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Saha A, Bhattacharya A, Ghosh SP, Roy SR. Morphology and morphometry of the anterior cerebral-anterior communicating artery complex. Surg Radiol Anat 2024; 46:1585-1593. [PMID: 39103573 DOI: 10.1007/s00276-024-03451-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Accepted: 07/24/2024] [Indexed: 08/07/2024]
Abstract
PURPOSE The variations of Cerebral arterial circle (Circle of Willis) are not rare. The study is done to assess the pattern of the component vessels of its anterior part with regard to Right- Left variations and compare with other studies. MATERIAL AND METHOD 56 formalin fixed cadavers were analyzed. The diameter, length and variations of the following vessels were observed: Anterior Cerebral Artery (proximal A1 segment to distal A2 segment) and anterior communicating artery. Statistical analysis was done by Statistica 14.0.1 software. RESULT 53.57% had normal anterior cerebral artery- anterior communicating artery complex. Length and diameter were slightly more on left side. Unilateral hypoplasia, Azygos and Tripple Anterior Cerebral Artery was present in 21.43%, 3.57 and 1.78% respectively. Aplastic, double and fenestration type anterior communicating artery were present in 5.3%, 8.92% and 1.78% respectively. CONCLUSION Anatomical knowledge of variations should be updated regularly for neurosurgeons, radiologists and clinicians to avoid unexpected consequences.
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Affiliation(s)
- Anubha Saha
- Anatomy, R G Kar Medical College, Kolkata, West Bengal, India
| | | | | | - Sanchita Roy Roy
- Anatomy, Diamond Harbour Government Medical College, Diamond Harbour, West Bengal, India
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2
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Ahmad AF, Galassi FM, Burlakoti A, Vaccarezza M, Papa V. Human cerebral blood supply via circulus arteriosus cerebri: A scoping review on its variations and clinical implications. Heliyon 2024; 10:e32648. [PMID: 38975214 PMCID: PMC11225744 DOI: 10.1016/j.heliyon.2024.e32648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 06/06/2024] [Accepted: 06/06/2024] [Indexed: 07/09/2024] Open
Abstract
Background Circulus arteriosus cerebri (CAC), responsible for supplying blood to the brain, presents anatomical variations that have been associated with both haemorrhagic and ischemic strokes. Therefore, it is crucial to conduct comprehensive investigations and comparisons of the diverse variant components of the CAC, published in various journals, and analyze them to identify individuals at risk of cerebrovascular pathologies, thereby ensuring enhanced and timely treatment. Methods A scoping review according to the five-stage protocol by Arksey and O'Malley was performed between February and June 2023. Seven hundred and seventy-seven records were initially identified, and a total of 51 studies were finally included. Results This scoping review focuses on the anatomical variations of the CAC and their clinical implications on cerebrovascular disease and includes more original articles than review s. Consistent with previous findings, most of the records included small populations or samples, while only three records reported larger populations. Surprisingly, the populations enclosed in the included records consisted of autopsied cadaveric specimens more than living subjects. Finally, the qualitative analysis highlighted three main themes concerning the relationship between the normal CAC morphology and the cerebrovascular disease onset as well as the variant CAC morphology and its main features that might be also involved in these diseases. Finally, techniques that can be used to measure CAC have also been assessed. Conclusion Variations in the CAC, more common in the posterior part, with genetic and environmental factors influencing these variations impact cerebrovascular disorders. Understanding variants components of CAC can aid in improving brain surgeries and post-stroke care.
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Affiliation(s)
- Adilah F. Ahmad
- Curtin Medical School, Faculty of Health Sciences, Curtin University, Bentley, Perth WA, Australia
| | - Francesco M. Galassi
- Department of Anthropology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Arjun Burlakoti
- UniSA Allied Health and Human Performance, University of South Australia, Adelaide, SA, Australia
| | - Mauro Vaccarezza
- Curtin Medical School, Faculty of Health Sciences, Curtin University, Bentley, Perth WA, Australia
- Curtin Health Innovation Research Institute (CHIRI), Curtin University, Bentley, Perth WA, Australia
- Department of Environmental and Preventive Sciences, University of Ferrara, Ferrara, Italy
| | - Veronica Papa
- Forensic Anthropology, Paleopathology and Bioarchaeology (FAPAB) Research Center, Avola, Italy
- Department of Economics, Law, Cybersecurity, and Sports Sciences, University of Naples "Parthenope," Naples, Italy
- School of Science, Engineering and Health, University of Naples "Parthenope," Naples, Italy
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3
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Zheng R, Han Q, Hong W, Yi X, He B, Liu Y. Hemodynamic characteristics and mechanism for intracranial aneurysms initiation with the circle of Willis anomaly. Comput Methods Biomech Biomed Engin 2024; 27:727-735. [PMID: 37078775 DOI: 10.1080/10255842.2023.2199902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 03/30/2023] [Indexed: 04/21/2023]
Abstract
Clinically, circle of Willis (CoW) is prone to anomaly and is also the predominant incidence site of intracranial aneurysms (IAs). This study aims to investigate the hemodynamic characteristics of CoW anomaly, and ascertain the mechanism of IAs initiation from the perspective of hemodynamics. Thus, the flow of IAs and pre-IAs were analyzed for one type of cerebral artery anomaly, that is, anterior cerebral artery A1 segment (ACA-A1) unilateral absence. Three patient geometrical models with IAs were selected from Emory University Open Source Data Center. IAs were virtually removed from the geometrical models to simulate the pre-IAs geometry. For calculation methods, a one-dimensional (1-D) solver and a three-dimensional (3-D) solver were combined to obtain the hemodynamic characteristics. The numerical simulation revealed that the average flow of Anterior Communicating Artery (ACoA) is almost zero when CoW is complete. In contrast, ACoA flow increases significantly in the case of ACA-A1 unilateral absence. For per-IAs geometry, the jet flow is found at the bifurcation between contralateral ACA-A1 and ACoA, which exhibits characteristics of high Wall Shear Stress (WSS) and high wall pressure in the impact region. It triggers the initiation of IAs from the perspective of hemodynamics. The vascular anomaly that leads to jet flow should be considered as a risk factor for IAs initiation.
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Affiliation(s)
- Rongye Zheng
- School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou, China
- Fujian Engineering Research Center of Joint Intelligent Medical Engineering, Fuzhou, China
| | - Qicheng Han
- School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou, China
| | - Wenyao Hong
- Fujian Engineering Research Center of Joint Intelligent Medical Engineering, Fuzhou, China
- Department of Neurosurgery, Fujian Provincial Hospital, Fuzhou, China
| | - Xu Yi
- School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou, China
| | - Bingwei He
- School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou, China
- Fujian Engineering Research Center of Joint Intelligent Medical Engineering, Fuzhou, China
| | - Yuqing Liu
- Fujian Engineering Research Center of Joint Intelligent Medical Engineering, Fuzhou, China
- Department of Neurosurgery, Fujian Provincial Hospital, Fuzhou, China
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Myrcha P, Pinheiro F, Rocha-Neves J, Myrcha J, Gloviczki P. The effect of the collateral cerebrovascular circulation on tolerance to carotid artery cross-clamping and on early outcome after carotid endarterectomy. J Vasc Surg 2024:S0741-5214(24)01078-4. [PMID: 38679219 DOI: 10.1016/j.jvs.2024.04.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 04/14/2024] [Accepted: 04/20/2024] [Indexed: 05/01/2024]
Abstract
OBJECTIVE The Circle of Willis (CoW) serves as the primary source of contralateral blood supply in patients who undergo carotid artery cross-clamping (CC) for carotid endarterectomy (CEA). It has been suggested that the CoW's anatomy influences CEA outcomes. The aim of this study was to evaluate associations between the cerebral collateral circulation, a positive awake test for intraoperative neurologic deficit after carotid CC, and postoperative adverse neurologic events. METHODS A systematic review was conducted searching MEDLINE, Cochrane, and Web of Science databases for studies that assessed the cerebral circulation, including CoW variations, using neuroimaging techniques in patients who underwent carotid CC. For the metanalytical incidence, the statistical technique used was weight averaging. Otherwise, descriptive analysis was used due to the excessive heterogeneity of the studies. RESULTS Eight publications, seven cohort and one case-controlled study, involving 1313 patients who underwent carotid artery CC under loco-regional anesthesia, were included in the systematic review. The incidence of positive awake test in the cohort studies ranged from 4.4% to 19.7%. Carotid artery CC resulted in positive awake test in 5% to 91% of patients with alterations in the anterior portion and in 27% to 74% with alterations in the posterior portion of the CoW. A positive awake test in patients with contralateral carotid stenosis or occlusion ranged from 5.8% to 45.7%. Contralateral carotid stenosis >70% or occlusion were associated with a positive awake test (P < .001). Patients with incomplete CoW did not have statistically significant correlation with intraoperative neurological deficits after CC. Data were insufficient to evaluate the effect of the collateral circulation on early outcome after CEA. CONCLUSIONS In this systematic review, contralateral carotid artery stenosis or occlusion, but not CoW abnormalities, were associated with a positive awake test after carotid artery CC. Further research is needed to evaluate which specific CoW anomaly predicts neurologic deficit after CC and to confirm association between a positive awake test and clinical outcome after CEA.
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Affiliation(s)
- Piotr Myrcha
- Faculty of Medicine, Department of General and Vascular Surgery, Medical University of Warsaw, Warsaw, Poland; Department of General, Vascular and Oncological Surgery, Masovian Brodnowski Hospital, Warsaw, Poland
| | - Filipe Pinheiro
- Faculdade de Medicina da Universidade do Porto, Porto, Portugal
| | - João Rocha-Neves
- Department of Angiology and Vascular Surgery, Centro Hospitalar Universitário de São João, Porto, Portugal; Department of Biomedicine - Unit of Anatomy, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.
| | - Jakub Myrcha
- Department of Vascular Surgery and Angiology, Bielanski Hospital, Warsaw, Portugal
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5
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Korte J, Klopp ES, Berg P. Multi-Dimensional Modeling of Cerebral Hemodynamics: A Systematic Review. Bioengineering (Basel) 2024; 11:72. [PMID: 38247949 PMCID: PMC10813503 DOI: 10.3390/bioengineering11010072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 12/23/2023] [Accepted: 01/06/2024] [Indexed: 01/23/2024] Open
Abstract
The Circle of Willis (CoW) describes the arterial system in the human brain enabling the neurovascular blood supply. Neurovascular diseases like intracranial aneurysms (IAs) can occur within the CoW and carry the risk of rupture, which can lead to subarachnoid hemorrhage. The assessment of hemodynamic information in these pathologies is crucial for their understanding regarding detection, diagnosis and treatment. Multi-dimensional in silico approaches exist to evaluate these hemodynamics based on patient-specific input data. The approaches comprise low-scale (zero-dimensional, one-dimensional) and high-scale (three-dimensional) models as well as multi-scale coupled models. The input data can be derived from medical imaging, numerical models, literature-based assumptions or from measurements within healthy subjects. Thus, the most realistic description of neurovascular hemodynamics is still controversial. Within this systematic review, first, the models of the three scales (0D, 1D, 3D) and second, the multi-scale models, which are coupled versions of the three scales, were discussed. Current best practices in describing neurovascular hemodynamics most realistically and their clinical applicablility were elucidated. The performance of 3D simulation entails high computational expenses, which could be reduced by analyzing solely the region of interest in detail. Medical imaging to establish patient-specific boundary conditions is usually rare, and thus, lower dimensional models provide a realistic mimicking of the surrounding hemodynamics. Multi-scale coupling, however, is computationally expensive as well, especially when taking all dimensions into account. In conclusion, the 0D-1D-3D multi-scale approach provides the most realistic outcome; nevertheless, it is least applicable. A 1D-3D multi-scale model can be considered regarding a beneficial trade-off between realistic results and applicable performance.
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Affiliation(s)
- Jana Korte
- Research Campus STIMULATE, University of Magdeburg, 39106 Magdeburg, Germany
- Department of Fluid Dynamics and Technical Flows, University of Magdeburg, 39106 Magdeburg, Germany
| | - Ehlar Sophie Klopp
- Research Campus STIMULATE, University of Magdeburg, 39106 Magdeburg, Germany
- Department of Medical Engineering, University of Magdeburg, 39106 Magdeburg, Germany
| | - Philipp Berg
- Research Campus STIMULATE, University of Magdeburg, 39106 Magdeburg, Germany
- Department of Medical Engineering, University of Magdeburg, 39106 Magdeburg, Germany
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6
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Yang W, Sam K, Qiao Y, Huang Z, Steinman DA, Wasserman BA. A Novel Window Into Human Vascular Remodeling and Diagnosing Carotid Flow Impairment: The Petro-Occipital Venous Plexus. J Am Heart Assoc 2023; 12:e031832. [PMID: 37830353 PMCID: PMC10757507 DOI: 10.1161/jaha.123.031832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 09/13/2023] [Indexed: 10/14/2023]
Abstract
Background Adaptive arterial remodeling caused by flow reduction from downstream stenosis has been demonstrated in animal studies. The authors sought to determine whether inward remodeling from downstream stenosis also occurs in humans and is detectable by ex vacuo expansion of the Rektorzik venous plexus (RVP) surrounding the petrous internal carotid artery. Methods and Results The authors analyzed 214 intracranial magnetic resonance imaging examinations that included contrast-enhanced vessel wall imaging. RVP symmetry was qualitatively assessed on vessel wall imaging. RVP thickness (RVPT) was measured on the thicker side if asymmetric or randomly assigned side if symmetric. Maximum stenosis (M1 or intracranial internal carotid artery) was measured. Posterior communicating artery and A1 diameters (>1.0 mm and 1.5 mm, respectively) defined adequate collateral outflow when proximal to the stenosis. Seventy-two patients had stenosis downstream from RVPT measurements. For those without adequate outflow (38 of 72), 95.0% with RVPT ≥1.0 mm had ≥50% stenosis compared with only 5.6% with RVPT <1.0 mm. For these 72 patients, higher RVPT (RVPT ≥1.0 mm versus <1.0 mm) and absent adequate outflow were associated with greater downstream stenosis (P<0.001) using multivariate regression. For patients with downstream stenosis without adequate outflow, asymmetric RVP thickening was associated with greater ipsilateral stenosis (P<0.001, all had ≥46% stenosis) when stenosis was unilateral and greater differences in stenosis between sides (P=0.005) when stenosis was bilateral. Conclusions Inward internal carotid artery remodeling measured by RVPT or RVP asymmetry occurs as downstream stenosis approaches 50%, unless flow is preserved through a sufficiently sized posterior communicating artery or A1, and may serve as a functional measure of substantial flow reduction from downstream stenosis.
