True fenestration of an extremely long anterior communicating artery diagnosed by magnetic resonance angiography

True fenestration of an extremely long anterior communicating artery diagnosed by magnetic resonance angiography | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article True fenestration of an extremely long anterior communicating artery diagnosed by magnetic resonance angiography Shiho Asami, Akira Uchino, Yoko Usami, Taisuke Nabeshima, Yasutaka Baba This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6208366/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 21 Apr, 2025 Read the published version in Surgical and Radiologic Anatomy → Version 1 posted 11 You are reading this latest preprint version Abstract Purpose To describe a case of true fenestration of an extremely long anterior communicating artery (ACoA). Methods A 3-year-old boy with a history of a ventricular septal defect and aortic coarctation underwent magnetic resonance (MR) imaging and MR angiography of the head and neck regions using a 3-Tesla scanner. Results MR angiography of the head region showed an extremely long ACoA of approximately 20 mm in length, with a fenestration of approximately 5 mm in size. No aneurysms were observed. Conclusion According to a meta-analysis, the mean length of the ACoA was 2.84 mm (0.38–10.4 mm). The ACoA has been reported to be the most frequent site of fenestration of intracranial arteries. However, most reported ACoA fenestrations are not true fenestrations, but duplications or partial duplications. We herein report a case of true fenestration of an extremely long ACoA, which is an extremely rare variant. To our knowledge, this is the first report of such an association in the relevant English language literature. Anterior cerebral artery Anterior communicating artery Arterial variation Duplication Fenestration Magnetic resonance angiography Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Various variations of the anterior communicating artery (ACoA) have been reported. The prevalence of atypical ACoA is 32.7%, with the most common types being ACoA hypoplasia (8%), anterior cerebral artery (ACA) fusion absent ACoA (5.9%), and ACoA fenestration (5%) [ 8 ]. However, true fenestration of the ACoA is extremely rare [ 10 ]. Duplication and partial duplication were misdiagnosed as fenestration. We herein report a case of true fenestration of an extremely long ACoA using magnetic resonance (MR) angiography. To our knowledge, this is the first report of such an association in the relevant English-language literature. Case report A 3-year-old boy with a history of a ventricular septal defect and aortic coarctation underwent MR imaging (MRI) and MR angiography (MRA) of the head and neck regions with a 3-Tesla scanner (Achieva dStream_3T; Philips Medical Systems, Best, The Netherlands) for follow-up of stenosis at the origin of the innominate artery, which was a complication of aortic arch coarctation surgery. MRA was performed using a standard three-dimensional (3D) time-of-flight (TOF) technique. The imaging parameters of the head region were as follows: flip angle, 18.0°; repetition time, 23.0 msec; echo time, 3.45 msec; slice thickness, 1.1 mm; number of slices, 210; slab thickness, 231 mm; field of view, 20.0 × 22.0 cm; and imaging matrix, 448×286. MRA showed high-grade stenosis at the origin of the brachiocephalic trunk and non-visualization of the right vertebral artery, except for the terminal segment, probably due to retrograde flow, which is well-known as the subclavian steal phenomenon (Fig. 1 ). Incidentally, a long ACoA arose from the proximal A1 segment of the left ACA. True fenestration of the ACoA was observed (Fig. 2 ). After creating partial volume-rendering (VR) images of the anterior circulatory system, it was determined that the ACoA was approximately 20 mm in length, and the fenestration was 5 mm in length (Fig. 3 ). Discussion Generally, fenestration is a variation in which a single vessel has a short interrupted lumen segment, which is reformed along the artery into a single vessel, whereas duplication is a variation characterized by two origins and one fusion. There have been many studies on the fenestration of the