Laboratory of Fluid Dynamics and Technical Flows, Otto-von-Guericke University, University of Magdeburg, Forschungscampus STIMULATE, Universitätsplatz 3, 39106, Magdeburg, Germany.
Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Kiel University, Kiel, Germany.
Int J Comput Assist Radiol Surg. 2021 Nov;16(11):1999-2008. doi: 10.1007/s11548-021-02486-y. Epub 2021 Sep 14.
Intracranial aneurysm (IA) wall enhancement on post-contrast vessel wall magnetic resonance imaging (VW-MRI) is assumed to be a biomarker for vessel wall inflammation and aneurysm instability. However, the exact factors contributing to enhancement are not yet clarified. This study investigates the relationship between luminal enhancement and intra-aneurysmal flow behaviour to assess the suitability of VW-MRI as a surrogate method for determining quantitative and qualitative flow behaviour in the aneurysm sac.
VW-MRI signal is measured in the lumen of three patient-specific IA flow models and compared with the intra-aneurysmal flow fields obtained using phase-contrast magnetic resonance imaging (PC-MRI) and computational fluid dynamics (CFD). The IA flow models were supplied with two different time-varying flow regimes.
Overall, the velocity fields acquired using PC-MRI or CFD were in good agreement with the VW-MRI enhancement patterns. Generally, the regions with slow-flowing blood show higher VW-MRI signal intensities, whereas high flow leads to a suppression of the signal. For all aneurysm models, a signal value above three was associated with velocity values below three cm/s.
Regions with lower enhancements have been correlated with the slow and high flow at the same time. Thus, further factors like flow complexity and stability can contribute to flow suppression in addition to the flow magnitude. Nevertheless, VW-MRI can qualitatively assess intra-aneurysmal flow phenomena and estimate the velocity range present in the corresponding region.
颅内动脉瘤（IA）在对比后血管壁磁共振成像（VW-MRI）上的壁增强被认为是血管壁炎症和动脉瘤不稳定的生物标志物。然而，导致增强的确切因素尚不清楚。本研究旨在调查管腔增强与瘤内血流行为之间的关系，以评估 VW-MRI 作为确定动脉瘤囊中定量和定性血流行为的替代方法的适用性。
在三个患者特定的 IA 血流模型的管腔中测量 VW-MRI 信号，并将其与使用相位对比磁共振成像（PC-MRI）和计算流体动力学（CFD）获得的瘤内血流场进行比较。IA 血流模型提供了两种不同的时变血流状态。
总体而言，使用 PC-MRI 或 CFD 获得的速度场与 VW-MRI 增强模式非常吻合。通常，血流缓慢的区域显示出更高的 VW-MRI 信号强度，而高速血流则会抑制信号。对于所有动脉瘤模型，信号值高于 3 与速度值低于 3cm/s 相关。
增强程度较低的区域与低速和高速血流同时相关。因此，除了流速外，其他因素如血流复杂性和稳定性也可能导致血流抑制。尽管如此，VW-MRI 可以定性评估瘤内血流现象并估计相应区域内的速度范围。
