Variants and vascular anomalies of supra-aortic trunks and circle of Willis: A Pictorial Review.

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1 Variants and vascular anomalies of supra-aortic trunks and circle of Willis: A Pictorial Review. Poster No.: C-1479 Congress: ECR 2013 Type: Educational Exhibit Authors: M. M. Padilla Deza, D. Rodriguez, L. Aja Rodriguez, P. Mora Montoya, Y. P. Velasco Díaz, A. Muntané Sánchez ; Hospitalet de Llobregat, Ba/ES, El Vendrell/ES, Barcelona/ES, Hospitalet de Llobregat/ES Keywords: Computer Applications-Detection, diagnosis, CT-Angiography, Catheter arteriography, Neuroradiology brain, Anatomy, Congenital DOI: /ecr2013/C-1479 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 53

2 Learning objectives To illustrate with multidetector computed tomographic (CT) angiography and digital subtraction angiography (DSA), the spectrum of variants and anomalies in the supra-aortic trunks (SAT) and Circle of Willis (CW); also, its relationship with some diseases. Background CT angiography and DSA are used for evaluating the extracraneal and intracranial circulation. Normal variants and anomalies of the supra-aortic trunks and Circle of Willis, are common images findings 1 Its knowledge and recognition is important in a radiological report, in order to make a correct diagnosis, management and aid in surgical planning. For example, the detection of trigeminal artery that frequently connects the internal carotid with the basilar artery, has a functional consequence, it creates a reversed in the vertebral system and may. cause trigeminal neuralgia and/or subarachnoidal hemorrhage This simple finding helps to plan a surgery or endovascular treatment 1,2,3,4. The aim of this pictographic review is to illustrate normal variants and anomalies by anatomic distribution of arterial branches. 1. VARIANTS OF SUPRA-AORTIC TRUNKS: Common Brachiocephalic Trunk Aberrant Right Subclavian or Brachiocephalic Artery Variant Branching Sequence Variants of Common Carotid Arteries Variant Origin of Vertebral Arteries 1.1. Common Brachiocephalic Trunk: Common brachiocephalic trunk, consists in both common carotid arteries and the right subclavian artery arise from a single trunk. It is the most frequent normal variant of aortic arch branching. Page 2 of 53

3 Fig. 1: Common brachiocephalic trunk: Both common carotid arteries and the right subclavian artery arise from a single trunk. References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES 1.2. Aberrant Right Subclavian or Brachiocephalic Artery: The right subclavian artery is the last branch of the aortic arch in l% of individuals. It courses to the right behind the esophagus in most of these cases. The aberrant right 5 brachiocephalic artery is uncommon. Page 3 of 53

4 Fig. 2: Aberrant Right Subclavian Artery: It courses to the right behind the esophagus in most of these cases. References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES 1.3. Other Variant Branching Sequence: Variations in the sequence of branching, occur rarely, like the left subclavian artery may be the second branch (before the left common carotid), or the internal and external carotid arteries may originate independently from the aortic arch 6. Page 4 of 53

5 Fig. 3: Variations in the sequence of branching References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES Variants of Common Carotid Arteries : Absence of the right common carotid. Common trunk for both carotids. A higher or lower bifurcation of the common carotids. External and internal carotids arising directly from the arch of the aorta. Common carotid may provide one or more of the branches usually derived from the external carotid (vertebral, inferior thyroid, or ascending laryngeal) Page 5 of 53

6 Fig. 4: Common trunk for both carotids. References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ES 1.5. Variant Origin of Vertebral Arteries: It will be explained with the vertebrobasilar system (see below) 2. VARIANTS AND ANOMALIES OF THE INTERNAL CAROTID ARTERY:. Page 6 of 53

7 We can study the variations and anomalies following the division of the artery segments. 2.1 C1 Anomalies: Absence, hypoplasia, duplication, fenestration. Hypoglossal Artery persistent or proatlantoidea intersegmental artery. (Carotid-basilar anastomosis: are fetal anastomosis usually regress to develop posterior communicating arteries). Fig. 5: Hypoplasia of the Internal carotid Artery Page 7 of 53

8 References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES Fig. 6: Hypoglosal artery: A.Angio-CT, axial view. B.VR reconstruction. References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES Page 8 of 53

9 Fig. 7: Hypoglosal artery. Sagital view References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES 2.2 C2 Anomalies: Aberrant petrous ICA. Persistent stapedial artery. Page 9 of 53

10 Fig. 8: Aberrant internal carotid artery.a(right). B(left) References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES 2.3 C3 or Lacerum Segment: No variations or anomalies. 2.4 C4 Segment: Variant: Internal carotid arteries paramedian "kissing carotid arteries". Importance in hypofisial surgery. Anomalies: Persistent trigeminal artery: Carotid-basilar embryonic anastomosis most cranial and most frequent (0.02 to 0.6%). In 25% is associated with vascular anomalies, particularly aneurysms. Anastomosis intracavernosal-rare, is associated with an ICA aplasia failure and the circle of Willis. Page 10 of 53

