RT Journal Article SR Electronic T1 E-017 Differences in circle of willis geometry between cerebral aneurysm patients and controls JF Journal of NeuroInterventional Surgery JO J NeuroIntervent Surg FD BMJ Publishing Group Ltd. SP A55 OP A56 DO 10.1136/neurintsurg-2018-SNIS.93 VO 10 IS Suppl 2 A1 Kappel, A A1 Swartwout, E A1 Lieber, B A1 Woo, H A1 Fiorella, D A1 Sadasivan, C YR 2018 UL http://jnis.bmj.com/content/10/Suppl_2/A55.2.abstract AB Introduction Current evidence suggests that hemodynamic factors are associated with the formation and rupture of cerebral aneurysms.1 As hemodynamics are strongly affected by geometry, objective parameters have also been developed to characterize the three-dimensional vascular geometry obtained from patient scans.2 Our goal is to evaluate whether such geometric parameters are different between aneurysm patients and controls.Methods Head and neck CTA acquisitions from 7 aneurysm patients and 10 age and gender matched controls were retrospectively and anonymously analyzed under IRB approval. All aneurysms had ruptured; there were four anterior-communicating (AComm), two posterior-communicating, and one carotid-terminus aneurysm. Mimics software (Materialise, Belgium) was used to segment the vasculature. When available, non-contrast CT scans of the head were linearly co-registered to CT angiograms using Advanced Normalization Tools3 and used to subtract the cranium and cervical spine for improved segmentation. The average cross-sectional area of the anterior (ACA) and posterior (PCA) cerebral arteries were obtained using VMTK software4; bifurcation angles at the AComm segment were also measured. These three variables were statistically compared (t-test) between the aneurysm and control groups.Results Both the ACA (p=0.045) and PCA (p=0.025) cross-sectional areas were statistically higher in the aneurysm group as compared to controls (figure 1). AComm bifurcation angles were also greater in aneurysm patients, but not significantly (p=0.55).Abstract E-017 Figure 1 Conclusions Previous autopsy studies have suggested an association of ACA asymmetry to the prevalence of ACom aneurysms.5,6 Variations in bifurcation and carotid siphon angles have been associated with aneurysms.7,8 Our preliminary results are in-line with these studies. A large sample size study is necessary in order to derive any diagnostically relevant associations between Circle of Willis morphology and the etiology of aneurysms.ReferencesCan, Du. Neurosurgery 2016;78:5102.Piccinelli, et al. IEEE Trans Med Imaging 2009;28:11413.Avants, et al. Front Neuroinform 2014;28:444.Antiga, et al. Med Biol Eng Comput 2008;46:10975.Kayembe, et al. Stroke 1984;15:8466.Stehbens. Arch Pathol 1963;75:457.Bor, et al. Neurology 2008;70:7008.Silva Neto ÂR, et al. Arq Neuropsiquiatr 2012;70:917.Disclosures A. Kappel: None. E. Swartwout: None. B. Lieber: 4; C; Vascular Simulations. H. Woo: 4; C; Vascular Simulations. 6; C; Cerenovus JnJ. D. Fiorella: 1; C; Penumbra, Microvention, Medtronic. 2; C; Penumbra, Microvention, Medtronic. 4; C; Vascular Simulations. 6; C; Cerenovus JnJ. C. Sadasivan: 4; C; Vascular Simulations.