Nicolai Spicher1, Stefan Maderwald2, Mark E. Ladd2,3, and Markus Kukuk1
1University of Applied Sciences and Arts Dortmund, Dortmund, Germany, 2Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, 3Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany
Videos of the human skin exhibit a subtle photoplethysmography signal, which resembles the one measured by pulse oximetry. It was investigated whether the whole photoplethysmography waveform (systolic/diastolic peak, dicrotic notch) can be extracted from two MR-compatible video cameras: A low-speed camera (30 frames-per-second) and a high-speed prototype (250 frames-per-second). We propose a potentially real-time feasible algorithm for signal filtering, which was applied to frames of both cameras. Using pulse oximetry as ground truth, revealed all features of the photoplethysmography waveform. Additionally, performing systolic peak detection showed that the high-speed camera allows for more accurate results in MRI pulse triggering.