Schwarz Janina C V, Duivenvoorden Raphaël, Nederveen Aart J, Stroes Erik S G, VanBavel Ed
Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Int J Cardiovasc Imaging. 2015 Mar;31(3):585-93. doi: 10.1007/s10554-014-0571-0. Epub 2014 Nov 18.
Endothelial shear stress (ESS) dynamics are a major determinant of atherosclerosis development. The frequently used Poiseuille method to estimate ESS dynamics has important limitations. Therefore, we investigated whether Womersley flow may provide a better alternative for estimation of ESS while requiring equally simple hemodynamic parameters. Common carotid blood flow, centerline velocity, lumen diameter and mean wall thickness (MWT) were measured with 3T-MRI in 45 subjects at three different occasions. Mean ESS and two measures of pulsatility [shear pulsatility index (SPI) and oscillatory shear index (OSI)] were estimated based on Poiseuille and Womersley flow and compared to the more complex velocity gradient modelling method. The association between ESS and MWT was tested with multiple linear regression analysis; interscan reproducibility was assessed using intraclass correlation coefficients (ICC). Mean ESS and pulsatility indices based on Womersley flow (ESSwq β = -0.18, P = 0.04; SPIwq β = 0.24, P = 0.02; OSIwq β = 0.18, P = 0.045), showed equally good correlations with carotid MWT as the velocity gradient method (ESSvg β = -0.23, P = 0.01; SPIvg β = 0.21, P = 0.02; OSIvg β = 0.07, P = 0.47). This in contrast to the Poiseuille flow method that only showed a good correlation for mean ESS (ESSpq β = -0.18, P = 0.04; SPIpq β = 0.14, P = 0.14; OSIpq β = 0.04, P = 0.69). Womersley and Poiseuille methods had high intraclass correlation coefficients indicating good interscan reproducibility (both ICC = 0.84, 95% confidence interval 0.75-0.90). Estimation of ESS dynamics based on Womersley flow modelling is superior to Poiseuille flow modelling and has good interscan reproducibility.
内皮剪切应力（ESS）动态变化是动脉粥样硬化发展的主要决定因素。常用的泊肃叶方法来估计ESS动态变化存在重要局限性。因此，我们研究了在需要同样简单的血流动力学参数的情况下，沃默斯利血流是否可能为ESS估计提供更好的替代方法。在45名受试者中，于三个不同时间点用3T磁共振成像测量了颈总动脉血流量、中心线速度、管腔直径和平均壁厚度（MWT）。基于泊肃叶血流和沃默斯利血流估计了平均ESS以及两种搏动性测量指标[剪切搏动性指数（SPI）和振荡剪切指数（OSI）]，并与更复杂的速度梯度建模方法进行比较。用多元线性回归分析检验了ESS与MWT之间的关联；使用组内相关系数（ICC）评估扫描间的可重复性。基于沃默斯利血流的平均ESS和搏动性指数（ESSwqβ = -0.18，P = 0.04；SPIwqβ = 0.24，P = 0.02；OSIwqβ = 0.18，P = 0.045）与颈动脉MWT的相关性与速度梯度方法（ESSvgβ = -0.23，P = 0.01；SPIvgβ = 0.21，P = 0.02；OSIvgβ = 0.07，P = 0.47）同样良好。这与仅在平均ESS方面显示出良好相关性的泊肃叶血流方法形成对比（ESSpqβ = -0.18，P = 0.
