Eugui Pablo, Lichtenegger Antonia, Augustin Marco, Harper Danielle J, Muck Martina, Roetzer Thomas, Wartak Andreas, Konegger Thomas, Widhalm Georg, Hitzenberger Christoph K, Woehrer Adelheid, Baumann Bernhard
Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
Institute of Neurology, General Hospital and Medical University of Vienna, Vienna, Austria.
Biomed Opt Express. 2018 May 1;9(6):2476-2494. doi: 10.1364/BOE.9.002476. eCollection 2018 Jun 1.
Optical coherence tomography (OCT) is a powerful technology for rapid volumetric imaging in biomedicine. The bright field imaging approach of conventional OCT systems is based on the detection of directly backscattered light, thereby waiving the wealth of information contained in the angular scattering distribution. Here we demonstrate that the unique features of few-mode fibers (FMF) enable simultaneous bright and dark field (BRAD) imaging for OCT. As backscattered light is picked up by the different modes of a FMF depending upon the angular scattering pattern, we obtain access to the directional scattering signatures of different tissues by decoupling illumination and detection paths. We exploit the distinct modal propagation properties of the FMF in concert with the long coherence lengths provided by modern wavelength-swept lasers to achieve multiplexing of the different modal responses into a combined OCT tomogram. We demonstrate BRAD sensing for distinguishing differently sized microparticles and showcase the performance of BRAD-OCT imaging with enhanced contrast for ex vivo tumorous tissue in glioblastoma and neuritic plaques in Alzheimer's disease.
光学相干断层扫描（OCT）是生物医学中用于快速容积成像的强大技术。传统OCT系统的明场成像方法基于对直接背向散射光的检测，从而舍弃了角散射分布中包含的大量信息。在此，我们证明少模光纤（FMF）的独特特性能够实现OCT的同时明场和暗场（BRAD）成像。由于背向散射光根据角散射模式被FMF的不同模式接收，我们通过解耦照明和检测路径，获得了不同组织的定向散射特征。我们利用FMF独特的模式传播特性，并结合现代扫频激光器提供的长相干长度，将不同模式响应复用为一个组合的OCT断层图像。我们展示了BRAD传感用于区分不同大小的微粒，并展示了BRAD - OCT成像在增强胶质母细胞瘤离体肿瘤组织和阿尔茨海默病神经炎性斑块对比度方面的性能。
