021 Mar 3;16(1):39-45. Epub 2021 Feb 3.

Department of Neurology, Pacific Medical College & Hospital, Pacific Medical University, Udaipur, India.

Purpose: The purpose of this study was to assess the microbiota in middle cerebral artery thrombi retrieved in mechanical thrombectomy arising out of symptomatic carotid plaque within 6 hours of acute ischemic stroke. Thrombi were subjected to next-generation sequencing for a bacterial signature to determine their role in atherosclerosis.

Materials And Methods: We included 4 human middle cerebral artery thrombus samples (all patients were male). Read More

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Widening the Indications for Intrasaccular Flow Disruption: WEB 17 in the Treatment of Aneurysm Locations Different from Those in the Good Clinical Practice Trials.

AJNR Am J Neuroradiol 2021 03 28;42(3):524-529. Epub 2021 Jan 28.

From the Institut für Diagnostische und Interventionelle Radiologie, Neuroradiologie, Nuklearmedizin (S.Z., V.M., W.W., S.F.), Universitätsklinik, Knappschaftskrankenhaus Bochum-Langendreer, Bochum, Germany

Background And Purpose: The safety and efficacy of the Woven EndoBridge (WEB) device has been shown in multiple good clinical practice trials, whereas aneurysm locations in these trials were restricted to bifurcation aneurysms located at the circle of Willis (MCA bifurcation, ICA bifurcation, anterior communicating artery, basilar artery tip). Our aim was to evaluate angiographic and clinical results with the WEB 17 in aneurysm locations that were excluded from the good clinical practice trials, assuming that the angiographic and clinical results are similar to those of the good clinical practice trials for aneurysms in traditional locations.

Materials And Methods: We performed retrospective analysis of immediate and follow-up results of aneurysms in locations outside the good clinical practice trials in which the WEB 17 was used on an intention-to-treat approach. Read More

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