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CIRCLE OF WILLIS: ANATOMICAL VARIATIONS IMPORTANT IN CEREBRAL VASCULAR PATHOLOGY

CIRCLE OF WILLIS: ANATOMICAL VARIATIONS IMPORTANT IN CEREBRAL VASCULAR PATHOLOGY. Raluca Pa ş cal ă u , Vlad Adrian P ă durean Coordinator : Conf. dr. Bianca Szabo Anatomy and Embryology Department Iuliu Ha ţ ieganu University of Medicine and Pharmacy Cluj-Napoca. Introduction.

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CIRCLE OF WILLIS: ANATOMICAL VARIATIONS IMPORTANT IN CEREBRAL VASCULAR PATHOLOGY

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  1. CIRCLE OF WILLIS: ANATOMICAL VARIATIONS IMPORTANT IN CEREBRAL VASCULAR PATHOLOGY Raluca Paşcalău, VladAdrian Pădurean Coordinator: Conf. dr. Bianca Szabo Anatomy and Embryology Department IuliuHaţieganuUniversity of Medicine and Pharmacy Cluj-Napoca

  2. Introduction • Circle of Willis -an anastomotic polygon at the base of the brain • A classical arterial circle is bilaterally symmetrical and a complete ring of vessels [1]. Schematic of the cerebral arteries and the general regions which they supply [2].

  3. 50%of healthy brains [3-7] • 80% of dysfunctional brains [3] vascular surgery[2, 4, 10, 21, 22] collateral perfusion infarct [11, 23-26] • Motivation: improve understanding in cerebral vascular pathology • Aim of study: to present circle of Willis anatomy from a clinical point of view [8-15] migraine [23, 27, 28] mental disease[23, 29, 30] Anatomical variants aneurysms[6, 7, 17, 31-37] branching geometry wall shear stress [7, 16-20] atherosclerosis[7, 38]

  4. Materials and methods 10 formalin injected human brains • macroscopic observation • Vernier caliper measurements • 3 standard photographs • descriptive statistics • anatomical variants • measurements 20 cm Vernier caliper Angles of photography

  5. indirect assessment of hemodynamics and wall shear stress • resistance to flow (Poisseuille’s law [39]) • vascular conductance [40] • branching points geometry • optimal position of flow divider to minimum wall shear stress [41, 42] • observed position of flow divider () • percentual departure from optimality • software: Microsoft Excel 2010, Xara Photo & Graphic Designer • Model of branching point geometry [42]. • Theoretic curve for optimal position of flow divider to minimum wall shear stress [41, 42]. BRAIN PERFUSION AND WALL SHEAR STRESS MODELS

  6. Results • Each of the brains showed at least one morphological change. • 40% presented multiple anomalies. 2 4 1 3 5 6 7 8 9 10

  7. Special findings duplicated anterior inferior cerebellar artery fusion of the anterior cerebral arteries median callosal artery duplicated superior cerebellar artery absent anterior inferior cerebellar artery

  8. Diameters 2,18 mm 2,12 mm 2,52 mm 4,35mm 2,70 mm 3,85mm 1,51 mm 3,90 mm 1,52 mm 2,59 mm 4,29 mm

  9. Lengths

  10. BRAIN PERFUSION AND WALL SHEAR STRESS MODELS 1 3 5 4 2

  11. BRAIN PERFUSION AND WALL SHEAR STRESS MODELS 6 8 10 9 7

  12. Discussions • Critical areas prone to pathological changes Localisation of aneurysms [43]

  13. Discussions Atherosclerosis sites [7].

  14. One limitation to our study could be the use of formalin fixed brains • Relevant findings for neurovascular anatomy and pathology • Particularly in - cerebral aneurysms (incidence, management and preventive treatment [6]) - intracranial bypass planning [1]

  15. Summary • Identification of variations such as asymmetries, hypoplasias, atypical origins • Study of the resistance, conductance and bifurcation geometrythroughout the circle of Willis to point out the clinical implications that can result • Our study is the first of its kind in terms of materials used and the properties studied on these materials [12, 13]

  16. Future prospective • Extended number of brains, preferably non-formalin fixed • Angiography-based study of the brains (or different imaging techniques) • Other vascular structures, mainly perforating arteries which are often overlooked

  17. Acknowledgements Conf. dr. BiancaSzabo, Anatomy and Embryology Department Iuliu Haţieganu University of Medicine and Pharmacy Cluj-Napoca

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