Some reasons to build a new laser Doppler flowmeter to monitor microvascular blood flow

Disturbance in the blood microcirculation is a frequent complication in a number of common diseases including diabetes, arteriosclerosis and Raynaud’s phenomenon. In order to effectively diagnose these diseases, clinical tools able to monitor non-invasively the microvascular perfusion are required. For that purpose several techniques have been proposed. Among them, laser Doppler flowmetry (LDF) has been developed over the years, from experimental tools into commercial products, and several thousands of publications cite its use in the scientific literature. Nowadays, the LDF technique is commonly proposed in diverse applications. However, the dependence of the LDF signal on the microvascular architecture is still not known. A scientific understanding and knowledge of the LDF signal origin is not yet accessible to clinicians. Some studies proposed the use of different fiber separations or several wavelengths in order to modify the sampling depth of the LDF technique. However, further work is required to have knowledge and control over the mean sampling depth (and hence volume) in skin tissue