ACoA. However, most reported cases of ACoA fenestration do not involve true fenestration but duplication or partial duplication [ 10 ]. As a result, studies that clearly define the frequency of true fenestration are limited and the actual prevalence remains unclear. Even when considering mixed cases, the frequency is low; therefore, if we focus only on true fenestration, it is expected to be even rarer. Triantafyllou et al. [ 8 ] reported that the prevalence of ACoA fenestration was 5% in 5 reports that included 792 vessels, while López-Sala et al. [ 6 ] reported that ACoA duplication/fenestration was present in 0.9% of 426 cases using computed tomography angiography (CTA). Krzyżewski et al. [ 4 ] reported that the prevalence of duplicated ACoA was 0.49%, with a female predominance in complex variations of the ACoA. Uchino et al. [ 9 ] studied 891 cases using MRA and reported 11 cases (1.2%) of A1 and/or A2 fenestration. There was no true fenestration of the ACoA. De Gast et al. [ 1 ] reported that ACoA fenestration was present in 12 (5.3%) of 227 patients on 3D rotational angiography (3DRA). Because it is difficult to distinguish between duplication and fenestration, there is a possibility that they have been confused. Owing to the short length and small diameter of the ACoA, the detectability of fenestration varies significantly depending on the spatial resolution of the imaging modality that is used. In current meta-analyses, Zurada et al. [ 11 ] reported that the mean length of the ACoA on CTA was 3.99 mm (0.42–7.66 mm), while Triantafyllou et al. [ 8 ] reviewed and reported that the pooled mean length of the ACoA was 2.84 mm (0.38–10.4 mm). They also reported that the mean length was shorter in cadaveric studies than in imaging studies, possibly because of changes in vessel size caused by formalin fixation. In our case, the ACoA was approximately 20 mm in length, which was significantly longer than the average length. Uchino et al. [ 9 ] found 9 ACA fenestrations among 891 patients. All of these were located at the distal A1 segment and exhibited a convex lens-like shape. A1 fenestrations are common in the distal region, and in our case, the possibility of incomplete fusion on the distal side of the fenestration is suggested (Fig. 4 ). Paladino et al. [ 7 ] reported a case of early bifurcation from the origin of the left ACA combined with hypoplasia of the right A1 segment. The medial branch of this early bifurcation of A1 could be considered to be a long ACoA. In our case, the ACoA originated near the origin of the left A1, and it can also be considered to be an early bifurcation of the left A1. Therefore, our case can also be considered as a fenestration combined with an early bifurcation of A1, where the contralateral A1 is present (Fig. 4 ). No aneurysm was associated in our case, but an association between fenestration and aneurysms has been previously noted. According to a report by Liu et al. [ 5 ], the incidence of aneurysms in the fenestration of an intracranial artery (FIA) is 17.0%, which is significantly higher than the incidence of aneurysms in non-FIA cases. This is thought to be related to turbulent blood flow and deficiency of the media in both the proximal and distal ends of the fenestration, which may contribute to aneurysmal development [ 8 ]. It has also been reported that the presence of ACoA fenestration is linked to an increased rupture risk in patients with ACoA aneurysms [ 2 ]. Our patient is a child. Thus, there is a high risk of future aneurysm formation. Our patient had a congenital heart disease and aortic coarctation. According to a review article by Kim et al. [ 3 ], cerebral arterial variations are not associated with aortic coarctation. Conclusion We encountered the first case of true fenestration of an extremely long ACoA. Such rare arterial variations are of great interest to neurosurgeons for preventing complications during suprasellar surgery and interventional radiology procedures. Declarations Author contributions SA and AU designed the study and drafted the manuscript. SA, AU, YU, NT, and YB critically reviewed, read, and approved the final manuscript. Funding The authors did not receive support from any organization for the submitted