Visualization of dermal blood vessels--capillaroscopy.

Intravital capillaroscopy is the only noninvasive method available that visualizes directly the nutritional dermal capillaries. It can determine (in vivo): capillary morphology, including size, shape and tortuosity; capillary density; intercapillary distance; volume fraction (the percentage of skin occupied by microvessels); and changes in red cell velocity within capillaries. When capillaroscopy is performed using a video recording system, this permits real-time imaging of the cutaneous capillaries with retrospective analysis of capillary dynamics. Furthermore, when fluorescent dyes are injected intravenously, plasma-perfused capillaries are delineated allowing the calculation of several perfusion indices. Intravital capillaroscopy therefore permits the assessment of static as well as dynamic aspects of the skin microcirculation.