Baumann Bernhard, Rauscher Sabine, Glösmann Martin, Götzinger Erich, Pircher Michael, Fialová Stanislava, Gröger Marion, Hitzenberger Christoph K
Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria Medical Imaging Cluster, Medical University of Vienna, Vienna, Austria.
Medical Imaging Cluster, Medical University of Vienna, Vienna, Austria Core Facility Imaging, Medical University of Vienna, Vienna, Austria.
Invest Ophthalmol Vis Sci. 2014 Oct 28;55(11):7686-96. doi: 10.1167/iovs.14-15037.
To demonstrate polarization-sensitive (PS) optical coherence tomography (OCT) for noninvasive, volumetric, and quantitative imaging of the birefringent properties of the peripapillary rat sclera; to compare the findings from PS-OCT images to state-of-the-art histomorphometric analysis of the same tissues.
A high-speed PS-OCT prototype operating at 840 nm was modified for imaging the rat eye. Densely sampled PS-OCT raster scans covering an area of ~1.5 × 1.5 mm centered at the papilla were acquired in the eyes of anesthetized male Sprague-Dawley rats. Cross-sectional PS-OCT images were computed, and fundus maps displaying the birefringent properties of the sclera were analyzed. Postmortem histomorphologic analysis was performed.
Polarization-sensitive OCT enables visualization of the polarization properties of ocular tissues in vivo. The birefringent characteristics of the rat sclera were quantitatively assessed. Scleral birefringence formed a donut-shaped pattern around the papilla with significantly increased values of 0.703 ± 0.089°/μm (i.e., 1.64 × 10(-3) ± 0.2 × 10(-3); mean ± standard deviation) and 0.721 ± 0.084°/μm (i.e., 1.68 × 10(-3) ± 0.2 × 10(-3)) at an eccentricity of 0.4 mm for the left and right eyes, respectively. Birefringent axis orientation maps revealed a ring-shaped distribution around the optic nerve. Postmortem PS-OCT micrographs provided access to retinal and scleral microstructure and were compared to standard histomorphologic analysis.
Polarization-sensitive OCT enables quantitative imaging of tissue polarization properties in addition to conventional OCT imaging based on reflectivity. In the rat sclera, in vivo PS-OCT provides access to volumetric mapping of birefringence. Scleral birefringence is associated with microstructural tissue organization. Therefore, PS-OCT should prove a valuable tool for the in vivo investigation of peripapillary sclera in glaucoma.
展示偏振敏感（PS）光学相干断层扫描（OCT）用于对大鼠视乳头周围巩膜双折射特性进行无创、容积性和定量成像；将PS-OCT图像的结果与对相同组织的最新组织形态计量学分析结果进行比较。
对一台工作在840nm的高速PS-OCT原型机进行改造以用于大鼠眼部成像。在麻醉的雄性Sprague-Dawley大鼠眼中获取以视乳头为中心、覆盖面积约为1.5×1.5mm的密集采样PS-OCT光栅扫描图像。计算横断面PS-OCT图像，并分析显示巩膜双折射特性的眼底图。进行死后组织形态学分析。
偏振敏感OCT能够在体内可视化眼部组织的偏振特性。对大鼠巩膜的双折射特征进行了定量评估。巩膜双折射在视乳头周围形成甜甜圈状模式，左眼和右眼在偏心距为0.4mm处的值分别显著增加至0.703±0.089°/μm（即1.64×10⁻³±0.2×10⁻³；平均值±标准差）和0.721±0.084°/μm（即1.68×10⁻³±0.2×10⁻³）。双折射轴取向图显示在视神经周围呈环形分布。死后PS-OCT显微照片可观察到视网膜和巩膜的微观结构，并与标准组织形态学分析进行了比较。
除了基于反射率的传统OCT成像外，偏振敏感OCT还能够对组织偏振特性进行定量成像。在大鼠巩膜中，活体PS-OCT可用于双折射的容积性测绘。巩膜双折射与组织结构有关。因此，PS-OCT应被证明是青光眼视乳头周围巩膜活体研究的有价值工具。
