Jou L D, van Tyen R, Berger S A, Saloner D
Department of Mechanical Engineering, University of California at Berkeley, USA.
Magn Reson Med. 1996 Apr;35(4):577-84. doi: 10.1002/mrm.1910350418.
The signal intensity in magnetic resonance angiography (MRA) images reflects both morphological and flow-related features of vascular anatomy. A thorough understanding of MRA, therefore, demands a careful analysis of flow-related effects. Computational fluid dynamics (CFD) methods are very powerful in determining flow patterns in 3D tortuous vessels for both steady and unsteady flow. Previous simulations of MRA images calculated the magnetization of flowing blood by tracking particles as they moved along flow streamlines that had been determined by a CFD calculation. This manuscript describes MRA simulations that use CFD calculations to determine magnetization variation at a fixed point and, therefore, do not require streamline tracking to calculate the distribution of magnetization in flowing fluids. This method inherently accounts for uniform particle density, avoids problems associated with tracking particles close to the wall, and is well-suited to modeling pulsatile flow.
磁共振血管造影（MRA）图像中的信号强度反映了血管解剖结构的形态学和血流相关特征。因此，要全面理解MRA，就需要仔细分析血流相关效应。计算流体动力学（CFD）方法在确定三维弯曲血管中稳定和不稳定血流的流动模式方面非常强大。以前的MRA图像模拟通过跟踪沿着CFD计算确定的流线移动的粒子来计算流动血液的磁化强度。本文描述了使用CFD计算来确定固定点处磁化强度变化的MRA模拟，因此不需要跟踪流线来计算流动流体中磁化强度的分布。该方法本质上考虑了均匀的粒子密度，避免了与跟踪靠近壁面的粒子相关的问题，并且非常适合于模拟脉动流。