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Affiliation(s)
- Wenjie Yang
- Department of Diagnostic Radiology & Nuclear MedicineUniversity of Maryland School of MedicineBaltimoreMD
| | - Kevin Sam
- Department of Diagnostic Radiology & Nuclear MedicineUniversity of Maryland School of MedicineBaltimoreMD
| | - Ye Qiao
- Russell H. Morgan Department of Radiology and Radiological SciencesJohns Hopkins School of MedicineBaltimoreMD
| | - Zhongqing Huang
- Department of Diagnostic Radiology & Nuclear MedicineUniversity of Maryland School of MedicineBaltimoreMD
| | - David A. Steinman
- Department of Mechanical & Industrial EngineeringUniversity of TorontoCanada
| | - Bruce A. Wasserman
- Department of Diagnostic Radiology & Nuclear MedicineUniversity of Maryland School of MedicineBaltimoreMD
- Russell H. Morgan Department of Radiology and Radiological SciencesJohns Hopkins School of MedicineBaltimoreMD
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7
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Kopylova V, Boronovskiy S, Nartsissov Y. Approaches to vascular network, blood flow, and metabolite distribution modeling in brain tissue. Biophys Rev 2023; 15:1335-1350. [PMID: 37974995 PMCID: PMC10643724 DOI: 10.1007/s12551-023-01106-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 07/24/2023] [Indexed: 11/19/2023] Open
Abstract
The cardiovascular system plays a key role in the transport of nutrients, ensuring a continuous supply of all cells of the body with the metabolites necessary for life. The blood supply to the brain is carried out by the large arteries located on its surface, which branch into smaller arterioles that penetrate the cerebral cortex and feed the capillary bed, thereby forming an extensive branching network. The formation of blood vessels is carried out via vasculogenesis and angiogenesis, which play an important role in both embryo and adult life. The review presents approaches to modeling various aspects of both the formation of vascular networks and the construction of the formed arterial tree. In addition, a brief description of models that allows one to study the blood flow in various parts of the circulatory system and the spatiotemporal metabolite distribution in brain tissues is given. Experimental study of these issues is not always possible due to both the complexity of the cardiovascular system and the mechanisms through which the perfusion of all body cells is carried out. In this regard, mathematical models are a good tool for studying hemodynamics and can be used in clinical practice to diagnose vascular diseases and assess the need for treatment.
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Affiliation(s)
- Veronika Kopylova
- Institute of Cytochemistry and Molecular Pharmacology, Moscow, 115404 Russia
| | | | - Yaroslav Nartsissov
- Institute of Cytochemistry and Molecular Pharmacology, Moscow, 115404 Russia
- Biomedical Research Group, BiDiPharma GmbH, Siek, 22962 Germany
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8
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Mihály Z, István L, Czakó C, Benyó F, Borzsák S, Varga A, Magyar-Stang R, Banga PV, Élő Á, Debreczeni R, Kovács I, Sótonyi P. The Effect of Circle of Willis Morphology on Retinal Blood Flow in Patients with Carotid Stenosis Measured by Optical Coherence Tomography Angiography. J Clin Med 2023; 12:5335. [PMID: 37629376 PMCID: PMC10455622 DOI: 10.3390/jcm12165335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/11/2023] [Accepted: 08/12/2023] [Indexed: 08/27/2023] Open
Abstract
The Circle of Willis (CoW) is the main collateral system, and its morphological variants are more common in patients who have severe carotid artery stenosis. Earlier data suggest that optical coherence tomography angiography (OCTA) may help to assess the changes in cerebral vascular perfusion by imaging the retinal blood flow. In this single-center prospective clinical study, patients scheduled for carotid endarterectomy (CEA) underwent preoperative computed tomography angiography (CTA) of the extra- and intracranial cerebral circulation. OCTA imaging was performed one week before surgery and postoperatively one month later. The patients were divided into two subgroups based on CTA evaluation of CoW: compromised CoW or non-compromised CoW (containing hypoplastic and normal segments). The effect of the patient's age, OCTA scan quality (SQ), CoW morphology, laterality, and surgery on superficial capillary vessel density (VD) in the macula were assessed in multivariable regression models using linear mixed models. We found that VD significantly decreased with aging (-0.12%; 95%CI: -0.07--0.15; p < 0.001) and was significantly higher in patients with non-compromised CoW morphology (by 0.87% 95%CI (0.26-1.50); p = 0.005). After CEA, retinal blood flow significantly improved by 0.71% (95%CI: 0.18-1.25; p = 0.01). These results suggest that in the case of carotid artery occlusion, patients with non-compromised CoW have more preserved ocular blood flow than subjects with compromised CoW due to remodeling of the intra-orbital blood flow. Measuring the retinal blood flow might be used as a relevant and sensitive indicator of collateral cerebrovascular circulation.
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Affiliation(s)
- Zsuzsanna Mihály
- Department of Vascular and Endovascular Surgery Heart and Vascular Centre, Semmelweis University, 1122 Budapest, Hungary; (Z.M.)
| | - Lilla István
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary (Á.É.)
| | - Cecilia Czakó
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary (Á.É.)
| | - Fruzsina Benyó
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary (Á.É.)
| | - Sarolta Borzsák
- Department of Vascular and Endovascular Surgery Heart and Vascular Centre, Semmelweis University, 1122 Budapest, Hungary; (Z.M.)
| | - Andrea Varga
- Department of Vascular and Endovascular Surgery Heart and Vascular Centre, Semmelweis University, 1122 Budapest, Hungary; (Z.M.)
| | - Rita Magyar-Stang
- Department of Neurology, Semmelweis University, 1085 Budapest, Hungary (R.D.)
| | - Péter Vince Banga
- Department of Vascular and Endovascular Surgery Heart and Vascular Centre, Semmelweis University, 1122 Budapest, Hungary; (Z.M.)
| | - Ágnes Élő
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary (Á.É.)
| | - Róbert Debreczeni
- Department of Neurology, Semmelweis University, 1085 Budapest, Hungary (R.D.)
| | - Illés Kovács
- Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary (Á.É.)
- Department of Ophthalmology, Weill Cornell Medical College, New York, NY 10021, USA
- Department of Clinical Ophthalmology, Faculty of Health Sciences, Semmelweis University, 1085 Budapest, Hungary
| | - Péter Sótonyi
- Department of Vascular and Endovascular Surgery Heart and Vascular Centre, Semmelweis University, 1122 Budapest, Hungary; (Z.M.)
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Garcia-Garcia B, Mattern H, Vockert N, Yakupov R, Schreiber F, Spallazzi M, Perosa V, Haghikia A, Speck O, Düzel E, Maass A, Schreiber S. Vessel Distance Mapping: A novel methodology for assessing vascular-induced cognitive resilience. Neuroimage 2023; 274:120094. [PMID: 37028734 DOI: 10.1016/j.neuroimage.2023.120094] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 03/30/2023] [Accepted: 04/04/2023] [Indexed: 04/09/2023] Open
Abstract
The association between cerebral blood supply and cognition has been widely discussed in the recent literature. One focus of this discussion has been the anatomical variability of the circle of Willis, with morphological differences being present in more than half of the general population. While previous studies have attempted to classify these differences and explore their contribution to hippocampal blood supply and cognition, results have been controversial. To disentangle these previously inconsistent findings, we introduce Vessel Distance Mapping (VDM) as a novel methodology for evaluating blood supply, which allows for obtaining vessel pattern metrics with respect to the surrounding structures, extending the previously established binary classification into a continuous spectrum. To accomplish this, we manually segmented hippocampal vessels obtained from high-resolution 7T time-of-flight MR angiographic imaging in older adults with and without cerebral small vessel disease, generating vessel distance maps by computing the distances of each voxel to its nearest vessel. Greater values of VDM-metrics, which reflected higher vessel distances, were associated with poorer cognitive outcomes in subjects affected by vascular pathology, while this relation was not observed in healthy controls. Therefore, a mixed contribution of vessel pattern and vessel density is proposed to confer cognitive resilience, consistent with previous research findings. In conclusion, VDM provides a novel platform, based on a statistically robust and quantitative method of vascular mapping, for addressing a variety of clinical research questions.
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Affiliation(s)
| | - Hendrik Mattern
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany; Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, 39120 Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany
| | - Niklas Vockert
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany
| | - Renat Yakupov
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany; Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Frank Schreiber
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany; Department of Neurology, Otto-von-Guericke University, 39120, Magdeburg, Germany
| | - Marco Spallazzi
- Department of Medicine and Surgery, Unit of Neurology, Azienda Ospedalierouniversitaria, 43126 Parma, Italy
| | - Valentina Perosa
- Department of Neurology, Otto-von-Guericke University, 39120, Magdeburg, Germany; J. Philip Kistler Stroke Research Center, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Aiden Haghikia
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany; Department of Neurology, Otto-von-Guericke University, 39120, Magdeburg, Germany
| | - Oliver Speck
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany; Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, 39120 Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany; Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Emrah Düzel
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany; Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University, 39120 Magdeburg, Germany; Department of Neurology, Otto-von-Guericke University, 39120, Magdeburg, Germany; Institute of Cognitive Neuroscience, University College London, London WCIN 3AZ, UK
| | - Anne Maass
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany
| | - Stefanie Schreiber
- German Center for Neurodegenerative Diseases, 39120 Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany; Department of Neurology, Otto-von-Guericke University, 39120, Magdeburg, Germany
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10
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Gyöngyösi Z, Belán I, Nagy E, Fülesdi Z, Farkas O, Végh T, Hoksbergen AW, Fülesdi B. Incomplete circle of Willis as a risk factor for intraoperative ischemic events during carotid endarterectomies performed under regional anesthesia - A prospective case-series. Transl Neurosci 2023; 14:20220293. [PMID: 37465373 PMCID: PMC10350890 DOI: 10.1515/tnsci-2022-0293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/08/2023] [Accepted: 05/26/2023] [Indexed: 07/20/2023] Open
Abstract
Background The role of the willisian collaterals during carotid endarterectomies (CEAs) is a debated issue. The aim of the present work was to test whether an incomplete or non-functional circle of Willis (CoW) is a risk factor for ischemic events during CEA. Patients and methods CEAs were performed under local anesthesia. Patients were considered symptomatic (SY) if neurological signs appeared after the cross-clamping phase. In SY patients shunt insertion was performed. CoW on CT angiograms (CTa) were analyzed offline and categorized as non-functional (missing or hypoplastic collaterals) or functional collaterals by three neuroradiologists. Near-infrared spectroscopy (NIRS) was performed throughout the procedure. Results Based on CTa, 67 incomplete circles were found, 54 were asymptomatic (ASY) and 13 were SY. No complete CoW was found among the SY patients. Significant differences could be detected between incomplete and complete circles between ASY and SY groups (Chi-square: 6.08; p = 0.013). The anterior communicating artery was missing or hypoplastic in 5/13 SY cases. There were no cases of the non-functional anterior communicating arteries in the ASY group (Chi-square: 32.9; p = 10-8). A missing or non-functional bilateral posterior communicating artery was observed in 9/13 SY and in 9/81 ASY patients (Chi-square: 24.4; p = 10-7). NIRS had a sensitivity of 76.9% and a specificity of 74.5% in detecting neurological symptoms. Conclusions Collateral ability of the CoW may be a risk factor for ischemic events during CEAs. Further studies should delineate whether the preoperative assessment of collateral capacity may be useful in decision-making about shunt use during CEA.
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Affiliation(s)
- Zoltán Gyöngyösi
- Department of Anesthesiology and Intensive Care, University of Debrecen, Debrecen, Hungary
| | - Ivett Belán
- Department of Radiology, University of Debrecen, Debrecen, Hungary
| | - Edit Nagy
- Department of Radiology, University of Debrecen, Debrecen, Hungary
| | - Zsófia Fülesdi
- Department of Radiology, University of Debrecen, Debrecen, Hungary
| | - Orsolya Farkas
- Department of Anesthesiology and Intensive Care, University of Debrecen, Debrecen, Hungary
| | - Tamás Végh
- Department of Anesthesiology and Intensive Care, University of Debrecen, Debrecen, Hungary
| | - Arjan Willem Hoksbergen
- Department of Vascular Surgery, Academic Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Béla Fülesdi
- Department of Anesthesiology and Intensive Care, University of Debrecen, Debrecen, Hungary
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11
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Yuhn C, Oshima M, Chen Y, Hayakawa M, Yamada S. Uncertainty quantification in cerebral circulation simulations focusing on the collateral flow: Surrogate model approach with machine learning. PLoS Comput Biol 2022; 18:e1009996. [PMID: 35867968 PMCID: PMC9307280 DOI: 10.1371/journal.pcbi.1009996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 06/07/2022] [Indexed: 11/18/2022] Open
Abstract
Collateral circulation in the circle of Willis (CoW), closely associated with disease mechanisms and treatment outcomes, can be effectively investigated using one-dimensional–zero-dimensional hemodynamic simulations. As the entire cardiovascular system is considered in the simulation, it captures the systemic effects of local arterial changes, thus reproducing collateral circulation that reflects biological phenomena. The simulation facilitates rapid assessment of clinically relevant hemodynamic quantities under patient-specific conditions by incorporating clinical data. During patient-specific simulations, the impact of clinical data uncertainty on the simulated quantities should be quantified to obtain reliable results. However, as uncertainty quantification (UQ) is time-consuming and computationally expensive, its implementation in time-sensitive clinical applications is considered impractical. Therefore, we constructed a surrogate model based on machine learning using simulation data. The model accurately predicts the flow rate and pressure in the CoW in a few milliseconds. This reduced computation time enables the UQ execution with 100 000 predictions in a few minutes on a single CPU core and in less than a minute on a GPU. We performed UQ to predict the risk of cerebral hyperperfusion (CH), a life-threatening condition that can occur after carotid artery stenosis surgery if collateral circulation fails to function appropriately. We predicted the statistics of the postoperative flow rate increase in the CoW, which is a measure of CH, considering the uncertainties of arterial diameters, stenosis parameters, and flow rates measured using the patients’ clinical data. A sensitivity analysis was performed to clarify the impact of each uncertain parameter on the flow rate increase. Results indicated that CH occurred when two conditions were satisfied simultaneously: severe stenosis and when arteries of small diameter serve as the collateral pathway to the cerebral artery on the stenosis side. These findings elucidate the biological aspects of cerebral circulation in terms of the relationship between collateral flow and CH.
