Feasibility of a snapshot hyperspectral imaging for detection of local skin oxygenation

Restoring normal functioning and tissue healing after surgical intervention is, among others, critically dependent on tissue oxygenation and perfusion. Tissue necrosis, caused by inadequate tissue perfusion and/or oxygenation, is a common complication after surgical reconstruction of e.g. bowel anastomoses or skin defects. Currently, several optical techniques, which do not require administration of contrast agents, have been used to evaluate tissue perfusion and oxygenation. An emerging technique is hyperspectral imaging, which is capable to detect the scattering and absorption of light delivered to the tissue, caused by inhomogeneity of biological structures, such as haemoglobin, fat or water. Recently, a snapshot hyperspectral camera was developed to measure tissue oxygenation non-invasively using relevant wavelengths in the VIS-NIR region (450-950 nm). In this study, the effect of occlusion-reperfusion of the brachial artery on cutaneous blood oxygenation is explored in three human volunteers as assessed by a snapshot hyperspectral camera system. Furthermore, measurements of local changes in skin oxygenation and blood flow after applying a local vasodilator (capsaicin-based cream) and a local vasoconstrictor (brimonidine gel) are compared to measurements of an untreated area of the skin. Hyperspectral results are correlated to the haemoglobin oxygen saturation measured by an oximeter. Simultaneously with the hyperspectral measurements, real-time blood perfusion mapping is performed using Laser Speckle Contrast Imaging, which is able to measure cutaneous skin blood flow through analysis of the speckle pattern.