In the latter case, LSCI data should be expressed as raw perfusion units, but not as a function of baseline.
Overall, correction for BZ makes data analysis more complicated click here without improving reproducibility. Among the different techniques reviewed, each has advantages and drawbacks. Microscopy-derived techniques are semi-quantitative, implemented in small devices that can be used at the bedside; they are mostly used to assess morphology rather than the function of the microvasculature. On the other hand, the advantage of laser Doppler and laser speckle techniques is that they can be coupled with various reactivity tests to challenge microvessels. However, these tests do not specifically assess distinct pathways, but provide an overall assessment of microvascular function. Indeed, recent studies have shown that the mechanisms underlying common reactivity tests (i.e., Ach iontophoresis, PORH, and LTH) are complex and involve several different pathways [15]. Besides a deeper exploration into their mechanisms, these tests should be standardized if they are to be used as surrogate markers of microvascular function. Another approach which has not been explored in this review concerns signal processing. Indeed, cutaneous blood flow has been studied through several processing tools, such as the Fourier transform and the wavelet transform [25]. Other methods, such as multifractality and sample entropy, have
recently been applied to LDF signals [67]. LY294002 In conclusion, different ID-8 techniques have been developed in the past 30 years to assess microvascular function. Although optical microscopy-derived techniques (such as nailfold videocapillaroscopy) have found clinical applications, they mainly provide morphological information
about the microvessels. Laser Doppler techniques coupled to reactivity tests are widespread in the field of microvascular function research. PORH and LTH have been shown to be reliable tests, although their underlying mechanisms are not fully understood yet. Despite its wide use as a specific test of endothelial function, acetylcholine iontophoresis has many limitations. In a general way, all these tests suffer from a lack of standardization and show highly variable reproducibility according to the skin site, recording conditions and the way of expressing data. Recent techniques like laser speckle contrast imaging are promising tools, although further work is needed to determine the strength of the technique. We thank Dr. Alison Foote for editing the manuscript. None declared. Matthieu Roustit is assistant professor of Clinical Pharmacology at Joseph Fourier University and Pharmacologist at the Clinical Research Center of the Grenoble University Hospital, France. His main areas of interest include methodological issues regarding the study of skin microvascular function, especially with laser Doppler and laser Speckle contrast imaging.