Li Shuying, Huang Kexin, Zhang Menghao, Uddin K M Shihab, Zhu Quing
Department of Biomedical Engineering, Washington University in St. Louis, 1 Brookings Dr, St. Louis 63130, USA.
Department of Electrical and Systems Engineering, Washington University in St. Louis, 1 Brookings Dr, St. Louis 63130, USA.
Biomed Opt Express. 2021 Jan 4;12(2):689-704. doi: 10.1364/BOE.411595. eCollection 2021 Feb 1.
In diffuse optical tomography (DOT) and spectroscopy (DOS) using handheld probes, tissue curvature can cause bad fiber-to-tissue contact. Understanding and minimizing image artifacts caused by these coupling errors would significantly improve DOT and DOS image quality. In this work, we utilized Monte Carlo simulations and experiments with gelatin-Intralipid phantoms to systematically study the influence of source or detector (optode) coupling errors. Optode coupling errors can increase the amplitude and decrease the phase of the measured diffuse reflectance, creating artifacts in the reconstructed absorption maps, such as hot spots on the edges. We propose an outlier removal algorithm that can correct these image artifacts, and we demonstrate its performance using simulations, phantom experiments, and breast patient data acquired with bad probe contact due to a dense or small breast. Further, we designed and implemented a new resistance-type thin-film force sensor array that provides real-time optode coupling feedback and guides the outlier removal to minimize optode coupling errors. Our approaches and study results have significant implications for reducing image artifacts arising from handheld probes, which are commonly used with mobile and wearable DOT and DOS devices.
在使用手持探头的漫射光学层析成像(DOT)和光谱学(DOS)中,组织曲率会导致光纤与组织接触不良。理解并最小化由这些耦合误差引起的图像伪影将显著提高DOT和DOS的图像质量。在这项工作中,我们利用蒙特卡罗模拟以及对明胶-脂质乳剂体模进行实验,系统地研究了光源或探测器(光极)耦合误差的影响。光极耦合误差会增大测量的漫反射率的幅度并减小其相位,在重建的吸收图中产生伪影,例如边缘上的热点。我们提出了一种异常值去除算法,该算法可以校正这些图像伪影,并通过模拟、体模实验以及因乳房致密或乳房较小而导致探头接触不良情况下采集的乳腺患者数据来展示其性能。此外,我们设计并实现了一种新型电阻式薄膜力传感器阵列,该阵列可提供实时光极耦合反馈,并指导异常值去除以最小化光极耦合误差。我们的方法和研究结果对于减少手持式探头产生的图像伪影具有重要意义这些探头常用于移动和可穿戴的DOT和DOS设备。