Somfai Gábor Márk, Salinas Harry M, Puliafito Carmen A, Fernández Delia Cabrera
Semmelweis University, Faculty of Medicine, Department of Ophthalmology, Mária Street 39, Budapest, Hungary 1085.
J Biomed Opt. 2007 Jul-Aug;12(4):041209. doi: 10.1117/1.2774827.
The development of improved segmentation algorithms for more consistently accurate detection of retinal boundaries is a potentially useful solution to the limitations of existing optical coherence tomography (OCT) software. We modeled artifacts related to operator errors that may normally occur during OCT imaging and evaluated their influence on segmentation results using a novel segmentation algorithm. These artifacts included: defocusing, depolarization, decentration, and a combination of defocusing and depolarization. Mean relative reflectance and average thickness of the automatically extracted intraretinal layers was then measured. Our results show that defocusing and depolarization errors together have the greatest altering effect on all measurements and on segmentation accuracy. A marked decrease in mean relative reflectance and average thickness was observed due to depolarization artifact in all intraretinal layers, while defocus resulted in a less-marked decrease. Decentration resulted in a marked but not significant change in average thickness. Our study demonstrates that care must be taken for good-quality imaging when measurements of intraretinal layers using the novel algorithm are planned in future studies. An awareness of these pitfalls and their possible solutions is crucial for obtaining a better quantitative analysis of clinically relevant features of retinal pathology.
开发改进的分割算法以更一致、准确地检测视网膜边界，是解决现有光学相干断层扫描（OCT）软件局限性的一种潜在有用方法。我们对OCT成像过程中可能正常出现的与操作者误差相关的伪像进行建模，并使用一种新颖的分割算法评估它们对分割结果的影响。这些伪像包括：散焦、去极化、偏心，以及散焦和去极化的组合。然后测量自动提取的视网膜内层的平均相对反射率和平均厚度。我们的结果表明，散焦和去极化误差共同对所有测量值和分割准确性产生最大的改变作用。在所有视网膜内层中，由于去极化伪像，平均相对反射率和平均厚度均显著下降，而散焦导致的下降幅度较小。偏心导致平均厚度有显著但不明显的变化。我们的研究表明，在未来研究中计划使用新算法测量视网膜内层时，必须注意进行高质量成像。了解这些陷阱及其可能的解决方案对于更好地定量分析视网膜病理学的临床相关特征至关重要。
