The vascular system can be divided into two systems: the macrocirculation and the microcirculation. Where the main purpose of the macrocirculation (the arteries and veins) is to transport the blood through the body, the microcirculation (arterioles, capillaries and venules) delivers oxygen and nutrients to the tissues, removes waste products, regulates blood pressure and is part of the thermoregulation in the skin. Both systems are of course very important, but the importance of the microcirculation is often underestimated.
Many different mechanisms play a role in the regulation of the microcirculation. The endothelial cells, besides building the inner wall of the vessels, also have an important signaling function. When these cells become dysfunctional, instead of protecting the vessel walls, they may actually promote pathophysiological changes. Since it plays such an important role, endothelial (dys-)function is an important part of microangiopathy research.
When Perimed released the first commercial system for laser Doppler flowmetry (LDF, also called laser Doppler perfusion monitoring, LDPM) in the early 1980s, this enabled assessing microvascular flow in ways not previously possible. Since then, tens of thousands of papers have been published on a multitude of applications. The addition of laser Doppler perfusion imaging (LDPI) made it possible to visualize the perfusion in a 2-D image, and laser speckle contrast analysis (LASCA) facilitated high-resolution, real-time visualization.