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Describe the anatomical variations in posterior half of the circle of Willis using computed tomography
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Abstract
Objective: To describe the anatomical variations in posterior half of the circle of Willis and to determine the rate of the anatomical variability of these arteries.
Materials and Methods: We conducted a cross-sectional study in 480 people who were performed CT angiography of the cerebral arteries at the University Medical Center Hospital between January 2019 and December 2020. The blood vessels to be investigated included: posterior communicating arteries, posterior cerebral arteries, basal artery, anterior inferior cerebellar arteries, posterior inferior cerebellar arteries, and the superior cerebellar artery. A radiologist who had more than 5 years of experience of CT brain evaluates these anatomical variations: hypoplasia, aplasia, fetal type, fenestration, duplication, triplication and double origin.
Results: The study was composed of 480 people (259 males, 221 females). The mean age of people was 55.7 ± 16.7 years (range,2 - 102 years). 50 - 69 age group accounts for the majority with 237 people (49.4%). The anatomical variations of posterior communicating artery: unilateral hypoplasia 38.5%, bilateral hypoplasia 19.4%, unilateral aplasia 22.9%, bilateral aplasia 4.0%, fenestration 0.4%. The anatomical variations of posterior cerebral artery: unilateral hypoplasia 10.2%, bilateral hypoplasia 3.5%, unilateral aplasia 8.8%, bilateral aplasia 1.3%, unilateral fetal 17.9%, bilateral fetal 5%. The anatomical
variations of basal artery: hypoplasia 5.6%, aplasia 0%, fenestration 0.6%. The anatomical variations of anterior inferior cerebellar artery:
unilateral aplasia 30%, bilateral aplasia 10.4%, unilateral duplication 1.3%, bilateral duplication 5.8%, triplication 0.2%. The anatomical variations of posterior inferior cerebellar artery: unilateral aplasia 29%, bilateral aplasia 5.8%, unilateral duplication 0.4%, bilateral duplication 0%, fenestration 0.2%, double origin 0.2%. The anatomical variations of the superior cerebellar artery: aplasia 0%, unilateral duplication 11.3%, bilateral duplication 2.9%, triplication 1.7%, double origin 0.4%.
Conclusion: The anatomical variations in posterior half of the circle of Willis are common. The most common abnormalities are the fetal type of
posterior cerebral artery, hypoplasia or aplasia of the posterior communicating artery, hypoplasia or aplasia anterior and posterior inferior cerebellar artery,
and the duplication of the superior cerebellar artery
Article Details
Keywords
posterior circulatory system, computed tomography, anatomical variations.
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