Pravdivtseva Mariya S, Peschke Eva, Lindner Thomas, Wodarg Fritz, Hensler Johannes, Gabbert Dominik, Voges Inga, Berg Philipp, Barker Alex J, Jansen Olav, Hövener Jan-Bernd
Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Kiel, Germany.
Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel, Germany.
Med Phys. 2021 Apr;48(4):1469-1484. doi: 10.1002/mp.14714. Epub 2021 Feb 17.
Flow models of intracranial aneurysms (IAs) can be used to test new and existing endovascular treatments with flow modulation devices (FMDs). Additionally, 4D flow magnetic resonance imaging (MRI) offers the ability to measure hemodynamics. This way, the effect of FMDs can be determined noninvasively and compared to patient data. Here, we describe a cost-effective method for producing flow models to test the efficiency of FMDs with 4D flow MRI.
The models were based on human radiological data (internal carotid and basilar arteries) and printed in 3D with stereolithography. The models were printed with three different printing layers (25, 50, and 100 µm thickness). To evaluate the models in vitro, 3D rotational angiography, time-of-flight MRI, and 4D flow MRI were employed. The flow and geometry of one model were compared with in vivo data. Two FMDs (FMD1 and FMD2) were deployed into two different IA models, and the effect on the flow was estimated by 4D flow MRI.
Models printed with different layer thicknesses exhibited similar flow and little geometric variation. The mean spatial difference between the vessel geometry measured in vivo and in vitro was 0.7 ± 1.1 mm. The main flow features, such as vortices in the IAs, were reproduced. The velocities in the aneurysms were similar in vivo and in vitro (mean velocity magnitude: 5.4 ± 7.6 and 7.7 ± 8.6 cm/s, maximum velocity magnitude: 72.5 and 55.1 cm/s). By deploying FMDs, the mean velocity was reduced in the IAs (from 8.3 ± 10 to 4.3 ± 9.32 cm/s for FMD1 and 9.9 ± 12.1 to 2.1 ± 5.6 cm/s for FMD2).
The presented method allows to produce neurovascular models in approx. 15 to 30 h. The resulting models were found to be geometrically accurate, reproducing the main flow patterns, and suitable for implanting FMDs as well as 4D flow MRI.
颅内动脉瘤（IA）血流模型可用于测试使用血流调节装置（FMD）的新型和现有血管内治疗方法。此外，四维血流磁共振成像（MRI）能够测量血流动力学。通过这种方式，可以无创地确定FMD的效果并与患者数据进行比较。在此，我们描述一种经济高效的方法来制作血流模型，以使用四维血流MRI测试FMD的效率。
模型基于人体放射学数据（颈内动脉和基底动脉），并通过立体光刻进行三维打印。模型以三种不同的打印层（厚度分别为25、50和100μm）进行打印。为了在体外评估模型，采用了三维旋转血管造影、时间飞跃MRI和四维血流MRI。将一个模型的血流和几何形状与体内数据进行比较。将两种FMD（FMD1和FMD2）植入两个不同的IA模型中，并通过四维血流MRI评估对血流的影响。
不同层厚打印的模型表现出相似的血流且几何形状变化很小。体内和体外测量的血管几何形状之间的平均空间差异为0.7±1.1mm。IA中的主要血流特征，如涡流，得以重现。动脉瘤内的速度在体内和体外相似（平均速度大小：5.4±7.6和7.7±8.6cm/s，最大速度大小：72.5和55.1cm/s）。通过部署FMD，IA内的平均速度降低（FMD1从8.3±10降至4.3±9.32cm/s，FMD2从9.9±12.1降至2.1±5.6cm/s）。
所提出的方法能够在约15至30小时内制作神经血管模型。结果发现，所得模型在几何形状上准确无误，能够重现主要血流模式，适用于植入FMD以及进行四维血流MRI检查。
