Purpose

Recent computational fluid dynamics (CFD) studies have demonstrated the concurrence of atherosclerotic changes in regions exposed to prolonged blood residence. In this proof-of-concept study, we investigated a small but homogeneous cohort of large, cavernous carotid aneurysms (CCAs) to establish the clinical feasibility of CFD analysis in treatment planning, based on the association between pathophysiology and hemodynamics.

Methods

This study included 15 patients with individual large CCAs. We identified calcifications, which indicated atherosclerotic changes, using the masking data of digital subtraction angiography. We conducted a CFD simulation under patient-specific inlet flow rates measured using magnetic resonance (MR) velocimetry. In the post-CFD analysis, we calculated the blood residence time (\(\xi\)) and segmented the surface exposed to blood residence time over 1 s (\({S}_{\xi >1}\)). We measured the decrease in volume after flow diversion using the original time-of-flight MR angiography data.

Results

Calcifications were observed in the region with \({S}_{\xi >1}\). In addition, the ratio of \({S}_{\xi >1}\) to the surface of the aneurysmal domain exhibited a negative relationship with the rate of volume reduction at the 6- and 12-month follow-ups. Post-CFD visualization demonstrated that intra-aneurysmal swirling flow prolonged blood residence time under the condition of a small inlet flow rate, when compared to the aneurysmal volume.

Conclusion

The results of this study suggest the usefulness of CFD analysis for the diagnosis of atherosclerotic changes in large CCAs that may affect the therapeutic response after flow diversion.

中文翻译：

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基于计算流体动力学分析预测颈动脉海绵状血管瘤的动脉粥样硬化变化：概念验证研究

目的

最近的计算流体动力学 (CFD) 研究表明，暴露于长期血液滞留的区域会同时发生动脉粥样硬化变化。在这项概念验证研究中，我们基于病理生理学和血流动力学之间的关联，调查了一个小型但同质的大型颈动脉海绵状动脉瘤 (CCA) 队列，以确定 CFD 分析在治疗计划中的临床可行性。

方法

这项研究包括 15 名患有个体大型 CCA 的患者。我们使用数字减影血管造影的掩蔽数据确定了表明动脉粥样硬化变化的钙化。我们在使用磁共振 (MR) 测速仪测量的患者特定入口流速下进行了 CFD 模拟。在后 CFD 分析中，我们计算了血液停留时间 ( \(\xi\) ) 并将暴露于血液停留时间超过 1 秒的表面分割 ( \({S}_{\xi >1}\) )。我们使用原始的飞行时间 MR 血管造影数据测量了分流后体积的减少。

结果

在具有\({S}_{\xi >1}\)的区域中观察到钙化。此外，在 6 个月和 12 个月的随访中， \({S}_{\xi >1}\)与动脉瘤区域表面的比率与体积减少率呈负相关。CFD 后可视化表明，与动脉瘤体积相比，在小入口流速的条件下，动脉瘤内旋流延长了血液停留时间。

结论

这项研究的结果表明，CFD 分析对诊断可能影响分流后治疗反应的大型 CCA 中的动脉粥样硬化变化的有用性。