Hybrid motion sensing with a wireless device, self-synchronized to the imaging pulse sequence.

Here we combine an accelerometer, angular rate sensor, magnetometer, pickup coil and active marker in a (single) small wireless device. The active marker is used to detect radio frequency pulses, enabling synchronisation to the imaging pulse sequence to within 1 μs accuracy. Sinusoidal waveforms inserted into the imaging pulse sequence (lasting 920 μs) are then measured using the onboard pickup coil to allow real-time position and ADC-gradient timing offsets in all 3 axes. Preliminary results suggest that sub-mm accuracy is possible with very low noise (<0.3 mm) in the raw data captured. The new hardware layout has the potential to enable full prospective motion correction from a single small device that fits on the bridge of the subject's nose.