Clinical and Experimental Research Laboratory on Vascular Biology (BioVasc), Biomedical Center, State University of Rio de Janeiro, Pavilhão Reitor Haroldo Lisboa da Cunha, Rua São Francisco Xavier 524, Maracanã, Rio de Janeiro, Brazil.
Arch Dermatol Res. 2011 Mar;303(2):69-78. doi: 10.1007/s00403-010-1087-7. Epub 2010 Oct 23.
Technological advances during the last years have enhanced the image quality of the microcirculation. Intravital microscopy (IM) has been considered the "gold standard" for many years, but it can be used mostly in anesthetized animals which is a disadvantage. The nailfold videocapillaroscopy, a non-invasive examination that includes a microscope with an epiillumination system, came afterward, but its major disadvantage is the restricted area available for investigation namely the nailfold capillary bed. The orthogonal polarization spectral (OPS) imaging technique, where reflected light allows the visualization of the microcirculation, was the next non-invasive exam, but it still presents some drawbacks such as suboptimal capillary visualization and image blurring due to red blood cell movements. Excessive probe pressure modifies red blood cell velocity. There is suboptimal imaging of capillaries due to motion-induced image blurring by movements of OPS device, tissue and/or flowing red blood cells. Sidestream dark field (SDF) imaging is the newest tool for microcirculatory research. Illumination is provided by concentrically placed light-emitting diodes to avoid image blurring and to enhance image contrast. It represents a simple and non-invasive imaging technique, with low cost, good portability and high sensitivity that provides fine, well-defined images. In addition, the microcirculation can be studied through laser Doppler flowmetry (LDF) or reflectance-mode confocal-laser-scanning microscopy (RCLM). However, LDF cannot show microcirculatory vessels and high cost of RCLM can be an inconvenience. New applications of SDF technique could include skin microcirculatory evaluation and allow dermatological studies on psoriasis, skin tumors and leprosy.
近年来，技术的进步提高了微循环的图像质量。活体显微镜（IM）多年来一直被认为是“金标准”，但它只能在麻醉动物身上使用，这是一个缺点。随后出现了非侵入性检查指甲褶微血管镜检查，它包括一个带有 epiillumination 系统的显微镜，但主要缺点是可用于研究的区域有限，即指甲褶毛细血管床。正交偏振光谱（OPS）成像技术，其中反射光允许可视化微循环，是下一个非侵入性检查，但它仍然存在一些缺点，如毛细血管可视化效果不佳，由于红细胞运动导致图像模糊。探头压力过大可改变红细胞速度。由于 OPS 设备、组织和/或流动的红细胞的运动导致图像模糊，毛细血管的成像效果不佳。旁流暗场（SDF）成像技术是微循环研究的最新工具。通过同心放置的发光二极管提供照明，以避免图像模糊并增强图像对比度。它代表了一种简单、非侵入性的成像技术，具有低成本、良好的便携性和高灵敏度，可提供精细、清晰的图像。此外，还可以通过激光多普勒流量测定法（LDF）或反射模式共聚焦激光扫描显微镜（RCLM）研究微循环。然而，LDF 不能显示微循环血管，而 RCLM 的高成本可能会带来不便。SDF 技术的新应用可能包括皮肤微循环评估，并允许对银屑病、皮肤肿瘤和麻风病进行皮肤学研究。
