Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
Ann Biomed Eng. 2010 Sep;38(9):2851-64. doi: 10.1007/s10439-010-0058-7. Epub 2010 May 11.
Early changes in branching geometry of microvasculature and its associated impact on the perfusion distribution in diseases, especially those in which different branching generations are affected differently, require the ability to analyze intact vascular trees over a wide range of scales. Micro-CT offers an excellent framework to analyze the microvascular branching geometry. Such an analysis requires methods to be developed that can accurately characterize branching properties, such as branch diameter, length, branching angle, and branch interconnectivity of the microvasculature. The purpose of this article is to report the results of a study of two human intramyocardial coronary vascular tree casts in which the accuracy of micro-CT vascular imaging and its analysis are tested against measurements made through an optical microscope (used as the "gold-standard"). Methods related to image segmentation of the vascular lumen, vessel tree centerline extraction, individual branch segment measurement, and compensating for the non-ideal modulation transfer function of micro-CT scanners are presented. The extracted centerline accurately characterized the hierarchical structure of the vascular tree casts in terms of "parent-branch" relationships which allowed each interbranch segments' dimensions to be compared to the optical measurement method. The comparison results show a close to ideal 1:1 relationship for both length and diameter measurements made by the two methods. Combining the results from both specimens, the standard deviation of the difference between measurement methods was 19 microm for the measurement of interbranch segment diameters (ranging from 12 to 769 microm), and 172 microm for the measurement of interbranch segment lengths (ranging from 14 to 3252 microm). These results suggest that our micro-CT image analysis method can be used to characterize a vascular tree's hierarchical structure, and accurately measure interbranch segment lengths and diameters.
早期微血管分支几何形状的变化及其对疾病灌注分布的相关影响，尤其是在不同分支世代受到不同影响的情况下，需要能够在广泛的尺度上分析完整的血管树。微计算机断层扫描（micro-CT）为分析微血管分支几何形状提供了一个极好的框架。这种分析需要开发能够准确描述分支特性的方法，例如分支直径、长度、分支角度和微血管的分支连通性。本文的目的是报告对两个人心肌内冠状动脉血管树铸型的研究结果，其中微计算机断层扫描血管成像及其分析的准确性是通过光学显微镜（用作“金标准”）进行的测量来测试的。本文介绍了与血管管腔的图像分割、血管树中心线提取、单个分支段测量以及补偿微计算机断层扫描扫描仪不理想的调制传递函数相关的方法。提取的中心线准确地描述了血管铸型的层次结构，即“父分支”关系，这使得可以将每个分支间段的尺寸与光学测量方法进行比较。比较结果表明，两种方法测量的长度和直径都非常接近理想的 1:1 关系。将两个标本的结果结合起来，两种方法测量的分支间段直径（范围为 12 至 769 微米）之间的差异的测量方法的标准偏差为 19 微米，分支间段长度（范围为 14 至 3252 微米）之间的差异的测量方法的标准偏差为 172 微米。这些结果表明，我们的微计算机断层扫描图像分析方法可用于描述血管树的层次结构，并准确测量分支间段的长度和直径。