work. Data availability Not applicable. Conflict of interest The authors declare no conflicts of interest in association with the present study. Ethical approval and consent to participate All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Consent for publication The parents of the patient provided written informed consent for publication of his data and figures. References de Gast AN, van Rooij WJ, Sluzewski M (2008) Fenestrations of the anterior communicating artery: incidence on 3D angiography and relationship to aneurysms. AJNR Am J Neuroradiol 29:296-298. doi: 10.3174/ajnr. A0807. Kashtiara A, Beldé S, Menovsky T (2024) Anatomical variations and anomalies of the anterior communicating artery complex. World Neurosurg 183: e218-e227. doi: 10.1016/j.wneu.2023.12.060. Kim YY, Andrade L, Cook SC (2020) Aortic Coarctation. Cardiol Clin 38: 337-351.doi: 10.1016/j.ccl.2020.04.003. Krzyżewski RM, Tomaszewski KA, Kochana M, Kopeć M, Klimek-Piotrowska W, Walocha JA (2015) Anatomical variations of the anterior communicating artery complex: gender relationship. Surg Radiol Anat 37:81-86. doi: 10.1007/s00276-014-1313-7. Liu H, Hong J, Wang S, Wei L (2020) Anterior communicating artery complex fenestration combined with tandem aneurysm: a case report and literature review. Medicine (Baltimore) 99: e20013. doi: 10.1097/MD.0000000000020013. López-Sala P, Alberdi N, Mendigaña M, Bacaicoa MC, Cabada T (2020) Anatomical variants of anterior communicating artery complex. A study by computerized tomographic angiography. J Clin Neurosci 80:182-187. doi: 10.1016/j.jocn. 2020.08.019. Paladino J, Pirker N, Gluncić V (2000) Early bifurcation of the left A1 segment giving rise to both A2 segments and a hypoplastic right A1 segment. Acta Neurochir (Wien)142:825-826. doi: 10.1007/s007010070100. Triantafyllou G, Tudose RC, Tsiouris C, Tsakotos G, Loukas M, Tubbs RS, Kalamatianos T, Chrissicopoulos C, Al-Nasraoui K, Koutserimpas C, Rusu MC, Natsis K, Kotrotsios A, Piagkou M (2024) The anterior communicating artery variants: A meta-analysis with a proposed classification system. Surg Radiol Anat 46:697-716. doi: 10.1007/s00276-024-03336-7. Uchino A, Nomiyama K, Takase Y, Kudo S (2006) Anterior cerebral artery variations detected by MR angiography. Neuroradiology 48:647-652. doi: 10.1007/s00234-006-0110-3. Uchino A, Saito N, Uehara T, Neki H, Kohyama S, Yamane F (2016) True fenestration of the anterior communicating artery diagnosed by magnetic resonance angiography. Surg Radiol Anat 38:1095-1098. doi: 10.1007/s00276-016-1646-5. Zurada A, Gielecki J, Tubbs RS, Loukas M, Maksymowicz W, Chlebiej M, Cohen-Gadol AA, Zawiliński J, Nowak D, Michalak M (2011) Detailed 3D-morphometry of the anterior communicating artery: potential clinical and neurosurgical implications. Surg Radiol Anat 33:531-538. doi: 10.1007/s00276-011-0792-z. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 21 Apr, 2025 Read the published version in Surgical and Radiologic Anatomy → Version 1 posted Editorial decision: Revision requested 04 Apr, 2025 Reviews received at journal 23 Mar, 2025 Reviews received at journal 22 Mar, 2025 Reviewers agreed at journal 14 Mar, 2025 Reviewers agreed at journal 13 Mar, 2025 Reviews received at journal 13 Mar, 2025 Reviewers agreed at journal 13 Mar, 2025 Reviewers invited by journal 13 Mar, 2025 Editor assigned by journal 13 Mar, 2025 Submission checks completed at journal 12 Mar, 2025 First submitted to journal 12 Mar, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6208366","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":429141043,"identity":"1ccef6ea-840e-4438-bee2-03c6c0cfaaa4","order_by":0,"name":"Shiho Asami","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8klEQVRIie2RP2sCMRiHf0dKbom4JhzqVwgcSEWhX8UuN51rxzZTnNz7PQqHYyRrPoDdWoRugocgOAhGoa1TODfBPBDyZnjy/gMikduFo02IQaL+3g0UMdXjqxRAOif/lRA9RVabffkILMsd389HXaTWYDAPfG5oX8wqjuR9UomZK3KwYgzhAgrQR8srhE8q3tL2WXEmIXSosHRbH7xCefkjDk0UGCazUxbGHM0aZZGGvWQdr/BU58OOLnLqezGhXnxhH/W6esWTJd+faz3qtlO7WInAxND7Ol9vCng4L5D6Y4UKKBeQzW+U1A2VSCQSuQuOLOFIg5xnCg0AAAAASUVORK5CYII=","orcid":"","institution":"Saitama Medical University International Medical