Replaced right posterior cerebral artery associated with ipsilateral superior cerebellar artery type persistent trigeminal artery variant diagnosed by magnetic resonance angiography

Replaced right posterior cerebral artery associated with ipsilateral superior cerebellar artery type persistent trigeminal artery variant 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 Replaced right posterior cerebral artery associated with ipsilateral superior cerebellar artery type persistent trigeminal artery variant diagnosed by magnetic resonance angiography Akira Uchino, Kazuo Tokushige This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5512462/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 27 Dec, 2024 Read the published version in Surgical and Radiologic Anatomy → Version 1 posted 10 You are reading this latest preprint version Abstract Purpose To describe a case in which a right replaced posterior cerebral artery (PCA) was associated with an ipsilateral superior cerebellar artery (SCA) type persistent trigeminal artery (PTA) variant. Methods A 53-year-old man who had been diagnosed with chronic dissection of the left vertebral artery (VA) 4 months previously underwent follow-up magnetic resonance (MR) angiography using a 3-Tesla scanner. Results MR angiography showed a slightly dilated left VA at the terminal segment without interval change. An artery arising from the cavernous segment of the right internal carotid artery (ICA) and continuing to the right SCA without connection to the basilar artery is indicative of the SCA type PTA variant. There was also a large artery arising from the supraclinoid segment of the right ICA and continuing to the right PCA. In addition, a tiny artery arose from the right ICA proximal to the origin of the large artery. There were no tiny arteries arising from the right ICA distal to the origin of the large artery. Therefore, the tiny artery is considered to be a hypoplastic posterior communicating artery and the large artery is considered to be a replaced PCA. Conclusion A replaced PCA is an extremely rare variation, from which all branches of the PCA arise from the anterior choroidal artery. The SCA type PTA variant is also rare. This is the first report of a case of a combination of these two variations; however, they had no developmental relationship. Thus, our patient incidentally had two extremely rare ipsilateral variations. Cerebral arterial variations Magnetic resonance angiography Persistent trigeminal artery Posterior cerebral artery Superior cerebellar artery Figures Figure 1 Figure 2 Figure 3 Introduction The anterior choroidal artery (AChA) is rarely hyperplastic because a branch of the posterior cerebral artery (PCA) arises from the AChA [ 6 ]. Extremely rarely, all branches of the PCA arise from the AChA, and this variation is referred to as a replaced PCA [ 2 , 9 , 11 , 12 ]. The cerebellar artery arising from the precavernous or cavernous segment of the internal carotid artery (ICA) without a connection to the basilar artery (BA) is regarded as a persistent trigeminal artery (PTA) variant. The majority of cerebellar arteries arising from a PTA variant are the anterior inferior cerebellar artery (AICA). Cases in which a superior cerebellar artery (SCA) arises from a PTA variant are rare [ 1 , 4 , 7 , 10 ]. We report a case of a right replaced PCA associated with an ipsilateral SCA type PTA variant that was diagnosed by magnetic resonance (MR) angiography. We could not find any such reports in the relevant English-language literature. Case report A 53-year-old man with chronic dissection of the left vertebral artery (VA) that was diagnosed 4 months previously underwent follow-up cranial MR angiography using a 3-Tesla scanner (MAGNETOM Skyra; Siemens Healthineers, Erlangen, Germany) for the evaluation of cerebral arteries. MR angiography was performed using a standard 3-dimensional time-of-flight technique. The imaging parameters were as follows: flip angle, 16°; repetition time, 30.0 s; echo time, 3.7 s; slice thickness, 0.6 mm; number of slices, 160; slab thickness, 96 mm; field of view, 28.0 × 20.0 cm; and imaging matrix, 320 × 272. MR angiography showed a slightly dilated left