The purpose of this study was to identify the anatomical variants (AVs) in the intracranial arterial circulation of patients who underwent neuro-interventional procedures (NIPs) and to describe their relationship with intracranial aneurysms (IA). We performed a cross-sectional analysis of angiographic images from patients who underwent NIP at the Interventional Neuroradiology Department of the National Institute of Neurology and Neurosurgery in México between July 1, 2020, and January 1, 2022. After reviewing images from 150 NIPs, we found 144 AVs., yielding a prevalence of 81%. Of these, 49 AVs (34%) were located in the anterior circulation (AC) and 95 (66%) in the posterior circulation (PC); 23 NIPs (16%) showed AVs in both the AC and PC. The most frequent AVs were the fetal pattern of the posterior cerebral artery (19%) and hypoplasia of the A1 segment (12%). AVs were significantly more common in patients with neurovascular disorders than those without (80% vs 49%, p = .003) and in patients with IA compared to those without (68% vs 47%, p = .048). In the studied population, AVs were predominantly located in the PC and are significantly more frequent in patients with neurovascular disorders, particularly those with IA.
PukenasB. Normal brain anatomy on magnetic resonance imaging. Magn Reson Imaging Clin N Am2011; 19(3): 429–437. DOI: 10.1016/j.mric.2011.05.015.
2.
VargaADi LeoGBangaPV, et al.Multidetector CT angiography of the Circle of Willis: association of its variants with carotid artery disease and brain ischemia. Eur Radiol2019; 29(1): 46–56. DOI: 10.1007/s00330-018-5577-x.
3.
WeiskopfNEdwardsLJHelmsG, et al.Quantitative magnetic resonance imaging of brain anatomy and in vivo histology. Nature Reviews Physics2021; 3(8): 570–588.
4.
Lopez-SalaPAlberdiNMendiganaM, et al.Anatomical variants of anterior communicating artery complex. A study by Computerized Tomographic Angiography. J Clin Neurosci2020; 80: 182–187. DOI: 10.1016/j.jocn.2020.08.019.
5.
MenshawiKMohrJPGutierrezJ. A functional perspective on the embryology and anatomy of the cerebral blood supply. J Stroke2015; 17(2): 144–158. DOI: 10.5853/jos.2015.17.2.144.
6.
KathuriaSGreggLChenJ, et al.Normal cerebral arterial development and variations. Semin Ultrasound CT MR2011; 32(3): 242–251. DOI: 10.1053/j.sult.2011.02.002.
7.
ShahPShrivastavaMKaleH, et al.Interventions and imaging in patients with anatomic variations of cerebral circulation: a pictorial review. Acta Radiol2023; 64(8): 2455–2469. DOI: 10.1177/02841851231171687.
8.
ShabanSHuasenBHaridasA, et al.Digital subtraction angiography in cerebrovascular disease: current practice and perspectives on diagnosis, acute treatment and prognosis. Acta Neurol Belg2022; 122(3): 763–780. DOI: 10.1007/s13760-021-01805-z.
9.
LeeSJLiuBRaneN, et al.Correlation between CT angiography and digital subtraction angiography in acute ischemic strokes. Clin Neurol Neurosurg2021; 200: 106399.
10.
De CaroJCiacciarelliATessitoreA, et al.Variants of the circle of Willis in ischemic stroke patients. J Neurol2021; 268(10): 3799–3807. DOI: 10.1007/s00415-021-10454-4.
11.
ParmarHSitohYYHuiF. Normal variants of the intracranial circulation demonstrated by MR angiography at 3T. Eur J Radiol2005; 56(2): 220–228. DOI: 10.1016/j.ejrad.2005.05.005.
12.
FengLMaoHJZhangDD, et al.Anatomical variations in the Circle of Willis and the formation and rupture of intracranial aneurysms: a systematic review and meta-analysis. Front Neurol2022; 13: 1098950. DOI: 10.3389/fneur.2022.1098950.
13.