Center","correspondingAuthor":true,"prefix":"","firstName":"Shiho","middleName":"","lastName":"Asami","suffix":""},{"id":429141047,"identity":"6cc74649-129b-4779-a2a4-ccf5b2a5750d","order_by":1,"name":"Akira Uchino","email":"","orcid":"","institution":"Saitama Sekishinkai Hospital","correspondingAuthor":false,"prefix":"","firstName":"Akira","middleName":"","lastName":"Uchino","suffix":""},{"id":429141049,"identity":"f0284c58-32db-46b1-a765-a7d1dafb6860","order_by":2,"name":"Yoko Usami","email":"","orcid":"","institution":"Saitama Medical University International Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Yoko","middleName":"","lastName":"Usami","suffix":""},{"id":429141050,"identity":"01ba8b0c-636d-4a7d-9e35-646e9a92abcf","order_by":3,"name":"Taisuke Nabeshima","email":"","orcid":"","institution":"Saitama Medical University International Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Taisuke","middleName":"","lastName":"Nabeshima","suffix":""},{"id":429141051,"identity":"7274cf3c-8d56-4629-8eeb-8d89dc16251e","order_by":4,"name":"Yasutaka Baba","email":"","orcid":"","institution":"Saitama Medical University International Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Yasutaka","middleName":"","lastName":"Baba","suffix":""}],"badges":[],"createdAt":"2025-03-12 04:08:20","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6208366/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6208366/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00276-025-03634-8","type":"published","date":"2025-04-21T15:57:22+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":78734370,"identity":"6f02cf94-dee5-4c10-a5eb-49cddf502c9d","added_by":"auto","created_at":"2025-03-18 07:59:43","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":148136,"visible":true,"origin":"","legend":"\u003cp\u003eAntero-posterior projection of magnetic resonance angiography (MRA) of the head and neck region shows high-grade stenosis at the origin of the brachiocephalic trunkand non-visualization of the right vertebral artery—except for the terminal segment—probably due to retrograde flow; that is well known as subclavian steal phenomenon (\u003cem\u003earrows\u003c/em\u003e).\u003c/p\u003e","description":"","filename":"OnlineFigure1.png","url":"https://assets-eu.researchsquare.com/files/rs-6208366/v1/6147afbca6e57e3e264bed3a.png"},{"id":78735054,"identity":"42f3bdd6-5213-46b3-9ffd-d08f19298f99","added_by":"auto","created_at":"2025-03-18 08:07:43","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":286068,"visible":true,"origin":"","legend":"\u003cp\u003eAntero-posterior (\u003cstrong\u003ea\u003c/strong\u003e) and anteroinferior to posterosuperior (\u003cstrong\u003eb\u003c/strong\u003e) projections of the maximum intensity projection (MIP) images of MRA of the head region show early bifurcation left A1 segment (\u003cem\u003eshort arrows\u003c/em\u003e) and fenestration of the anterior communicating artery (ACoA) (\u003cem\u003elong arrow\u003c/em\u003e).\u003c/p\u003e","description":"","filename":"OnlineFigure2.png","url":"https://assets-eu.researchsquare.com/files/rs-6208366/v1/c9f93fce358dcfe14c1b3850.png"},{"id":78734371,"identity":"c7319846-89e9-47ff-bcf9-1a43e5ee994a","added_by":"auto","created_at":"2025-03-18 07:59:43","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":114645,"visible":true,"origin":"","legend":"\u003cp\u003eAntero-posterior (\u003cstrong\u003ea\u003c/strong\u003e), postero-anterior (\u003cstrong\u003eb\u003c/strong\u003e), infero-superior (\u003cstrong\u003ec\u003c/strong\u003e) and supero-inferior (\u003cstrong\u003ed\u003c/strong\u003e) projections of the partial volume-rendering (VR) images of MRA of the anterior circulation clearly shows an early bifurcated left A1 segment and an extremely long ACoA (\u003cem\u003eshort arrows\u003c/em\u003e). There is a true fenestration of the ACoA (\u003cem\u003elong arrows\u003c/em\u003e).\u003c/p\u003e","description":"","filename":"OnlineFigure3.png","url":"https://assets-eu.researchsquare.com/files/rs-6208366/v1/82d16c8174e3fcb75796aabb.png"},{"id":78732815,"identity":"c6f2f782-3b96-49fc-9647-fb77e2779e21","added_by":"auto","created_at":"2025-03-18 07:51:43","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":12246,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic illustrations of the anterior circulation in antero-posterior projection.