VA at its terminal segment, with a diagnosis of a chronic stage of dissection without interval change. An artery arising from the cavernous segment of the right ICA and continuing to the right SCA without connection to the BA is indicative of the SCA type PTA variant. There was also a large artery arising from the supraclinoid segment of the right ICA and continuing to the right PCA. In addition, a tiny artery arose from the right ICA proximal to the origin of the large artery. There were no tiny arteries arising from the right ICA distal to the origin of the large artery. Therefore, the tiny artery was considered to be a hypoplastic posterior communicating artery (PCoA), and the large artery was considered to be a replaced PCA (Figs. 1–3). Catheter angiography was not performed in this case. No further treatment was administered. The patient’s clinical course was uneventful for 4 years. Discussion Replaced PCA The AChA is rarely hyperplastic because a branch of the PCA arises from the AChA. Takahashi et al. [ 6 ] reported that the hyperplastic variation in the AChA was 2.3%. Most of this variation supplied the temporal branch of the PCA, including the small uncal branch. In contrast, the first author (A.U.) reported that the MR angiographic prevalence of hyperplastic AChAs was 0.55% [ 11 ]. This discrepancy in the prevalence between catheter angiography and MR angiography may be due to the low spatial resolution of MR angiography. Extremely rarely, the hyperplastic AChA supplies all branches of the PCA. In such a variation, the PCoA is a tiny artery and may be misdiagnosed as a transposition of the PCoA and AChA. According to a textbook [ 3 ], the AChA always arises from the ICA, distal to the origin of the PCoA. Therefore, in our patient, the tiny artery arising proximally was hypoplastic PCoA. In 2016, the first author (A.U.) proposed that “accessory PCA” to describe the variation in which the AChA supplies the temporal branch of the PCA and “replaced PCA” to describe the AChA that supplies all branches of the PCA [ 11 ]. Since then, three cases of replaced PCA have been reported in this journal [ 2 , 9 , 12 ]. Using catheter angiography, Endo et al. [ 2 ] reported a case of a replaced PCA in which a tiny original part of the AChA arose. In our case, however, we could not identify the original part of the AChA on MR angiography. Extremely rarely, an accessory PCA supplies the parieto-occipital and calcarine arteries instead of the temporal artery [ 5 ]. SCA type PTA variant PTA and PTA variants are the most common types of carotid-vertebrobasilar anastomoses. The PTA arises from the precavernous and cavernous segments of the ICA and connects to the distal BA. There are two types: lateral (usual) and medial types [ 4 , 10 ]. PTA variants have no connection to the BA, and there are three types according to the cerebellar artery supplied: SCA, AICA, and posterior inferior cerebellar artery (PICA) [ 1 , 4 , 10 ]. According to a meta-analysis [ 1 ], the prevalence of PTA variants is reported to be 0.2%; however, this percentage may be underestimated because tiny PTA variants cannot be clearly identified on MR angiography. The first author (A.U.) reported the MR angiographic prevalence of the PTA variant using a 1.5-tesla MR scanner as 0.17% [ 10 ]. According to the above meta-analysis [ 1 ], the arteries supplied by PTA variants included the AICA (72.1%), PICA (17.7%), and SCA (10.2%). Thus, the SCA type is rare among PTA variants. In addition, an SCA rarely arises from a lateral-type PTA [ 4 , 10 ]. This variation can be regarded as another type of PTA variants [ 4 ]. In this variation, if the distal segment of the PTA was occluded postnatally, its configuration became similar to that of the SCA type PTA variant. The first author (A.U.) previously reported a case of duplicated SCAs, one of which was supplied by a PTA variant [ 7 ], and also reported a case of a large PTA variant that supplied the subtotal cerebellar hemisphere, including the caudal branch of the SCA, and caused trigeminal neuralgia [ 8 ]. Association of the replaced PCA and ipsilateral SCA type PTA variant We could not any reports on an association between a replaced PCA