Nailfold Video Capillaroscopy Based on Sidestream Dark Field and Stacking Algorithm

Nailfold video-capillaroscopy (NVC) is a diagnostic technique that allows direct observation of microcirculation. NVC has gained significance for its non-invasive evaluation of subtle abnormalities, contributing to the diagnosis and monitoring of various pathologies. In recent years, technological advances have led to the development of new capillaroscopy techniques, as the Sidestream dark-field (SDF) capillaroscopy. It enables real-time visualization of microcirculation with high resolution and it is less susceptible to motion artifacts. A ring of light-emitting diodes (LEDs) provides structural and functional images of the microcirculation with high contrast. However, SDF can be susceptible to artifacts caused by pressure applied during imaging. These artifacts may distort the observed microvascular patterns, requiring careful interpretation by trained professionals. In this context, we developed an NVC based on the sidestream technique, employing off-the-shelf components, 3D printing and stacking algorithm. The aim is to provide a high quality, easy-to-fabricate NVC with reduced artifacts caused by the oil (immersion microscopy topology). The NCV is designed to be applied to the periungual area. Using a black 3D printed case compared to a white 3D case, the NVC enhances image quality by minimizing light glare. Furthermore, we conducted experiments using different illumination wavelengths and processing algorithms to evaluate the most effective image quality. The green LED crown produced superior images due to its absorption by hemoglobin. Our device provides further insights and advancement into early diagnosis and monitoring for Raynaud's phenomenon.