Improving the computational modeling of coiled cerebral aneurysms through synchrotron microtomography

在这里，我们试图提高螺旋状脑动脉瘤血流动力学建模的准确性。这个目标是 由于脑动脉瘤的盛行、破裂时预后不佳以及治疗的原因， 失败率(导致动脉瘤复发和脑出血或需要重新治疗的风险) 高达25%。血流动力被认为会影响动脉瘤的治疗结果，但标准 计算流体动力学(CFD)模拟螺旋动脉瘤内这种作用力的方法(称为 “多孔介质技术”)容易出错。提高螺旋动脉瘤CFD建模的准确性将 加强患者特异性CFD的预测价值，可以提高动脉瘤的治疗效果和 减少死亡和残疾，以及与多次住院相关的医疗费用。 这个项目建立在我们正在进行的NIH资助的创建脑动脉瘤CFD模型的专业知识的基础上， 以及与欧洲同步加速器研究机构的合作，以开发一种改进的CFD方法 可应用于临床的螺旋状脑动脉瘤模型。首先，我们将创建高保真 基于患者特定动脉瘤解剖的3D打印动脉瘤模型，并将相同的商业- 可在实际患者治疗中使用的动脉瘤弹簧圈分为每种型号。这些螺旋状动脉瘤模型将 使用同步加速器x射线显微断层摄影术以12微米的分辨率扫描，提供详细的 复杂的线圈几何形状。这些图像将被合并到临床相关血流动力学的CFD模型中 变量，并将被视为比较其他建模技术的参考标准。 然后，我们将创建一组相同动脉瘤的新的CFD模型，使用标准的多孔 表示线圈质量的中等技术。这项技术将复杂的线圈几何形状简化为 孔隙度均匀的材料，我们的初步分析表明，这是一个重大误差的来源 血流动力学变量的计算。我们将通过将这些CFD模型与 参考使用微层析技术创建的标准CFD模型。 然后，我们将使用多尺度扩展的均化技术，其中复杂的 线圈质量的结构由宏观方程表示，可以更好地逼近渗透率。我们 我将开发一套修正因子(一个“线圈建模工具包”)，可用于未来的CFD模型 与标准的多孔介质技术相比，螺旋动脉瘤的准确性更高。 最后，我们将通过使用线圈建模工具包来确定此技术的改进精度 创建一组新动脉瘤的CFD模型，不需要3D打印和显微断层扫描。 我们将把这些结果与参考标准(使用CFD和使用体外流量测量)进行比较 通过3D打印的模型)，并量化使用线圈建模工具包获得的精度改进。 这一改进的准确性将加强CFD研究对动脉瘤治疗的临床影响。

Here we seek to improve the accuracy of hemodynamic modeling of coiled cerebral aneurysms. This goal is significant due to the prevalence of cerebral aneurysms, their dismal prognosis when ruptured, and treatment failure rates (resulting in aneurysm recurrence and risk of either brain hemorrhage or need for retreatment) of up to 25%. Hemodynamic forces are thought to influence aneurysm treatment outcomes, but the standard method of computational fluid dynamics (CFD) modeling of such forces within coiled aneurysms (termed the “porous medium technique”) is error-prone. Improving the accuracy of CFD modeling of coiled aneurysms will strengthen the predictive value of patient-specific CFD, which could improve aneurysm treatment efficacy and reduce death and disability, as well as health care costs associated with multiple hospitalizations. This project builds on our ongoing NIH-funded expertise at creating CFD models of brain aneurysms, and a partnership with the European Synchrotron Research Facility, to develop an improved method of CFD modeling of coiled cerebral aneurysms that can be applied in a clinical setting. First, we will create high-fidelity 3D-printed aneurysm models based on patient-specific aneurysm anatomy, and place the same commercially- available aneurysm coils used in actual patient treatment into each model. These coiled aneurysm models will be scanned at 12 µm resolution using synchrotron x-ray microtomography, providing detailed 3D images of the complex coil geometry. These images will be incorporated into CFD models of clinically relevant hemodynamic variables, and will be considered a reference standard to which other modeling techniques are compared. Then, we will create a new set of CFD models of the same aneurysms, using the standard porous medium technique to represent the coil mass. This technique simplifies the complex coil geometry into a material of uniform porosity, which our preliminary analysis suggests is a source of significant error in the calculation of hemodynamic variables. We will quantify this error by comparing these CFD models to the reference standard CFD models created using microtomography. Then, we will employ the homogenization of multiple scale expansions technique, in which the complex structure of the coil mass is represented by macroscopic equations that better approximate permeability. We will develop a set of corrective factors (a “coil modeling toolkit”) that can be used in future CFD models of coiled aneurysms with better accuracy than the standard porous medium technique. Finally, we will determine the improved accuracy of this technique by using the coil modeling toolkit to create CFD models of a new set of aneurysms, for which 3D-printing and microtomography are not required. We will compare these results to the reference standard (both using CFD and using in vitro flow measurements through 3D-printed models) and quantify the improvement in accuracy gained using the coil modeling toolkit. This improved accuracy will strengthen the clinical impact of CFD studies of aneurysm treatment.