Gelfand Bradley D, Epstein Frederick H, Blackman Brett R
Department of Biomedical Engineering, University of Virginia Health System, Charlottesville, Virginia 22908, USA.
J Magn Reson Imaging. 2006 Dec;24(6):1386-92. doi: 10.1002/jmri.20765.
To determine the heterogeneity of the time-varying shear stress profiles in the human carotid bifurcation, a region prone to atherosclerosis.
Lagrangian bicubic interpolation of phase-contrast MRI images was used to determine the shear stress profiles for three adult healthy male volunteers. Frequency spectra for the common and internal carotid artery (CCA and ICA, respectively)-derived shear stresses were examined in order to determine the presence of significant heterogeneity in the intensity distribution.
Hemodynamic characteristics (peak, minimum, average shear stress, and oscillatory shear index [OSI]) were highly heterogeneous both along the length of the vessel as well as circumferentially around the CCA and ICA. In the frequency domain, intensities below 4 Hz were significantly higher in the CCA compared to the sinus region of the ICA, indicating that shear stress heterogeneity can be detected in the frequency domain. The harmonic index, a measure of the relative contributions of dynamic and static components of the shear stress signal, colocalizes with OSI, which implies a relationship between specific frequency components and atherosclerosis development.
These findings indicate that the time and frequency dependent parameters of in vivo shear stress have important implications for regional development of atherosclerosis.
确定人类颈动脉分叉处（一个易患动脉粥样硬化的区域）随时间变化的剪应力分布的异质性。
使用相位对比磁共振成像（MRI）图像的拉格朗日双三次插值法来确定三名成年健康男性志愿者的剪应力分布。检查了颈总动脉和颈内动脉（分别为CCA和ICA）衍生的剪应力的频谱，以确定强度分布中是否存在显著异质性。
血流动力学特征（峰值、最小值、平均剪应力和振荡剪应力指数[OSI]）在血管长度方向以及CCA和ICA周围的圆周方向上都高度异质。在频域中，与ICA的窦区相比，CCA中低于4Hz的强度明显更高，这表明在频域中可以检测到剪应力异质性。谐波指数（一种衡量剪应力信号动态和静态成分相对贡献的指标）与OSI共定位，这意味着特定频率成分与动脉粥样硬化发展之间存在关联。
这些发现表明，体内剪应力的时间和频率相关参数对动脉粥样硬化的区域发展具有重要意义。
