Zhu Yue, Zhou Yuan, Guo Zhenyan
Department of Optical Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei, Nanjing, 210094, China.
Department of Vascular Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310020, China.
Biomed Opt Express. 2023 Jun 27;14(7):3775-3797. doi: 10.1364/BOE.485090. eCollection 2023 Jul 1.
The Kolmogorov turbulence model has been validated as a quantitative 3D light scattering model of the inhomogeneous refraction index of biological tissue using full-field OCT (FF-OCT). A fractal-based computational compensation approach was proposed for correcting of depth-resolved aberrations with volumetric FF-OCT. First, the power-spectral density spectrum of the index inhomogeneities was measured by radial Fourier transformation of volumetric data. The spectrum's shape indicates the spatial correlation function and can be quantified as the fractal dimension of tissue. The defocusing correction matrix was built by applying fractal-based analysis as an image quality metric. For comparison, tissue-induced in-depth aberration models were built by phase compensation. After digital aberration correction of FF-OCT images, it enables extracting the temporal contrast indicating the sample dynamics in onion in mitosis and mouse heart during delayed neuronal death. The proposed fractal-based contrast augmented images show subcellular resolution recording of dynamic scatters of the growing-up onion cell wall and some micro activities. In addition, low-frequency chamber and high-frequency cardiac muscle fibers from mouse heart tissue. Therefore, the depth-resolved changes in fractal parameters may be regarded as a quantitative indicator of defocus aberration compensation. Also the enhanced temporal contrast in FF-OCT has the potential to be a label-free, non-invasive, and three-dimensional imaging tool to investigate sub-cellular activities in metabolism studies.
柯尔莫哥洛夫湍流模型已被验证为一种使用全场光学相干断层扫描（FF-OCT）对生物组织非均匀折射率进行定量的三维光散射模型。提出了一种基于分形的计算补偿方法，用于校正体积FF-OCT的深度分辨像差。首先，通过对体积数据进行径向傅里叶变换来测量折射率不均匀性的功率谱密度谱。该谱的形状表明了空间相关函数，并可量化为组织的分形维数。通过应用基于分形的分析作为图像质量指标来构建散焦校正矩阵。为了进行比较，通过相位补偿构建组织诱导的深度像差模型。在对FF-OCT图像进行数字像差校正后，能够提取出表示有丝分裂期洋葱和延迟神经元死亡期间小鼠心脏中样本动态的时间对比度。所提出的基于分形的对比度增强图像显示了生长中的洋葱细胞壁动态散射和一些微观活动的亚细胞分辨率记录。此外，从小鼠心脏组织中观察到低频腔室和高频心肌纤维。因此，分形参数的深度分辨变化可被视为散焦像差补偿的定量指标。此外，FF-OCT中增强的时间对比度有潜力成为代谢研究中用于研究亚细胞活动的无标记、非侵入性三维成像工具。
