The microvessels are the most important part of the circulatory system, and damage to them can have profound clinical consequences. This part discusses non-invasive methods to assess microvascular endothelial function, with a focus on laser Doppler imaging with iontophoresis and nailfold capillaroscopy.
More information can be found in my review paper:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3040999/pdf/TOCMJ-4-302.pdf