Van Houten E E, Weaver J B, Miga M I, Kennedy F E, Paulsen K D
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA.
Med Phys. 2000 Jan;27(1):101-7. doi: 10.1118/1.598861.
The determination of the elastic property distribution in heterogeneous gel samples with a finite element based reconstruction scheme is considered. The algorithm operates on small overlapping subzones of the total field to allow for a high degree of spatial discretization while maintaining computational tractability. By including a Maxwellian-type viscoelastic property in the model physics and optimizing the spatial distribution of this property in the same manner as elasticity, a Young's modulus image is obtained which reasonably reflects the true distribution within the gel. However, the image lacks the clarity and accuracy expected based on simulation experience. Preliminary investigations suggest that transient effects in the data are the cause of a significant mismatch between the inversion model, which assumes steady-state conditions, and the actual displacements as measured by a phase contrast MR technique.
本文考虑了基于有限元重建方案来确定非均质凝胶样品中的弹性特性分布。该算法在全场的小重叠子区域上运行，以实现高度的空间离散化，同时保持计算的可处理性。通过在模型物理中纳入麦克斯韦型粘弹性特性，并以与弹性相同的方式优化该特性的空间分布，获得了杨氏模量图像，该图像合理地反映了凝胶内的真实分布。然而，该图像缺乏基于模拟经验所期望的清晰度和准确性。初步研究表明，数据中的瞬态效应是反演模型（该模型假设为稳态条件）与通过相衬磁共振技术测量的实际位移之间存在显著不匹配的原因。