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Affiliation(s)
- Changyoung Yuhn
- Department of Mechanical Engineering, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Marie Oshima
- Interfaculty Initiative in Information Studies, The University of Tokyo, Meguro-ku, Tokyo, Japan
- * E-mail:
| | - Yan Chen
- Interfaculty Initiative in Information Studies, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Motoharu Hayakawa
- Department of Neurosurgery, Fujita Health University, Toyoake, Aichi, Japan
| | - Shigeki Yamada
- Interfaculty Initiative in Information Studies, The University of Tokyo, Meguro-ku, Tokyo, Japan
- Department of Neurosurgery, Shiga University of Medical Science, Otsu, Shiga, Japan
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12
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Neidlin M, Yousefian E, Luisi C, Sichtermann T, Minkenberg J, Hasan D, Ridwan H, Steinseifer U, Wiesmann M, Nikoubashman O. Flow control in the middle cerebral artery during thrombectomy: the effect of anatomy, catheter size and tip location. J Neurointerv Surg 2022; 15:502-506. [PMID: 35414603 DOI: 10.1136/neurintsurg-2021-018621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/03/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND Catheter size, location and circle of Willis anatomy impact the flow conditions during interventional stroke therapy. The aim of the study was to systematically investigate the influence of these factors on flow control in the middle cerebral artery by means of a computational model based on 100 patients with stroke who received endovascular treatment. METHODS The dimensions of the cervical and intracranial cerebral arteries of 100 patients who received endovascular mechanical thrombectomy for acute ischemic stroke were measured and a three-dimensional model of the circle of Willis was created based on these data. Flow control in the middle cerebral artery with variations in catheter size, catheter location and configurations of collateral vessels was determined using a computational model. A total of 48 scenarios were analyzed. RESULTS Flow reversal with a distal aspiration catheter alone was not possible in the internal carotid artery and only sometimes possible in the middle cerebral artery (14 of 48 cases). The Catalyst 7 catheter was more often successful in achieving flow reversal than Catalyst 5 or 6 catheters (p<0.001). In a full circle of Willis anatomy, flow reversal was almost never possible. The absence of one or more communicating arteries significantly influenced flow direction compared with the full anatomy with all communicating arteries present (p=0.028). CONCLUSION Choosing the biggest possible aspiration catheter and locating it in the middle cerebral artery significantly increases the chances of successful flow control. Flow through the collaterals may impair the flow, and circle of Willis anatomy should be considered during aspiration thrombectomy.
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Affiliation(s)
- Michael Neidlin
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty, RWTH Aachen University, Aachen, Nordrhein-Westfalen, Germany
| | - Ehsan Yousefian
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Aachen, Aachen, Nordrhein-Westfalen, Germany
| | - Claudio Luisi
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty, RWTH Aachen University, Aachen, Nordrhein-Westfalen, Germany
| | - Thorsten Sichtermann
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Aachen, Aachen, Nordrhein-Westfalen, Germany
| | - Jan Minkenberg
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Aachen, Aachen, Nordrhein-Westfalen, Germany
| | - Dimah Hasan
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Aachen, Aachen, Nordrhein-Westfalen, Germany
| | - Hani Ridwan
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Aachen, Aachen, Nordrhein-Westfalen, Germany
| | - Ulrich Steinseifer
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty, RWTH Aachen University, Aachen, Nordrhein-Westfalen, Germany
| | - Martin Wiesmann
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Aachen, Aachen, Nordrhein-Westfalen, Germany
| | - Omid Nikoubashman
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Aachen, Aachen, Nordrhein-Westfalen, Germany
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13
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Orosz L, Gyöngyösi Z, Susán Z, Siró P, Hoksbergen AW, Csiba L, Fülesdi B. Assessment of malformations, variations and diameters of vessels forming the circle of Willis - An autopsy study in a non-cerebrovascular cohort. Transl Neurosci 2022; 13:398-406. [PMID: 36406464 PMCID: PMC9644724 DOI: 10.1515/tnsci-2022-0253] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/05/2022] [Accepted: 09/15/2022] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND A PURPOSE The collateral capacity of the circle of Willis (CoW) may play an important role in the development of ischemic strokes. The occurrence of classical polygon shows wide geographical variations and morphological data on diameters of the Willisian collaterals are scarce. We aimed to assess CoW variations and vessel diameters in a Central European cohort. SUBJECTS AND METHODS CoWs were removed during routine autopsy. The morphological pattern of the circles was recorded. The prepared circles were then put between two glass plates and tightly compressed. The length of the vessels and half of the circumference were measured under a light microscope enabling measurement with an approximation of 0.1 mm. Vessel diameters were calculated from vessel circumference. RESULTS A total of 110 circles were analysed. Incomplete circles (missing one or two segments of CoW) were found in 25 cases (22.7%). Any forms of anatomical variations were detected in 14 cases (12.7%). When applying the <1 mm diameter threshold for analysis, 36 anterior communicating arteries (32.7%), 53 right posterior communicating arteries (48.2%), 73 left posterior communicating arteries (66.4%) and 18 posterior communicating arteries (16.3%) on both the sides were considered hypoplastic. CONCLUSIONS In patients without stroke in their history, complete CoW may be present in >60% of the cases. Our diameter data may serve as reference values for the Central-European population.
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Affiliation(s)
- László Orosz
- Department of Surgery, University of Debrecen, Debrecen, Hungary
| | - Zoltán Gyöngyösi
- Department of Anesthesiology and Intensive Care, University of Debrecen, H-4032, Nagyerdei krt. 98, Debrecen, Hungary
| | - Zsolt Susán
- Department of Surgery, University of Debrecen, Debrecen, Hungary
| | - Péter Siró
- Department of Anesthesiology and Intensive Care, University of Debrecen, H-4032, Nagyerdei krt. 98, Debrecen, Hungary
| | | | - László Csiba
- Department of Neurology, Faculty of Medicine, University of Debrecen, H-4032, Nagyerdei krt. 98, Debrecen, Hungary
| | - Béla Fülesdi
- Department of Anesthesiology and Intensive Care, University of Debrecen, H-4032, Nagyerdei krt. 98, Debrecen, Hungary
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14
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Wang Y, Haddad Y, Patel R, Geng X, Du H, Ding Y. Factors influencing the outcome of cardiogenic cerebral embolism: a literature review. Neurol Res 2021; 44:187-195. [PMID: 34423741 DOI: 10.1080/01616412.2021.1968704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE The onset of cardiogenic cerebral embolism is sudden, dangerous, and often has high morbidity and mortality. Improving understanding of factors contributing to outcomes of cardiogenic cerebral embolism will improve prognostic and therapeutic capabilities. METHODS Through PubMed and Google Scholar, this paper examined and analyzed the factors implicated in the outcome of patients with cardiogenic cerebral embolism using the key terms 'cardiogenic cerebral embolism', 'atrial fibrillation', 'stroke related diseases', 'collateral circulation', 'emboli profile', 'epigenetic' up to 28 February 2021. Full texts of the retrieved articles were accessed. In general, in these literatures, National Institute Health of Stroke Scale (NIHSS) score ≥ 17, modified Rankin Scale (mRS) score ≥ 2, stroke recurrence, death caused by stroke are regarded as the criteria of poor prognosis. As long as one of these conditions occurs, it is judged as poor prognosis. RESULTS Factors influencing patient outcomes including patient outcome include severity of neurological impairment, types and severity of combined heart diseases, establishment of cerebral collateral circulation, treatments, components of emboli causing cardiogenic cerebral embolism, existence and control of other system complications, distribution and expression of inflammatory immune cells and molecules in the course of cardiogenic cerebral embolism, and epigenetic changes related to disease prognosis. CONCLUSION Regarding to prevention and treatment of cardiogenic cerebral embolism, the related factors, such as clinical setting, emboli pathological profile, and epigenetic changes should be emphasized so that outcomes and recurrence of cardiogenic cerebral embolism can be improvised.
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Affiliation(s)
- Yanling Wang
- Department of Neurology, Beijing Luhe Hospital, Capital Medical University, Beijing, China
| | - Yazeed Haddad
- Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI USA
| | - Radhika Patel
- Drexel University, College of Medicine, Philadelphia, PA, USA
| | - Xiaokun Geng
- Department of Neurology, Beijing Luhe Hospital, Capital Medical University, Beijing, China.,Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI USA
| | - Huishan Du
- Department of Neurology, Beijing Luhe Hospital, Capital Medical University, Beijing, China
| | - Yuchuan Ding
- Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI USA
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15
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Nyasa C, Mwakikunga A, Tembo L, Dzamalala C, Ihunwo AO. Distribution of variations in anatomy of the circle of Willis: results of a cadaveric study of the Malawian population and review of literature. Pan Afr Med J 2021; 38:11. [PMID: 34567338 PMCID: PMC8444123 DOI: 10.11604/pamj.2021.38.11.27126] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 12/18/2020] [Indexed: 12/03/2022] Open
Abstract
INTRODUCTION the circle of Willis is an anatomical structure of clinical importance particularly in the evaluation of neurovascular diseases. Individuals show considerable variations in the anatomical configuration of the circle of Willis. A cross-sectional study was conducted to determine the distribution of morphological variations of the circle of Willis in Malawians and compare with other ethnic groups. METHODS brains were collected from twenty-four recently deceased black Malawians during autopsy at Queen Elizabeth Central Hospital, a referral teaching hospital in Blantyre, Malawi and fixed in 10% buffered formalin. Digital images of the interpeduncular region (exposing the circle of Willis) were taken with an 18.4 megapixels camera from the base of the brain. Whole-circle and segmental parameters of the circle of Willis were assessed using the Osiris computer programme and classified based on a 22-type classification scheme. RESULTS the following morphological variations were observed: hypoplasia, aplasia, asymmetry and accessory vessels. Typical circle of Willis was seen in 26% of the cases. Only six of the original twenty-two types were observed. Consistent with most previous studies, types 1, 3, 4, 6, 8 and 9 were common while types 10-22 were rare. Three variants not previously described in the original scheme (unilateral PcoA aplasia, AcoA duplication, and PcoA aplasia with contralateral PcoA hypoplasia) were observed in this study. CONCLUSION anatomical variations of the circle of Willis in Malawians seem to be distributed in similar frequencies and patterns as in other more-diverse populations. Circle of Willis variants with potential predilection for atherogenesis and aneurysm formation exist in the Malawian population. These should be considered in clinical practice.
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Affiliation(s)
- Charles Nyasa
- Biomedical Sciences Department, Anatomy Division, College of Medicine, University of Malawi, Blantyre, Malawi
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Anthony Mwakikunga
- Biomedical Sciences Department, Anatomy Division, College of Medicine, University of Malawi, Blantyre, Malawi
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Johannesburg, South Africa
| | - Lackson Tembo
- Biomedical Sciences Department, Anatomy Division, College of Medicine, University of Malawi, Blantyre, Malawi
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Johannesburg, South Africa
| | - Charles Dzamalala
- Pathology Department, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Amadi Ogonda Ihunwo
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Johannesburg, South Africa
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16
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Lukyanchikov VA, Orlov EA, Oganesyan MV, Gordeeva AA, Pavliv MP. [Anatomical bases of brain revascularization: choosing an extra-intracranial bypass option]. ZHURNAL VOPROSY NEIROKHIRURGII IMENI N. N. BURDENKO 2021; 85:120-126. [PMID: 34951769 DOI: 10.17116/neiro202185061120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Surgical brain revascularization is an important treatment for acute or chronic ischemia, intracranial aneurysms and skull base tumors. Individual anatomy of brain vessels should be clearly understood for this procedure. Variants of collateral cerebral blood flow in patients with cerebrovascular diseases depend on individual characteristics of circle of Willis and reserve mechanisms of collateral circulation. These anatomical variations require careful preoperative planning to choose the optimal revascularization option.
