Brown University, PROBE Lab, School of Engineering, Providence, Rhode Island, United States.
Brown University, Division of Applied Mathematics, Providence, Rhode Island, United States.
J Biomed Opt. 2022 Jan;27(1). doi: 10.1117/1.JBO.27.1.016503.
The spatial organization of collagen fibers has been used as a biomarker for assessing injury and disease progression. However, quantifying this organization for complex structures is challenging.
To quantify and classify complex collagen fiber organizations.
Using quantitative second-harmonic generation (SHG) microscopy, we show that collagen-fiber orientation can be viewed as pseudovector fields. Subsequently, we analyze them using fluid mechanic metrics, such as energy U, enstrophy E, and tortuosity τ.
We show that metrics used in fluid mechanics for analyzing fluid flow can be adapted to analyze complex collagen fiber organization. As examples, we consider SHG images of collagenous tissue for straight, wavy, and circular fiber structures.
The results of this study show the utility of the chosen metrics to distinguish diverse and complex collagen organizations. We find that the distribution of values for E and U increases with collagen fiber disorganization, where they divide between low and high values corresponding to uniformly aligned fibers and disorganized collagen fibers, respectively. We also confirm that the values of τ cluster around 1 when the fibers are straight, and the range increases up to 1.5 when wavier fibers are present.
胶原纤维的空间组织已被用作评估损伤和疾病进展的生物标志物。然而，对复杂结构的这种组织进行量化具有挑战性。
量化和分类复杂的胶原纤维组织。
使用定量二次谐波产生（SHG）显微镜，我们表明胶原纤维的取向可以看作是伪矢量场。随后，我们使用流体力学术语，如能量 U、旋度 E 和扭曲度 τ 来分析它们。
我们表明，用于分析流体流动的流体力学术语可以被改编来分析复杂的胶原纤维组织。例如，我们考虑了胶原组织的 SHG 图像，其中包括直纤维结构、波浪形纤维结构和圆形纤维结构。
这项研究的结果表明，所选择的度量标准可用于区分不同和复杂的胶原组织。我们发现，E 和 U 的分布值随着胶原纤维的无序而增加，它们在低值和高值之间划分，分别对应于均匀排列的纤维和无序的胶原纤维。我们还证实，当纤维是直的时，τ 的值大约在 1 左右，当存在更弯曲的纤维时，范围增加到 1.5。