and an ipsilateral SCA type PTA variant in the relevant English-language literature. The supratentorial and infratentorial arteries are completely different from an embryological point of view. The PCoA and AChA belong to the supratentorial portion, and PTA and SCA are related to the arteries of the brainstem and cerebellum. Therefore, the replaced PCA and SCA type PTA variants have no developmental relationship with each other [ 4 ]. Our patient incidentally had two extremely rare ipsilateral variations. Conclusions We diagnosed the first case of right-replaced PCA associated with an SCA type right PTA variant using a 3-tesla MR scanner. These variations are extremely rare, but they have no developmental relationship with each other. Thus, our patient incidentally had two extremely rare ipsilateral variations. Declarations Acknowledgements We thank Mr. Yasuo Inoue, R,T., for his technical support. Author contributions AU carried out the study design and drafted the manuscript. AU and KT reviewed the manuscript critically, and have 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 competing interests. 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 patient signed informed consent regarding publishing his data and figures. References Brzegowy K, Pękala PA, Zarzecki MP, Pękala JR, Roy J, Aziz HM, Tubbs RS, Walocha JA, Tomaszewski KA, Mikos M (2020) Prevalence and Clinical Implications of the Primitive Trigeminal Artery and its Variants: A Meta-Analysis. World Neurosurg 133:e401-e411. doi: 10.1016/j.wneu.2019.09.042 Endo H, Ishikawa K, Ono H, Honjo K, Nakamura H (2024) Replaced posterior cerebral artery. Surg Radiol Anat 46:299-302. doi: 10.1007/s00276-023-03294-6 Lasjaunias P, Berenstein A, ter Brugge KG (2001) The anterior choroidal artery. In: Lasjaunias P, Berenstein A, ter Brugge KG (eds) Surgical neuro-angiography. Vol. 1. Clinical vascular anatomy and variations. 2nd edn. Springer, Berlin Heiderberg New York, pp 563-575 O'uchi E, O'uchi T (2010) Persistent primitive trigeminal arteries (PTA) and its variant (PTAV): analysis of 103 cases detected in 16,415 cases of MRA over 3 years. Neuroradiology 52:1111-1119. doi: 10.1007/s00234-010-0669-6 Rusu MC, Vrapciu AD, Lazăr M (2023) A rare variant of accessory posterior cerebral artery. Surg Radiol Anat 45:523-526. doi: 10.1007/s00276-023-03127-6 Takahashi S, Suga T, Kawata Y, Sakamoto K (1990) Anterior choroidal artery: angiographic analysis of variations and anomalies. AJNR Am J Neuroradiol 11:719-729 Uchino A (2023) Duplicated superior cerebellar arteries, one of which was supplied by a persistent trigeminal artery variant diagnosed by magnetic resonance angiography. Surg Radiol Anat 45:39-42. doi: 10.1007/s00276-022-03057-9 Uchino A (2023) Large persistent trigeminal artery variant that supplied the subtotal cerebellar hemisphere and caused trigeminal neuralgia, which was diagnosed by magnetic resonance (MR) angiography and MR cisternography. Surg Radiol Anat 45:363-366. doi: 10.1007/s00276-023-03098-8 Uchino A, Kamide T, Kurita H (2019) Replaced posterior cerebral artery (PCA): origin of all branches of the PCA from the anterior choroidal artery diagnosed by MR angiography. Surg Radiol Anat 41:703-705. doi: 10.1007/s00276-019-02209-8 Uchino A, Saito N, Okada Y, Kozawa E, Mizukoshi W, Inoue K, Takahashi M (2012) Persistent trigeminal artery and its variants on MR angiography. Surg Radiol Anat 34:271-276. doi: 10.1007/s00276-011-0848-0 Uchino A, Saito N, Takahashi M, Okano N, Tanisaka M (2016) Variations of the posterior cerebral artery diagnosed by MR angiography at 3 tesla. Neuroradiology 58:141-146. doi: 10.1007/s00234-015-1614-5 Uchino A, Tsuzuki N (2024) Replaced posterior cerebral artery with early branching temporal artery diagnosed by magnetic resonance angiography. Surg Radiol Anat 46:1621-1624. doi: 10.1007/s00276-024-03454-2 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 27 Dec, 2024 Read the published version in Surgical and Radiologic Anatomy → Version 1 posted Editorial decision: Revision requested 19 Dec, 2024 Reviews received at journal 19 Dec, 2024 Reviewers agreed at journal 15 Dec, 2024 Reviews received at journal 14 Dec, 2024 Reviewers agreed at