Ngo Minh Tri, Lee Ui Yun, Ha Hojin, Jung Jinmu, Lee Dong Hwan, Kwak Hyo Sung
Department of Radiology of Hue Central Hospital, Hue, Thua Thien Hue 530000, Vietnam.
Division of Mechanical Design Engineering, College of Engineering, Jeonbuk National University, Jeon-ju 54896, Korea.
Diagnostics (Basel). 2021 Oct 13;11(10):1890. doi: 10.3390/diagnostics11101890.
Assessment of carotid bulb hemodynamics using four-dimensional (4D) flow magnetic resonance imaging (MRI) requires accurate segmentation of recirculation regions that is frequently hampered by limited resolution. This study aims to improve the accuracy of 4D flow MRI carotid bulb segmentation and subsequent recirculation regions analysis. Time-of-flight (TOF) MRI and 4D flow MRI were performed on bilateral carotid artery bifurcations in seven healthy volunteers. TOF-MRI data was segmented into 3D geometry for computational fluid dynamics (CFD) simulations. ITK-SNAP segmentation software was included in the workflow for the semi-automatic generation of 4D flow MRI angiographic data. This study compared the velocities calculated at the carotid bifurcations and the 3D blood flow visualization at the carotid bulbs obtained by 4D flow MRI and CFD. By applying ITK-SNAP segmentation software, an obvious improvement in the 4D flow MRI visualization of the recirculation regions was observed. The 4D flow MRI images of the recirculation flow characteristics of the carotid artery bulbs coincided with the CFD. A reasonable agreement was found in terms of velocity calculated at the carotid bifurcation between CFD and 4D flow MRI. However, the dispersion of velocity data points relative to the local errors of measurement in 4D flow MRI remains. Our proposed strategy showed the feasibility of improving recirculation regions segmentation and the potential for reliable blood flow visualization in 4D flow MRI. However, quantitative analysis of recirculation regions in 4D flow MRI with ITK-SNAP should be enhanced for use in clinical situations.
使用四维（4D）血流磁共振成像（MRI）评估颈动脉球部血流动力学需要准确分割再循环区域，而这常常因分辨率有限而受阻。本研究旨在提高4D血流MRI对颈动脉球部的分割准确性以及后续再循环区域分析的准确性。对7名健康志愿者的双侧颈动脉分叉处进行了飞行时间（TOF）MRI和4D血流MRI检查。将TOF-MRI数据分割成三维几何结构用于计算流体动力学（CFD）模拟。工作流程中纳入了ITK-SNAP分割软件，用于半自动生成4D血流MRI血管造影数据。本研究比较了通过4D血流MRI和CFD获得的颈动脉分叉处计算速度以及颈动脉球部的三维血流可视化情况。通过应用ITK-SNAP分割软件，观察到4D血流MRI对再循环区域的可视化有明显改善。颈动脉球部再循环血流特征的4D血流MRI图像与CFD结果相符。在CFD和4D血流MRI计算的颈动脉分叉处速度方面发现了合理的一致性。然而，4D血流MRI中速度数据点相对于局部测量误差的离散情况仍然存在。我们提出的策略显示了改善再循环区域分割的可行性以及在4D血流MRI中实现可靠血流可视化的潜力。然而，在临床应用中，应加强使用ITK-SNAP对4D血流MRI中的再循环区域进行定量分析。
