Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hong Kong, People's Republic of China.
Phys Med Biol. 2009 Nov 21;54(22):6837-52. doi: 10.1088/0031-9155/54/22/006. Epub 2009 Oct 28.
Optical coherence tomography (OCT) is a promising new technique for characterizing the structural changes of articular cartilage in osteoarthritis (OA). The calculation of quantitative parameters from the OCT signal is an important step to develop OCT as an effective diagnostic technique. In this study, two novel parameters for the quantification of optical surface reflection and surface roughness from OCT measurements are introduced: optical surface reflection coefficient (ORC), describing the amount of a ratio of the optical reflection from cartilage surface with respect to that from a reference material, and OCT roughness index (ORI) indicating the smoothness of the cartilage surface. The sensitivity of ORC and ORI to detect changes in bovine articular cartilage samples after enzymatic degradations of collagen and proteoglycans using collagenase and trypsin enzymes, respectively, was tested in vitro. A significant decrease (p < 0.001) in ORC as well as a significant increase (p < 0.001) in ORI was observed after collagenase digestion. After trypsin digestion, no significant changes in ORC or ORI were observed. To conclude, the new parameters introduced were demonstrated to be feasible and sensitive to detect typical OA-like degenerative changes in the collagen network. From the clinical point of view, the quantification of OCT measurements is of great interest since OCT probes have been already miniaturized and applied in patient studies during arthroscopy or open knee surgery in vivo. Further studies are still necessary to demonstrate the clinical capability of the introduced parameters for naturally occurring early OA changes in the cartilage.
光学相干断层扫描（OCT）是一种有前途的新技术，可用于描述骨关节炎（OA）中关节软骨的结构变化。从 OCT 信号中计算定量参数是将 OCT 发展为有效诊断技术的重要步骤。在这项研究中，引入了两个用于从 OCT 测量中量化光学表面反射和表面粗糙度的新参数：光学表面反射系数（ORC），用于描述软骨表面的光反射量与参考材料的光反射量之比；OCT 粗糙度指数（ORI），用于指示软骨表面的平滑度。在体外测试了 ORC 和 ORI 对胶原酶和胰蛋白酶酶分别降解牛关节软骨样本后检测到的胶原和蛋白聚糖变化的敏感性。在胶原酶消化后，ORC 显著降低（p < 0.001），ORI 显著增加（p < 0.001）。在胰蛋白酶消化后，ORC 或 ORI 没有明显变化。总之，新引入的参数被证明是可行的，并且能够敏感地检测到胶原网络中典型的 OA 样退行性变化。从临床角度来看，OCT 测量的定量分析非常有趣，因为 OCT 探头已经小型化，并在关节镜或开放性膝关节手术中活体应用于患者研究。仍需要进一步的研究来证明所引入的参数对软骨中自然发生的早期 OA 变化的临床能力。
