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. 2015:2015:976340.
doi: 10.1155/2015/976340. Epub 2015 Jan 5.

MRA study on variation of the circle of willis in healthy Chinese male adults

Chuanya Qiu  1 , Yong Zhang  1 , Caixia Xue  1 , Shanshan Jiang  1 , Wei Zhang  1
Affiliations

MRA study on variation of the circle of willis in healthy Chinese male adults

Chuanya Qiu et al. Biomed Res Int. 2015.

Abstract

Aim: To investigate the morphology and variation of the circle of Willis (COW) in healthy Chinese male adults.

Materials and methods: We analyzed cerebral magnetic resonance angiography (MRA) images of 2,246 healthy subjects using typical magnetic resonance imaging (MRI) and MRA. 3D-time of flight (TOF) MRA method was applied to all subjects and the classification was therefore achieved according to the integrity level of COW and the developmental situation of vessels.

Results: The overall incidence of COW integrity was 12.24%, with 7.57% nonvariation integral COW. The incidences of partial integrity and nonintegrity were 70.17% and 17.59%, respectively. The integrity rate of anterior circulation was 78.58%, with a close correlation with A1 segment of the anterior cerebral artery (ACA-A1) developmental condition. The developmental variation rate of ACA-A1 was 28.23% and the variation of the right side was higher than that of the left side. The nonintegrity rate of posterior circulation was 83.93% as the hypoplasia of P1 segment of the posterior cerebral artery (PCA-P1) with an incidence rate of 15.85% for PCA-P1 variation.

Conclusions: The COW variation is a common phenomenon among the healthy subjects. MRA could enable reflecting the physiological morphology of COW in a comprehensive manner.

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Figures

Figure 1
Figure 1
Ideographs 1 and 2 in the present study. Ideograph 1: type I: normal, balanced development of bilateral A1 segment, where ACoA exists; type II: noneven integral type, that is, ACoA exists and unilateral A1 segment is I°; type III: maldevelopment type; type IV: A1 segment is absent. Type V1: A1 segment is evenly developed while ACoA is absent. Type V2: A1 segment is not balanced and ACoA is absent. Ideograph 2: (a) normal posterior circulation; (b) bilateral quasi-FTP type; (c) unilateral quasi-FTP type; (d) bilateral PCoA absent with normal PCA at both left and right rides; (e) unilateral PCoA exists, while contralateral PCoA is absent; (f) unilateral quasi-FTP, with one PcoA absent; (g) unilateral pure FTP, with one PCoA absent; (h) unilateral pure FTP; (i) unilateral pure FTP combining contralateral quasi-FTP; (j) bilateral pure FTP; (k) unilateral duel PCA, extended from internal carotid artery and basilar artery, respectively, without any connection between the two.
Figure 2
Figure 2
The types of the morphology and variation of Willis' circle (COW). (1) Integral type (type I-a). All the blood vessels are shown, and A1 segment is balanced, PCoA
Figure 3
Figure 3
The different shapes of the ACoA.
See this image and copyright information in PMC

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