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(a)\u003c/strong\u003e Distal A1 fenestration\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(b)\u003c/strong\u003e Early bifurcation of the left A1 combined with hypoplasia of the right A1. There is a long ACoA, but no ACoA at the usual point.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(c)\u003c/strong\u003e Our case. A long ACoA was associated with true fenestration of the ACoA. ACoA was not observed at the usual point.\u003c/p\u003e\n\u003cp\u003eACA, anterior cerebral artery; ACoA, anterior communicating artery; ICA, internal carotid artery; MCA, middle cerebral artery.\u003c/p\u003e","description":"","filename":"OnlineFigure4.png","url":"https://assets-eu.researchsquare.com/files/rs-6208366/v1/dd8cc2a826161bceee089aa9.png"},{"id":81570165,"identity":"9cbdb7b1-5641-4a61-9e9e-f6e04b681745","added_by":"auto","created_at":"2025-04-28 16:12:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1298558,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6208366/v1/1d90fd33-3d7f-4fbf-8c29-a27d6e072ebf.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"True fenestration of an extremely long anterior communicating artery diagnosed by magnetic resonance angiography","fulltext":[{"header":"Introduction","content":"\u003cp\u003eVarious variations of the anterior communicating artery (ACoA) have been reported. The prevalence of atypical ACoA is 32.7%, with the most common types being ACoA hypoplasia (8%), anterior cerebral artery (ACA) fusion absent ACoA (5.9%), and ACoA fenestration (5%) [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. However, true fenestration of the ACoA is extremely rare [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Duplication and partial duplication were misdiagnosed as fenestration.\u003c/p\u003e \u003cp\u003eWe herein report a case of true fenestration of an extremely long ACoA using magnetic resonance (MR) angiography. To our knowledge, this is the first report of such an association in the relevant English-language literature.\u003c/p\u003e"},{"header":"Case report","content":"\u003cp\u003eA 3-year-old boy with a history of a ventricular septal defect and aortic coarctation underwent MR imaging (MRI) and MR angiography (MRA) of the head and neck regions with a 3-Tesla scanner (Achieva dStream_3T; Philips Medical Systems, Best, The Netherlands) for follow-up of stenosis at the origin of the innominate artery, which was a complication of aortic arch coarctation surgery. MRA was performed using a standard three-dimensional (3D) time-of-flight (TOF) technique. The imaging parameters of the head region were as follows: flip angle, 18.0\u0026deg;; repetition time, 23.0 msec; echo time, 3.45 msec; slice thickness, 1.1 mm; number of slices, 210; slab thickness, 231 mm; field of view, 20.0 \u0026times; 22.0 cm; and imaging matrix, 448\u0026times;286.\u003c/p\u003e \u003cp\u003eMRA showed high-grade stenosis at the origin of the brachiocephalic trunk and non-visualization of the right vertebral artery, except for the terminal segment, probably due to retrograde flow, which is well-known as the subclavian steal phenomenon (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Incidentally, a long ACoA arose from the proximal A1 segment of the left ACA. True fenestration of the ACoA was observed (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). After creating partial volume-rendering (VR) images of the anterior circulatory system, it was determined that the ACoA was approximately 20 mm in length, and the fenestration was 5 mm in length (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eGenerally, fenestration is a variation in which a single vessel has a short interrupted lumen segment, which is reformed along the artery into a single vessel, whereas duplication is a variation characterized by two origins and one fusion. There have been many studies on the fenestration of the ACoA. However, most reported cases of ACoA fenestration do not involve true fenestration but duplication or partial duplication [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. As a result, studies that clearly define the frequency of true fenestration are limited and the actual prevalence remains unclear. Even when considering mixed cases, the frequency is low; therefore, if we focus only on true fenestration, it is expected to be even rarer. Triantafyllou et al. [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e8\u003c/span\u003e] reported that the prevalence of ACoA fenestration was 5% in 5 reports that included 792 vessels, while L\u0026oacute;pez-Sala et al. