Mittal N, Zhou Y, Ung S, Linares C, Molloi S, Kassab G S
Department of Biomedical Engineering, Rockwell Engineering Center, University of California, Irvine, CA 92697-2715, USA.
Ann Biomed Eng. 2005 Aug;33(8):1015-26. doi: 10.1007/s10439-005-5758-z.
A rigorous analysis of blood flow must be based on the branching pattern and vascular geometry of the full vascular circuit of interest. It is experimentally difficult to reconstruct the entire vascular circuit of any organ because of the enormity of the vessels. The objective of the present study was to develop a novel method for the reconstruction of the full coronary vascular tree from partial measurements. Our method includes the use of data on those parts of the tree that are measured to extrapolate the data on those parts that are missing. Specifically, a two-step approach was employed in the reconstruction of the entire coronary arterial tree down to the capillary level. Vessels > 40 microm were reconstructed from cast data while vessels < 40 microm were reconstructed from histological data. The cast data were reconstructed one-bifurcation at a time while histological data were reconstructed one-sub-tree at a time by "cutting" and "pasting" of data from measured to missing vessels. The reconstruction algorithm yielded a full arterial tree down to the first capillary bifurcation with 1.9, 2.04 and 1.15 million vessel segments for the right coronary artery (RCA), left anterior descending (LAD) and left circumflex (LCx) trees, respectively. The node-to-node connectivity along with the diameter and length of every vessel segment was determined. Once the full tree was reconstructed, we automated the assignment of order numbers, according to the diameter-defined Strahler system, to every vessel segment in the tree. Consequently, the diameters, lengths, number of vessels, segments-per-element ratio, connectivity and longitudinal matrices were determined for every order number. The present model establishes a morphological foundation for future analysis of blood flow in the coronary circulation.
对血流的严格分析必须基于感兴趣的完整血管回路的分支模式和血管几何形状。由于血管数量庞大,通过实验重建任何器官的整个血管回路都很困难。本研究的目的是开发一种从部分测量数据重建完整冠状动脉树的新方法。我们的方法包括利用已测量的树的那些部分的数据来推断缺失部分的数据。具体而言,在重建直至毛细血管水平的整个冠状动脉树时采用了两步法。直径大于40微米的血管根据铸型数据重建,而直径小于40微米的血管根据组织学数据重建。铸型数据一次重建一个分叉,而组织学数据则通过将测量血管的数据“剪切”和“粘贴”到缺失血管上,一次重建一个子树。重建算法生成了直至第一个毛细血管分叉的完整动脉树,右冠状动脉(RCA)、左前降支(LAD)和左旋支(LCx)树分别有190万、204万和115万个血管段。确定了每个血管段的节点到节点连接以及直径和长度。一旦重建了完整的树,我们根据直径定义的斯特拉勒系统自动为树中的每个血管段分配序号。因此,确定了每个序号的直径、长度、血管数量、每单元段数比、连接性和纵向矩阵。本模型为未来冠状动脉循环中血流分析奠定了形态学基础。