UyanikSAUyanikHUOgusluU, et al.Intracranial arterial variations and their relation with cerebral aneurysms: analysis of 640 patients. 2020.
14.
YilmazAÖzkulA. Anatomical variations of anterior circulation in the brains of patients with and without intracranial aneurysm. Turkish Journal of Cerebrovascular Diseases2018; 24(1): 8–13.
15.
KayembeKNSasaharaMHazamaF. Cerebral aneurysms and variations in the circle of Willis. Stroke1984; 15(5): 846–850. DOI: 10.1161/01.str.15.5.846.
16.
PlazaOAMatambaETVelaMT. Prevalencia de variantes anatómicas del polígono de Willis en cadáveres sometidos a necropsia medicolegal. International Journal of Medical and Surgical Sciences2022; 9(1): 1–9.
17.
BerensteinALasjauniasP. Surgical neuroangiography: vol. 2: clinical and endovascular treatment aspects in adults. Berlin, Germany: Springer Science & Business Media, 2012.
18.
van RaamtAFMaliWPvan LaarPJ, et al.The fetal variant of the circle of Willis and its influence on the cerebral collateral circulation. Cerebrovasc Dis2006; 22(4): 217–224. DOI: 10.1159/000094007.
19.
DumitrescuAMEvaLHabaD, et al.Anatomical study of circle of Willis on fresh autopsied brains. A study of a Romanian population. Rom J Morphol Embryol2022; 63(2): 395–406. DOI: 10.47162/RJME.63.2.10.
20.
FattahianRGorjiRASadeghiM, et al.Assessment of the prevalence of vascular anomalies of the circle of Willis based on the autopsy of cadavers in Kurdish race between 2016 and 2017. Mater Soc Med2018; 30(3): 189.
21.
HashemiSMMahmoodiRAmirjamshidiA. Variations in the Anatomy of the Willis' circle: a 3-year cross-sectional study from Iran (2006-2009). Are the distributions of variations of circle of Willis different in different populations? Result of an anatomical study and review of literature. Surg Neurol Int2013; 4: 65. DOI: 10.4103/2152-7806.112185.
22.
IqbalS. A comprehensive study of the anatomical variations of the circle of willis in adult human brains. J Clin Diagn Res2013; 7(11): 2423–2427. DOI: 10.7860/JCDR/2013/6580.3563.
23.
StockKWRadueEWJacobAL, et al.Intracranial arteries: prospective blinded comparative study of MR angiography and DSA in 50 patients. Radiology1995; 195(2): 451–456. DOI: 10.1148/radiology.195.2.7724765.
24.
ManninenA-LIsokangasJ-MKarttunenA, et al.A comparison of radiation exposure between diagnostic CTA and DSA examinations of cerebral and cervicocerebral vessels. Am J Neuroradiol2012; 33(11): 2038–2042.
25.
HanleyMZenzenWJBrownMD, et al.Comparing the accuracy of digital subtraction angiography, CT angiographyand MR angiography at estimating the volume of cerebral aneurysms. Interv Neuroradiol2008; 14(2): 173–177. DOI: 10.1177/159101990801400208.
26.
ForgoBTarnokiADTarnokiDL, et al.Are the variants of the circle of willis determined by genetic or environmental factors? Results of a twin study and review of the literature. Twin Res Hum Genet2018; 21(5): 384–393. DOI: 10.1017/thg.2018.50.
27.
BrunerEMantiniSMussoF, et al.The evolution of the meningeal vascular system in the human genus: from brain shape to thermoregulation. Am J Hum Biol2011; 23(1): 35–43. DOI: 10.1002/ajhb.21123.
28.
EisovaSPisovaHVeleminskyP, et al.Normal craniovascular variation in two modern European adult populations. J Anat2019; 235(4): 765–782. DOI: 10.1111/joa.13019.
29.
KarazincirSAdaESarsilmazA, et al.[Frequency of vascular variations and anomalies accompanying intracranial aneurysms]. Tani Girisim Radyol2004; 10(2): 103–109.
