Vibration Isolation for Seismocardiogram Measurement in the OpenMRI-Guided Operating Theater

The purpose of this study is to establish a method of measuring precisely the seismocardiogram (SCG) of a patient who lying in an open magnetic resonance imaging (openMRI) machine for myocardial ischemia monitoring during surgery. Vibration isolation was examined by analyzing the gantry vibration during MRI scanning and the SCG of a healthy volunteer. The MRI gantry vibration had maximum amplitude of 2.5m/s², which are several peaks more than 100Hz up to 500Hz. Up to 94% reduction in amplitude was observed in the patient bed vibration under both T1-weighted and T2-weighted sequences. The power spectrum center of the patient bed vibration was more than 30Hz. The maximum amplitude of SCG was 0.92m/s² and a FFT analysis revealed that the SCG was not higher than 25Hz. The signal-to-noise ratio between the SCG and the patient bed vibration was calculated to be from 4 to 7. These results demonstrate that the peak acceleration of the SCG can be monitored during openMRI scanning. In conclusion, vibration analysis showed the feasibility of using the piezoelectric acceleration sensor for seismocardiogram measurement in the openMRI-guided operating theater.