journal 12 Dec, 2024 Reviewers agreed at journal 12 Dec, 2024 Reviewers invited by journal 25 Nov, 2024 Editor assigned by journal 25 Nov, 2024 Submission checks completed at journal 24 Nov, 2024 First submitted to journal 24 Nov, 2024 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-5512462","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":383561172,"identity":"6df44127-be83-4d57-9453-e7d0f5b4bbff","order_by":0,"name":"Akira Uchino","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA50lEQVRIiWNgGAWjYHACNoYEBgYe+/bmgw+APB4+YrXIGfAcSzYAaWEjSgsQGBtI5JhJwLn4AP+M5GcPHu6wSdzOkJZW+TXHToaNgfnhoxt4tEjcSDM3SDyTlriz4fCx27LbkoEOYzM2zsFnzY0cNonEtsOJDQfb0m5LbmMGauFhk8anRR6u5TCPWbHktnrCWgygWowNjvGYMX7cdpiwFsMzz8yAWtLkJHvYkqUZtx3nYWMm4Be548nPJH+22fDwyz8++PHntmp7fvbmh4/xeh8ZMPOASWKVgwDjD1JUj4JRMApGwYgBAKOfRxxHpWQSAAAAAElFTkSuQmCC","orcid":"","institution":"Saitama Sekishinkai Hospital","correspondingAuthor":true,"prefix":"","firstName":"Akira","middleName":"","lastName":"Uchino","suffix":""},{"id":383561173,"identity":"8e8bddcb-c3c3-4e2a-93c2-b2906f49fc43","order_by":1,"name":"Kazuo Tokushige","email":"","orcid":"","institution":"Saitama Sekishinkai Hospital","correspondingAuthor":false,"prefix":"","firstName":"Kazuo","middleName":"","lastName":"Tokushige","suffix":""}],"badges":[],"createdAt":"2024-11-24 05:23:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5512462/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5512462/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00276-024-03557-w","type":"published","date":"2024-12-27T15:57:12+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":71894369,"identity":"7155f6e1-09a9-4910-a4de-0d492708fa20","added_by":"auto","created_at":"2024-12-19 13:34:17","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":671940,"visible":true,"origin":"","legend":"\u003cp\u003eRight lateral (\u003cstrong\u003ea\u003c/strong\u003e), right posterior oblique (\u003cstrong\u003eb\u003c/strong\u003e), infero-superior (\u003cstrong\u003ec\u003c/strong\u003e) and anteroinferior- posterosuperior (\u003cstrong\u003ed\u003c/strong\u003e) projections of volume-rendering (VR) images of magnetic resonance (MR) angiography. There is an artery arising from the cavernous segment of the right internal carotid artery (ICA) and continuing to the right superior cerebellar artery (SCA) without connection to the basilar artery, indicative of the SCA type persistent trigeminal artery (PTA) variant (\u003cem\u003elong arrows\u003c/em\u003e). There is a large artery arising from the supraclinoid segment of the right ICA and continuing to the right posterior cerebral artery (PCA) (\u003cem\u003eshort arrows\u003c/em\u003e). A tiny artery is arising from the right ICA just proximal to the large artery, suggestive of a replaced PCA (\u003cem\u003ethin long arrows\u003c/em\u003e). \u003cem\u003eThin short arrows\u003c/em\u003e indicate chronic stage of the left vertebral artery dissection. Neither a right PCA nor a right SCA arises from the basilar artery (d).\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-5512462/v1/aebcc78a9af40790b84e7267.png"},{"id":71894368,"identity":"615d35ac-8183-4034-a649-c54e872e3701","added_by":"auto","created_at":"2024-12-19 13:34:17","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":265183,"visible":true,"origin":"","legend":"\u003cp\u003eLeft lateral (\u003cstrong\u003ea\u003c/strong\u003e) and slightly left posterior oblique (\u003cstrong\u003eb\u003c/strong\u003e) projections of a partial VR image of the right carotid system. A tiny artery (\u003cem\u003ethin long arrows\u003c/em\u003e) arises from the right ICA proximal to the origin of the large artery (\u003cem\u003eshort arrows\u003c/em\u003e). There is no tiny artery arising from the right ICA distal to the origin of the large artery. Therefore, the tiny artery is a hypoplastic posterior communicating artery (PCoA) and the large artery can be considered to be a replaced PCA. However, the tiny original part of the anterior choroidal artery which is arising from this large artery cannot be identified. \u003cem\u003eLong arrows\u003c/em\u003eindicate an SCA type PTA variant.