Purpose

For the status evaluation of intracranial aneurysms (IAs), morphological and hemodynamic parameters can provide valuable information. For their extraction, a separation of the aneurysm sac from its parent vessel is required that yields the neck curve and the ostium. However, manual and subjective neck curve and ostium definitions might lead to inaccurate IA assessments.

Methods

The research project VICTORIA was initiated, allowing users to interactively define the neck curve of five segmented IA models using a web application. The submitted results were qualitatively and quantitatively compared to identify the minimum, median and maximum aneurysm surface area. Finally, image-based blood flow simulations were carried out to assess the effect of variable neck curve definitions on relevant flow- and shear-related parameters.

Results

In total, 55 participants (20 physicians) from 18 countries participated in VICTORIA. For relatively simple aneurysms, a good agreement with respect to the neck curve definition was found. However, differences among the participants increased with increasing complexity of the aneurysm. Furthermore, it was observed that the majority of participants excluded any small arteries occurring in the vicinity of an aneurysm. This can lead to non-negligible deviations among the flow- and shear-related parameters, which need to be carefully evaluated, if quantitative analysis is desired. Finally, no differences between participants with medical and non-medical background could be observed.

Conclusions

VICTORIAs findings reveal the complexity of aneurysm neck curve definition, especially for bifurcation aneurysms. Standardization appears to be mandatory for future sac-vessel-separations. For hemodynamic simulations a careful neck curve definition is crucial to avoid inaccuracies during the quantitative flow analysis.

中文翻译：

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VICTORIA：颅内动脉瘤的虚拟颈曲线和真口重建

目的

对于颅内动脉瘤 (IA) 的状态评估，形态学和血流动力学参数可以提供有价值的信息。对于它们的提取，需要将动脉瘤囊与其母血管分离，以产生颈部曲线和开口。然而，手动和主观的颈部曲线和开口定义可能会导致 IA 评估不准确。

方法

启动了 VICTORIA 研究项目，允许用户使用 Web 应用程序以交互方式定义五个分段 IA 模型的颈部曲线。对提交的结果进行定性和定量比较，以确定最小、中值和最大动脉瘤表面积。最后，进行了基于图像的血流模拟，以评估可变颈部曲线定义对相关流量和剪切相关参数的影响。

结果

共有来自 18 个国家的 55 名参与者（20 名医生）参加了 VICTORIA。对于相对简单的动脉瘤，发现了颈部曲线定义的良好一致性。然而，参与者之间的差异随着动脉瘤复杂性的增加而增加。此外，据观察，大多数参与者排除了发生在动脉瘤附近的任何小动脉。这可能导致流量和剪切相关参数之间出现不可忽视的偏差，如果需要进行定量分析，则需要仔细评估这些偏差。最后，没有观察到具有医学和非医学背景的参与者之间的差异。

结论

VICTORIAs 的研究结果揭示了动脉瘤颈部曲线定义的复杂性，尤其是分叉动脉瘤。标准化似乎是未来囊管分离的强制性要求。对于血流动力学模拟，仔细的颈部曲线定义对于避免定量流量分析过程中的不准确至关重要。