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Affiliation(s)
- V A Lukyanchikov
- University's Hospital of the Evdokimov Moscow State University of Medicine and Dentistry, Moscow, Russia
- Russian People's Friendship University, Moscow, Russia
| | - E A Orlov
- Sechenov First Moscow State Medical University, Moscow, Russia
| | - M V Oganesyan
- Sechenov First Moscow State Medical University, Moscow, Russia
| | - A A Gordeeva
- Sechenov First Moscow State Medical University, Moscow, Russia
| | - M P Pavliv
- Sechenov First Moscow State Medical University, Moscow, Russia
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17
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Abstract
PURPOSE OF REVIEW This article reviews the actual indications for mechanical thrombectomy in patients with acute ischemic stroke and how the opportunities for endovascular therapy can be expanded by using the concept of clinical-imaging or perfusion-imaging mismatch (as a surrogate for salvageable tissue) rather than time of ischemia. RECENT FINDINGS Six randomized controlled trials undoubtedly confirmed the benefits of using endovascular thrombectomy on the clinical outcome of patients with stroke with large vessel occlusion within 6 hours from symptom onset compared with those receiving only standard medical care. In a meta-analysis of individual patient data, the number needed to treat with endovascular thrombectomy to reduce disability by at least one level on the modified Rankin Scale for one patient was 2.6. Recently, the concept of "tissue window" versus time window has proved useful for selecting patients for mechanical thrombectomy up to 24 hours from symptom onset. The DAWN (DWI or CTP Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention) trial included patients at a median of 12.5 hours from onset and showed the largest effect in functional outcome ever described in any acute stroke treatment trial (35.5% increase in functional independence). In DEFUSE 3 (Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution 3), patients treated with mechanical thrombectomy at a median of 11 hours after onset had a 28% increase in functional independence and an additional 20% absolute reduction in death or severe disability. SUMMARY For patients with acute ischemic stroke and a large vessel occlusion in the proximal anterior circulation who can be treated within 6 hours of stroke symptom onset, mechanical thrombectomy with a second-generation stent retriever or a catheter aspiration device should be indicated regardless of whether the patient received treatment with intravenous (IV) recombinant tissue plasminogen activator (rtPA) in patients with limited signs of early ischemic changes on neuroimaging. Two clinical trials completely disrupted the time window concept in acute ischemic stroke, showing excellent clinical outcomes in patients treated up to 24 hours from symptom onset. Time of ischemia is, on average, a good biomarker for tissue viability; however, the window of opportunity for treatment varies across different individuals because of a range of compensatory mechanisms. Adjusting time to the adequacy of collateral flow leads to the concept of tissue window, a paradigm shift in stroke reperfusion therapy.
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18
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Bhanu SP, Pentyala S, Sankar DK. Incidence of hypoplastic posterior communicating artery and fetal posterior cerebral artery in Andhra population of India: a retrospective 3-Tesla magnetic resonance angiographic study. Anat Cell Biol 2020; 53:272-278. [PMID: 32647075 PMCID: PMC7527118 DOI: 10.5115/acb.20.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/16/2020] [Accepted: 05/21/2020] [Indexed: 11/27/2022] Open
Abstract
The posterior communicating arteries (PCoA) are important component of collateral circulation between the anterior and posterior part of circle of Willis (CW). The hypoplasia or aplasia of PCoA will reflect on prognosis of the neurological diseases. Precise studies of the incidence of hypoplastic PCoA in Andhra Pradesh population of India are hitherto unreported, since the present study was undertaken. Two hundred and thirty one magnetic resonance angiography (MRA) images were analyzed to identify the hypoplasia of PCoA and presence of fetal type of posterior cerebral artery (f-PCA) in patients with different neurological symptoms. All the patients underwent 3.0T MRI exposure. The results were statistically analysed. A total of 63 (27.3%) PCoA hypoplasia and 13 cases with f-PCA (5.6%) cases were identified. The hypoplastic PCoA was noted more in males than females (P<0.05) and right side hypoplasia was common than the left (P<0.04); bilateral hypoplasia of PCoA was seen in 37 cases out of 63 and is significant. The hypoplastic cases of the present study also were associated with variations of anterior cerebral arteries and one case was having vertebral artery hypoplasia. Incidence of PCoA as unilateral or bilateral with other associated anomalies of CW is more prone to develop stroke, migraine and cognitive dysfunction. Knowledge of these variations in the PCoA plays a pivotal role in diagnoses of neurological disorders and in neurovascular surgeries and angiographic point of view.
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Affiliation(s)
- Sharmila P Bhanu
- Department of of Anatomy, Narayana Medical College, Nellore, Andhra Pradesh, India
| | - Suneetha Pentyala
- Department of of Radiology, Narayana Medical College & General Hospital, Nellore, Andhra Pradesh, India
| | - Devi K Sankar
- Department of of Anatomy, Narayana Medical College, Nellore, Andhra Pradesh, India
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19
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Ravindran AV, Killingsworth MC, Bhaskar S. Cerebral collaterals in acute ischaemia: Implications for acute ischaemic stroke patients receiving reperfusion therapy. Eur J Neurosci 2020; 53:1238-1261. [PMID: 32871623 DOI: 10.1111/ejn.14955] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/20/2020] [Accepted: 08/22/2020] [Indexed: 12/21/2022]
Abstract
The cerebral collaterals play an important role in penumbral tissue sustenance after an acute ischaemic stroke. Recent studies have demonstrated the potential role of collaterals in the selection of acute ischaemic stroke patients eligible for reperfusion therapy. However, the understanding of the significance and evidence around the role of collateral status in predicting outcomes in acute ischaemic stroke patients treated with reperfusion therapy is still unclear. Moreover, the use of pre-treatment collaterals in patient selection and prognosis is relatively underappreciated in clinical settings. A focused review of the literature was performed on the various methods of collateral evaluation and the role of collateral status in acute ischaemic stroke patients receiving reperfusion therapy. We discuss the methods of evaluating pre-treatment collaterals in clinical settings. The patient selection based on collateral status as well as the prognostic and therapeutic value of collaterals in acute ischaemic stroke, in settings of intravenous thrombolysis or endovascular therapy alone, and bridge therapy, are summarized. Recommendations for future research and possible pharmacological intervention strategies aimed at collateral enhancement are also discussed. Collaterals may play an important role in identifying acute ischaemic stroke patients who are likely to benefit from endovascular treatment in an extended time window. Future neuroscientific efforts to better improve our understanding of the role of collaterals in acute ischaemia as well as clinical studies to delineate its role in patient selection and acute stroke prognosis are warranted.
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Affiliation(s)
- Abina Vishni Ravindran
- South Western Sydney Clinical School, University of New South Wales (UNSW), Sydney, NSW, Australia.,Neurovascular Imaging Laboratory, Clinical Sciences Stream, Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.,Thrombolysis and Endovascular WorkFLOw Network (TEFLON), Sydney, NSW, Australia
| | - Murray C Killingsworth
- South Western Sydney Clinical School, University of New South Wales (UNSW), Sydney, NSW, Australia.,NSW Brain Clot Bank, NSW Health Statewide Biobank and NSW Health Pathology, Sydney, NSW, Australia.,Correlative Microscopy Facility, Ingham Institute for Applied Medical Research and Department of Anatomical Pathology, NSW Health Pathology and Liverpool Hospital, Liverpool, NSW, Australia
| | - Sonu Bhaskar
- South Western Sydney Clinical School, University of New South Wales (UNSW), Sydney, NSW, Australia.,Department of Neurology & Neurophysiology, Liverpool Hospital & South West Sydney Local Health District (SWSLHD), Sydney, NSW, Australia.,Neurovascular Imaging Laboratory, Clinical Sciences Stream, Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.,Stroke & Neurology Research Group, Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.,NSW Brain Clot Bank, NSW Health Statewide Biobank and NSW Health Pathology, Sydney, NSW, Australia.,Thrombolysis and Endovascular WorkFLOw Network (TEFLON), Sydney, NSW, Australia
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20
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Wu TC, Chen TY, Ko CC, Chen JH, Lin CP. Correlation of internal carotid artery diameter and carotid flow with asymmetry of the circle of Willis. BMC Neurol 2020; 20:251. [PMID: 32563264 PMCID: PMC7305584 DOI: 10.1186/s12883-020-01831-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 06/15/2020] [Indexed: 11/10/2022] Open
Abstract
Background The purpose of this study was to clarify the effect of asymmetric COW variants on carotid flow changes, and proposed an easy estimate of the representative carotid flow volume for accurate numerical simulation. Methods A total of 210 healthy adults receiving magnetic resonance angiography and carotid duplex sonography were included. Three anterior cerebral artery asymmetry (AA) groups were defined based on the diameter ratio difference (DRD) of bilateral A1 segments: AA1 group, one-side A1 aplasia; AA2, A1 DRD ≥ 50%; AA3, A1 DRD between 10 and 50%. Similarly, 3 posterior communicating artery (PcomA) asymmetry (PA) groups were defined: PA1 group, one fetal-origin posterior cerebral artery and absent contralateral PcomA; PA2, PcomA DRD ≥ 50%; PA3, PcomA DRD between 10 and 50%. Results With A1 asymmetry, the ICA diameter of the dominant A1 is significantly greater than the contralateral side. Significant differences of bilateral ICA flow were present in the AA1 and AA2 groups (mean flow difference 42.9 and 30.7%, respectively). Significant bilateral ICA diameter and flow differences were only found in the PA1 group. Linear regression analysis of ICA diameter and flow found a moderately positive correlation between ICA diameter and flow in all AA groups, with a 1 mm increment in vessel diameter corresponding to a 62.6 ml increment of flow volume. The product of bilateral ICA diameter and flow volume difference (ICA-PDF) could be a potential discriminator with a cutoff of 4.31 to predict A1 asymmetry ≥50% with a sensitivity of 0.81 and specificity of 0.76. Conclusions The study verifies that A1 asymmetry causes unequal bilateral carotid inflow, and consequently different bilateral ICA diameters. Adjustment of the inflow boundary conditions according to the COW variants would be necessary to improve the accuracy of numerical simulation.
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Affiliation(s)
- Te-Chang Wu
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan. .,Department of Medical Sciences Industry, Chang Jung Christian University, Tainan, Taiwan. .,Department of Medical Imaging, Chi-Mei Medical Center, Tainan City, Taiwan.
| | - Tai-Yuan Chen
- Department of Medical Imaging, Chi-Mei Medical Center, Tainan City, Taiwan.,Graduate Institute of Medical Sciences, Chang Jung Christian University, Tainan, Taiwan
| | - Ching-Chung Ko
- Department of Medical Imaging, Chi-Mei Medical Center, Tainan City, Taiwan.,Center of General Education, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Jeon-Hor Chen
- Department of Radiology, E-DA Hospital, E-DA Cancer Hospital, I-Shou University, Kaohsiung, Taiwan.,Center for Functional Onco-Imaging of Radiological Sciences, School of Medicine, University of California, Irvine, California, USA
| | - Ching-Po Lin
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan.,Institute of Neuroscience, School of Life Science, National Yang-Ming University, Taipei, Taiwan
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21
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Thiarawat P, Jahromi BR, Kozyrev DA, Intarakhao P, Teo MK, Choque-Velasquez J, Niemelä M, Hernesniemi J. Are Fetal-Type Posterior Cerebral Arteries Associated With an Increased Risk of Posterior Communicating Artery Aneurysms? Neurosurgery 2020; 84:1306-1312. [PMID: 29788502 DOI: 10.1093/neuros/nyy186] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 04/11/2018] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Fetal-type posterior cerebral arteries (F-PCAs) might result in alterations in hemodynamic flow patterns and may predispose an individual to an increased risk of posterior communicating artery aneurysms (PCoAAs). OBJECTIVE To determine the association between PCoAAs and the presence of ipsilateral F-PCAs. METHODS We retrospectively reviewed the radiographic findings from 185 patients harboring 199 PCoAAs that were treated at our institution between 2005 and 2015. Our study population consisted of 4 cohorts: (A) patients with 171 internal carotid arteries (ICAs) harboring unilateral PCoAAs; (B) 171 unaffected ICAs in the same patients from the first group; (C) 28 ICAs of 14 patients with bilateral PCoAAs; and (D) 180 ICAs of 90 patients with aneurysms in other locations. We then determined the presence of ipsilateral F-PCAs and recorded all aneurysm characteristics. RESULTS Group A had the highest prevalence of F-PCAs (42%) compared to 19% in group B, 3% in group C, and 14% in group D (odds ratio A : B = 3.041; A : C = 19.626; and A : D = 4.308; P < .001). PCoAAs were associated with larger diameters of the posterior communicating arteries (median value 1.05 vs 0.86 mm; P = .001). The presence of F-PCAs was associated with larger sizes of the aneurysm necks (median value 3.3 vs 3.0 mm; P = .02). CONCLUSION PCoAAs were associated with a higher prevalence of ipsilateral F-PCAs. This variant was associated with larger sizes of the aneurysm necks but was not associated with the sizes of the aneurysm domes or with their rupture statuses.
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Affiliation(s)
- Peeraphong Thiarawat
- Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland.,De-partment of Surgery, Naresuan University, Phitsanulok, Thailand
| | | | - Danil A Kozyrev
- Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland.,Department of Paediatric Neurology and Neurosurgery, North-western State Medical University, St. Petersburg, Russia
| | - Patcharin Intarakhao
- Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland.,Department of Anesthesiology, Naresuan University, Phitsanulok, Thailand
| | - Mario K Teo
- Bristol Institute of Clinical Neurosciences, North Bristol University Hospital, Bristol, United Kingdom
| | | | - Mika Niemelä
- Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland
| | - Juha Hernesniemi
- Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland
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22
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Wiegers EJA, Mulder MJHL, Jansen IGH, Venema E, Compagne KCJ, Berkhemer OA, Emmer BJ, Marquering HA, van Es ACGM, Sprengers ME, van Zwam WH, van Oostenbrugge RJ, Roos YBWEM, Majoie CBLM, Roozenbeek B, Lingsma HF, Dippel DWJ, van der Lugt A. Clinical and Imaging Determinants of Collateral Status in Patients With Acute Ischemic Stroke in MR CLEAN Trial and Registry. Stroke 2020; 51:1493-1502. [PMID: 32279619 DOI: 10.1161/strokeaha.119.027483] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Background and Purpose- Collateral circulation status at baseline is associated with functional outcome after ischemic stroke and effect of endovascular treatment. We aimed to identify clinical and imaging determinants that are associated with collateral grade on baseline computed tomography angiography in patients with acute ischemic stroke due to an anterior circulation large vessel occlusion. Methods- Patients included in the MR CLEAN trial (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands; n=500) and MR CLEAN Registry (n=1488) were studied. Collateral status on baseline computed tomography angiography was scored from 0 (absent) to 3 (good). Multivariable ordinal logistic regression analyses were used to test the association of selected determinants with collateral status. Results- In total, 1988 patients were analyzed. Distribution of the collateral status was as follows: absent (7%, n=123), poor (32%, n=596), moderate (39%, n=735), and good (23%, n=422). Associations for a poor collateral status in a multivariable model existed for age (adjusted common odds ratio, 0.92 per 10 years [95% CI, 0.886-0.98]), male (adjusted common odds ratio, 0.64 [95% CI, 0.53-0.76]), blood glucose level (adjusted common odds ratio, 0.97 [95% CI, 0.95-1.00]), and occlusion of the intracranial segment of the internal carotid artery with occlusion of the terminus (adjusted common odds ratio 0.50 [95% CI, 0.41-0.61]). In contrast to previous studies, we did not find an association between cardiovascular risk factors and collateral status. Conclusions- Older age, male sex, high glucose levels, and intracranial internal carotid artery with occlusion of the terminus occlusions are associated with poor computed tomography angiography collateral grades in patients with acute ischemic stroke eligible for endovascular treatment.