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e6\u003c/span\u003e] reported that ACoA duplication/fenestration was present in 0.9% of 426 cases using computed tomography angiography (CTA). Krzyżewski et al. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e4\u003c/span\u003e] reported that the prevalence of duplicated ACoA was 0.49%, with a female predominance in complex variations of the ACoA. Uchino et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e9\u003c/span\u003e] studied 891 cases using MRA and reported 11 cases (1.2%) of A1 and/or A2 fenestration. There was no true fenestration of the ACoA. De Gast et al. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] reported that ACoA fenestration was present in 12 (5.3%) of 227 patients on 3D rotational angiography (3DRA). Because it is difficult to distinguish between duplication and fenestration, there is a possibility that they have been confused. Owing to the short length and small diameter of the ACoA, the detectability of fenestration varies significantly depending on the spatial resolution of the imaging modality that is used.\u003c/p\u003e \u003cp\u003eIn current meta-analyses, Zurada et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e11\u003c/span\u003e] reported that the mean length of the ACoA on CTA was 3.99 mm (0.42\u0026ndash;7.66 mm), while Triantafyllou et al. [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e8\u003c/span\u003e] reviewed and reported that the pooled mean length of the ACoA was 2.84 mm (0.38\u0026ndash;10.4 mm). They also reported that the mean length was shorter in cadaveric studies than in imaging studies, possibly because of changes in vessel size caused by formalin fixation. In our case, the ACoA was approximately 20 mm in length, which was significantly longer than the average length.\u003c/p\u003e \u003cp\u003eUchino et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e9\u003c/span\u003e] found 9 ACA fenestrations among 891 patients. All of these were located at the distal A1 segment and exhibited a convex lens-like shape. A1 fenestrations are common in the distal region, and in our case, the possibility of incomplete fusion on the distal side of the fenestration is suggested (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Paladino et al. [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e7\u003c/span\u003e] reported a case of early bifurcation from the origin of the left ACA combined with hypoplasia of the right A1 segment. The medial branch of this early bifurcation of A1 could be considered to be a long ACoA. In our case, the ACoA originated near the origin of the left A1, and it can also be considered to be an early bifurcation of the left A1. Therefore, our case can also be considered as a fenestration combined with an early bifurcation of A1, where the contralateral A1 is present (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eNo aneurysm was associated in our case, but an association between fenestration and aneurysms has been previously noted. According to a report by Liu et al. [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e5\u003c/span\u003e], the incidence of aneurysms in the fenestration of an intracranial artery (FIA) is 17.0%, which is significantly higher than the incidence of aneurysms in non-FIA cases. This is thought to be related to turbulent blood flow and deficiency of the media in both the proximal and distal ends of the fenestration, which may contribute to aneurysmal development [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. It has also been reported that the presence of ACoA fenestration is linked to an increased rupture risk in patients with ACoA aneurysms [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Our patient is a child. Thus, there is a high risk of future aneurysm formation. Our patient had a congenital heart disease and aortic coarctation. According to a review article by Kim et al. [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], cerebral arterial variations are not associated with aortic coarctation.