11 Fig. 9: DSA. Persistent trigeminal artery References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ES Page 11 of 53

12 Fig. 10: DSA. Persistent trigeminal artery References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES 2.5 C5 Segment: No branches arise from C5. Page 12 of 53

13 2.6 C6 or ophthalmic segment: Variants: Middle meningeal artery originated in the ophthalmic artery. Anomalies: Ophthalmic artery originating from the middle meningeal artery. 2.7 C7Segment : Variants: Posterior communicating artery: high variability in size. If P1 is hypoplastic or absent, posterior cerebral artery has a provision fetal and vascularized ACoPost its territory. Anterior choroidal artery: hemodynamic equilibrium with posteromedial and posterolateral choroidal arteries (VB system), so their size and territory are variables. Anomalies: Rare. Hypo or hyperplastic anterior choroidal artery. Origin of the anterior choroidal artery proximal to the origin of the posterior communicating artery. 3. VARIANTS AND ANOMALIES OF THE CIRCLE OF WILLIS 1,2,3,7,8 : Normal variants include fenestrations and duplications. A normal circle of Willis to be one in which there is a complete anastomotic polygon, which may show considerable variability not only of its components but also its branches. The so-called normal or textbook description holds true in about 34.5% of cases. 3.1 Anterior Cerebral Artery (ACA): Variants: A1 hypoplasia (10-25%). The vascularized contralateral ACA vascular territory of both hemispheres through ACoAnt Page 13 of 53

14 Fig. 11: Fenestration of the anterior cerebral artery References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES Page 14 of 53

15 Fig. 12: Fenestration of the comunicante anterior artery and hypoplasia A1. References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES Page 15 of 53

16 Fig. 13: Hypoplasia A1 References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES Anomalies: Bihemispheric ACA (2-7%). A2 segment hypoplasia, the contralateral gives branches to both hemispheres. Azygos ACA (0.2-4%). Persistence of embryonic half artery of the corpus callosum. A single ACA vascularized both hemispheres, may be associated with holoprosencephaly, neuronal migration abnormalities and aneurysms. Multiple ACA. (2-13%). Over two A2 segment. Page 16 of 53

17 Anomalous origin of the ACA. In the internal carotid artery at the level of the ophthalmic artery. Rare, is associated with other abnormalities such as aneurysms and carotid agenesis. 3.2 Medial Cerebral Artery: Variants: Bifurcation, trifurcation, division early. Anomalies: Duplication. (1-3%) arises from the internal carotid artery and travels parallel to M1. Accessory middle cerebral artery. (2.7%) arises from the ACA and travels parallel to M1. It is associated with aneurysms. Page 17 of 53

18 Fig. 14: cerebral media accesory References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ES Page 18 of 53

19 Fig. 15: MCA. A. Duplication B. Accesory References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES 3.3 Posterior Cerebral Artery: Variants: Hypoplasia P1 (20%). The distal posterior cerebral artery is opacified mainly through the internal carotid artery by posterior communicating artery route. Page 19 of 53

20 Fig. 16: Hypoplasia P1 References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES Anomaly: Carotid-basilar anastomosis 3.4 Vertebral-basilar system: Anomalies: Vertebral artery origin in the aortic arch (5%) Anomalous origin of the Posterior-inferior cerebellar artery (PICA). It is associated with higher prevalence of aneurysms. Page 20 of 53

21 Duplication and fenestration of the vertebral artery. Represents a persistence of embryonic plexiform ducts. It is associated with higher prevalence of aneurysms and vascular malformations. Duplication or fenestration of the basilar artery (1.3%), associated with increased incidence of aneurysms Carotid-basilar anastomosis Anomalous origin of cerebellar arteries. Fig. 17: Fenestration of the basilar artery References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ES Variants: Anterior-inferior cerebellar artery (AICA)-PICA common Trunk Accessory AICA Multiple anterior cerebellar artery. Page 21 of 53

22 Images for this section: Fig. 1: Common brachiocephalic trunk: Both common carotid arteries and the right subclavian artery arise from a single trunk. Page 22 of 53

23 Fig. 2: Aberrant Right Subclavian Artery: It courses to the right behind the esophagus in most of these cases. Page 23 of 53