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Affiliation(s)
- Eveline J A Wiegers
- From the Department of Public Health (E.J.A.W., E.V., H.F.L.), Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Maxim J H L Mulder
- Department of Neurology (M.J.H.L.M., E.V., K.C.J.C., O.A.B., B.R., D.W.J.D.), Erasmus University Medical Center, Rotterdam, the Netherlands.,Department of Radiology and Nuclear Medicine (M.J.H.L.M., K.C.J.C., O.A.B., A.C.G.M.v.E., B.R., A.v.d.L.), Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Ivo G H Jansen
- Department of Radiology and Nuclear Medicine (I.G.H.J., B.J.E., H.A.M., M.E.S., C.B.L.M.M.), Amsterdam UMC, location AMC, the Netherlands
| | - Esmee Venema
- From the Department of Public Health (E.J.A.W., E.V., H.F.L.), Erasmus University Medical Center, Rotterdam, the Netherlands.,Department of Neurology (M.J.H.L.M., E.V., K.C.J.C., O.A.B., B.R., D.W.J.D.), Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Kars C J Compagne
- Department of Neurology (M.J.H.L.M., E.V., K.C.J.C., O.A.B., B.R., D.W.J.D.), Erasmus University Medical Center, Rotterdam, the Netherlands.,Department of Radiology and Nuclear Medicine (M.J.H.L.M., K.C.J.C., O.A.B., A.C.G.M.v.E., B.R., A.v.d.L.), Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Olvert A Berkhemer
- Department of Neurology (M.J.H.L.M., E.V., K.C.J.C., O.A.B., B.R., D.W.J.D.), Erasmus University Medical Center, Rotterdam, the Netherlands.,Department of Radiology and Nuclear Medicine (M.J.H.L.M., K.C.J.C., O.A.B., A.C.G.M.v.E., B.R., A.v.d.L.), Erasmus University Medical Center, Rotterdam, the Netherlands.,Cardiovascular Research Institute Maastricht, the Netherlands (O.A.B., W.H.v.Z., R.J.v.O.)
| | - Bart J Emmer
- Department of Radiology and Nuclear Medicine (I.G.H.J., B.J.E., H.A.M., M.E.S., C.B.L.M.M.), Amsterdam UMC, location AMC, the Netherlands
| | - Henk A Marquering
- Department of Radiology and Nuclear Medicine (I.G.H.J., B.J.E., H.A.M., M.E.S., C.B.L.M.M.), Amsterdam UMC, location AMC, the Netherlands.,Department of Biomedical Engineering and Physics (H.A.M.), Amsterdam UMC, location AMC, the Netherlands
| | - Adriaan C G M van Es
- Department of Radiology and Nuclear Medicine (M.J.H.L.M., K.C.J.C., O.A.B., A.C.G.M.v.E., B.R., A.v.d.L.), Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Marieke E Sprengers
- Department of Radiology and Nuclear Medicine (I.G.H.J., B.J.E., H.A.M., M.E.S., C.B.L.M.M.), Amsterdam UMC, location AMC, the Netherlands
| | - Wim H van Zwam
- Cardiovascular Research Institute Maastricht, the Netherlands (O.A.B., W.H.v.Z., R.J.v.O.).,Department of Radiology (W.H.v.Z.), Maastricht University Medical Center, the Netherlands
| | - Robert J van Oostenbrugge
- Cardiovascular Research Institute Maastricht, the Netherlands (O.A.B., W.H.v.Z., R.J.v.O.).,Department of Neurology (R.J.v.O.), Maastricht University Medical Center, the Netherlands
| | - Yvo B W E M Roos
- Department of Neurology, Academic Medical Center, Amsterdam, the Netherlands (Y.B.W.E.M.R.)
| | - Charles B L M Majoie
- Department of Radiology and Nuclear Medicine (I.G.H.J., B.J.E., H.A.M., M.E.S., C.B.L.M.M.), Amsterdam UMC, location AMC, the Netherlands
| | - Bob Roozenbeek
- Department of Neurology (M.J.H.L.M., E.V., K.C.J.C., O.A.B., B.R., D.W.J.D.), Erasmus University Medical Center, Rotterdam, the Netherlands.,Department of Radiology and Nuclear Medicine (M.J.H.L.M., K.C.J.C., O.A.B., A.C.G.M.v.E., B.R., A.v.d.L.), Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Hester F Lingsma
- From the Department of Public Health (E.J.A.W., E.V., H.F.L.), Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Diederik W J Dippel
- Department of Neurology (M.J.H.L.M., E.V., K.C.J.C., O.A.B., B.R., D.W.J.D.), Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Aad van der Lugt
- Department of Radiology and Nuclear Medicine (M.J.H.L.M., K.C.J.C., O.A.B., A.C.G.M.v.E., B.R., A.v.d.L.), Erasmus University Medical Center, Rotterdam, the Netherlands
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Wijesinghe P, Steinbusch HWM, Shankar SK, Yasha TC, De Silva KRD. Circle of Willis abnormalities and their clinical importance in ageing brains: A cadaveric anatomical and pathological study. J Chem Neuroanat 2020; 106:101772. [PMID: 32165168 DOI: 10.1016/j.jchemneu.2020.101772] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/24/2020] [Accepted: 02/27/2020] [Indexed: 01/30/2023]
Abstract
The circle of Willis (CW) located at the base of the brain forms an important collateral network to maintain adequate cerebral perfusion, especially in clinical situations requiring compensatory changes in blood flow. Morphopathological changes in the CW may relate to the severity of the symptoms of certain neurodegenerative and cerebrovascular disorders. The purpose of this study was to investigate the CW abnormalities and their clinical importance in ageing brains. The CW was examined macroscopically in 73 formalin-fixed samples to determine the degree of stenosis of each CW component, atherosclerosis of the CW, hypoplasia (threshold diameter < 1 mm), anatomical variations and aneurysms. Age-related neurodegenerative and cerebrovascular pathologies were screened using immunohistopathological techniques on specific neuroanatomical regions based on standard guidelines. The majority of the elderly brains -93 % (68/73) presented at least a single hypoplastic CW component at death. Anatomical variations were mostly identified in communicating arteries, followed by proximal posterior and anterior cerebral arteries. Arterial bifurcations were found to be the predominant sites for cerebral aneurysms. More than 90 % of the elderly brains presented CW atherosclerosis at death. CW abnormalities did not show any strong associations with neurodegenerative pathologies except for an "at risk" significant association observed between Braak's neurofibrillary tangle (NFT) stages 1-VI and CW atherosclerosis grades ≥ mild (p = 0.05). However, a significant association was observed between microscopic infarcts in deep white matter and hypoplasia in communicating arteries with Fisher's exact test (p < 0.05). Overall, CW abnormalities were predominant in the ageing brains, however their relationships to the occurrence and severity of the symptoms of neurodegenerative pathologies were found to be low.
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Affiliation(s)
- P Wijesinghe
- Interdisciplinary Center for Innovation in Biotechnology & Neuroscience, Genetic Diagnostic & Research Laboratory and Human Brain Tissue and DNA Repository, Dept. Anatomy, Faculty of Medical Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka; EURON - European Graduate School of Neuroscience, Maastricht, The Netherlands
| | - H W M Steinbusch
- Dept. Translational Neuroscience, Faculty Health, Medicine & Life Sciences, University of Maastricht, Maastricht, Netherlands; EURON - European Graduate School of Neuroscience, Maastricht, The Netherlands
| | - S K Shankar
- Dept. Neuropathology, National Institute of Mental Health & Neurosciences (NIMHANS), Bangalore, India
| | - T C Yasha
- Dept. Neuropathology, National Institute of Mental Health & Neurosciences (NIMHANS), Bangalore, India
| | - K R D De Silva
- Interdisciplinary Center for Innovation in Biotechnology & Neuroscience, Genetic Diagnostic & Research Laboratory and Human Brain Tissue and DNA Repository, Dept. Anatomy, Faculty of Medical Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka; EURON - European Graduate School of Neuroscience, Maastricht, The Netherlands.
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Zarrinkoob L, Wåhlin A, Ambarki K, Birgander R, Eklund A, Malm J. Blood Flow Lateralization and Collateral Compensatory Mechanisms in Patients With Carotid Artery Stenosis. Stroke 2020; 50:1081-1088. [PMID: 30943887 PMCID: PMC6485302 DOI: 10.1161/strokeaha.119.024757] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Background and Purpose- Four-dimensional phase-contrast magnetic resonance imaging enables quantification of blood flow rate (BFR; mL/min) in multiple cerebral arteries simultaneously, making it a promising technique for hemodynamic investigation in patients with stroke. The aim of this study was to quantify the hemodynamic disturbance and the compensatory pattern of collateral flow in patients with symptomatic carotid stenosis. Methods- Thirty-eight patients (mean, 72 years; 27 men) with symptomatic carotid stenosis (≥50%) or occlusion were investigated using 4-dimensional phase-contrast magnetic resonance imaging. For each patient, BFR was measured in 19 arteries/locations. The ipsilateral side to the symptomatic carotid stenosis was compared with the contralateral side. Results- Internal carotid artery BFR was lower on the ipsilateral side (134±87 versus 261±95 mL/min; P<0.001). BFR in anterior cerebral artery (A1 segment) was lower on ipsilateral side (35±58 versus 119±72 mL/min; P<0.001). Anterior cerebral artery territory bilaterally was primarily supplied by contralateral internal carotid artery. The ipsilateral internal carotid artery mainly supplied the ipsilateral middle cerebral artery (MCA) territory. MCA was also supplied by a reversed BFR found in the ophthalmic and the posterior communicating artery routes on the ipsilateral side (-5±28 versus 10±28 mL/min, P=0.001, and -2±12 versus 6±6 mL/min, P=0.03, respectively). Despite these compensations, BFR in MCA was lower on the ipsilateral side, and this laterality was more pronounced in patients with severe carotid stenosis (≥70%). Although comparing ipsilateral MCA BFR between stenosis groups (<70% and ≥70%), there was no difference ( P=0.95). Conclusions- With a novel approach using 4-dimensional phase-contrast magnetic resonance imaging, we could simultaneously quantify and rank the importance of collateral routes in patients with carotid stenosis. An important observation was that contralateral internal carotid artery mainly secured the bilateral anterior cerebral artery territory. Because of the collateral recruitment, compromised BFR in MCA is not necessarily related to the degree of carotid stenosis. These findings highlight the importance of simultaneous investigation of the hemodynamics of the entire cerebral arterial tree.
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Affiliation(s)
- Laleh Zarrinkoob
- From the Department of Pharmacology and Clinical Neuroscience, Umeå, Sweden (L.Z., J.M.).,Department of Surgical and Perioperative Sciences, Umeå, Sweden (L.Z.)
| | - Anders Wåhlin
- Department of Radiation Science, Umeå, Sweden (A.W., K.A., R.B., A.E.).,Centre for Biomedical Engineering and Physics, Umeå, Sweden (A.W., K.A., A.E.).,Umeå Center for Functional Brain Imaging, Sweden (A.W., A.E.)
| | - Khalid Ambarki
- Department of Radiation Science, Umeå, Sweden (A.W., K.A., R.B., A.E.).,Centre for Biomedical Engineering and Physics, Umeå, Sweden (A.W., K.A., A.E.)
| | - Richard Birgander
- Department of Radiation Science, Umeå, Sweden (A.W., K.A., R.B., A.E.)
| | - Anders Eklund
- Department of Radiation Science, Umeå, Sweden (A.W., K.A., R.B., A.E.).,Centre for Biomedical Engineering and Physics, Umeå, Sweden (A.W., K.A., A.E.).,Umeå Center for Functional Brain Imaging, Sweden (A.W., A.E.)
| | - Jan Malm
- From the Department of Pharmacology and Clinical Neuroscience, Umeå, Sweden (L.Z., J.M.)
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Abstract
PURPOSE OF REVIEW Multimodal CT imaging (non-contrast CT, NCCT; CT angiography, CTA; and CT Perfusion, CTP) is central to acute ischemic stroke diagnosis and treatment. We reviewed the purpose and interpretation of each component of multimodal CT, as well as the evidence for use in routine care. RECENT FINDINGS Acute stroke thrombolysis can be administered immediately following NCCT in acute ischemic stroke patients assessed within 4.5 h of symptom onset. Definitive identification of a large vessel occlusion (LVO) requires vascular imaging, which is easily achieved with CTA. This is critical, as the standard of care for LVO within 6 h of onset is now endovascular thrombectomy (EVT). CTA source images can also be used to estimate the efficacy of collateral flow in LVO patients. The final component (CTP) permits a more accurate assessment of the extent of the ischemic penumbra. Complete multimodal CT, including objective penumbral measurement with CTP, has been used to extend the EVT window to 24 h. There is also randomized controlled trial evidence for extension of the IV thrombolysis window to 9 h with multimodal CT. Although there have been attempts to assess for responders to reperfusion strategies beyond 6 h ("late window") using collateral grades, the only evidence for treatment of this group of patients is based on selection using multimodal CT including CTP. The development of fully automated software providing quantitative ischemic penumbral and core volumes has facilitated the adoption of CTP and complete multimodal CT into routine clinical use. Multimodal CT is a powerful imaging algorithm that is central to current ischemic stroke patient care.
