MacDonald C J, Hellmuth R, Priba L, Murphy E, Gandy S, Matthew S, Ross R, Houston J G
Imaging and Technology, University of Dundee, Dundee, UK.
Vascular Flow Technologies LTD, Dundee, UK.
Cardiovasc Eng Technol. 2020 Aug;11(4):416-430. doi: 10.1007/s13239-020-00473-z. Epub 2020 Jul 1.
Recent studies have noted a degree of variance between the geometries segmented by different groups from 3D medical images that are used in computational fluid dynamics (CFD) simulations of patient-specific cardiovascular systems. The aim of this study was to determine if the applied sequence of magnetic resonance imaging (MRI) also introduced observable variance in CFD results.
Using a series of phantoms MR images of vessels of known diameter were assessed for the time-of-flight and multi-echo data image combination sequences. Following this, patient images of arterio-venous fistulas were acquired using the same sequences. Comparisons of geometry were made using the phantom and patient images, and of wall shear stress quantities using the CFD results from the patient images.
Phantom images showed deviations in diameter between 0 and 15% between the sequences, depending on vessel diameter. Patient images showed different geometrical features such as narrowings that were not present on both sequences. Distributions of wall shear stress (WSS) quantities differed from simulations between the geometries obtained from the sequences.
In conclusion, choosing different MRI sequences resulted in slightly different geometries of the same anatomy, which led to compounded errors in WSS quantities from CFD simulation.
最近的研究指出，不同团队从三维医学图像中分割出的几何结构之间存在一定程度的差异，这些图像用于患者特异性心血管系统的计算流体动力学（CFD）模拟。本研究的目的是确定所应用的磁共振成像（MRI）序列是否也会在CFD结果中引入可观察到的差异。
使用一系列体模，对已知直径血管的磁共振图像进行飞行时间和多回波数据图像组合序列评估。在此之后，使用相同序列采集动静脉瘘患者的图像。使用体模和患者图像进行几何结构比较，并使用患者图像的CFD结果进行壁面剪应力量的比较。
体模图像显示，根据血管直径不同，序列之间的直径偏差在0%至15%之间。患者图像显示出不同的几何特征，如狭窄，并非两个序列上都存在。壁面剪应力（WSS）量的分布在序列获得的几何结构之间的模拟中有所不同。
总之，选择不同的MRI序列会导致相同解剖结构的几何结构略有不同，这会导致CFD模拟中WSS量的复合误差。