24 Fig. 3: Variations in the sequence of branching Page 24 of 53

25 Fig. 4: Common trunk for both carotids. Page 25 of 53

26 Fig. 5: Hypoplasia of the Internal carotid Artery Page 26 of 53

27 Fig. 6: Hypoglosal artery: A.Angio-CT, axial view. B.VR reconstruction. Page 27 of 53

28 Fig. 8: Aberrant internal carotid artery.a(right). B(left) Page 28 of 53

29 Fig. 7: Hypoglosal artery. Sagital view Page 29 of 53

30 Fig. 9: DSA. Persistent trigeminal artery Page 30 of 53

31 Fig. 10: DSA. Persistent trigeminal artery Page 31 of 53

32 Fig. 11: Fenestration of the anterior cerebral artery Page 32 of 53

33 Fig. 12: Fenestration of the comunicante anterior artery and hypoplasia A1. Page 33 of 53

34 Fig. 13: Hypoplasia A1 Page 34 of 53

35 Fig. 14: cerebral media accesory Page 35 of 53

36 Fig. 15: MCA. A. Duplication B. Accesory Page 36 of 53

37 Fig. 16: Hypoplasia P1 Page 37 of 53

38 Fig. 17: Fenestration of the basilar artery Page 38 of 53

39 Imaging findings OR Procedure details A retrospective analysis including CT angiograms obtained from October 2011 to October 2012 and reported by neuroradiologists senior at our institution was performed. We classified the images findings in normal variants or vascular anomalies. Fig. 18 References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES The most frequent findings in the Circle of Willis are: 1) Normal variants: hypoplasias (25,8%), fetal presentation of the posterior cerebral artery (12,3%). 2) Anomalies: anterior communicating complex anomalies as anterior cerebral artery azygos or bihemispheric, abnormalities of the origin of the middle cerebral artery and fenestrations. Page 39 of 53

40 Fig. 19: Fenestration of basilar artery asociated with aneurysm. A. Before interventional procedure. B. After embolization References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES Page 40 of 53

41 Fig. 20: Azygos. DSA. A.AP view. Right carotid artery angiogram. B.AP view. Left carotid artery angiogram. References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES At SAT our analysis found: 1) Normal variants, common hypoplasia of the vertebral artery (VA) (8,6 %), a common SAT trunk and origin of left VA in aorta. 2) Anomalies were aberrant subclavian artery and retropharyngeal internal carotid. Page 41 of 53

42 Fig. 21: Retropharyngeal carotid associated with dissecant aneurysms References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES Page 42 of 53

43 Fig. 22: Retropharyngeal carotid associated with dissecant aneurysms References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES We also detected uncommon anomalies in literature, such as embryonic anastomosis like persistent trigeminal artery or persistent hypoglossal artery, aberrant internal carotid artery or posteroinfeior cerebellar artery originated from internal carotid artery. Page 43 of 53

44 Fig. 23: Temporal anterior branch originated in ICA, associated with aneurysm References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES Page 44 of 53

45 Fig. 24: A. PICA with origin in ICA. B. In this patient was asociated with AVM. References: Radiology, Hospital Universitario de Bellvitge - Hospitalet de Llobregat/ ES Images for this section: Page 45 of 53

46 Fig. 18 Page 46 of 53

47 Fig. 19: Fenestration of basilar artery asociated with aneurysm. A. Before interventional procedure. B. After embolization Fig. 20: Azygos. DSA. A.AP view. Right carotid artery angiogram. B.AP view. Left carotid artery angiogram. Page 47 of 53

48 Fig. 21: Retropharyngeal carotid associated with dissecant aneurysms Page 48 of 53

49 Fig. 22: Retropharyngeal carotid associated with dissecant aneurysms Page 49 of 53

50 Fig. 23: Temporal anterior branch originated in ICA, associated with aneurysm Page 50 of 53

51 Fig. 24: A. PICA with origin in ICA. B. In this patient was asociated with AVM. Page 51 of 53

52 Conclusion This pictorial review illustrates the most frequent and relevant cases reported in our institution during one-year period. Our results compared with the medical literature match in the prevalence and the anomalies associated. Recognition of these variants and anomalies by the radiologist are important in the diagnosis and management planning. References 1. Dimmick S, Faulder K. Normal Variants of the Cerebral Circulation at Multidetector CT Angiography. RadioGraphics.2009; 29: Whu HM, Chuang HM. The clinical relevance of fetal variant of the circle of Willis and its influence on the cerebral collateral circulation.acta NeurolTaiwan. 2011; 20(4): De Silva KR, Silva R, Gunasekera WS, Jayesekera RW. Prevalence of typical circle of Willis and the variation in the anterior communicating artery: A study of a Sri Lankan population. Ann Indian Acad Neurol. 2009; 12(3): Pérez-Carrillo GJ, Hogg JP.Intracranial vascular lesions and anatomical variants all residents should know. Curr Probl Diagn Radiol May-Jun;39(3): Ka-tak W, Lam WW, Yu SC. MDCT of an aberrant right subclavian artery and of bilateral vertebral arteries with anomalous origins. AJR Am J Roentgenol. 2007;188 (3): W Caldemeyer K, Carrico J,. Mathews V. Radiology and Embryology of Anomalous Arteries ofthe Head and Neck.AJR 1998;1 70: X/98/i Okahara M, Kiyosue H, Mori H, Tanou S, Sainou M, Nagatomi H. Anatomic variations of the cerebral arteries and their embryology: a pictorial review. Eur Radiol (2002) 12: Boleaga-Durán, Ameller-Terrazas, Criales-Cortés. Variantes anatómicas del círculo arterial de la base de cráneo. Anales de Radiología de México.2004; 4: Page 52 of 53

53 Personal Information Page 53 of 53