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-5512462/v1/3930bb877983b560afcb5a8b.png"},{"id":71894372,"identity":"807609df-1ff1-44b7-b0f6-fd63d7b0af29","added_by":"auto","created_at":"2024-12-19 13:34:17","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":337690,"visible":true,"origin":"","legend":"\u003cp\u003eAxial reformatted source images of MR angiography at 5 mm thickness (a-d). \u003cem\u003eLong arrows\u003c/em\u003e indicate SCA type PTA variant. \u003cem\u003eShort arrows\u003c/em\u003e indicate a replaced PCA. \u003cem\u003eThin arrows\u003c/em\u003e indicate a hypoplastic PCoA.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-5512462/v1/8234f31d866d2e0f0ba91812.png"},{"id":72640720,"identity":"cb3be4d6-df2d-4d8a-acef-a88eb4eb4bed","added_by":"auto","created_at":"2024-12-30 16:09:06","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2056466,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5512462/v1/692307a9-a5da-4a4b-a33f-d3db5e2408f4.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Replaced right posterior cerebral artery associated with ipsilateral superior cerebellar artery type persistent trigeminal artery variant diagnosed by magnetic resonance angiography","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe anterior choroidal artery (AChA) is rarely hyperplastic because a branch of the posterior cerebral artery (PCA) arises from the AChA [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Extremely rarely, all branches of the PCA arise from the AChA, and this variation is referred to as a replaced PCA [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The cerebellar artery arising from the precavernous or cavernous segment of the internal carotid artery (ICA) without a connection to the basilar artery (BA) is regarded as a persistent trigeminal artery (PTA) variant. The majority of cerebellar arteries arising from a PTA variant are the anterior inferior cerebellar artery (AICA). Cases in which a superior cerebellar artery (SCA) arises from a PTA variant are rare [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWe report a case of a right replaced PCA associated with an ipsilateral SCA type PTA variant that was diagnosed by magnetic resonance (MR) angiography. We could not find any such reports in the relevant English-language literature.\u003c/p\u003e"},{"header":"Case report","content":"\u003cp\u003eA 53-year-old man with chronic dissection of the left vertebral artery (VA) that was diagnosed 4 months previously underwent follow-up cranial MR angiography using a 3-Tesla scanner (MAGNETOM Skyra; Siemens Healthineers, Erlangen, Germany) for the evaluation of cerebral arteries. MR angiography was performed using a standard 3-dimensional time-of-flight technique. The imaging parameters were as follows: flip angle, 16°; repetition time, 30.0 s; echo time, 3.7 s; slice thickness, 0.6 mm; number of slices, 160; slab thickness, 96 mm; field of view, 28.0 × 20.0 cm; and imaging matrix, 320 × 272.\u003c/p\u003e\n\u003cp\u003eMR angiography showed a slightly dilated left VA at its terminal segment, with a diagnosis of a chronic stage of dissection without interval change. An artery arising from the cavernous segment of the right ICA and continuing to the right SCA without connection to the BA is indicative of the SCA type PTA variant. There was also a large artery arising from the supraclinoid segment of the right ICA and continuing to the right PCA. In addition, a tiny artery arose from the right ICA proximal to the origin of the large artery. There were no tiny arteries arising from the right ICA distal to the origin of the large artery. Therefore, the tiny artery was considered to be a hypoplastic posterior communicating artery (PCoA), and the large artery was considered to be a replaced PCA (Figs.\u0026nbsp;1–3).\u003c/p\u003e\n\u003cp\u003eCatheter angiography was not performed in this case. No further treatment was administered. The patient’s clinical course was uneventful for 4 years.