Abstract：
Collagen fiber arrangement is decisive for constitutive description of anisotropic mechanical response of arterial wall. In this study, their orientation in human common carotid artery was investigated using polarized light microscopy and an automated algorithm giving more than 4·106 fiber angles per slice. In total 113 slices acquired from 18 arteries taken from 14 cadavers were used for fiber orientation in the circumferential-axial plane. All histograms were approximated with unimodal von Mises distribution to evaluate dominant direction of fibers and their concentration parameter. 10 specimens were analyzed also in circumferential-radial and axial-radial planes (2-4 slices per specimen in each plane); the portion of radially oriented fibers was found insignificant. In the circumferential-axial plane, most specimens showed a pronounced unimodal distribution with angle to circumferential direction μ = 0.7° ± 9.4° and concentration parameter b = 3.4 ± 1.9. Suitability of the unimodal fit was confirmed by high values of coefficient of determination (mean R2 = 0.97, median R2 = 0.99). Differences between media and adventitia layers were not found statistically significant. The results are directly applicable as structural parameters in the GOH constitutive model of arterial wall if the postulated two fiber families are unified into one with circumferential orientation.
摘要：
胶原纤维排列对于动脉壁各向异性机械响应的本构描述至关重要。在这项研究中,他们的方向在人类颈总动脉使用偏振光显微镜和一个自动算法研究了每片超过4·106纤维角度。从14具尸体的18条动脉中获取的总共113个切片用于在周向平面中的纤维定向。所有直方图均用单峰vonMises分布近似，以评估纤维的主导方向及其浓度参数。还在周向-径向和轴向-径向平面中分析了10个样本(每个平面中的每个样本2-4个切片);发现径向取向纤维的部分不显著。在周向-轴向平面中，大多数标本表现出明显的单峰分布，与圆周方向成角度μ=0.7°±9.4°，浓度参数b=3.4±1.9。确定系数的高值（平均R2=0.97，中值R2=0.99）证实了单峰拟合的适用性。培养基和外膜层之间的差异在统计学上没有发现。如果将假定的两个纤维家族统一为一个具有圆周方向的纤维家族，则结果可直接用作动脉壁GOH本构模型的结构参数。
