Department of Medicine, Department of Biomedical Engineering, School of Medicine, Emory University, 101 Woodruff Circle, Atlanta, GA 30322; Georgia Institute of Technology, Emory University, 101 Woodruff Circle, Atlanta, GA 30322.
Department of Biomedical Engineering, Scientific Computing and Imaging Institute, University of Utah, 36 S. Wasatch Drive SMBB, Rm. 3100, Salt Lake City, UT 84112.
J Biomech Eng. 2022 Sep 1;144(9). doi: 10.1115/1.4054236.
Wall shear stress (WSS) is an important mediator of cardiovascular pathologies and there is a need for its reliable evaluation as a potential prognostic indicator. The purpose of this work was to develop a method that quantifies WSS from two-dimensional (2D) phase contrast magnetic resonance (PCMR) imaging derived flow waveforms, apply this method to PCMR data acquired in the abdominal aorta of healthy volunteers, and to compare PCMR-derived WSS values to values predicted from a computational fluid dynamics (CFD) simulation. The method uses PCMR-derived flow versus time waveforms constrained by the Womersley solution for pulsatile flow in a cylindrical tube. The method was evaluated for sensitivity to input parameters, intrastudy repeatability and was compared with results from a patient-specific CFD simulation. 2D-PCMR data were acquired in the aortas of healthy men (n = 12) and women (n = 15) and time-averaged WSS (TAWSS) was compared. Agreement was observed when comparing TAWSS between CFD and the PCMR flow-based method with a correlation coefficient of 0.88 (CFD: 15.0 ± 1.9 versus MRI: 13.5 ± 2.4 dyn/cm2) though comparison of WSS values between the PCMR-based method and CFD predictions indicate that the PCMR method underestimated instantaneous WSS by 3.7 ± 7.6 dyn/cm2. We found no significant difference in TAWSS magnitude between the sexes; 8.19 ± 2.25 versus 8.07 ± 1.71 dyn/cm2, p = 0.16 for men and women, respectively.
壁面切应力（WSS）是心血管病变的重要介质，因此需要可靠地评估其作为潜在预后指标的能力。本研究旨在开发一种从二维（2D）相位对比磁共振（PCMR）成像衍生的流场波形中定量评估 WSS 的方法，将该方法应用于健康志愿者腹主动脉的 PCMR 数据，并将 PCMR 衍生的 WSS 值与计算流体动力学（CFD）模拟预测的值进行比较。该方法使用 PCMR 衍生的流速随时间变化的波形，该波形受圆柱形管中脉动流的沃默斯利解的限制。该方法评估了其对输入参数的敏感性、组内重复性，并与特定于患者的 CFD 模拟的结果进行了比较。在健康男性（n=12）和女性（n=15）的主动脉中采集了 2D-PCMR 数据，并比较了时间平均壁面切应力（TAWSS）。当比较 CFD 和基于 PCMR 流的方法之间的 TAWSS 时，观察到了一致性，相关系数为 0.88（CFD：15.0±1.9 与 MRI：13.5±2.4 dyn/cm2），尽管基于 PCMR 的方法和 CFD 预测之间的 WSS 值比较表明 PCMR 方法低估了 3.7±7.6 dyn/cm2 的瞬时 WSS。我们没有发现性别之间 TAWSS 大小的显著差异；男性的 TAWSS 分别为 8.19±2.25 和 8.07±1.71 dyn/cm2，p=0.16；女性分别为 8.19±2.25 和 8.07±1.71 dyn/cm2，p=0.16。