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26
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Rapadamnaba R, Nicoud F, Mohammadi B. Backward sensitivity analysis and reduced-order covariance estimation in noninvasive parameter identification for cerebral arteries. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3170. [PMID: 30426715 DOI: 10.1002/cnm.3170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 11/02/2018] [Accepted: 11/03/2018] [Indexed: 06/09/2023]
Abstract
Using a previously developed inversion platform for functional cerebral medical imaging with ensemble Kalman filters, this work analyzes the sensitivity of the results with respect to different parameters entering the physical model and inversion procedure, such as the inlet flow rate from the heart, the choice of the boundary conditions, and the nonsymmetry in the network terminations. It also proposes an alternative low complexity construction for the covariance matrix of the hemodynamic parameters of a network of arteries including the circle of Willis. The platform takes as input patient-specific blood flow rates extracted from magnetic resonance angiography and magnetic resonance imaging (dicom files) and is applied to several available patients data. The paper presents full analysis of the results for one of these patients, including a sensitivity study with respect to the proximal and distal boundary conditions. The results notably show that the uncertainties on the inlet flow rate led to uncertainties of the same order of magnitude in the estimated parameters (blood pressure and elastic parameters) and that three-lumped parameters boundary conditions are necessary for a correct retrieval of the target signals.
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Affiliation(s)
| | - Franck Nicoud
- IMAG, Université de Montpellier, CC051, Montpellier, France
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Zhang L, Dai D, Li Z, Duan G, Zhang YW, Yang P, Huang Q, Xu Y, Hong B, Liu J. Risk factors for hyperperfusion-induced intracranial hemorrhage after carotid artery stenting in patients with symptomatic severe carotid stenosis evaluation. J Neurointerv Surg 2018; 11:474-478. [DOI: 10.1136/neurintsurg-2018-013998] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 08/09/2018] [Accepted: 08/23/2018] [Indexed: 11/03/2022]
Abstract
BackgroundAnalyzing risk factors for hyperperfusion-induced intracranial hemorrhage (HICH) after carotid artery stenting (CAS) in patients with symptomatic severe carotid stenosis.MethodsThis study retrospectively analyzed clinical data of 210 patients, who had symptomatic severe carotid stenosis (70–99%) and received CAS treatment between June 2009 and June 2015, and evaluated the relationship of HICH with patients’ clinical baseline data, imaging features, and treatment strategies.ResultsSeven patients (3.3%) developed HICH after CAS. The incidence of HICH among patients with near total occlusion was significantly higher than among those without (10.1% vs 0%, P<0.001). Out of the seven, five had no development of either anterior or posterior circulations, and two had no development of anterior circulation and poor development of posterior circulation. Results showed that patients with poor compensation of Willis’ Circle were more likely to develop HICH compared with other patients (P<0.001). All patients received preoperative CT perfusion. TTP index was defined as the TTP ratio between the affected and contralateral side. The results showed that the TTP index was significantly different between the HICH group and non-HICH group (1.15±0.10 vs 1.30±0.15, P<0.001). An analysis of the ROC curve indicated that patients with TTP index >1.22 were more likely to develop HICH compared with other patients (sensitivity 100%, specificity 75.9%).ConclusionsPatients with severe unilateral carotid stenosis, the presence of near total occlusion, poor compensation of Willis’ Circle, and preoperative TTP index>1.22, have a higher risk of developing HICH after CAS.
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Saqqur M, Khan K, Derksen C, Alexandrov A, Shuaib A. Transcranial Doppler and Transcranial Color Duplex in Defining Collateral Cerebral Blood Flow. J Neuroimaging 2018; 28:455-476. [DOI: 10.1111/jon.12535] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 06/18/2018] [Indexed: 12/31/2022] Open
Affiliation(s)
- Maher Saqqur
- Division of Neurology, Department of Medicine; University of Alberta; Edmonton AB Canada
- Neuroscience Institute; Hamad General Hospital Doha Qatar
| | - Khurshid Khan
- Division of Neurology, Department of Medicine; University of Alberta; Edmonton AB Canada
| | - Carol Derksen
- Division of Neurology, Department of Medicine; University of Alberta; Edmonton AB Canada
| | - Andrei Alexandrov
- Department of Neurology; University of Tennessee Health Science Center; Memphis TN USA
| | - Ashfaq Shuaib
- Division of Neurology, Department of Medicine; University of Alberta; Edmonton AB Canada
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29
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Ogawa M, Omata S, Kan H, Arai N, Asai M, Urano M, Shibamoto Y. Utility of the variable flip angle 3D fast-spin echo (isoFSE) sequence on 3T MR for diagnosing vertebrobasilar artery dissection. Radiol Phys Technol 2018; 11:228-234. [PMID: 29696529 DOI: 10.1007/s12194-018-0460-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 04/20/2018] [Accepted: 04/20/2018] [Indexed: 12/01/2022]
Abstract
We aimed to investigate the utility of the isoFSE sequence, one of the variable flip angle 3D fast-spin echo sequences, on 3T-MR for displaying vessel walls and diagnosing vertebrobasilar artery dissection (VAD). We retrospectively evaluated 12 initial and 28 follow-up images from 12 patients diagnosed with either intracranial VAD or carotid artery dissection. The image quality for displaying the vessel wall was scored using a five-point scale (1 poor, 5 excellent) on initial T1-weighted isoFSE images for each region of the arteries. The intracranial artery dissection findings assessed at time points after onset were evaluated on initial and follow-up T1/T2-weighted isoFSE images. For small arteries, including the anterior/posterior inferior cerebellar artery, similar high scores were obtained on both unenhanced and contrast-enhanced T1-weighted isoFSE images (average: 4.7-5.0, p > 0.2). On unenhanced images, dissected vertebral arteries showed significantly lower scores than non-dissected vertebral arteries for both readers (p = 0.017 and 0.015, respectively), but the scores were high (3.9 and 4.0, respectively). Definitive findings of VAD were observed on the initial images except in one case. For all cases, definitive findings were seen on at least one of the initial or follow-up images. Temporal changes in the findings could be observed for all cases. In conclusion, we showed favorable wall visualization on T1-weighted isoFSE images and the utility of follow-up imaging using unenhanced-T1/T2-weighted and contrast-enhanced T1-weighted isoFSE sequences with acceptable scan times, which could promote the regular use of 3D black-blood vessel wall imaging.
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Affiliation(s)
- Masaki Ogawa
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan.
| | - Shingo Omata
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Hirohito Kan
- Department of Radiology, Nagoya City University Hospital, 1, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Nobuyuki Arai
- Department of Radiology, Nagoya City University Hospital, 1, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Marehiko Asai
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Misugi Urano
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Yuta Shibamoto
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
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30
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The Role of Circle of Willis Anatomy Variations in Cardio-embolic Stroke: A Patient-Specific Simulation Based Study. Ann Biomed Eng 2018; 46:1128-1145. [DOI: 10.1007/s10439-018-2027-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 04/11/2018] [Indexed: 11/25/2022]
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Cilliers K, Vorster W, Page BJ. The anatomical variation of the circulus arteriosus cerebri in a cadaver cohort representing the population dynamics of the Western Cape. Br J Neurosurg 2017; 32:61-67. [DOI: 10.1080/02688697.2017.1374348] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Karen Cilliers
- Anatomy & Histology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Willie Vorster
- Department of Anatomy, School of Medicine, Faculty of Health Sciences, University of Namibia, Windhoek, Namibia
| | - Benedict John Page
- Anatomy & Histology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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Lal R, Nicoud F, Bars EL, Deverdun J, Molino F, Costalat V, Mohammadi B. Non Invasive Blood Flow Features Estimation in Cerebral Arteries from Uncertain Medical Data. Ann Biomed Eng 2017; 45:2574-2591. [DOI: 10.1007/s10439-017-1904-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 08/12/2017] [Indexed: 11/30/2022]
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Kuyumcu G, Byrne RW, Dawe RJ, Kocak M. Incomplete Circle of Willis: A risk factor for mesial temporal sclerosis? Epilepsy Res 2017; 132:29-33. [PMID: 28284050 DOI: 10.1016/j.eplepsyres.2017.02.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 01/15/2017] [Accepted: 02/27/2017] [Indexed: 12/01/2022]
Abstract
OBJECTIVE The aim of this study was to investigate whether there may be a correlation between the anatomical variants of Circle of Willis (CoW) and presence/laterality of mesial temporal sclerosis (MTS). METHODS We retrospectively identified the CoW variants on Wada angiograms in 71 patients with pathologically proven MTS. Angiograms were interpreted by two radiologists independently and blinded to clinical data. We divided the anterior and posterior components of the CoW into functionally complete and functionally incomplete groups. We then sought its correlation with the presence and laterality of MTS. RESULTS No statistically significant relationship was found between the functional status of the anterior circulation and the laterality of the MTS (p=0.657). Relationship of the posterior incomplete circle to MTS was statistically significant on both sides (p=0.023 for the left, p=0.04 for the right), with an effect size moderate to large for the left side and moderate for the right side. Although the fetal variant appeared to be related to the ipsilateral MTS, it did not reach to a level of statistical significance (p=0.15). SIGNIFICANCE The study demonstrates a statistically significant association of the incomplete posterior circulation of the CoW to the presence of ipsilateral MTS. Further studies in larger patient populations may be needed to seek whether an incomplete circulation may facilitate development of MTS, especially affecting the watershed zones.
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Affiliation(s)
- Gokhan Kuyumcu
- Rush University Medical Center, Department of Radiology & Nuclear Medicine, 1725 West Harrison Street, Suite 437, Chicago, IL 60612, USA.
| | - Richard W Byrne
- Rush University Medical Center, Department of Neurosurgery, 1725 West Harrison Street, Suite 855, Chicago, IL 60612, USA.
| | - Robert J Dawe
- Rush University Medical Center, Department of Radiology & Nuclear Medicine, 1725 West Harrison Street, Suite 437, Chicago, IL 60612, USA; Rush Alzheimer's Disease Center, Johnston R Bowman Health Center, 600 S. Paulina Street, Chicago, IL, 60612, USA.
| | - Mehmet Kocak
- Rush University Medical Center, Department of Radiology & Nuclear Medicine, 1725 West Harrison Street, Suite 437, Chicago, IL 60612, USA.
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Komatsu M, Suda K, Takahata M, Matsumoto S, Ushiku C, Yamada K, Yamane J, Endo T, Iwasaki N, Minami A. Delayed bilateral vertebral artery occlusion after cervical spine injury: a case report. Spinal Cord Ser Cases 2016; 2:16031. [PMID: 28053772 DOI: 10.1038/scsandc.2016.31] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 07/19/2016] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION There are considerable risks for the secondary spinal cord injury and the initial and/or delayed vertebral artery occlusion in cases of cervical fracture dislocation. CASE PRESENTATION An 86-year-old man was injured in a car accident and was diagnosed with no fracture or dislocation of the cervical spine by the emergency physician. However, he was transferred to our hospital 3 days later because he had motor weakness that was evaluated to be 32 points (out of 50 points) on the upper limb American Spinal Injury Association (ASIA) motor score and was diagnosed with spontaneously reduced fracture dislocation at C5/6. Magnetic resonance images revealed that the bilateral vertebral arteries were occluded, and there were some microinfarction lesions in the brain. On the first visit to his previous doctor, he was found to have a flow void in the right vertebral artery. This indicated that it was occluded during the waiting period at his previous doctor. On the day of his arrival at our hospital, the patient underwent a C5/6 posterior spinal fusion. Three months after surgery, he recovered to 46 points on the upper extremity ASIA motor score, and blood flow in the left vertebral artery was resumed. DISCUSSION Early reduction and stabilization are necessary for cervical spine fracture dislocation; however, it is important not only for the prevention of the secondary injury but also for the reduction of the risk of vertebral artery occlusion.
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Affiliation(s)
- Miki Komatsu
- Department of Orthopaedic Surgery, Hokkaido Chuo Rosai Hospital Spinal Cord Injury Center , Bibai, Japan
| | - Kota Suda
- Department of Orthopaedic Surgery, Hokkaido Chuo Rosai Hospital Spinal Cord Injury Center , Bibai, Japan
| | - Masahiko Takahata
- Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine , Sapporo, Japan
| | - Satoko Matsumoto
- Department of Orthopaedic Surgery, Hokkaido Chuo Rosai Hospital Spinal Cord Injury Center , Bibai, Japan
| | - Chikara Ushiku
- Department of Orthopaedic Surgery, Hokkaido Chuo Rosai Hospital Spinal Cord Injury Center , Bibai, Japan
| | - Katsuhisa Yamada
- Department of Orthopaedic Surgery, Hokkaido Chuo Rosai Hospital Spinal Cord Injury Center , Bibai, Japan
| | - Junichi Yamane
- Department of Orthopaedic Surgery, Hokkaido Chuo Rosai Hospital Spinal Cord Injury Center , Bibai, Japan
| | - Tsutomu Endo
- Department of Orthopaedic Surgery, Hokkaido Chuo Rosai Hospital Spinal Cord Injury Center , Bibai, Japan
| | - Norimasa Iwasaki
- Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine , Sapporo, Japan
| | - Akio Minami
- Department of Orthopaedic Surgery, Hokkaido Chuo Rosai Hospital Spinal Cord Injury Center , Bibai, Japan
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Liu X, Pu Y, Pan Y, Zhang Y, Dou X, Tan Y, Liu L, Wang Y. Multi-mode CT in the evaluation of leptomeningeal collateral flow and the related factors: comparing with digital subtraction angiography. Neurol Res 2016; 38:504-9. [DOI: 10.1080/01616412.2016.1187828] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Zhu G, Yuan Q, Yang J, Yeo JH. The role of the circle of Willis in internal carotid artery stenosis and anatomical variations: a computational study based on a patient-specific three-dimensional model. Biomed Eng Online 2015; 14:107. [PMID: 26608827 PMCID: PMC4659208 DOI: 10.1186/s12938-015-0105-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 11/18/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The aim of this study is to provide better insights into the cerebral perfusion patterns and collateral mechanism of the circle of Willis (CoW) under anatomical and pathological variations. METHODS In the current study, a patient-specific three-dimensional computational model of the CoW was reconstructed based on the computed tomography (CT) images. The Carreau model was applied to simulate the non-Newtonian property of blood. Flow distributions in five common anatomical variations coexisting with different degrees of stenosis in the right internal carotid artery (RICA) were investigated to obtain detailed flow information. RESULTS With the development of stenosis in unilateral internal carotid artery (ICA), the cerebral blood supply decreased when the degree of stenosis increased. The blood supply of the ipsilateral middle cerebral artery (MCA) was most affected by the stenosis of ICA. The anterior communicating artery (ACoA) and ipsilateral posterior communicating artery (PCoA) functioned as the important collateral circulation channels when unilateral stenosis occurred. The blood flow of the anterior circulation and the total cerebral blood flow (CBF) reached to the minimum in the configuration of the contralateral proximal anterior cerebral artery (A1) absence coexisting with unilateral ICA stenosis. CONCLUSIONS Communicating arteries provided important collateral channels in the complete CoW when stenosis in unilateral ICA occurred. The cross-flow in the ACoA is a sensitive indicator of the morphological change of the ICA. The collateral function of the PCoA on the affected side will not be fully activated until a severe stenosis occurred in unilateral ICA. The absence of unilateral A1 coexisting with the stenosis in the contralateral ICA could be the most dangerous configuration in terms of the total cerebral blood supply. The findings of this study would enhance the understanding of the collateral mechanism of the CoW under different anatomical variations.
