Kookmin Univ., Korea, Republic of.
J Biomed Opt. 2021 Feb;26(2). doi: 10.1117/1.JBO.26.2.026003.
Dry or moist skin-contact thermal stimulation for vein puncture (VP) and vein cannulation (VC) may not be feasible for sensitive skin. For a damaged, burned, or dark skin, near-infrared (NIR) imaging is preferred to visualize a vein. Postprocessing of NIR images is always required because the skin is a reflective material and veins need segmentation for quantitative analysis.
Our pilot study aims to observe the effect of noncontact local heating on the superficial metacarpal veins in the dorsal surface of the hand and to visualize vein dynamics using an NIR imaging system.
Our experiment consists of studies A and B at two ambient temperatures, 19°C and 25°C. A simple reflection-based NIR imaging system was installed to acquire sequential vein images for 5 min before and after applying 10 min of radiant thermal stimulation. To measure the vein diameter (VD), we trained a convolutional neural network (CNN) on sequential raw images to predict vein-segmentation masks as output images. Later these masked images were postprocessed for the VD measurements.
The average VD was significantly increased after thermal stimulation in study A. The maximum increments in VD were 39.3% and 9.19%, 1 min after thermal stimulation in studies A and B, respectively. Both the VD and skin temperature (Tskin) follow negative exponentials in time, and the VD is proportional to Tskin. A multiple linear-regression model was made to predict the final VD. A significant difference was observed in the change of the VD.
NIR imaging with CNN can be used for quantitative analyses of vein dynamics. This finding can be further extended to develop real-time, image-guided medical devices by integrating them with a radiant heater and to assist medical practitioners in achieving high success rates for VP or VC.
对于敏感皮肤，干或湿的皮肤接触热刺激（VP）和静脉插管（VC）可能不可行。对于受损、烧伤或深色皮肤，近红外（NIR）成像首选用于可视化静脉。由于皮肤是一种反射性材料，并且静脉需要分割进行定量分析，因此总是需要对 NIR 图像进行后处理。
我们的初步研究旨在观察非接触局部加热对手背表面的浅表掌侧静脉的影响，并使用 NIR 成像系统观察静脉动力学。
我们的实验包括在两个环境温度 19°C 和 25°C 下进行的研究 A 和研究 B。安装了一个简单的基于反射的 NIR 成像系统，用于在施加 10 分钟辐射热刺激前后采集 5 分钟的连续静脉图像。为了测量静脉直径（VD），我们在连续原始图像上训练卷积神经网络（CNN），将静脉分割掩模作为输出图像进行预测。然后，对这些掩模图像进行后处理以测量 VD。
在研究 A 中，热刺激后平均 VD 显著增加。在研究 A 和 B 中，热刺激后 1 分钟，VD 的最大增量分别为 39.3%和 9.19%。VD 和皮肤温度（Tskin）随时间呈负指数关系，并且 VD 与 Tskin 成正比。建立了一个多元线性回归模型来预测最终的 VD。观察到 VD 变化的显著差异。
CNN 结合 NIR 成像可用于静脉动力学的定量分析。这一发现可以进一步扩展，通过将其与辐射加热器集成来开发实时、图像引导的医疗设备，并帮助医疗从业者提高 VP 或 VC 的成功率。
