Perspective Study of Anatomical Variations of Circle of Willis – A Magnetic Resonance Imaging Study in North Karnataka Population: A Retrospective Study
Background: Two main arteries that supply to brain originate from circle of Willis (COW). The COW exhibits considerable anatomical variations which have clinical and surgical importance.
Method: Fifty-five healthy volunteers aged between 25 and 50 years were studied by the technique used which was three-dimensional times-of-flight magnetic resonance angiography, only arteries forming the COW are studied. For the purpose of identification, COW is divided into anterior and posterior configuration.
Results: The variations of COW were 9 (39%) hyperplasia of ant. cerebral artery, 5 (21.7%) hypoplasia of post-cerebral arteries, 6 (26%) analogous origin of post-cerebellar artery, and 3 (13%) hypoplasia of post-communicating artery.
Conclusion: Complete anatomical knowledge of COW and its variations such as hypoplasia, attenuation of vessels, and analogous origin is necessary for clinician, neurosurgeon vascular surgeon, and radiologist. This baseline study will enable them for proper diagnose and surgery without fatal outcome.
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Figure 1: Circle of Willis magnetic resonance imaging image Figure 3: Anomalous (fetal) origin of posterior cerebral artery
magnetic resonance imaging image
Figure 2: Hypoplastic segments in three different patients.
(a) Volume-rendered (VR) three-dimensional time-of-flight
magnetic resonance angiography (3D-TOF-MRA) showing
hypoplastic A2 segment (the second segment of the anterior
cerebral artery [ACA]) (blue arrow) and hypoplastic A1
segment (first segment of ACA) (green arrow). Dominant A2
(gray arrow) is also known as bihemispheric ACA. (b) Axial
maximum intensity projection of CT angiography showing
hypoplasia of the right Pcom (yellow arrow). Notice occlusion
of the contralateral internal carotid artery. (c) VR 3D TOF MRA
showing hypoplastic vertebral artery (orange arrow), which
ends as posterior inferior cerebellar artery (white arrow)
Morab and Budi: Perspective Study of Anatomical Variations of Circle of Willis – A Magnetic Resonance Imaging Study in North Karnataka
Population: A Retrospective Study
4 IJSS Journal of Surgery | May-Jun 2021 | Volume 7 | Issue 3
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