我们已经证实，Willis环变异导致血流动力学改变影响颅内动脉瘤形成和破裂，其中切应力起关键作用。如何准确评估Willis环变异类型，无创获取切应力大小，是评估颅内动脉瘤形成和破裂风险的关键所在。目前血流动力学影响动脉瘤形成和破裂的研究多建立在计算机流体力学(CFD)及PC-MRI对血流参数的模拟研究上。虽然此方法使复杂的流体力学简单化，但其运算复杂，且模拟研究多基于一定的假设，势必影响结果的可靠性。基于以上不足，我们拟采用3D-DSA三维重建图像判断Willis环变异类型，测量动脉瘤大小、倾斜角、体颈比；采用经颅彩色双功超声(TCCD)检测颅内血流动力学参数，计算切应力大小，旨在建立动脉瘤风险预测模型，评估Willis环变异及血流动力学改变影响颅内动脉瘤形成和破裂的风险，指导随访期动脉瘤高危患者的临床防治；同时与CFD和PC-MRI方法进行一致性检验，为无创检测血流动力学参数提供新方法。

Our previous study have found that the hemodynamic changes caused by variation of Circle of Willis result in intracranial aneurysm formation and rupture. Significantly, wall shear stress (WSS) is recognized as a critical factor. How to accurately evaluate the variation of Circle of Willis and noninvasively obtain the magnitude of WSS are essential to assess the risk factors of intracranial aneurysm formation and rupture. In recent years, many researches more emphasis on the hemodynamic forces to determining aneurysm initiation, growth, and, ultimately, rupture, using numeral simulation of computational fluid dynamics (CFD) and cine phase-contrast MRI. In spite of wide application of CFD and PC-MIR simulation, the results are skeptical due to the ignorance of some parameters, and may result in wrong conclusion. In this term, we mainly assess the multivariate predictors of intracranial aneurysm formation and rupture by regression analysis with emphasis on the variation of Circle of Willis, aneurysm size, angle, aspect ratio (AR), aneurysmal neck area/diameter of parent artery (AD) and hemodynamic forces parameters, such as wall shear stress (WSS), using 3D-DSA combined with TCCD. Moreover, the consistency tests in 3D-DSA combined with TCCD versus CFD and PC-MRI will be performed to gain the theoretical support for a new method for noninvasive detection of hemodynamic parameters in intracranial aneurysms.