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eReplaced PCA\u003c/h2\u003e \u003cp\u003eThe AChA is rarely hyperplastic because a branch of the PCA arises from the AChA. Takahashi et al. [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] reported that the hyperplastic variation in the AChA was 2.3%. Most of this variation supplied the temporal branch of the PCA, including the small uncal branch. In contrast, the first author (A.U.) reported that the MR angiographic prevalence of hyperplastic AChAs was 0.55% [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. This discrepancy in the prevalence between catheter angiography and MR angiography may be due to the low spatial resolution of MR angiography. Extremely rarely, the hyperplastic AChA supplies all branches of the PCA. In such a variation, the PCoA is a tiny artery and may be misdiagnosed as a transposition of the PCoA and AChA. According to a textbook [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], the AChA always arises from the ICA, distal to the origin of the PCoA. Therefore, in our patient, the tiny artery arising proximally was hypoplastic PCoA. In 2016, the first author (A.U.) proposed that \u0026ldquo;accessory PCA\u0026rdquo; to describe the variation in which the AChA supplies the temporal branch of the PCA and \u0026ldquo;replaced PCA\u0026rdquo; to describe the AChA that supplies all branches of the PCA [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Since then, three cases of replaced PCA have been reported in this journal [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Using catheter angiography, Endo et al. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] reported a case of a replaced PCA in which a tiny original part of the AChA arose. In our case, however, we could not identify the original part of the AChA on MR angiography. Extremely rarely, an accessory PCA supplies the parieto-occipital and calcarine arteries instead of the temporal artery [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSCA type PTA variant\u003c/h3\u003e\n\u003cp\u003ePTA and PTA variants are the most common types of carotid-vertebrobasilar anastomoses. The PTA arises from the precavernous and cavernous segments of the ICA and connects to the distal BA. There are two types: lateral (usual) and medial types [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. PTA variants have no connection to the BA, and there are three types according to the cerebellar artery supplied: SCA, AICA, and posterior inferior cerebellar artery (PICA) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. According to a meta-analysis [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], the prevalence of PTA variants is reported to be 0.2%; however, this percentage may be underestimated because tiny PTA variants cannot be clearly identified on MR angiography. The first author (A.U.) reported the MR angiographic prevalence of the PTA variant using a 1.5-tesla MR scanner as 0.17% [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. According to the above meta-analysis [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], the arteries supplied by PTA variants included the AICA (72.1%), PICA (17.7%), and SCA (10.2%). Thus, the SCA type is rare among PTA variants. In addition, an SCA rarely arises from a lateral-type PTA [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. This variation can be regarded as another type of PTA variants [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In this variation, if the distal segment of the PTA was occluded postnatally, its configuration became similar to that of the SCA type PTA variant. The first author (A.U.) previously reported a case of duplicated SCAs, one of which was supplied by a PTA variant [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], and also reported a case of a large PTA variant that supplied the subtotal cerebellar hemisphere, including the caudal branch of the SCA, and caused trigeminal neuralgia [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003eAssociation of the replaced PCA and ipsilateral SCA type PTA variant\u003c/h3\u003e\n\u003cp\u003eWe could not any reports on an association between a replaced PCA and an ipsilateral SCA type PTA variant in the relevant English-language literature. The supratentorial and infratentorial arteries are completely different from an embryological point of view. The PCoA and AChA belong to the supratentorial portion, and PTA and SCA are related to the arteries of the brainstem and cerebellum. Therefore, the replaced PCA and SCA type PTA variants have no developmental relationship with each other [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Our patient incidentally had two extremely rare ipsilateral variations.