Singh Jaykrishna, Brunner Gerd, Morrisett Joel D, Ballantyne Christie M, Lumsden Alan B, Shah Dipan J, Decuzzi Paolo
Department of Translational Imaging, The Houston Methodist Research Institute (HMRI), Houston, TX.
Division of Atherosclerosis and Vascular Medicine, Department of Medicine, Baylor College of Medicine, Houston, TX.
Comput Methods Biomech Biomed Eng Imaging Vis. 2018;6(2):119-127. doi: 10.1080/21681163.2016.1184589. Epub 2016 Oct 12.
MRI-based hemodynamics have been applied to study the relationship between time-averaged wall shear stresses (TAWSS), oscillatory shear index (OSI) and atherosclerotic lesions in the coronary arteries, carotid artery, and human aorta. However, the role of TAWSS and OSI are poorly understood in lower extremity arteries. The aim of this work was to investigate the feasibility of hemodynamic assessment of the superficial femoral artery (SFA) in patients with peripheral artery disease (PAD) and we hypothesized that there is an association between TAWSS and OSI, respectively, and atherosclerotic burden expressed as the normalized wall index (NWI).
Six cases of 3D vascular geometries of the SFA and related inlet/outlet flow conditions were extracted from patient-specific MRI data including baseline, 12 and 24 months. Blood flow simulations were performed to compute flow descriptors, including TAWSS and OSI, and NWI.
NWI was correlated positively with TAWSS (correlation coefficient: r = 0.592; p < 0.05). NWI was correlated negatively with OSI (correlation coefficient: r = -0.310, p < 0.01). Spatially averaged TAWSS and average NWI increased significantly between baseline and 24-months, whereas OSI decreased over 2-years.
In this pilot study with a limited sample size, TAWSS was positively associated with NWI, a measure of plaque burden, whereas OSI showed an inverse relationship. However, our findings need to be verified in a larger prospective study. MRI-based study of hemodynamics is feasible in the superficial femoral artery.
基于磁共振成像（MRI）的血流动力学已被应用于研究冠状动脉、颈动脉和人体主动脉中时间平均壁面剪应力（TAWSS）、振荡剪切指数（OSI）与动脉粥样硬化病变之间的关系。然而，TAWSS和OSI在下肢动脉中的作用尚不清楚。本研究旨在探讨在周围动脉疾病（PAD）患者中对股浅动脉（SFA）进行血流动力学评估的可行性，我们假设TAWSS和OSI分别与以标准化壁指数（NWI）表示的动脉粥样硬化负担之间存在关联。
从特定患者的MRI数据中提取6例SFA的三维血管几何结构及相关的进出口血流条件，包括基线、12个月和24个月的数据。进行血流模拟以计算血流描述符，包括TAWSS、OSI和NWI。
NWI与TAWSS呈正相关（相关系数：r = 0.592；p < 0.05）。NWI与OSI呈负相关（相关系数：r = -0.310，p < 0.01）。在基线和24个月之间，空间平均TAWSS和平均NWI显著增加，而OSI在2年期间下降。
在这项样本量有限的初步研究中，TAWSS与斑块负担指标NWI呈正相关，而OSI呈负相关。然而，我们的研究结果需要在更大规模的前瞻性研究中得到验证。基于MRI的血流动力学研究在股浅动脉中是可行的。
