Non‐invasive imaging of cold‐induced pain related dermal blood flow

The microvasculature at the digits include the arteriovenous anastomoses (AVA) that enable fast increase or decrease of blood flow through the skin regulating body temperature. Determination of dermal blood flow changes at the phalanges and the inter‐phalangeal joints can be useful screening of atherosclerotic pathologies and endothelial dysfunction. A recent long‐term follow up study indicate that a positive response to cold pressor test is a potential predictor of hypertension. Sensitive methods to evaluate autonomic dysfunction and the related microcirculatory disturbances are warranted. Here, the autonomic sympathetic nervous system is assessed by measuring the cold induced pain related blood flow changes by Laser Doppler Flowmetry (LDF) and using a planar fluorescence imaging methods. Dermal blood flow was measured on the dominant hand while the non‐dominant hand of caucasian and asian adult volunteers were immersed in cold water up to 2 min. The resultant changes in the natural fluorescence were captured by the planar florescence imaging. The LDF measurements obtained before and after immersion show significant changes, with a 65% and above reduction in dermal blood flow from the baseline. The results indicate the possibility of utilizing imaging methodologies in microvascular dynamic analysis in clinical studies.