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eWe diagnosed the first case of right-replaced PCA associated with an SCA type right PTA variant using a 3-tesla MR scanner. These variations are extremely rare, but they have no developmental relationship with each other. Thus, our patient incidentally had two extremely rare ipsilateral variations.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e We thank Mr. Yasuo Inoue, R,T., for his technical support.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003eAU carried out the study design and drafted the manuscript. AU and KT reviewed the manuscript critically, and have 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 competing interests.\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 patient signed informed consent regarding publishing his data and figures.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBrzegowy K, Pękala PA, Zarzecki MP, Pękala JR, Roy J, Aziz HM, Tubbs RS, Walocha JA, Tomaszewski KA, Mikos M (2020) Prevalence and Clinical Implications of the Primitive Trigeminal Artery and its Variants: A Meta-Analysis. World Neurosurg 133:e401-e411. doi: 10.1016/j.wneu.2019.09.042\u003c/li\u003e\n\u003cli\u003eEndo H, Ishikawa K, Ono H, Honjo K, Nakamura H (2024) Replaced posterior cerebral artery. Surg Radiol Anat 46:299-302. doi: 10.1007/s00276-023-03294-6\u003c/li\u003e\n\u003cli\u003eLasjaunias P, Berenstein A, ter Brugge KG (2001) The anterior choroidal artery. In: Lasjaunias P, Berenstein A, ter Brugge KG (eds) Surgical neuro-angiography. Vol. 1. Clinical vascular anatomy and variations. 2nd edn. Springer, Berlin Heiderberg New York, pp 563-575\u003c/li\u003e\n\u003cli\u003eO\u0026apos;uchi E, O\u0026apos;uchi T (2010) Persistent primitive trigeminal arteries (PTA) and its variant (PTAV): analysis of 103 cases detected in 16,415 cases of MRA over 3 years. Neuroradiology 52:1111-1119. doi: 10.1007/s00234-010-0669-6\u003c/li\u003e\n\u003cli\u003eRusu MC, Vrapciu AD, Lazăr M (2023) A rare variant of accessory posterior cerebral artery. Surg Radiol Anat 45:523-526. doi: 10.1007/s00276-023-03127-6\u003c/li\u003e\n\u003cli\u003eTakahashi S, Suga T, Kawata Y, Sakamoto K (1990) Anterior choroidal artery: angiographic analysis of variations and anomalies. AJNR Am J Neuroradiol 11:719-729\u003c/li\u003e\n\u003cli\u003eUchino A (2023) Duplicated superior cerebellar arteries, one of which was supplied by a persistent trigeminal artery variant diagnosed by magnetic resonance angiography. Surg Radiol Anat 45:39-42. doi: 10.1007/s00276-022-03057-9\u003c/li\u003e\n\u003cli\u003eUchino A (2023) Large persistent trigeminal artery variant that supplied the subtotal cerebellar hemisphere and caused trigeminal neuralgia, which was diagnosed by magnetic resonance (MR) angiography and MR cisternography. Surg Radiol Anat 45:363-366. doi: 10.1007/s00276-023-03098-8\u003c/li\u003e\n\u003cli\u003eUchino A, Kamide T, Kurita H (2019) Replaced posterior cerebral artery (PCA): origin of all branches of the PCA from the anterior choroidal artery diagnosed by MR angiography. Surg Radiol Anat 41:703-705. doi: 10.1007/s00276-019-02209-8\u003c/li\u003e\n\u003cli\u003eUchino A, Saito N, Okada Y, Kozawa E, Mizukoshi W, Inoue K, Takahashi M (2012) Persistent trigeminal artery and its variants on MR angiography. Surg Radiol Anat 34:271-276. doi: 10.1007/s00276-011-0848-0\u003c/li\u003e\n\u003cli\u003eUchino A, Saito N, Takahashi M, Okano N, Tanisaka M (2016) Variations of the posterior cerebral artery diagnosed by MR angiography at 3 tesla. Neuroradiology 58:141-146. doi: 10.1007/s00234-015-1614-5\u003c/li\u003e\n\u003cli\u003eUchino A, Tsuzuki N (2024) Replaced posterior cerebral artery with early branching temporal artery diagnosed by magnetic resonance angiography. Surg Radiol Anat 46:1621-1624. doi: 10.1007/s00276-024-03454-2\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":"Cerebral arterial variations, Magnetic resonance angiography, Persistent trigeminal artery, Posterior cerebral artery, Superior cerebellar artery","lastPublishedDoi":"10.21203/rs.3.rs-5512462/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5512462/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003ePurpose\u003c/b\u003e\u003c/p\u003e \u003cp\u003eTo describe a case in which a right replaced posterior cerebral artery (PCA) was associated with an ipsilateral superior cerebellar artery (SCA) type persistent trigeminal artery (PTA) variant.