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWe encountered the first case of true fenestration of an extremely long ACoA. Such rare arterial variations are of great interest to neurosurgeons for preventing complications during suprasellar surgery and interventional radiology procedures.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003eSA and AU designed the study and drafted the manuscript. SA, AU, YU, NT, and YB critically reviewed, read, and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e The authors did not receive support from any organization for the submitted work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e The authors declare no conflicts of interest in association with the present study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval and consent to participate\u003c/strong\u003e All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e The parents of the patient provided written informed consent for publication of his data and figures.\u003c/p\u003e"},{"header":"References","content":"\u003col class=\"decimal_type\"\u003e\n \u003cli\u003ede Gast AN, van Rooij WJ, Sluzewski M (2008) Fenestrations of the anterior communicating artery: incidence on 3D angiography and relationship to aneurysms. AJNR Am J Neuroradiol 29:296-298. doi: 10.3174/ajnr. A0807.\u003c/li\u003e\n \u003cli\u003eKashtiara A, Beld\u0026eacute; S, Menovsky T (2024) Anatomical variations and anomalies of the anterior communicating artery complex. World Neurosurg 183: e218-e227. doi: 10.1016/j.wneu.2023.12.060.\u003c/li\u003e\n \u003cli\u003eKim YY, Andrade L, Cook SC (2020) Aortic Coarctation. Cardiol Clin 38: 337-351.doi: 10.1016/j.ccl.2020.04.003.\u003c/li\u003e\n \u003cli\u003eKrzyżewski RM, Tomaszewski KA, Kochana M, Kopeć M, Klimek-Piotrowska W, Walocha JA (2015) Anatomical variations of the anterior communicating artery complex: gender relationship. Surg Radiol Anat 37:81-86. doi: 10.1007/s00276-014-1313-7.\u003c/li\u003e\n \u003cli\u003eLiu H, Hong J, Wang S, Wei L (2020) Anterior communicating artery complex fenestration combined with tandem aneurysm: a case report and literature review. Medicine (Baltimore) 99: e20013. doi: 10.1097/MD.0000000000020013.\u003c/li\u003e\n \u003cli\u003eL\u0026oacute;pez-Sala P, Alberdi N, Mendiga\u0026ntilde;a M, Bacaicoa MC, Cabada T (2020) Anatomical variants of anterior communicating artery complex. A study by computerized tomographic angiography. J Clin Neurosci 80:182-187. doi: 10.1016/j.jocn. 2020.08.019.\u003c/li\u003e\n \u003cli\u003ePaladino J, Pirker N, Gluncić V (2000) Early bifurcation of the left A1 segment giving rise to both A2 segments and a hypoplastic right A1 segment. Acta Neurochir (Wien)142:825-826. doi: 10.1007/s007010070100.\u003c/li\u003e\n \u003cli\u003eTriantafyllou G, Tudose RC, Tsiouris C, Tsakotos G, Loukas M, Tubbs RS, Kalamatianos T, Chrissicopoulos C, Al-Nasraoui K, Koutserimpas C, Rusu MC, Natsis K, Kotrotsios A, Piagkou M (2024) The anterior communicating artery variants: A meta-analysis with a proposed classification system. Surg Radiol Anat 46:697-716. doi: 10.1007/s00276-024-03336-7.\u003c/li\u003e\n \u003cli\u003eUchino A, Nomiyama K, Takase Y, Kudo S (2006) Anterior cerebral artery variations detected by MR angiography. Neuroradiology 48:647-652. doi: 10.1007/s00234-006-0110-3.\u003c/li\u003e\n \u003cli\u003eUchino A, Saito N, Uehara T, Neki H, Kohyama S, Yamane F (2016) True fenestration of the anterior communicating artery diagnosed by magnetic resonance angiography. Surg Radiol Anat 38:1095-1098. doi: 10.1007/s00276-016-1646-5.\u003c/li\u003e\n \u003cli\u003eZurada A, Gielecki J, Tubbs RS, Loukas M, Maksymowicz W, Chlebiej M, Cohen-Gadol AA, Zawiliński J, Nowak D, Michalak M (2011) Detailed 3D-morphometry of the anterior communicating artery: potential clinical and neurosurgical implications. Surg Radiol Anat 33:531-538. doi: 10.1007/s00276-011-0792-z.