Sadık Ahmet UYANIK, Handan UZUNÇAKMAK UYANIK, Umut OGUSLU, Doğan DEDE

Intracranial arterial variations and their relation with cerebral aneurysms: Analysis of 640 patients

Aim: To evaluate prevalence of cerebral arterial variations in Turkish population and association of the variations with cerebralaneurysmsMaterials and Methods: Digital subtraction angiography of 640 consecutive patients between January 2011-December 2013 wereevaluated retrospectively. Patients with aneurysms were compared with patients without aneurysm to determine the effect ofvariations. Comparisons were made using Chi square or Fisher exact test for categorical variables and Student's t test or MannWhitney U test for continuous variables.Results: The most common variation in the anterior circulation was hypoplasia of anterior cerebral artery A1 segment and themost common variation in the posterior circulation was fetal origin of the posterior cerebral artery. Hypoplasia and aplasia of theanterior cerebral artery A1 segment was significantly more frequent in patients with anterior communicating artery aneurysms thanthe control group (p:

PDF

___

1. Alpers BJ, Berry RG, Paddison RM. Anatomical studies of the circle of Willis in normal brain. AMA Arch Neurol Psychiatry 1959;81:409-18.
2. Iqbal S. A comprehensive study of the anatomical variations of the circle of willis in adult human brains. J Clin Diagn Res 2013;7:2423-7.
3. Kapoor K, Singh B, Dewan LI. Variations in the configuration of the circle of Willis. Anat Sci Int 2008; 83:96-106.
4. de Rooij NK, Velthuis BK, Algra A, et al.Configuration of the circle of Willis, direction of flow, and shape of the aneurysm as risk factors for rupture of intracranial aneurysms. J Neurol 2009;256:45-50.
5. Kayembe KN, Sasahara M, Hazama F. Cerebral aneurysms and variations in the circle of Willis. Stroke 1984;15:846-50.
6. Nixon AM, Gunel M, Sumpio BE. The critical role of hemodynamics in the development of cerebral vascular disease. J Neurosurg 2010;112:1240-53.
7. Tanaka H, Fujita N, Enoki T, et al. Relationship between variations in the circle of Willis and flow rates in internal carotid and basilar arteries determined by means of magnetic resonance imaging with semiautomated lumen segmentation: reference data from 125 healthy volunteers. AJNR Am J Neuroradiol 2006;27:1770-5.
8. Padget D. The circle of Willis: its embryology and anatomy. In: Dandy W, ed. Intracranial arterial aneurysms. New York: Comstock Publishing 1944:67- 90.
9. Kamath S. Observations on the length and diameter of vessels forming the circle of Willis. J Anat 1981;133:419-23.
10. Riggs HE, Rupp C. Variation in form of circle of Willis. The relation of the variations to collateral circulation: anatomic analysis. Arch Neurol 1963;8:8-14.
11. Dimmick SJ, Faulder KC. Normal variants of the cerebral circulation at multidetector CT angiography. Radiographics 2009;29:1027-43.
12. Krasny A, Nensa F, Sandalcioglu IE, et al. Association of aneurysms and variation of the A1 segment. J Neurointerv Surg 2014;6:178-83.
13. Tarulli E, Fox AJ. Potent risk factor for aneurysm formation: termination aneurysms of the anterior communicating artery and detection of A1 vessel asymmetry by flow dilution. AJNR Am J Neuroradiol 2010;31:1186-91.
14. Lazzaro MA, Ouyang B, Chen M. The role of circle of Willis anomalies in cerebral aneurysm rupture. J Neurointerv Surg 2012;4:22-6.
15. Songsaeng D, Geibprasert S, Willinsky R, Tymianski M, TerBrugge KG, Krings T. Impact of anatomical variations of the circle of Willis on the incidence of aneurysms and their recurrence rate following endovascular treatment. Clin Radiol 2010; 65:895- 901.
16. Rinaldo L, McCutcheon BA, Murphy ME, et al. Relationship of A1 segment hypoplasia to anterior communicating artery aneurysm morphology and risk factors for aneurysm formation. J Neurosurg 2017; 127:89-95.
17. Parmar H, Sitoh YY, Hui F. Normal variants of the intracranial circulation demonstrated by MR angiography at 3T. Eur J Radiol 2005;56:220-8.
18. Perlmutter D, Rhoton AL, Jr. Microsurgical anatomy of the anterior cerebral-anterior communicatingrecurrent artery complex. J Neurosurg 1976;45:259- 72.
19. Perlmutter D, Rhoton AL, Jr. Microsurgical anatomy of the distal anterior cerebral artery. J Neurosurg 1978; 49:204-28.
20. Uchino A, Nomiyama K, Takase Y, Kudo S. Anterior cerebral artery variations detected by MR angiography. Neuroradiology 2006;48:647-52.
21. Bisaria KK. Anomalies of the posterior communicating artery and their potential clinical significance. J Neurosurg 1984; 60:572-6.
22. Saeki N, Rhoton AL, Jr. Microsurgical anatomy of the upper basilar artery and the posterior circle of Willis. J Neurosurg 1977;46:563-78.
23. Horikoshi T, Akiyama I, Yamagata Z, et al. Magnetic resonance angiographic evidence of sex-linked variations in the circle of willis and the occurrence of cerebral aneurysms. J Neurosurg 2002;96:697-703.
24. Zada G, Breault J, Liu CY, et al. Internal carotid artery aneurysms occurring at the origin of fetal variant posterior cerebral arteries: surgical and endovascular experience. Neurosurgery 2008;63:ONS55-61; discussion ONS61-52.
25. He Z, Wan Y. Is fetal-type posterior cerebral artery a risk factor for intracranial aneurysm as analyzed by multislice CT angiography? Exp Ther Med 2018;15:838-46.