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Affiliation(s)
- Guangyu Zhu
- School of Energy and Power Engineering, Xi'an Jiaotong University, 28 Xian Ning West Rd, Xi'an, 710049, Shaanxi, China.
| | - Qi Yuan
- School of Energy and Power Engineering, Xi'an Jiaotong University, 28 Xian Ning West Rd, Xi'an, 710049, Shaanxi, China.
| | - Jian Yang
- Department of Radiology and Medical Imaging, The First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, 710061, Shaanxi, China.
| | - Joon Hock Yeo
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore, 639798, Singapore.
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Spacek M, Tesar D, Veselka J. The Paramount Role of the Anterior Communicating Artery in the Collateral Cerebral Circulation. Int J Angiol 2015; 24:236-40. [PMID: 26417193 DOI: 10.1055/s-0034-1370889] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Clinical manifestation of carotid occlusive disease is largely dependent on the severity of stenosis and the capability of collateral circulation. However, due to the complexity and difficulty in evaluation, cerebral collateral circulation has, so far, remained underappreciated. We report a patient with advanced extracranial arterial disease (including the right subclavian steal, occlusion of the right external carotid artery, and severe stenosis of the left vertebral artery), who underwent transient right internal carotid artery occlusion during carotid intervention. Throughout the occlusion, the flow into the right hemisphere (monitored by transcranial Doppler ultrasound in the right middle cerebral artery) was sufficient despite almost totally dependent on the anterior communicating artery, which highlights its role as the most potent collateral pathway.
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Affiliation(s)
- Miloslav Spacek
- Department of Cardiology, University Hospital Motol, Charles University, Prague, Czech Republic
| | - David Tesar
- Department of Cardiology, University Hospital Motol, Charles University, Prague, Czech Republic
| | - Josef Veselka
- Department of Cardiology, University Hospital Motol, Charles University, Prague, Czech Republic
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Spacek M, Stechovsky C, Horvath M, Hajek P, Veselka J. Predicting Hemodynamic Changes of Cerebral Blood Flow during Temporal Carotid Occlusion: A Review of Current Knowledge with Implication for Carotid Artery Stenting. Int J Angiol 2015; 24:210-4. [PMID: 26417190 DOI: 10.1055/s-0035-1555132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Carotid artery disease (CAD) plays an important role in the stroke development and its prevalence increases with aging of the population. Its wide variability of clinical manifestation ranges from incidental asymptomatic finding to devastating or fatal stroke, although cerebral collateral circulation is considered one of the major modifying factors. Over time, carotid artery stenting (CAS) has evolved into a reputable method for the treatment of patients with severe CAD. With expanding use of proximal protection systems resembling surgical clamp, there is an increasing demand to understand collateral cerebral circulation to protect patients from periprocedural hypoperfusion, which increases the risk of cerebral events. Transcranial Doppler ultrasound (TCD) is a useful tool allowing monitoring in real time during procedure patient́s cerebral hemodynamic status providing the operator with valuable information. Its role in predicting periprocedural hypoperfusion is, however, less well established. In this article, we discuss the role of cerebral collateral circulation, summarize the current knowledge regarding its evaluation with TCD and suggest future implications for CAS.
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Affiliation(s)
- Miloslav Spacek
- Department of Cardiology, Motol University Hospital, 2nd Medical School, Charles University, V Úvalu, Prague, Czech Republic
| | - Cyril Stechovsky
- Department of Cardiology, Motol University Hospital, 2nd Medical School, Charles University, V Úvalu, Prague, Czech Republic
| | - Martin Horvath
- Department of Cardiology, Motol University Hospital, 2nd Medical School, Charles University, V Úvalu, Prague, Czech Republic
| | - Petr Hajek
- Department of Cardiology, Motol University Hospital, 2nd Medical School, Charles University, V Úvalu, Prague, Czech Republic
| | - Josef Veselka
- Department of Cardiology, Motol University Hospital, 2nd Medical School, Charles University, V Úvalu, Prague, Czech Republic
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Low prevalence of collateral cerebral circulation in the circle of Willis in patients with severe carotid artery stenosis and recent ischemic stroke. ADVANCES IN INTERVENTIONAL CARDIOLOGY 2015; 11:312-7. [PMID: 26677381 PMCID: PMC4679799 DOI: 10.5114/pwki.2015.55602] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 08/12/2015] [Accepted: 08/30/2015] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION The circle of Willis is thought to play a key role in development of collateral flow in patients with internal carotid artery stenosis (ICAS). AIM To assess flow in the circle of Willis in patients with recent ischemic stroke (IS). MATERIAL AND METHODS The study included 371 patients, 102 symptomatic with severe ICAS and recent IS (within the last 3 months) (group I) and 269 asymptomatic with severe ICAS (group II). Flow in the middle (MCA), anterior (ACA) and posterior (PCA) cerebral arteries and pattern of the cross-flow through anterior (ACoA) and posterior (PCoA) communicating arteries were assessed with transcranial color-coded Doppler ultrasonography (TCCD). RESULTS The ACoA or PCoA was less prevalent in group I than in group II (54% vs. 78%, p < 0.001 and 20% vs. 42%, p < 0.001, respectively), resulting in lower peak-systolic velocity (PSV) in the MCA in group I vs. group II (p = 0.015). Any collateral pathway was present in 67% of patients in group I, compared to 86% in group II (p < 0.001). Both PSV and end-diastolic (EDV) flow velocity in the ACA were lower in patients with recent IS, compared to asymptomatic subjects (71 ±24 cm/s vs. 86 ±34 cm/s, p < 0.001 and 32 ±12 cm/s vs. 37 ±17 cm/s, p = 0.038, respectively). Presence of ACoA or PCoA and higher PSV in the MCA and ACA were associated with significant risk reduction of IS (RR = 0.28 (95% CI = 0.16-0.49, p < 0.001), RR = 0.28 (95% CI = 0.15-0.52, p < 0.001), RR = 0.97 (95% CI = 0.96-0.99, p < 0.001), RR = 0.99 (95% CI = 0.98-0.99, p < 0.032), respectively). However, ROC curves failed to show reliable MCA or ACA PSV cut-offs for IS risk assessment. CONCLUSIONS The ACoA and PCoA seem to play a key role in the evaluation of IS risk in subjects with severe ICAS.
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Abstract
BACKGROUND The Circle of Willis (CoW) is an important collateral pathway of the cerebral blood flow. An experimental study of the cerebral blood flow (CBF) distribution in different anatomical variations may help to a better understanding of the collateral mechanism of the CoW. METHODS An in-vitro test rig was developed to simulate the physiological cerebral blood flow in the CoW. Ten anatomical variations were considered in this study, include a set of different degrees of stenosis in L-ICA and L-ICA occlusion coexist with common anatomical variations. Volume flow rates of efferent arteries and pressure signals at the end of communicating arteries of each case were recorded. Physiological pressure waveforms were applied as inlet boundary condition. RESULTS In the development of L-ICA stenosis, the total CBF decreases with the increase of stenosis degree. The blood supply of ipsilateral middle cerebral artery (MCA) was affected most by the stenosis of L-ICA. Anterior communicating artery (ACoA) and ipsilateral posterior communicating artery (PCoA) function as important collateral pathways of cerebral collateral circulation when unilateral stenosis occurred. The blood supply of anterior cerebral circulation was compensated by the posterior cerebral circulation through ipsilateral PCoA when L-ICA stenosis degree is greater than 40% and the affected side was compensated immediately by the unaffected side through ACoA. Blood flow of the anterior circulation and the total CBF reached the minimum among all cases studied when L-ICA occlusion coexist with the absence of PCoA. CONCLUSION The results demonstrated the flow distribution patterns of the CoW under anatomical variations and clarified the collateral mechanism of the CoW. The flow ACoA is the most sensitive indexes to the morphology change of ipsilateral ICA. The relative independence of the circulation in anterior and posterior sections of the CoW is not broken and the function of ipsilateral PCoA is not activated until a severe stenosis of unilateral ICA occurs. PCoA is the most important collateral pathway of the collateral circulation and the missing of PCoA has the highest risk of stroke when the ipsilateral ICA has severe stenosis. These findings may provide the basis for future therapeutic and diagnosis applications.
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Sadraie SH, Abdi M, Navidbakhsh M, Hassani K, Kaka GR. MODELING THE HEART BEAT, CIRCLE OF WILLIS AND RELATED CEREBRAL STENOSIS USING AN EQUIVALENT ELECTRONIC CIRCUIT. BIOMEDICAL ENGINEERING: APPLICATIONS, BASIS AND COMMUNICATIONS 2014. [DOI: 10.4015/s1016237214500525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this study, the cardiovascular system is modeled using an equivalent electronic system focusing on the circle of Willis (COW). COW supports adequate blood supply to the brain. Each cardiovascular artery is modeled using electrical elements such as resistor, capacitor and inductor. MATLAB Simulink software was used to obtain the left and right ventricles pressure as well as pressure distribution at efferent arteries of the COW. Firstly, the normal operation of the system was shown then the stenosis of cerebral arteries was induced in the circuit and the effects were studied. In the normal condition, the difference between pressure distribution of right and left efferent arteries (left and right anterior cerebral arteries (ACA-A2), left and right middle cerebral arteries (MCA), left and right posterior cerebral arteries (PCA-P2) was calculated to see the effect of anatomical difference between left and right sides of supplying arteries of COW. In stenosis cases, the effect of internal carotid artery (ICA) occlusion on efferent arteries pressure was investigated. The model results were verified by comparing to the clinical observation reported in the literature.
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Affiliation(s)
- S. H. Sadraie
- Neuroscience Research Center, Department of Anatomy, School of Medicine, Baqiyatallah University of Medical Sciences, Tehran 1956837173, Iran
| | - M. Abdi
- Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
- Tissue Engineering and Biological Systems Research Lab, School of Mechanical Engineering, Iran University of Science and Technology, Tehran Science and Research Branch, 16844, Iran
| | - M. Navidbakhsh
- Department of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
- Tissue Engineering and Biological Systems Research Lab, School of Mechanical Engineering, Iran University of Science and Technology, Tehran Science and Research Branch, 16844, Iran
| | - K. Hassani
- Department of Biomechanics, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - G. R. Kaka
- Department of Anatomy, School of Medicine, Baqiyatallah University of Medical Sciences, Tehran 1956837173, Iran
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Vrselja Z, Brkic H, Mrdenovic S, Radic R, Curic G. Function of circle of Willis. J Cereb Blood Flow Metab 2014; 34:578-84. [PMID: 24473483 PMCID: PMC3982101 DOI: 10.1038/jcbfm.2014.7] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 12/31/2013] [Accepted: 01/06/2014] [Indexed: 12/21/2022]
Abstract
Nearly 400 years ago, Thomas Willis described the arterial ring at the base of the brain (the circle of Willis, CW) and recognized it as a compensatory system in the case of arterial occlusion. This theory is still accepted. We present several arguments that via negativa should discard the compensatory theory. (1) Current theory is anthropocentric; it ignores other species and their analog structures. (2) Arterial pathologies are diseases of old age, appearing after gene propagation. (3) According to the current theory, evolution has foresight. (4) Its commonness among animals indicates that it is probably a convergent evolutionary structure. (5) It was observed that communicating arteries are too small for effective blood flow, and (6) missing or hypoplastic in the majority of the population. We infer that CW, under physiologic conditions, serves as a passive pressure dissipating system; without considerable blood flow, pressure is transferred from the high to low pressure end, the latter being another arterial component of CW. Pressure gradient exists because pulse wave and blood flow arrive into the skull through different cerebral arteries asynchronously, due to arterial tree asymmetry. Therefore, CW and its communicating arteries protect cerebral artery and blood-brain barrier from hemodynamic stress.