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"surgical-and-radiologic-anatomy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sara","sideBox":"Learn more about [Surgical and Radiologic Anatomy](http://link.springer.com/journal/276)","snPcode":"276","submissionUrl":"https://submission.nature.com/new-submission/276/3","title":"Surgical and Radiologic Anatomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Anterior cerebral artery, Anterior communicating artery, Arterial variation, Duplication, Fenestration, Magnetic resonance angiography","lastPublishedDoi":"10.21203/rs.3.rs-6208366/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6208366/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo describe a case of true fenestration of an extremely long anterior communicating artery (ACoA).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA 3-year-old boy with a history of a ventricular septal defect and aortic coarctation underwent magnetic resonance (MR) imaging and MR angiography of the head and neck regions using a 3-Tesla scanner.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMR angiography of the head region showed an extremely long ACoA of approximately 20 mm in length, with a fenestration of approximately 5 mm in size. No aneurysms were observed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAccording to a meta-analysis, the mean length of the ACoA was 2.84 mm (0.38–10.4 mm). The ACoA has been reported to be the most frequent site of fenestration of intracranial arteries. However, most reported ACoA fenestrations are not true fenestrations, but duplications or partial duplications.\u003c/p\u003e\n\u003cp\u003eWe herein report a case of true fenestration of an extremely long ACoA, which is an extremely rare variant. To our knowledge, this is the first report of such an association in the relevant English language literature.\u003c/p\u003e","manuscriptTitle":"True fenestration of an extremely long anterior communicating artery diagnosed by magnetic resonance angiography","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-18 07:51:38","doi":"10.21203/rs.3.rs-6208366/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-04T09:43:34+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-03-23T06:09:11+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-03-22T22:38:26+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"93721988284847522991404256029837665279","date":"2025-03-14T04:05:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"248745304700574329761442554307643649684","date":"2025-03-13T11:12:34+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-03-13T09:52:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"297380964092214123459049646725896102136","date":"2025-03-13T07:25:52+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-03-13T07:13:22+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-03-13T06:37:37+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-03-13T03:33:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"Surgical and Radiologic Anatomy","date":"2025-03-12T04:02:28+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"surgical-and-radiologic-anatomy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sara","sideBox":"Learn more about [Surgical and Radiologic Anatomy](http://link.springer.com/journal/276)","snPcode":"276","submissionUrl":"https://submission.nature.com/new-submission/276/3","title":"Surgical and Radiologic Anatomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"9bcac0aa-bfd9-4c1c-bdd7-de43b0a188ef","owner":[],"postedDate":"March 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-04-28T16:08:11+00:00","versionOfRecord":{"articleIdentity":"rs-6208366","link":"https://doi.org/10.1007/s00276-025-03634-8","journal":{"identity":"surgical-and-radiologic-anatomy","isVorOnly":false,"title":"Surgical and Radiologic Anatomy"},"publishedOn":"2025-04-21 15:57:22","publishedOnDateReadable":"April 21st, 2025"},"versionCreatedAt":"2025-03-18 07:51:38","video":"","vorDoi":"10.1007/s00276-025-03634-8","vorDoiUrl":"https://doi.org/10.1007/s00276-025-03634-8","workflowStages":[]},"version":"v1","identity":"rs-6208366","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6208366","identity":"rs-6208366","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}