New Insights in the Phenomenon of Distributed Dermal Perfusion Rhythmicity using Computer Aided Optoelectronic Sensor Measuring Strategies

In recent years optoelectronic sensor concepts have gained an important role in medical diagnosis because of their non-invasive nature. They are generally accepted by the patients since they don't cause pain and are devoid of harmful radiation or ionising phenomena. One method which is nowadays an accepted and widely used diagnosis technique for assessment of skin perfusion is Photoplethysmography (PPG). It assesses the optical attenuation of the skin, which is modulated by the time varying blood contents. This non-invasive technique allows acquiring functional data from the arterial and/or venous system. However the classical PPG sensors, which consist of a LED as light source and a photodiode as detector, need skin contact for the measurements and can only assess a single spot of a few square millimetres. Advancement to classical PPG is camera based Photoplethysmography-Imaging Method (PPGI), which is not only non-invasive but can assess dermal perfusion completely without skin contact and also delivers spatially resolved measurements.