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e \u003cp\u003eA 53-year-old man who had been diagnosed with chronic dissection of the left vertebral artery (VA) 4 months previously underwent follow-up magnetic resonance (MR) angiography using a 3-Tesla scanner.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e \u003cp\u003eMR angiography showed a slightly dilated left VA at the terminal segment without interval change. An artery arising from the cavernous segment of the right internal carotid artery (ICA) and continuing to the right SCA without connection to the basilar artery is indicative of the SCA type PTA variant. There was also a large artery arising from the supraclinoid segment of the right ICA and continuing to the right PCA. In addition, a tiny artery arose from the right ICA proximal to the origin of the large artery. There were no tiny arteries arising from the right ICA distal to the origin of the large artery. Therefore, the tiny artery is considered to be a hypoplastic posterior communicating artery and the large artery is considered to be a replaced PCA.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion\u003c/b\u003e\u003c/p\u003e \u003cp\u003eA replaced PCA is an extremely rare variation, from which all branches of the PCA arise from the anterior choroidal artery. The SCA type PTA variant is also rare. This is the first report of a case of a combination of these two variations; however, they had no developmental relationship. Thus, our patient incidentally had two extremely rare ipsilateral variations.\u003c/p\u003e","manuscriptTitle":"Replaced right posterior cerebral artery associated with ipsilateral superior cerebellar artery type persistent trigeminal artery variant diagnosed by magnetic resonance angiography","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-19 13:34:12","doi":"10.21203/rs.3.rs-5512462/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-12-19T21:06:13+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-12-19T15:01:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"49643167326733879255613349386982993393","date":"2024-12-15T14:50:54+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-12-14T05:21:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"119995699724355514749843936701053497325","date":"2024-12-12T12:51:10+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"237528421013523671508302231493886593196","date":"2024-12-12T10:30:51+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-11-25T10:27:41+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-11-25T10:13:36+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-11-24T12:41:44+00:00","index":"","fulltext":""},{"type":"submitted","content":"Surgical and Radiologic Anatomy","date":"2024-11-24T05:16:31+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":"59514b13-280a-41af-a43f-5ac7a3f1ca97","owner":[],"postedDate":"December 19th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-12-30T16:04:12+00:00","versionOfRecord":{"articleIdentity":"rs-5512462","link":"https://doi.org/10.1007/s00276-024-03557-w","journal":{"identity":"surgical-and-radiologic-anatomy","isVorOnly":false,"title":"Surgical and Radiologic Anatomy"},"publishedOn":"2024-12-27 15:57:12","publishedOnDateReadable":"December 27th, 2024"},"versionCreatedAt":"2024-12-19 13:34:12","video":"","vorDoi":"10.1007/s00276-024-03557-w","vorDoiUrl":"https://doi.org/10.1007/s00276-024-03557-w","workflowStages":[]},"version":"v1","identity":"rs-5512462","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5512462","identity":"rs-5512462","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}