open access

Vol 78, No 4 (2019)
Original article
Submitted: 2019-01-30
Accepted: 2019-02-06
Published online: 2019-02-07
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Configuration of the circle of Willis and its two parts among Egyptian: a magnetic resonance angiographic study

S. M. Zaki12, M. H. Shaaban1, W. A. Abd Al Galeel12, A. A.W. El Husseiny1
·
Pubmed: 30761512
·
Folia Morphol 2019;78(4):703-709.
Affiliations
  1. Department of Anatomy and Embryology, Faculty of Medicine, Cairo University, Cairo, Egypt
  2. Fakeeh College for Medical Sciences, Jeddah, Saudi Arabia

open access

Vol 78, No 4 (2019)
ORIGINAL ARTICLES
Submitted: 2019-01-30
Accepted: 2019-02-06
Published online: 2019-02-07

Abstract

Background: We hypothesized that the collateral circulation differs in different ethnic groups. So, the aim of our work was to study variations of the circle of Willis (COW) among Egyptian and to compare our findings with the findings of other nationalities. Materials and methods: One hundred patients were studied using magnetic resonance angiography (3D-TOF-MRA). Frequency and morphologic variations in COW were studied. The diameters of the arteries of the anterior and posterior circle were verified. Finally, the differences among the mean diameters of these arteries regarding age and sex were also studied. Results: Complete, partially complete and incomplete COW were encountered in 28%, 38% and 34% in the studied cases. The incomplete anterior circle was found in 34% (10% isolated incomplete anterior circle and 24% combined incomplete anterior and posterior circles) and the incomplete posterior circle came across in 62% (38% isolated incomplete posterior circle and 24% combined incomplete anterior and posterior circles). Seven anterior circle variations were found. The commonest type was the classical type “a” with a prevalence of 56%, being higher in male (57.1%). The 2nd common type was type “g” (hypoplasia or aplasia of the anterior communicating artery) with a prevalence of 24%, being higher in male (66.7%). Six posterior circle variations were found. The commonest variation was the classic type “a” with a prevalence of 26%, being higher in male (61.5%). Posterior circles types “d, e, h” (18%, 24%, 20%) constituted 62% and were characterised by hypoplasia/absent of the posterior communicating arteries. Conclusions: The prevalence of complete COW (classic or textbook type) was encountered only 28% of the studied cases. Variations of COW were found to be more common in the posterior circulation (62%). The incomplete anterior circle was found in 34% and it is mostly caused by hypoplasia or aplasia of the anterior communicating artery which was found to be more common compared to the literature.

Abstract

Background: We hypothesized that the collateral circulation differs in different ethnic groups. So, the aim of our work was to study variations of the circle of Willis (COW) among Egyptian and to compare our findings with the findings of other nationalities. Materials and methods: One hundred patients were studied using magnetic resonance angiography (3D-TOF-MRA). Frequency and morphologic variations in COW were studied. The diameters of the arteries of the anterior and posterior circle were verified. Finally, the differences among the mean diameters of these arteries regarding age and sex were also studied. Results: Complete, partially complete and incomplete COW were encountered in 28%, 38% and 34% in the studied cases. The incomplete anterior circle was found in 34% (10% isolated incomplete anterior circle and 24% combined incomplete anterior and posterior circles) and the incomplete posterior circle came across in 62% (38% isolated incomplete posterior circle and 24% combined incomplete anterior and posterior circles). Seven anterior circle variations were found. The commonest type was the classical type “a” with a prevalence of 56%, being higher in male (57.1%). The 2nd common type was type “g” (hypoplasia or aplasia of the anterior communicating artery) with a prevalence of 24%, being higher in male (66.7%). Six posterior circle variations were found. The commonest variation was the classic type “a” with a prevalence of 26%, being higher in male (61.5%). Posterior circles types “d, e, h” (18%, 24%, 20%) constituted 62% and were characterised by hypoplasia/absent of the posterior communicating arteries. Conclusions: The prevalence of complete COW (classic or textbook type) was encountered only 28% of the studied cases. Variations of COW were found to be more common in the posterior circulation (62%). The incomplete anterior circle was found in 34% and it is mostly caused by hypoplasia or aplasia of the anterior communicating artery which was found to be more common compared to the literature.

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Keywords

circle of Willis, variations, Egyptian

About this article
Title

Configuration of the circle of Willis and its two parts among Egyptian: a magnetic resonance angiographic study

Journal

Folia Morphologica

Issue

Vol 78, No 4 (2019)

Article type

Original article

Pages

703-709

Published online

2019-02-07

Page views

1480

Article views/downloads

1337

DOI

10.5603/FM.a2019.0015

Pubmed

30761512

Bibliographic record

Folia Morphol 2019;78(4):703-709.

Keywords

circle of Willis
variations
Egyptian

Authors

S. M. Zaki
M. H. Shaaban
W. A. Abd Al Galeel
A. A.W. El Husseiny

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