In vivo visualization and analysis of 3-D hemodynamics in cerebral aneurysms with flow-sensitized 4-D MR imaging at 3 T
In vivo visualization and analysis of 3-D hemodynamics in cerebral aneurysms with flow-sensitized 4-D MR imaging at 3 T
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DOI：
10.1007/s00234-008-0367-9
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发表时间：
2008-06-01
期刊：
影响因子：
2.8
通讯作者：
Wetzel, Stephan G.
中科院分区：
文献类型：
--
作者：
Meckel, Stephan;Stalder, Aurelien F.;Wetzel, Stephan G.
简介 血流模式和壁剪切应力 (WSS) 被认为在脑动脉瘤的发生和破裂中发挥着重要作用。这些血流动力学方面已使用几何真实动脉瘤模型在体外进行了广泛研究。本研究的目的是评估体内血流敏化 4-D MR 成像用于分析动脉瘤内血流动力学的可行性。方法 使用心电门控、血流敏化 4-D MR 成像在 3 T 下对 3 名患者的 5 个脑动脉瘤进行检查。后处理包括流速量化、时间分辨 2D 矢量图和 3D 粒子轨迹的可视化、涡流分析和 WSS 估计。分析了与动脉瘤几何形状和纵横比相关的流动模式。结果 动脉瘤之间涡流的大小、空间和时间演变存在显着差异。在宽颈眼旁 ICA 动脉瘤（高纵横比）中证实了特别不稳定的涡流。在纵横比较低的动脉瘤中观察到相对稳定的涡流。除宽颈海绵状ICA动脉瘤（低纵横比）外，所有动脉瘤的WSS均减少，并表现出较高的空间变化。结论体内血流敏化4-D MR成像可用于分析动脉瘤内血流的复杂模式。血流模式、流速分布和 WSS 似乎由动脉瘤的血管几何形状决定。时间和空间平均效应是基于 MR 的血流模式分析以及 WSS 估计的缺点，特别是在小动脉瘤中。需要进一步的研究来建立确定的血流模式和不同动脉瘤几何形状之间的直接联系。
Introduction Blood-flow patterns and wall shear stress (WSS) are considered to play a major role in the development and rupture of cerebral aneurysms. These hemodynamic aspects have been extensively studied in vitro using geometric realistic aneurysm models. The purpose of this study was to evaluate the feasibility of in vivo flow-sensitized 4-D MR imaging for analysis of intraaneurysmal hemodynamics.Methods Five cerebral aneurysms were examined using ECG-gated, flow-sensitized 4-D MR imaging at 3 T in three patients. Postprocessing included quantification of flow velocities, visualization of time-resolved 2-D vector graphs and 3-D particle traces, vortical flow analysis, and estimation of WSS. Flow patterns were analyzed in relation to aneurysm geometry and aspect ratio.Results Magnitude, spatial and temporal evolution of vortical flow differed markedly among the aneurysms. Particularly unstable vortical flow was demonstrated in a wide-necked parophthalmic ICA aneurysm (high aspect ratio). Relatively stable vortical flow was observed in aneurysms with a lower aspect ratio. Except for a wide-necked cavernous ICA aneurysm (low aspect ratio), WSS was reduced in all aneurysms and showed a high spatial variation.Conclusion In vivo flow-sensitized 4-D MR imaging can be applied to analyze complex patterns of intraaneurysmal flow. Flow patterns, distribution of flow velocities, and WSS seem to be determined by the vascular geometry of the aneurysm. Temporal and spatial averaging effects are drawbacks of the MR-based analysis of flow patterns as well as the estimation of WSS, particularly in small aneurysms. Further studies are needed to establish a direct link between definitive flow patterns and different aneurysm geometries.