Multi-channel wearable PPG sensors for measurements in weak magnetic field environments

Investigator: Jiří PŘIBIL

In the field of mapping the physiological and mental effects of scanning in MRI tomograph on the examined person, our research in 2024 was focused on refining the method of estimating blood pressure values directly from the PPG signal, without the use of an external blood pressure monitor. Several series of measurement experiments were carried out with newly developed two-/three-channel PPG sensors to obtain additional parameters Pulse Transition Time (PTT) and Pulse Wave Velocity (PWV), the application of which reduced the pressure estimation error by about 6 %. Furthermore, mapping of short-term and long-term changes in skin temperature at the point of measurement of the PPG signal was performed. Our latest research was focused on the design and implementation of a new prototype of a wearable PPG sensor, which will serve for the purpose of analysis and evaluation of the influence of the pressure of the optical sensor itself on the properties of the measured PPG signal. All newly created wearable PPG sensors have been implemented to enable the scanning of PPG signals in real time – during scanning in an MRI tomograph operating with a low magnetic field up to 0.2 T (see Fig. 1).

Fig. 1: Measurement with a dual-channel PPG sensor equipped with contact thermometers under laboratory conditions (a), acquisition of a three-channel PPG signal during scanning in an open NMR tomograph (b).

Project: VEGA 2/0004/23 Research of properties of magnetic nanoparticles for imaging purposes in biomedical diagnostics based on magnetic resonance methods.

Publications 2024:

  • Přibil, J., Přibilová, A., Frollo, I.: Contact Measurement of Skin Temperature Using the Wearable Two-Channel PPG Optical Sensor Supplemented by Thermometers. Journal of Electrical Engineering, Vol. 75, No. 2, 2024, pp. 113–123. DOI:10.2478/jee-2024-0015
  • Přibil, J., Přibilová, A., Frollo, I.: Cuffless Estimation of Arterial Blood Pressure Based on Heart Pulse Transmission Parameters Determined from Multi-Channel PPG Signals, in Sergey Y. Yurish (Ed): Proceedings of the 6th International Conference on Advances in Signal Processing and Artificial Intelligence (ASPAI’ 2024), 17-19 April 2024, Funchal (Madeira Island), Portugal, pp. 8-12. ISBN: 978-84-09-60540-8, DOI: 10.13140/RG.2.2.23368.53763.
  • Přibil, J., Přibilová, A., Frollo, I.: Stress Detection and Classification from PPG Signals Recorded in Different Conditions – Pilot Study. In Herencsár N. (Ed): Proceedings of the 47th International Conference on Telecommunications and Signal Processing TSP 2024, July 10-12, 2024 (Virtual), pp. 21-25. IEEE Catalog Number: CFP2388P-ART. ISBN 979-8-3503-6559-7, DOI: 10.1109/TSP63128.2024.10605949
  • Přibil, J., Přibilová, A., Frollo, I.: Heart Pulse Transmission Parameters of Multi-Channel PPG Signals for Cuffless Estimation of Arterial Blood Pressure: Preliminary Study. Electronics 2024, 13, 3297. https://doi.org/10.3390/electronics13163297
  • Přibil, J., Přibilová, A., Frollo, I.: Wearable Photoplethysmography Sensors Applicable for Measurement in a Weak Magnetic Field Environment of an MRI device. Advances in Signal Processing: Reviews, Book Series, Vol. 3, 29 p., 2024, IFSA Publishing S.L., (in Print).
  • Přibil, J., Přibilová, A., Frollo, I.: A Wearable Reflectance PPG Optical Sensor Enabling Contact Pressure and Skin Temperature Measurement. In:11th International Electronic Conference on Sensors and Applications, Section: Wearable Sensors and Healthcare Applications, 26-28 November 2024 (Virtual), 8 p. Available online: https://sciforum.net/event/ecsa-11, resp. https://doi.org/10.3390/ecsa-11-101273 (registering DOI)