30.
KovacJDStankovicAStankovicD, et al.Intracranial arterial variations: a comprehensive evaluation using CT angiography. Med Sci Monit2014; 20: 420–427. DOI: 10.12659/MSM.890265.
31.
AhmadS. E-142 Variations, anomalies and collateralization of intracranial vascular anatomy and association with intracranial aneurysms. British Medical Journal Publishing Group. 2021; 13.
32.
Jiménez SosaMSCantú GonzálezJRMorales AvalosR, et al.Anatomical variants of anterior cerebral arterial circle: a study by multidetector computerized 3D tomographic angiography. Int J Morphol2017; 35(3): 1121–1128.
33.
ObermanDZAklyMSPRabeloNN, et al.Morphologic variations in the circle of Willis as a risk factor for aneurysm rupture in the anterior and posterior communicating arteries. World neurosurgery2021; 154: e155–e162.
34.
HindenesLBIngebrigtsenTIsaksenJG, et al.Anatomical variations in the circle of Willis are associated with increased odds of intracranial aneurysms: the Tromso study. J Neurol Sci2023; 452: 120740. DOI: 10.1016/j.jns.2023.120740.
35.
ScullenTMathkourMDumontA, et al.Intracranial aneurysms in the context of variant cerebrovascular anatomy: a review of the literature. World Neurosurg2022; 165: 58–68. DOI: 10.1016/j.wneu.2022.05.127.
36.
OrakdogenMEmonSTSomayH, et al.Vascular variations associated with intracranial aneurysms. Turk Neurosurg2017; 27(6): 853–862. DOI: 10.5137/1019-5149.JTN.17839-16.1.
37.
UchidaKMatsukawaHSowlatMM, et al.Gender differences in procedural clinical complications and outcomes of intracranial aneurysms: analysis of the stroke thrombectomy and aneurysm registry. Neurosurgery2024; 94(3): 545–551. DOI: 10.1227/neu.0000000000002695.
38.
KongableGLLanzinoGGermansonTP, et al.Gender-related differences in aneurysmal subarachnoid hemorrhage. J Neurosurg1996; 84(1): 43–48. DOI: 10.3171/jns.1996.84.1.0043.
39.
MenghiniVVBrownRDJr.SicksJD, et al.Incidence and prevalence of intracranial aneurysms and hemorrhage in Olmsted County, Minnesota, 1965 to 1995. Neurology1998; 51(2): 405–411. DOI: 10.1212/wnl.51.2.405.
40.
CanADuR. Association of hemodynamic factors with intracranial aneurysm formation and rupture: systematic review and meta-analysis. Neurosurgery2016; 78(4): 510–520. DOI: 10.1227/NEU.0000000000001083.
41.
LuGHuangLZhangXL, et al.Influence of hemodynamic factors on rupture of intracranial aneurysms: patient-specific 3D mirror aneurysms model computational fluid dynamics simulation. AJNR Am J Neuroradiol2011; 32(7): 1255–1261. DOI: 10.3174/ajnr.A2461.
42.
ZhangYYangXWangY, et al.Influence of morphology and hemodynamic factors on rupture of multiple intracranial aneurysms: matched-pairs of ruptured-unruptured aneurysms located unilaterally on the anterior circulation. BMC Neurol2014; 14: 253. DOI: 10.1186/s12883-014-0253-5.
43.
BurlesonACTurittoVT. Identification of quantifiable hemodynamic factors in the assessment of cerebral aneurysm behavior. On behalf of the Subcommittee on Biorheology of the Scientific and Standardization Committee of the ISTH. Thromb Haemost1996; 76(1): 118–123.
44.
SadasivanCFiorellaDJWooHH, et al.Physical factors effecting cerebral aneurysm pathophysiology. Ann Biomed Eng2013; 41(7): 1347–1365. DOI: 10.1007/s10439-013-0800-z.
