Department of Biomedical Engineering, Ryerson University, Toronto, ON M5B 2K3, Canada.
Department of Physics, Ryerson University, Toronto, ON M5B 2K3, Canada.
Sensors (Basel). 2022 Apr 7;22(8):2830. doi: 10.3390/s22082830.
Specular reflection from tissue is typically considered as undesirable, and managed through device design. However, we believe that specular reflection is an untapped light-tissue interaction, which can be used for imaging subcutaneous blood flow. To illustrate the concept of subcutaneous blood flow visualization using specular reflection from the skin, we have developed a ray tracing for the neck and identified conditions under which useful data can be collected. Based on our model, we have developed a prototype Specular Reflection Vascular Imaging (SRVI) device and demonstrated its feasibility by imaging major neck vessels in a case study. The system consists of a video camera that captures a video from a target area illuminated by a rectangular LED source. We extracted the SRVI signal from 5 × 5 pixels areas (local SRVI signal). The correlations of local SRVIs to the SRVI extracted from all pixels in the target area do not appear to be randomly distributed, but rather form cohesive sub-regions with distinct boundaries. The obtained waveforms were compared with the ECG signal. Based on the time delays with respect to the ECG signal, as well as the waveforms themselves, the sub-regions can be attributed to the jugular vein and carotid artery. The proposed method, SRVI, has the potential to contribute to extraction of the diagnostic information that the jugular venous pulse can provide.
组织的镜面反射通常被认为是不理想的，可以通过设备设计来管理。然而，我们认为镜面反射是一种未开发的光-组织相互作用，可以用于成像皮下血流。为了说明利用皮肤镜面反射可视化皮下血流的概念，我们已经为颈部开发了光线追踪，并确定了可以收集有用数据的条件。基于我们的模型，我们开发了一种镜面反射血管成像（SRVI）设备原型，并通过案例研究成像主要颈部血管来证明其可行性。该系统由一个视频摄像机组成，该摄像机从由矩形 LED 光源照亮的目标区域捕获视频。我们从 5x5 个像素区域（局部 SRVI 信号）中提取 SRVI 信号。局部 SRVI 与从目标区域中所有像素提取的 SRVI 的相关性似乎不是随机分布的，而是形成了具有明显边界的凝聚子区域。所获得的波形与 ECG 信号进行了比较。基于相对于 ECG 信号的时间延迟以及波形本身，可以将子区域归因于颈静脉和颈动脉。所提出的方法 SRVI 有可能有助于提取颈静脉脉搏可以提供的诊断信息。
