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ORIGINAL RESEARCH article

Front. Neurol.
Sec. Applied Neuroimaging
Volume 15 - 2024 | doi: 10.3389/fneur.2024.1491247

Impact of A1 Segment Asymmetry on Hemodynamic Conditions around the Circle of Willis and Anterior Communicating Artery Aneurysm Formation

Provisionally accepted
Joonho Lee Joonho Lee 1Seul-Ki Jeong Seul-Ki Jeong 2Ji Man Hong Ji Man Hong 1,3*
  • 1 School of Medicine, Ajou University, Suweon, Gyeonggi, Republic of Korea
  • 2 Seul-Ki Jeong Neurology Clinic, seoul, Republic of Korea
  • 3 Ajou University Graduate School of Medicine, Suwon, Republic of Korea

The final, formatted version of the article will be published soon.

    Background: This study investigates how A1 segment asymmetry, known as A1 dominancy, influences the development of the anterior communicating artery aneurysm (AcomA) as it affects hemodynamic conditions within the Circle of Willis (COW). Using time-of-flight magnetic resonance angiography (TOF-MRA), the research introduces a novel approach to assessing shear stress in A1 segments to uncover the hemodynamic factors contributing to AcomA formation.Method: An observational study was conducted over a period of 6 years at a tertiary university hospital's outpatient clinic. Recruited patients who underwent TOF-MRA imaging were divided into AcomA and non-AcomA groups. MRA images were analyzed using semi-automatic software (VINT, Mediimage, Inc) to calculate the signal intensity gradient (SIG), which reflects wall shear stress. The comparison metrics included general demographics, anatomical characteristics, and hemodynamic attributes of the COW, particularly focusing on A1 segments asymmetry.Results: Among the 700 subjects, 106 were categorized into the AcomA group, while 594 were placed in the non-AcomA group. The AcomA group showed a greater difference in the bilateral A1 diameter (49.0% vs. 20.8%, p<0.001) and a greater prevalence of unilateral A1 aplasia (32.1% vs. 6.7%, p<0.001) compared to the non-AcomA group. Increased bilateral A1 asymmetry in the AcomA group corresponded with notable variations in A1 SIG, indicating increased wall shear stress. The occurrence of AcomA is associated with both anatomical factors of the Circle of Willis, represented by the bilateral A1 diameter ratio, and hemodynamic factors, represented by the bilateral A1 SIG ratio, suggesting that both factors are almost equally significant.Our findings suggest that A1 segment asymmetry influences hemodynamic changes within the COW, contributing to AcomA formation. Hemodynamic factors provide an intuitive understanding of how anatomical characteristics within the COW can lead to aneurysm development.

    Keywords: circle of Willis (CoW), Anterior communicating aneurysm, A1 asymmetry, Signal intensity gradient, shear stress

    Received: 04 Sep 2024; Accepted: 18 Dec 2024.

    Copyright: © 2024 Lee, Jeong and Hong. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Ji Man Hong, School of Medicine, Ajou University, Suweon, 443-749, Gyeonggi, Republic of Korea

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.