2021
Статьи / главы в тематических сборниках
A. A. Kamshilin and O. V. Mamontov, “Physiological origin of camera-based PPG imaging,” in Contactless Vital Signs Monitoring, W. Wang and X. Wang, Eds. London: Academic Press, 2021, Ch. 2, pp. 27–50.
Imaging photoplethysmography (PPG) is a fast-growing technology capable of monitoring human vital signs remotely at low cost. The most remarkable feature of the PPG method is the modulation of the light at the heartbeat frequency after being returned from a biological tissue in-vivo. However, the physiological model of light interaction with pulsatile blood vessels remains a subject of continuing debate. In this chapter, we review various mechanisms responsible for the generation of PPG waveforms. Particular attention is paid to the model recently proposed in our group, which claims that the heart-related light modulation arises from mechanical compression—decompression of the intercapillary tissue due to changes in the transmural arterial pressure. To support this new model, we refer to several recently published experimental observations. The method of imaging PPG allows noninvasive assessment of microvasculature blood flow on the vast surface of the skin and internal organs, both at rest and under various functional tests. An in-depth understanding of the physiological origin of PPG waveforms may enable quantitative characterization of the mechanisms of systemic vascular regulation and solution of the most important problem—the assessment of neurogenic vasomotor reactivity, the value of which is no less important than the neurogenic regulation of heart rhythm to maintain systemic hemodynamic parameters. Based on profound understanding of the physiological mechanism behind PPG, new methods for early diagnosis of socially important diseases, such as diabetes mellitus, systemic sclerosis, skin, stomach, and intestines cancer among others, can be developed.
10.1016/B978-0-12-822281-2.00010-X