Simultaneous Measurement of PPG and Functional MRI

Abstract

The purpose of the current study was to develop a magnetic resonance (MR)-compatible photoplethysmograph (PPG) system which could measure the raw PPG signal during MR image acquisition. The system consisted of an optic sensor which measured the optic signal, an optic cable which transmitted a near-infrared optic signal, a signal amplifier, and a filter for noise removal. To minimize interactive noise, only the optic cable and the optic sensor module were located inside the MR room; the signal amplifier and filter were located outside the MR room. The experiment verified that a reliable PPG signal can be obtained without deteriorating the MR image. Especially, it was possible to get a reliable PPG signal while acquiring MR images with EPI method which has been used for functional magnetic resonance imaging (fMRI) study. This system can simultaneously measure the response of the central nervous system using fMRI and that of the peripheral nervous system using the PPG.