MRI-compatible non-invasive continuous blood pressure measurement using fiber optics

This report focuses on designing and implementing a non-invasive blood pressure measuring device capable of being used during magnetic resonance imaging. This device is based on measuring pulse wave velocity in arterial blood and using the obtained result to estimate diastolic blood pressure. Pulse transit times are measured by two fibre optical accelerometers placed over chest and carotid artery. The fabricated accelerometer contains two static fibres and a cantilever beam. The free end of the beam is angled at 90 degrees to act as a reflecting surface. Optical fibres are used for both illuminating the surface and receiving the reflected light. Acceleration applied to the sensor causes deflection of the beam, whereupon the amount of reflected light changes. The sensor output voltage is proportional to the intensity of the reflected light. Tests conducted on the electronics and sensors inside an MRI room during scanning proved that the device is MR conditional. No artifacts or distortions were detected.