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Affiliation(s)
- Zvonimir Vrselja
- 1] Department of Anatomy and Neuroscience, Medical School of J. J. Strossmayer University in Osijek, Osijek, Croatia [2] Department of Radiology, Osijek University Medical Center, Osijek, Croatia
| | - Hrvoje Brkic
- Department of Biophysics, Medical Statistics and Medical Informatics, Medical School of J. J. Strossmayer University in Osijek, Osijek, Croatia
| | - Stefan Mrdenovic
- Department of Hematology, Osijek University Medical Center, Osijek, Croatia
| | - Radivoje Radic
- Department of Anatomy and Neuroscience, Medical School of J. J. Strossmayer University in Osijek, Osijek, Croatia
| | - Goran Curic
- 1] Department of Chemistry and Biochemistry, Laboratory for DNA Analysis, Medical School of J. J. Strossmayer University in Osijek, Osijek, Croatia [2] Department of Pathology and Legal Medicine, Osijek University Medical Center, Osijek, Croatia
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Fahy P, Delassus P, McCarthy P, Sultan S, Hynes N, Morris L. An In Vitro Assessment of the Cerebral Hemodynamics Through Three Patient Specific Circle of Willis Geometries. J Biomech Eng 2013; 136:011007. [DOI: 10.1115/1.4025778] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Indexed: 11/08/2022]
Abstract
The Circle of Willis (CoW) is a complex pentagonal network comprised of fourteen cerebral vessels located at the base of the brain. The collateral flow feature within the circle of Willis allows the ability to maintain cerebral perfusion of the brain. Unfortunately, this collateral flow feature can create undesirable flow impact locations due to anatomical variations within the CoW. The interaction between hemodynamic forces and the arterial wall are believed to be involved in the formation of cerebral aneurysms, especially at irregular geometries such as tortuous segments, bends, and bifurcations. The highest propensity of aneurysm formation is known to form at the anterior communicating artery (AcoA) and at the junctions of the internal carotid and posterior communicating arteries (PcoAs). Controversy still remains as to the existence of blood flow paths through the communicating arteries for a normal CoW. This paper experimentally describes the hemodynamic conditions through three thin walled patient specific models of a complete CoW based on medical images. These models were manufactured by a horizontal dip spin coating method and positioned within a custom made cerebral testing system that simulated symmetrical physiological afferent flow conditions through the internal carotid and vertebral arteries. The dip spin coating procedure produced excellent dimensional accuracy. There was an average of less than 4% variation in diameters and wall thicknesses throughout all manufactured CoW models. Our cerebral test facility demonstrated excellent cycle to cycle repeatability, with variations of less than 2% and 1% for the time and cycle averaged flow rates, respectively. The peak systolic flow rates had less than a 4% variation. Our flow visualizations showed four independent flow sources originating from all four inlet arteries impacting at and crossing the AcoA with bidirectional cross flows. The flow paths entering the left and right vertebral arteries dissipated throughout the CoW vasculature from the posterior to anterior sides, exiting through all efferent vessels. Two of the models had five flow impact locations, while the third model had an additional two impact locations within the posterior circulation caused by an additional bidirectional cross flows along the PcoAs during the accelerating and part of the decelerating phases. For a complete CoW, bidirectional cross flows exist within the AcoA and geometrical variations within the CoW geometry can either promote uni- or bidirectional cross flows along the PcoAs.
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Affiliation(s)
| | - Patrick Delassus
- Galway Medical Technologies Centre (GMedTech), Department of Mechanical and Industrial Engineering, Galway Mayo Institute of Technology, Dublin Road, Galway,Ireland
| | - Peter McCarthy
- Department of Diagnostic Radiology, University Hospital, Newcastle Road, Galway,Ireland
| | - Sheriff Sultan
- Department of Vascular and Endovascular Surgery, Western Vascular Institute, University Hospital, Newcastle Road, Galway,Ireland
- Department of Vascular and Endovascular Surgery, Galway Clinic, Doughiska, Galway, Ireland
| | - Niamh Hynes
- Department of Vascular and Endovascular Surgery, Galway Clinic, Doughiska, Galway,Ireland
| | - Liam Morris
- Galway Medical Technologies Centre (GMedTech), Department of Mechanical and Industrial Engineering, Galway Mayo Institute of Technology, Dublin Road, Galway,Ireland e-mail:
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Iqbal S. A comprehensive study of the anatomical variations of the circle of willis in adult human brains. J Clin Diagn Res 2013; 7:2423-7. [PMID: 24392362 DOI: 10.7860/jcdr/2013/6580.3563] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 09/17/2013] [Indexed: 11/24/2022]
Abstract
BACKGROUND Cerebrovascular diseases such as stroke, aneurysms and arterio-venous malformations are very much prevalent in our country. Circle of Willis, as an anastomotic polygon at the base of the brain forms an important collateral network to maintain adequate cerebral perfusion. Changes in the normal morphology of the circle may condition the appearance and severity of symptoms of cerebrovascular disorders, such as aneurysms, infarctions and other vascular anomalies. A possible link between abnormalities of the circle of Willis and the mentally ill patients has been observed. AIM AND OBJECTIVES The aim of the present study is to have an intimate knowledge of the variations in the cerebral arterial circle and to clarify the clinical importance of these variations in certain forms of cerebrovascular diseases. So an attempt was made to analyse the anatomical variations of the circle in a random population. MATERIAL AND METHODS The work was based on fifty adult brains from persons died of diverse causes. The materials were obtained during routine autopsy studies. The base of the brain including the brain stem with intact arterial circle was preserved in 10% formalin for 10 days. The circle of Willis and its major branches were carefully dissected under water using a magnifying lens. The variations were recorded and photographed. RESULTS Majority of the circles (52%) showed anomalies. Hypoplasia was the most frequent anomaly and was found in 24% of the brains. Accessory vessels in the form of duplications/triplications of anterior communicating artery were seen in 12% of the circles. The embryonic origin of the posterior cerebral artery from the internal carotid persisted in 10% of the circles. An incomplete circle due to the absence of one or other posterior communicating artery was found in 6% of the specimens.Variations are more frequent in posterior half of the circle. CONCLUSION The anatomical variations of the circle of Willis were probably genetically determined, develop in early embryonic stage and persist in post natal life. The amplitude of neck movements, racial, environmental and hemodynamic factors may also modify these variations. These anomalies may alter the occurrence, severity of symptoms, treatment options and recovery from certain cerebrovascular disorders viz., stroke and aneurysms. A detailed knowledge of the vascular variants is useful to surgeons in planning their shunt operations, choice of the patients and also keeps away inadvertent vascular traumas during surgeries.
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Affiliation(s)
- S Iqbal
- Associate Professor, Department of Anatomy, Amala Institute of Medical Sciences , Amala Nagar, Thrissur, Kerala, India
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Ito K, Sasaki M, Kobayashi M, Ogasawara K, Nishihara T, Takahashi T, Natori T, Uwano I, Yamashita F, Kudo K. Noninvasive evaluation of collateral blood flow through circle of Willis in cervical carotid stenosis using selective magnetic resonance angiography. J Stroke Cerebrovasc Dis 2013; 23:1019-23. [PMID: 24103664 DOI: 10.1016/j.jstrokecerebrovasdis.2013.08.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 08/12/2013] [Accepted: 08/21/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Preoperative assessment of intracranial collateral circulation is helpful in predicting cerebral ischemia during surgical procedures for cervical internal carotid artery (ICA) stenosis. However, magnetic resonance angiography (MRA) and other less-invasive techniques cannot evaluate collateral blood flow because these techniques are nonselective. Hence, by using a newly developed selective MRA technique, we attempted to visualize collaterals via the circle of Willis in patients with ICA stenosis. METHODS Twelve patients who underwent carotid endarterectomy were prospectively examined with a 1.5-T MR scanner. Both selective and nonselective MRA were obtained using a 3-dimensional time-of-flight technique, with or without a cylindrical saturation pulse that suppresses the flow signal from the region of the target ICA. Maximum intensity projection MRA images were generated and compared with digital subtraction angiography (DSA) images. RESULTS In all patients, the distal flow signal of the ipsilateral ICA was completely suppressed on selective MRA compared with nonselective MRA. In addition, collateral blood flow through the anterior and posterior communicating arteries was visualized in 5 and 2 patients, respectively. These findings corresponded well with the DSA imaging. CONCLUSIONS Selective MRA techniques can readily suppress signals from the distal blood flow of the target artery and visualize the presence of collateral flows through the circle of Willis in patients with cervical ICA stenosis.
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Affiliation(s)
- Kenji Ito
- Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University, Yahaba, Japan
| | - Makoto Sasaki
- Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University, Yahaba, Japan.
| | | | - Kuniaki Ogasawara
- Department of Neurosurgery, Iwate Medical University, Morioka, Japan
| | | | | | - Tatsunori Natori
- Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University, Yahaba, Japan
| | - Ikuko Uwano
- Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University, Yahaba, Japan
| | - Fumio Yamashita
- Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University, Yahaba, Japan
| | - Kohsuke Kudo
- Division of Ultrahigh Field MRI, Institute for Biomedical Sciences, Iwate Medical University, Yahaba, Japan
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Fahy P, McCarthy P, Sultan S, Hynes N, Delassus P, Morris L. An experimental investigation of the hemodynamic variations due to aplastic vessels within three-dimensional phantom models of the circle of Willis. Ann Biomed Eng 2013; 42:123-38. [PMID: 24018609 DOI: 10.1007/s10439-013-0905-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 08/29/2013] [Indexed: 11/26/2022]
Abstract
A complete circle of Willis (CoW) is found in approximately 30-50% of the population. Anatomical variations, such as absent or surgically clamped vessels, can result in undesirable flow patterns. These can affect the brain's ability to maintain cerebral perfusion and the formation of cerebral aneurysms. An experimental test system was developed to simulate cerebral physiological conditions through three flexible 3D patient-specific models of complete and incomplete CoW geometries. Flow visualizations were performed with isobaric dyes and the mapped dye streamlines were tracked throughout the models. Three to seven flow impact locations were observed for all configurations, corresponding to known sites for aneurysmal formation. Uni and bi-directional cross-flows occurred along the communicating arteries. The greatest shunting of flow occurred for a missing pre-communicating anterior (A1) and posterior (P1) cerebral arteries. The anterior cerebral arteries had the greatest reduction (15-37%) in efferent flow rates for missing either a unilateral A1 or bilateral P1 segments. The bi-directional cross-flows, with multiple afferent flow mixing, observed along the communicating arteries may explain the propensity of aneurysm formation at these sites. Reductions in efferent flow rates due to aplastic vessel configurations may affect normal brain function.
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Affiliation(s)
- Paul Fahy
- Galway Medical Technologies Centre (GMedTech), Department of Mechanical and Industrial Engineering, Galway Mayo Institute of Technology, Galway, Ireland
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Hashemi SMR, Mahmoodi R, Amirjamshidi A. Variations in the Anatomy of the Willis' circle: A 3-year cross-sectional study from Iran (2006-2009). Are the distributions of variations of circle of Willis different in different populations? Result of an anatomical study and review of literature. Surg Neurol Int 2013; 4:65. [PMID: 23772335 PMCID: PMC3680999 DOI: 10.4103/2152-7806.112185] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 04/12/2013] [Indexed: 11/17/2022] Open
Abstract
Background: It is not well known whether the distributions of variations of circle of Willis (CW) are different in different populations. Previous studies have indicated: (a) The variations of the structure of the CW in different populations and ethnic and (b) some correlation between those congenital anatomical variations and possible cerebrovascular diseases. The frequency of such anatomical variations has not been evaluated sufficiently in the Iranian population. The aim of this study is to find the variations of the anatomy of the vessels in the CW in sample population of Iranian people and compare it with other available studies in the literature, providing a new grouping for variations. Methods: Samples were obtained from 200 autopsies in different ages, all retrieved in the department of Forensic Medicine, Tehran university of Medical Sciences after achieving permission from the Department of Ethics and Medico-legal Sciences. The CW was examined directly, using magnification, at the base of the brain. The cerebral vessels were observed for their configuration and their calibers were measured directly. Variations were noted and grouped into different categories. Results: Out of the 200 specimens examined, 69 (34.5%) were compatible with the typical anatomy of the CW. In the remaining 65.5% of the specimens, there were variations in the CW. Hypoplasia of the posterior communicating arteries was the most common variation in our study. One of the autopsies showed the presence of an aneurysm (0.5%). Conclusion: The anatomical variations found in our study were not significantly different from those reported in the literature. Based on the available data; (a) there is no evidence that the distribution of the variations of the anatomy of the CW is different in various societies and (b) the prevalence of the congenital aneurysmal changes in this region is not low in the Iranian population.
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Montisci R, Sanfilippo R, Bura R, Branca C, Piga M, Saba L. Status of the Circle of Willis and Intolerance to Carotid Cross-clamping During Carotid Endarterectomy. Eur J Vasc Endovasc Surg 2013; 45:107-12. [DOI: 10.1016/j.ejvs.2012.11.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 11/12/2012] [Indexed: 11/27/2022]
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De Silva KRD, Silva R, Gunasekera WSL, Jayesekera RW. Prevalence of typical circle of Willis and the variation in the anterior communicating artery: A study of a Sri Lankan population. Ann Indian Acad Neurol 2011; 12:157-61. [PMID: 20174495 PMCID: PMC2824931 DOI: 10.4103/0972-2327.56314] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 05/21/2009] [Accepted: 06/18/2009] [Indexed: 11/05/2022] Open
Abstract
Objective: To determine the extent of hypoplasia of the component vessels of the circle of Willis (CW) and the anatomical variations in the anterior communicating artery (AcomA) in the subjects who have died of causes unrelated to the brain and compare with previous autopsy studies. Materials and Methods: The external diameter of all the arteries forming the CW in 225 normal Sri Lankan adult cadaver brains was measured using a calibrated grid to determine the occurrence of “typical” CWs, where all of the component vessels had a diameter of more than 1 mm. Variations in the AcomA were classified into 12 types based on Ozaki et al., 1977. Results: 193 (86%) showed “hypoplasia”, of which 127 (56.4%) were with multiple anomalies. Posterior communicating artery (PcoA) was hypoplastic bilaterally in 93 (51%) and unilaterally in 49 (13%). Precommunicating segment of the posterior cerebral arteries (P1) was hypoplastic bilaterally in 3 (2%), unilaterally in 14 (4%), and AcomA was hypoplastic in 91 (25%). The precommunicating segment of the anterior cerebral arteries (A1) was hypoplastic unilaterally in 17 (5%). Types of variations in the AcomA were: single 145 (65%), fusion 52 (23%), double 22 (10%) [V shape, Y shape, H shape, N shape], triplication 1 (0.44%), presence of median anterior cerebral artery 5 (2%), and aneurysm 1 (0.44%). Conclusion: The occurrence of “typical” CW in autopsy brains was rare. Further studies would be necessary to determine if these anatomical variations could predispose to cerebral ischemia and premature stroke in the Sri Lankan population.
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Affiliation(s)
- K Ranil D De Silva
- Department of Anatomy, Faculty of Medical Sciences, University of Sri Jayewardenepura, Sri Lanka
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